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Sample records for ultrananocrystalline diamond layers

  1. Nitrogen-incorporated ultrananocrystalline diamond and multi-layer-graphene-like hybrid carbon films

    PubMed Central

    Tzeng, Yonhua; Yeh, Shoupu; Fang, Wei Cheng; Chu, Yuehchieh

    2014-01-01

    Nitrogen-incorporated ultrananocrystalline diamond (N-UNCD) and multi-layer-graphene-like hybrid carbon films have been synthesized by microwave plasma enhanced chemical vapor deposition (MPECVD) on oxidized silicon which is pre-seeded with diamond nanoparticles. MPECVD of N-UNCD on nanodiamond seeds produces a base layer, from which carbon structures nucleate and grow perpendicularly to form standing carbon platelets. High-resolution transmission electron microscopy and Raman scattering measurements reveal that these carbon platelets are comprised of ultrananocrystalline diamond embedded in multilayer-graphene-like carbon structures. The hybrid carbon films are of low electrical resistivity. UNCD grains in the N-UNCD base layer and the hybrid carbon platelets serve as high-density diamond nuclei for the deposition of an electrically insulating UNCD film on it. Biocompatible carbon-based heaters made of low-resistivity hybrid carbon heaters encapsulated by insulating UNCD for possible electrosurgical applications have been demonstrated. PMID:24681781

  2. Nitrogen-incorporated ultrananocrystalline diamond and multi-layer-graphene-like hybrid carbon films.

    PubMed

    Tzeng, Yonhua; Yeh, Shoupu; Fang, Wei Cheng; Chu, Yuehchieh

    2014-01-01

    Nitrogen-incorporated ultrananocrystalline diamond (N-UNCD) and multi-layer-graphene-like hybrid carbon films have been synthesized by microwave plasma enhanced chemical vapor deposition (MPECVD) on oxidized silicon which is pre-seeded with diamond nanoparticles. MPECVD of N-UNCD on nanodiamond seeds produces a base layer, from which carbon structures nucleate and grow perpendicularly to form standing carbon platelets. High-resolution transmission electron microscopy and Raman scattering measurements reveal that these carbon platelets are comprised of ultrananocrystalline diamond embedded in multilayer-graphene-like carbon structures. The hybrid carbon films are of low electrical resistivity. UNCD grains in the N-UNCD base layer and the hybrid carbon platelets serve as high-density diamond nuclei for the deposition of an electrically insulating UNCD film on it. Biocompatible carbon-based heaters made of low-resistivity hybrid carbon heaters encapsulated by insulating UNCD for possible electrosurgical applications have been demonstrated. PMID:24681781

  3. Systematic studies of the nucleation and growth of ultrananocrystalline diamond films on silicon substrates coated with a tungsten layer

    SciTech Connect

    Chu, Yueh-Chieh; Jiang, Gerald; Tu, Chia-Hao; Chang Chi; Liu, Chuan-pu; Ting, Jyh-Ming; Lee, Hsin-Li; Tzeng, Yonhua; Auciello, Orlando

    2012-06-15

    We report on effects of a tungsten layer deposited on silicon surface on the effectiveness for diamond nanoparticles to be seeded for the deposition of ultrananocrystalline diamond (UNCD). Rough tungsten surface and electrostatic forces between nanodiamond seeds and the tungsten surface layer help to improve the adhesion of nanodiamond seeds on the tungsten surface. The seeding density on tungsten coated silicon thus increases. Tungsten carbide is formed by reactions of the tungsten layer with carbon containing plasma species. It provides favorable (001) crystal planes for the nucleation of (111) crystal planes by Microwave Plasma Enhanced Chemical Vapor Deposition (MPECVD) in argon diluted methane plasma and further improves the density of diamond seeds/nuclei. UNCD films grown at different gas pressures on tungsten coated silicon which is pre-seeded by nanodiamond along with heteroepitaxially nucleated diamond nuclei were characterized by Raman scattering, field emission-scanning electron microscopy, and high resolution-transmission electron microscopy.

  4. Nanopatterning of ultrananocrystalline diamond nanowires.

    PubMed

    Wang, Xinpeng; Ocola, Leonidas E; Divan, Ralu S; Sumant, Anirudha V

    2012-02-24

    We report the fabrication of horizontally aligned ultrananocrystalline diamond (UNCD) nanowires (NWs) via two different approaches. First, with the top-down approach by using electron beam lithography (EBL) and reactive ion etching (RIE) with a photo resist layer as an etch mask. Using this approach, we demonstrate fabrication of 50m long UNCD NWs with widths as narrow as 40nm. We further present an alternative approach to grow UNCD NWs at pre-defined positions through a selective seeding process. No RIE was needed either to etch the NWs or to remove the mask. In this case, we achieved UNCD NWs with lengths of 50m and smallest width of 90nm respectively. Characterization of these nanowires by using scanning electron microscopy (SEM) and atomic force microscopy (AFM) shows that the UNCD NWs are well defined and fully released, with no indication of residual stress. Characterization using visible and ultraviolet (UV) Raman spectroscopy indicates that in both fabrication approaches, UNCD NWs maintain their intrinsic diamond structure. PMID:22261094

  5. In vitro and in vivo evaluation of ultrananocrystalline diamond as an encapsulation layer for implantable microchips.

    PubMed

    Chen, Ying-Chieh; Tsai, Che-Yao; Lee, Chi-Young; Lin, I-Nan

    2014-05-01

    Thin ultrananocrystalline diamond (UNCD) films were evaluated for use as hermetic and bioinert encapsulating coatings for implantable microchips, where the reaction to UNCD in vitro and in vivo tissue was investigated. Leakage current tests showed that depositing UNCD coatings, which were conformally grown in (1% H2) Ar/CH4 plasma, on microchips rendered the surface electrochemically inactive, i.e. with a very low leakage current density (2.810(-5)Acm(-2) at -1V and 1.910(-3)Acm(-2) at 5V) ex vivo. The impact of UNCD with different surface modifications on the growth and activation of macrophages was compared to that of standard-grade polystyrene. Macrophages attached to oxygen-terminated UNCD films down-regulated their production of cytokines and chemokines. Moreover, with UNCD-coated microchips, which were implanted subcutaneously into BALB/c mice for up to 3months, the tissue reaction and capsule formation was significantly decreased compared to the medical-grade titanium alloy Ti-6Al-4V and bare silicon. Additionally, the leakage current density, elicited by electrochemical activity, on silicon chips encapsulated in oxygen-terminated UNCD coatings remained at the low level of 2.510(-3)Acm(-2) at 5V for up to 3months in vivo, which is half the level of those encapsulated in hydrogen-terminated UNCD coatings. Thus, controlling the surface properties of UNCDs makes it possible to manipulate the in vivo functionality and stability of implantable devices so as to reduce the host inflammatory response following implantation. These observations suggest that oxygen-terminated UNCDs are promising candidates for use as encapsulating coatings for implantable microelectronic devices. PMID:24440422

  6. Observation of a carbon-based protective layer on the sidewalls of boron doped ultrananocrystalline diamond-based MEMS during in situ tribotests

    NASA Astrophysics Data System (ADS)

    Buja, Federico; Kokorian, Jaap; Gulotty, Richard; Sumant, Anirudha V.; Merlijn van Spengen, W.

    2015-12-01

    We have fabricated dedicated MEMS tribotesters made from boron doped ultrananocrystalline diamond (B-UNCD) as the structural material, and carried out comprehensive nano-tribological measurements when two B-UNCD sidewall surfaces underwent sliding interaction in a micro-electromechanical systems (MEMS) in a humid and dry atmosphere. We have investigated the evolution of tribological contacts during sliding interactions and corresponding surface modification under repeated cyclic sliding conditions, while measuring displacement and lateral force with 4?nm and 64 nN resolution, respectively. We have observed the formation of carbon-based ultra-thin protective layer at the sliding interface as characterized by Raman spectroscopy and scanning electron microscopy. Interestingly, the formation of this protective layer occurs in both a dry and wet atmosphere, albeit at different rates when the energy dissipated due to friction reaches a plateau, starting from 200?000 and 400?000 cycles, respectively. Once this layer is formed, we do not observe any measurable wear indicating stable operation for an extended time period. Our results demonstrate that B-UNCD is a very promising material to overcome the wear-related reliability problems in MEMS.

  7. Nanopatterning of ultrananocrystalline diamond thin films via block copolymer lithography.

    SciTech Connect

    Ramanathan, M.; Darling, S. B.; Sumant, A. V.; Auciello, O.

    2010-07-01

    Nanopatterning of diamond surfaces is critical for the development of diamond-based microelectromechanical system/nanoelectromechanical system (MEMS/NEMS), such as resonators or switches. Micro-/nanopatterning of diamond materials is typically done using photolithography or electron beam lithography combined with reactive ion etching (RIE). In this work, we demonstrate a simple process, block copolymer (BCP) lithography, for nanopatterning of ultrananocrystalline diamond (UNCD) films to produce nanostructures suitable for the fabrication of NEMS based on UNCD. In BCP lithography, nanoscale self-assembled polymeric domains serve as an etch mask for pattern transfer. The authors used thin films of a cylinder-forming organic-inorganic BCP, poly(styrene-block-ferrocenyldimethylsilane), PS-b-PFS, as an etch mask on the surface of UNCD films. Orientational control of the etch masking cylindrical PFS blocks is achieved by manipulating the polymer film thickness in concert with the annealing treatment. We have observed that the surface roughness of UNCD layers plays an important role in transferring the pattern. Oxygen RIE was used to etch the exposed areas of the UNCD film underneath the BCP. Arrays of both UNCD posts and wirelike structures have been created using the same starting polymeric materials as the etch mask.

  8. Ultra-nanocrystalline diamond electrodes: optimization towards neural stimulation applications

    NASA Astrophysics Data System (ADS)

    Garrett, David J.; Ganesan, Kumaravelu; Stacey, Alastair; Fox, Kate; Meffin, Hamish; Prawer, Steven

    2012-02-01

    Diamond is well known to possess many favourable qualities for implantation into living tissue including biocompatibility, biostability, and for some applications hardness. However, conducting diamond has not, to date, been exploited in neural stimulation electrodes due to very low electrochemical double layer capacitance values that have been previously reported. Here we present electrochemical characterization of ultra-nanocrystalline diamond electrodes grown in the presence of nitrogen (N-UNCD) that exhibit charge injection capacity values as high as 163 C cm-2 indicating that N-UNCD is a viable material for microelectrode fabrication. Furthermore, we show that the maximum charge injection of N-UNCD can be increased by tailoring growth conditions and by subsequent electrochemical activation. For applications requiring yet higher charge injection, we show that N-UNCD electrodes can be readily metalized with platinum or iridium, further increasing charge injection capacity. Using such materials an implantable neural stimulation device fabricated from a single piece of bio-permanent material becomes feasible. This has significant advantages in terms of the physical stability and hermeticity of a long-term bionic implant.

  9. Ultrananocrystalline diamond-decorated silicon nanowire field emitters.

    PubMed

    Palomino, Javier; Varshney, Deepak; Resto, Oscar; Weiner, Brad R; Morell, Gerardo

    2014-08-27

    Silicon nanowires (SiNWs) were uniformly decorated with ultrananocrystalline diamond (UNCD) by a novel route using paraffin wax as the seeding source, which is more efficient in the creation of diamond nuclei than traditional methods. These one-dimensional ultrananocrystalline diamond-decorated SiNWs (UNCD/SiNWs) exhibit uniform diameters ranging from 100 to 200 nm with a bulbous catalytic tip of ?250 nm in diameter and an UNCD grain size of ?5 nm. UNCD/SiNW nanostructures demonstrated enhanced electron field emission (EFE) properties with a turn-on field of about 3.7 V/?m. Current densities around 2 mA/cm(2) were achieved at 25 V/?m, which is significantly enhanced as compared to bare SiNWs. PMID:25046006

  10. Characterization of ultrananocrystalline diamond microsensors for in vivo dopamine detection

    NASA Astrophysics Data System (ADS)

    Arumugam, Prabhu U.; Zeng, Hongjun; Siddiqui, Shabnam; Covey, Dan P.; Carlisle, John A.; Garris, Paul A.

    2013-06-01

    We show the technical feasibility of coating and micro patterning boron-doped ultrananocrystalline diamond (UNCD) on metal microwires and of applying them as microsensors for the detection of dopamine in vivo using fast-scan cyclic voltammetry. UNCD electrode surface consistently generated electrochemical signals with high signal-to-noise ratio of >800 using potassium ferrocyanide-ferricyanide redox couple. Parylene patterned UNCD microelectrodes were effectively applied to detect dopamine reliably in vitro using flow injection analysis with a detection limit of 27 nM and in the striatum of the anesthetized rat during electrical stimulation of dopamine neurons.

  11. Charging characteritiscs of ultrananocrystalline diamond in RF MEMS capacitive switches.

    SciTech Connect

    Sumant, A. V.; Goldsmith, C.; Auciello, O.; Carlisle, J.; Zheng, H.; Hwang, J. C. M.; Palego, C.; Wang, W.; Carpick, R.; Adiga, V.; Datta, A.; Gudeman, C.; O'Brien, S.; Sampath, S.

    2010-05-01

    Modifications to a standard capacitive MEMS switch process have been made to allow the incorporation of ultra-nano-crystalline diamond as the switch dielectric. The impact on electromechanical performance is minimal. However, these devices exhibit uniquely different charging characteristics, with charging and discharging time constants 5-6 orders of magnitude quicker than conventional materials. This operation opens the possibility of devices which have no adverse effects of dielectric charging and can be operated near-continuously in the actuated state without significant degradation in reliability.

  12. Softening of ultra-nanocrystalline diamond at small grain sizes

    NASA Astrophysics Data System (ADS)

    Kopidakis, Georgios; Remediakis, Ioannis; Kelires, Pantelis

    2008-03-01

    Ultra-nanocrystalline diamond is a polycrystalline material, having crystalline diamond grains of sizes in the nanometer regime. We study the structure and mechanical properties of this material as a function of the average grain size, employing atomistic simulations. Using the bulk and Young's moduli as probes of stiffness, we observe softening of the material as the size of its grains decreases, similar to the reverse Hall-Petch effect observed for nanocrystalline metals. This softening is attributed to the enhanced fraction of interfacial atoms. The calculated scaling of the cohesive energy and bulk modulus with respect to average grain size agrees very well with this picture. Our results suggest that softening at very small grain sizes might be a generic property of nanocrystalline materials.

  13. Ultrananocrystalline diamond thin films functionalized with therapeutically active collagen networks.

    SciTech Connect

    Huang, H.; Chen, M.; Bruno, P.; Lam, R.; Robinson, E.; Gruen, D.; Ho, D.; Materials Science Division; Northwestern Univ.

    2009-01-01

    The fabrication of biologically amenable interfaces in medicine bridges translational technologies with their surrounding biological environment. Functionalized nanomaterials catalyze this coalescence through the creation of biomimetic and active substrates upon which a spectrum of therapeutic elements can be delivered to adherent cells to address biomolecular processes in cancer, inflammation, etc. Here, we demonstrate the robust functionalization of ultrananocrystalline diamond (UNCD) with type I collagen and dexamethasone (Dex), an anti-inflammatory drug, to fabricate a hybrid therapeutically active substrate for localized drug delivery. UNCD oxidation coupled with a pH-mediated collagen adsorption process generated a comprehensive interface between the two materials, and subsequent Dex integration, activity, and elution were confirmed through inflammatory gene expression assays. These studies confer a translational relevance to the biofunctionalized UNCD in its role as an active therapeutic network for potent regulation of cellular activity toward applications in nanomedicine.

  14. Enhanced electron field emission properties by tuning the microstructure of ultrananocrystalline diamond film

    NASA Astrophysics Data System (ADS)

    Cheng, Hsiu-Fung; Chiang, Horng-Yi; Horng, Chuang-Chi; Chen, Huang-Chin; Wang, Chuan-Sheng; Lin, I.-Nan

    2011-02-01

    Synthesis of microcrystalline-ultrananocrystalline composite diamond (MCD-UNCD) films, which exhibit marvelous electron field emission (EFE) properties, was reported. The EFE of MCD-UNCD composite diamond film can be turned on at a low field as 6.5 V/?m and attain large EFE current density about 1.0 mA/cm2 at 30 V/?m applied field, which is better than the EFE behavior of the nondoped planar diamond films ever reported. The MCD-UNCD films were grown by a two-step microwave plasma enhanced chemical vapor deposition (MPECVD) process, including forming an UNCD layer in CH4/Ar plasma that contains no extra H2, followed by growing MCD layer using CH4/H2/Ar plasma that contains large proportion of H2. Microstructure examinations using high resolution transmission electron microscopy shows that the secondary MPECVD process modifies the granular structure of the UNCD layer, instead of forming a large grain diamond layer on top of UNCD films. The MCD-UNCD composite diamond films consist of numerous ultrasmall grains (5 nm in size), surrounding large grains about hundreds of nanometer in size. Moreover, there exist abundant nanographites in the interfacial region between the grains that were presumed to form interconnected channels for electron transport, resulting in superior EFE properties for MCD-UNCD composite films.

  15. Carbon Nanocomposite Based on Carbon Nanotubes and Ultrananocrystalline Diamond

    NASA Astrophysics Data System (ADS)

    Xiao, Xingcheng; Wang, Jian; Auciello, Orlando; Carlisle, John A.

    2004-03-01

    Carbon-based nanostructured materials exhibit many interesting properties that are dictated by the many different bonding configurations available to carbon. Two typical examples are carbon nanotubes (CNTs) and ultrananocrystalline diamond (UNCD), with the former being sp2 bonded carbon and latter being sp3 bonded carbon. Recent advances in micro and nanofabrication techniques have made possible the development of microscale and perhaps even nanoscale devices that capitalize on the many intrinsic strengths of these carbon-based materials. The focus of our study has been to prepare CNTs/UNCD composites. We demonstrate in this presentation the simultaneous growth of carbon nanotubes and diamond with the Ar/CH4 (99:1) plasma chemistry. The relative fraction of UNCD and CNTs was controlled by adjusting the relative density of diamond seeds and catalyst particles for the nucleation of UNCD and CNTs. Different methods, including Scanning Electron Microscopy (SEM), Raman Spectroscopy, Transmission Electron Microscopy (TEM) and Near Edge X-ray Absorption Fine Structure (NEXAFS) were used to characterize the composite nanostructures. The field emission and electrochemical properties of the composites were investigated. All these studies provide guidance to further explore the application of the CNTs/UNCD composites as field emitters and novel biosensors.

  16. Mechanical stiffness and dissipation in ultrananocrystalline diamond micro-resonators.

    SciTech Connect

    Sumant, A. V.; Adiga, V. P.; Suresh, S.; Gudeman, C.; Auciello, O.; Carlis, J. A.; Carpick, R. W.

    2009-01-01

    We have characterized mechanical properties of ultrananocrystalline diamond (UNCD) thin films grown using the hot filament chemical vapor deposition (HFCVD) technique at 680 C, significantly lower than the conventional growth temperature of {approx}800 C. The films have {approx}4.3% sp{sup 2} content in the near-surface region as revealed by near edge x-ray absorption fine structure spectroscopy. The films, {approx}1 {micro}m thick, exhibit a net residual compressive stress of 370 {+-} 1 MPa averaged over the entire 150 mm wafer. UNCD microcantilever resonator structures and overhanging ledges were fabricated using lithography, dry etching, and wet release techniques. Overhanging ledges of the films released from the substrate exhibited periodic undulations due to stress relaxation. This was used to determine a biaxial modulus of 838 {+-} 2 GPa. Resonant excitation and ring-down measurements in the kHz frequency range of the microcantilevers were conducted under ultrahigh vacuum (UHV) conditions in a customized UHV atomic force microscope system to determine Young's modulus as well as mechanical dissipation of cantilever structures at room temperature. Young's modulus is found to be 790 {+-} 30 GPa. Based on these measurements, Poisson's ratio is estimated to be 0.057 {+-} 0.038. The quality factors (Q) of these resonators ranged from 5000 to 16000. These Q values are lower than theoretically expected from the intrinsic properties of diamond. The results indicate that surface and bulk defects are the main contributors to the observed dissipation in UNCD resonators.

  17. Integration of piezoelectric aluminum nitride and ultrananocrystalline diamond films for implantable biomedical microelectromechanical devices

    NASA Astrophysics Data System (ADS)

    Zalazar, M.; Gurman, P.; Park, J.; Kim, D.; Hong, S.; Stan, L.; Divan, R.; Czaplewski, D.; Auciello, O.

    2013-03-01

    The physics for integration of piezoelectric aluminum nitride (AlN) films with underlying insulating ultrananocrystalline diamond (UNCD), and electrically conductive grain boundary nitrogen-incorporated UNCD (N-UNCD) and boron-doped UNCD (B-UNCD) layers, as membranes for microelectromechanical system implantable drug delivery devices, has been investigated. AlN films deposited on platinum layers on as grown UNCD or N-UNCD layer (5-10 nm rms roughness) required thickness of 400 nm to induce (002) AlN orientation with piezoelectric d33 coefficient 1.91 pm/V at 10 V. Chemical mechanical polished B-UNCD films (0.2 nm rms roughness) substrates enabled (002) AlN film 200 nm thick, yielding d33 = 5.3 pm/V.

  18. Using an Au interlayer to enhance electron field emission properties of ultrananocrystalline diamond films

    NASA Astrophysics Data System (ADS)

    Chen, Huang-Chin; Jothiramalingam Sankaran, Kamatchi; Lo, Shen-Chuan; Lin, Li-Jiaun; Tai, Nyan-Hwa; Lee, Chi-Young; Lin, I.-Nan

    2012-11-01

    We observe that an Au interlayer markedly enhances the electrical field emission (EFE) properties of ultrananocrystalline diamond (UNCD) films on Si substrates. The EFE properties of UNCD/Au/Si films can be turned on at a lower field and attain a higher current density than in UNCD films grown on Si substrates without an Au interlayer. Transmission electron microscopy reveals that the Au interlayer induces the formation of SiC clusters, preventing the formation of a resistive amorphous carbon layer that nucleates the diamond clusters. This improves the diamond-to-substrate interfacial conductivity. Moreover, there is an abundant nano-graphite phase, which is presumably induced by the coalescence of nano-sized diamond clusters. The percolation of the nano-graphite clusters helps transport electrons, improving the conductivity of the UNCD films. We believe that the simultaneous increase in the conductivity of the UNCD-to-Si interface and the bulk of the UNCD films is the main factor enhancing electrical conductivity and EFE properties of the films.

  19. Anisotropic pattern transfer in ultrananocrystalline diamond films by inductively coupled plasma etching.

    PubMed

    Park, Jong Cheon; Kim, Seong Hak; Cha, Seung Uk; Jeong, Geun; Kim, Tae Gyu; Kim, Jin Kon; Cho, Hyun

    2014-12-01

    High density plasma etching of ultrananocrystalline diamond (UNCD) films wasperformed in O2 and O2/Ar inductively coupled plasma (ICP) discharges. The O2/Ar ICP discharges produced higher etch rates due to enhanced physical component of the etching, and a maximum etch rate of -280 nm/min was obtained in 10 sccm O2/5 sccm Ar discharges. Very high etch selectivities up to -140:1 were obtained for the UNCD over Al mask layer. Anisotropic pattern transfer with a vertical sidewall profile was achieved in the 10 sccm O2/5 sccm Ar discharges at a relatively low source power (300 W) and a moderate rf chuck power (200 W). PMID:25971013

  20. Two- and three-dimensional ultrananocrystalline diamond (UNCD) structures for a high resolution diamond-based MEMS technology.

    SciTech Connect

    Auciello, O.; Krauss, A. R.; Gruen, D. M.; Busmann, H. G.; Meyer, E. M.; Tucek, J.; Sumant, A.; Jayatissa, A.; Moldovan, N.; Mancini, D. C.; Gardos, M. N.

    2000-01-17

    Silicon is currently the most commonly used material for the fabrication of microelectromechanical systems (MEMS). However, silicon-based MEMS will not be suitable for long-endurance devices involving components rotating at high speed, where friction and wear need to be minimized, components such as 2-D cantilevers that may be subjected to very large flexural displacements, where stiction is a problem, or components that will be exposed to corrosive environments. The mechanical, thermal, chemical, and tribological properties of diamond make it an ideal material for the fabrication of long-endurance MEMS components. Cost-effective fabrication of these components could in principle be achieved by coating Si with diamond films and using conventional lithographic patterning methods in conjunction with e. g. sacrificial Ti or SiO{sub 2} layers. However, diamond coatings grown by conventional chemical vapor deposition (CVD) methods exhibit a coarse-grained structure that prevents high-resolution patterning, or a fine-grained microstructure with a significant amount of intergranular non-diamond carbon. The authors demonstrate here the fabrication of 2-D and 3-D phase-pure ultrananocrystalline diamond (UNCD) MEMS components by coating Si with UNCD films, coupled with lithographic patterning methods involving sacrificial release layers. UNCD films are grown by microwave plasma CVD using C{sub 60}-Ar or CH{sub 4}-Ar gas mixtures, which result in films that have 3--5 nm grain size, are 10--20 times smoother than conventionally grown diamond films, are extremely resistant to corrosive environments, and are predicted to have a brittle fracture strength similar to that of single crystal diamond.

  1. Methane induced electrical property change of nitrogen doped ultrananocrystalline diamond nanowires

    NASA Astrophysics Data System (ADS)

    Feng, Peter; Wang, Xinpeng; Aldalbahi, Ali; Zhou, Andrew F.

    2015-12-01

    The methane induced electrical property change of nitrogen doped ultrananocrystalline diamond (UNCD) nanowires has been investigated. The experimental data indicated a significant decrease in the resistance caused by the presence of the methane impurity at room temperature. Our primary results show that its high sensitivity, fast response, and recovery time make the nitrogen doped UNCD an excellent material platform for methane gas sensor applications.

  2. Surface Functionalization of Plasma Treated Ultrananocrystalline Diamond/Amorphous Carbon Composite Films

    NASA Astrophysics Data System (ADS)

    Koch, Hermann; Popov, Cyril; Kulisch, Wilhelm; Spassov, G.; Reithmaier, Johann Peter

    Diamond possesses a number of outstanding properties which make it a perspective material as platform for preparation of biosensors. The diamond surface needs to be activated before the chemical attachment of crosslinkers with which biomolecules can interact. In the current work we have investigated the modification of ultrananocrystalline diamond/amorphous carbon (UNCD/a-C) films by oxygen and ammonia plasmas. Afterwards the layers were functionalized in a further step to obtain thiol-active maleimide groups on the surface. We studied the possibility for direct binding of maleimide to terminal OH-groups on the UNCD surface and for silanization with 3-aminopropyltriethoxysilane (APTES) to obtain NH2-groups for the following attachment of sulfosuccinimidyl 4-(N-maleimidomethyl)-cyclohexane-1-carboxylate (SSMCC). The thiol-bearing fluorescein-related dye 5-((2-(and-3)-S-(acetylmercapto) succinoyl) amino) fluorescein (SAMSA) was immobilized as an model biomolecule to evaluate the achieved thiol-activity by fluorescence microscopy. The results of the above mentioned surface modification and functionalization steps were investigated by Auger electron spectroscopy (AES) and contact angle measurements.

  3. A conversion model of graphite to ultrananocrystalline diamond via laser processing at ambient temperature and normal pressure

    SciTech Connect

    Ren, X. D. Yang, H. M.; Zheng, L. M.; Tang, S. X.; Ren, N. F.; Xu, S. D.; Yuan, S. Q.

    2014-07-14

    The synthesis mechanism of ultrananocrystalline diamond via laser shock processing of graphite suspension was presented at room temperature and normal pressure, which yielded the ultrananocrystalline diamond in size of about 5 nm. X-ray diffraction, high-resolution transmission electron microscopy, and laser Raman spectroscopy were used to characterize the nano-crystals. The transformation model and growth restriction mechanism of high power density with short-pulsed laser shocking of graphite particles in liquid was put forward.

  4. Bias-enhanced post-treatment process for enhancing the electron field emission properties of ultrananocrystalline diamond films

    SciTech Connect

    Saravanan, A.; Huang, B. R.; Sankaran, K. J.; Tai, N. H.; Dong, C. L.; Lin, I. N.

    2015-03-16

    The electron field emission (EFE) properties of ultrananocrystalline diamond films were markedly improved via the bias-enhanced plasma post-treatment (bep) process. The bep-process induced the formation of hybrid-granular structure of the diamond (bep-HiD) films with abundant nano-graphitic phase along the grain boundaries that increased the conductivity of the films. Moreover, the utilization of Au-interlayer can effectively suppress the formation of resistive amorphous-carbon (a-C) layer, thereby enhancing the transport of electrons crossing the diamond-to-Si interface. Therefore, bep-HiD/Au/Si films exhibit superior EFE properties with low turn-on field of E{sub 0} = 2.6 V/μm and large EFE current density of J{sub e} = 3.2 mA/cm{sup 2} (at 5.3 V/μm)

  5. Diamond nanowires and the insulator-metal transition in ultrananocrystalline diamond films.

    SciTech Connect

    Arenal, R.; Bruno, P.; Miller, D. J.; Bleuel, M.; Lai, J.; Gruen, D. M.

    2007-05-01

    Further progress in the development of the remarkable electrochemical, electron field emission, high-temperature diode, and optical properties of n-type ultrananocrystalline diamond films requires a better understanding of electron transport in this material. Of particular interest is the origin of the transition to the metallic regime observed when about 10% by volume of nitrogen has been added to the synthesis gas. Here, we present data showing that the transition to the metallic state is due to the formation of partially oriented diamond nanowires surrounded by an sp{sup 2}-bonded carbon sheath. These have been characterized by scanning electron microscopy, transmission electron microscopy techniques (high-resolution mode, selected area electron diffraction, and electron-energy-loss spectroscopy), Raman spectroscopy, and small-angle neutron scattering. The nanowires are 80-100 nm in length and consist of {approx}5 nm wide and 6-10 nm long segments of diamond crystallites exhibiting atomically sharp interfaces. Each nanowire is enveloped in a sheath of sp{sup 2}-bonded carbon that provides the conductive path for electrons. Raman spectroscopy on the films coupled with a consideration of plasma chemical and physical processes reveals that the sheath is likely composed of a nanocarbon material resembling in some respects a polymer-like mixture of polyacetylene and polynitrile. The complex interactions governing the simultaneous growth of the diamond core and the sp{sup 2} sheath responsible for electrical conductivity are discussed as are attempts at a better theoretical understanding of the transport mechanism.

  6. Diamond nanowires and the insulator-metal transition in ultrananocrystalline diamond films

    NASA Astrophysics Data System (ADS)

    Arenal, R.; Bruno, P.; Miller, D. J.; Bleuel, M.; Lal, J.; Gruen, D. M.

    2007-05-01

    Further progress in the development of the remarkable electrochemical, electron field emission, high-temperature diode, and optical properties of n -type ultrananocrystalline diamond films requires a better understanding of electron transport in this material. Of particular interest is the origin of the transition to the metallic regime observed when about 10% by volume of nitrogen has been added to the synthesis gas. Here, we present data showing that the transition to the metallic state is due to the formation of partially oriented diamond nanowires surrounded by an sp2 -bonded carbon sheath. These have been characterized by scanning electron microscopy, transmission electron microscopy techniques (high-resolution mode, selected area electron diffraction, and electron-energy-loss spectroscopy), Raman spectroscopy, and small-angle neutron scattering. The nanowires are 80-100nm in length and consist of 5nm wide and 6-10nm long segments of diamond crystallites exhibiting atomically sharp interfaces. Each nanowire is enveloped in a sheath of sp2 -bonded carbon that provides the conductive path for electrons. Raman spectroscopy on the films coupled with a consideration of plasma chemical and physical processes reveals that the sheath is likely composed of a nanocarbon material resembling in some respects a polymer-like mixture of polyacetylene and polynitrile. The complex interactions governing the simultaneous growth of the diamond core and the sp2 sheath responsible for electrical conductivity are discussed as are attempts at a better theoretical understanding of the transport mechanism.

  7. Extreme synthesis and characterization of an ultrananocrystalline diamond aerogel in a diamond anvil cell

    NASA Astrophysics Data System (ADS)

    Pauzauskie, Peter

    2013-06-01

    High-surface-area mesostructured carbon materials have attracted a great amount attention in recent years because of a growing number of applications in energy storage, chemical catalysis, separations, and sensing. In particular, amorphous carbon aerogels have attracted much interest since the 1980's due to their low density, large intrinsic surface areas (>1000 m2/g), large pore volume, low dielectric constant, and high strength. In this talk we present the use of high-pressure (>20 GPa) laser-heating (>1500 C) within a diamond anvil cell (DAC) to convert the amorphous network of a low-density (40 mg/cc) carbon aerogel into an ultrananocrystalline diamond aerogel. Raman spectroscopy is used to probe the amorphous-to-diamond phase transition at pressure within the DAC. High-resolution transmission electron microscopy images of recovered material indicate diamond crystallite sizes range from 1 to 100 nm, with electron diffraction and electron energy loss confirming the presence of the diamond phase. Photoluminescence spectroscopy and confocal time-correlated single-photon counting indicate the recovered material contains both negatively-charged and neutral nitrogen-vacancy (NV) complexes. Synchrotron scanning transmission x-ray microscopy (STXM) is used to compare the carbon electronic density-of-states of the amorphous starting material with the recovered diamond aerogel with <100 meV energy resolution. Finally, we use nanoscale secondary ion mass spectrometry to investigate doping of the resorcinol-formaldehyde starting material with the aim of chemically tuning heteroatomic point defects within this diamond material system.

  8. Planar ultrananocrystalline diamond field emitter in accelerator radio frequency electron injector: Performance metrics

    SciTech Connect

    Baryshev, Sergey V. Antipov, Sergey; Jing, Chunguang; Qiu, Jiaqi; Shao, Jiahang; Liu, Wanming; Gai, Wei; Pérez Quintero, Kenneth J.; Sumant, Anirudha V.; Kanareykin, Alexei D.

    2014-11-17

    A case performance study of a planar field emission cathode (FEC) based on nitrogen-incorporated ultrananocrystalline diamond, (N)UNCD, was carried out in an RF 1.3 GHz electron gun. The FEC was a 100 nm (N)UNCD film grown on a 20 mm diameter stainless steel disk with a Mo buffer layer. At surface gradients 45–65 MV/m, peak currents of 1–80 mA (equivalent to 0.3–25 mA/cm{sup 2}) were achieved. Imaging with two YAG screens confirmed emission from the (N)UNCD surface with (1) the beam emittance of 1.5 mm × mrad/mm-rms and (2) longitudinal FWHM and rms widths of non-Gaussian energy spread of 0.7% and 11% at an electron energy of 2 MeV. Current stability was tested over the course of 36 × 10{sup 3} RF pulses (equivalent to 288 × 10{sup 6 }GHz oscillations)

  9. Synthesis method for ultrananocrystalline diamond in powder employing a coaxial arc plasma gun

    NASA Astrophysics Data System (ADS)

    Naragino, Hiroshi; Tominaga, Aki; Hanada, Kenji; Yoshitake, Tsuyoshi

    2015-07-01

    A new method that enables us to synthesize ultrananocrystalline diamond (UNCD) in powder is proposed. Highly energetic carbon species ejected from a graphite cathode of a coaxial arc plasma gun were provided on a quartz plate at a high density by repeated arc discharge in a compact vacuum chamber, and resultant films automatically peeled from the plate were aggregated and powdered. The grain size was easily controlled from 2.4 to 15.0 nm by changing the arc discharge energy. It was experimentally demonstrated that the proposed method is a new and promising method that enables us to synthesize UNCD in powder easily and controllably.

  10. Ultrananocrystalline and nanocrystalline diamond thin films for NEMS/MEMS applications.

    SciTech Connect

    Sumant, A. V.; Auciello, O.; Carpick, R. W.; Srinivasan, S.; Butler, J. E.

    2010-04-01

    There has been a tireless quest by the designers of micro- and nanoelectro mechanical systems (MEMS/NEMS) to find a suitable material alternative to conventional silicon. This is needed to develop robust, reliable, and long-endurance MEMS/NEMS with capabilities for working under demanding conditions, including harsh environments, high stresses, or with contacting and sliding surfaces. Diamond is one of the most promising candidates for this because of its superior physical, chemical, and tribomechanical properties. Ultrananocrystalline diamond (UNCD) and nanocrystalline diamond (NCD) thin films, the two most studied forms of diamond films in the last decade, have distinct growth processes and nanostructures but complementary properties. This article reviews the fundamental and applied science performed to understand key aspects of UNCD and NCD films, including the nucleation and growth, tribomechanical properties, electronic properties, and applied studies on integration with piezoelectric materials and CMOS technology. Several emerging diamond-based MEMS/NEMS applications, including high-frequency resonators, radio frequency MEMS and photonic switches, and the first commercial diamond MEMS product - monolithic diamond atomic force microscopy probes - are discussed.

  11. Direct observation of enhanced emission sites in nitrogen implanted hybrid structured ultrananocrystalline diamond films

    SciTech Connect

    Panda, Kalpataru; Sundaravel, B.; Panigrahi, B. K.; Chen, Huang-Chin; Lin, I.-Nan

    2013-02-07

    A hybrid-structured ultrananocrystalline diamond (h-UNCD) film, synthesized on Si-substrates by a two-step microwave plasma enhanced chemical vapour deposition (MPECVD) process, contains duplex structure with large diamond aggregates evenly dispersed in a matrix of ultra-small grains ({approx}5 nm). The two-step plasma synthesized h-UNCD films exhibit superior electron field emission (EFE) properties than the one-step MPECVD deposited UNCD films. Nitrogen-ion implantation/post-annealing processes further improve the EFE properties of these films. Current imaging tunnelling spectroscopy in scanning tunnelling spectroscopy mode directly shows increased density of emission sites in N implanted/post-annealed h-UNCD films than as-prepared one. X-ray photoelectron spectroscopy measurements show increased sp{sup 2} phase content and C-N bonding fraction in N ion implanted/post-annealed films. Transmission electron microscopic analysis reveals that the N implantation/post-annealing processes induce the formation of defects in the diamond grains, which decreases the band gap and increases the density of states within the band gap of diamond. Moreover, the formation of nanographitic phase surrounding the small diamond grains enhanced the conductivity at the diamond grain boundaries. Both of the phenomena enhance the EFE properties.

  12. Low-temperature electrical transport in B-doped ultrananocrystalline diamond film

    SciTech Connect

    Li, Lin; Zhao, Jing; Hu, Zhaosheng; Quan, Baogang; Li, Junjie Gu, Changzhi

    2014-05-05

    B-doped ultrananocrystalline diamond (UNCD) films are grown using hot-filament chemical vapor deposition method, and their electrical transport properties varying with temperature are investigated. When the B-doped concentration of UNCD film is low, a step-like increase feature of the resistance is observed with decreasing temperature, reflecting at least three temperature-modified electronic state densities at the Fermi level according to three-dimensional Mott's variable range hopping transport mechanism, which is very different from that of reported B-doped nanodiamond. With increasing B-doped concentration, a superconductive transformation occurs in the UNCD film and the highest transformation temperature of 5.3?K is observed, which is higher than that reported for superconducting nanodiamond films. In addition, the superconducting coherence length is about 0.63?nm, which breaks a reported theoretical and experimental prediction about ultra-nanoscale diamond's superconductivity.

  13. Low-loss lateral-extensional piezoelectric filters on ultrananocrystalline diamond.

    PubMed

    Fatemi, Hediyeh; Abdolvand, Reza

    2013-09-01

    In this work, lateral-extensional thin-film piezoelectric- on-diamond (TPoD) filters with very low insertion loss (IL) values (<4 dB) are reported. Two different lateral-extensional modes of a resonant structure are coupled together to realize a two-pole filter. The filters of this work exhibit low IL values, with fractional bandwidth between 0.08% and 0.2%, and have a very small footprint. This paper reports on the lowest IL in the literature for lateral-extensional thin-film piezoelectric filters with 50 ? terminations in the GSM frequency band (~900 MHz). The narrow-band filters of this work are fabricated on three ultrananocrystalline diamond substrates to achieve higher frequencies without excessive reduction in the feature size. The paper also thoroughly studies the parameters that affect the performance of such filters and then discussions are evaluated by the statistical data collected from the fabricated wafers. PMID:24658729

  14. Fabrication of free-standing highly conducting ultrananocrystalline diamond films with enhanced electron field emission properties

    NASA Astrophysics Data System (ADS)

    Sankaran, K. J.; Chen, H. C.; Lee, C. Y.; Tai, N. H.; Lin, I. N.

    2012-12-01

    Fabrication of free-standing/highly conducting ultrananocrystalline diamond (fc-UNCD) films at low growth temperature (<475 C) is demonstrated. The fc-UNCD films show high conductivity of ? = 146 (? cm)-1 with superior electron field emission (EFE) properties, viz. low turn-on field of 4.35 V/?m and high EFE current density of 3.76 mA/cm2 at an applied field of 12.5 V/?m. Transmission electron microscopy examinations reveal the presence of Au/Cu clusters in film-to-substrate interface, which consequences in the induction of nanographite phases, surrounding the diamond grains that form conduction channels for electrons transport, ensuing in marvelous EFE properties of fc-UNCD films.

  15. Flexible electron field emitters fabricated using conducting ultrananocrystalline diamond pyramidal microtips on polynorbornene films

    SciTech Connect

    Sankaran, K. J.; Tai, N. H.; Lin, I. N.

    2014-01-20

    High performance flexible field emitters made of aligned pyramidal shaped conducting ultrananocrystalline diamond (C-UNCD) microtips on polynorbornene substrates is demonstrated. Flexible C-UNCD pyramidal microtips show a low turn-on field of 1.80?V/?m with a field enhancement factor of 4580 and a high emission current density of 5.8?mA/cm{sup 2} (at an applied field of 4.20?V/?m) with life-time stability of 210 min. Such an enhancement in the field emission is due to the presence of sp{sup 2}-graphitic sheath with a nanowire-like diamond core. This high performance flexible C-UNCD field emitter is potentially useful for the fabrication of diverse, flexible electronic devices.

  16. Piezoelectric/ultrananocrystalline diamond heterostructures for a new generation of multifunctional micro/nanoelectromechanical systems.

    SciTech Connect

    Srinivasan, S.; Hiller, J.; Kabius, B.; Auciello, O.

    2007-01-01

    Most current micro/nanoelectromechanical systems (MEMS/NEMS) are based on silicon. However, silicon exhibits relatively poor mechanical/tribological properties, compromising applications to some devices. Diamond films with superior mechanical/tribological properties provide an excellent alternative platform material. Ultrananocrystalline diamond (UNCD{reg_sign}) in film form with 2-5 nm grains exhibits excellent properties for high-performance MEMS/NEMS devices. Concurrently, piezoelectric Pb(Zr{sub x}Ti{sub 1-x})O{sub 3} (PZT) films provide high sensitivity/low electrical noise for sensing/high-force actuation at relatively low voltages. Therefore, integration of PZT and UNCD films provides a high-performance platform for advanced MEMS/NEMS devices. This letter describes the bases of such integration and demonstration of low voltage piezoactuated hybrid PZT/UNCD cantilevers.

  17. Flexible electron field emitters fabricated using conducting ultrananocrystalline diamond pyramidal microtips on polynorbornene films

    NASA Astrophysics Data System (ADS)

    Sankaran, K. J.; Tai, N. H.; Lin, I. N.

    2014-01-01

    High performance flexible field emitters made of aligned pyramidal shaped conducting ultrananocrystalline diamond (C-UNCD) microtips on polynorbornene substrates is demonstrated. Flexible C-UNCD pyramidal microtips show a low turn-on field of 1.80 V/?m with a field enhancement factor of 4580 and a high emission current density of 5.8 mA/cm2 (at an applied field of 4.20 V/?m) with life-time stability of 210 min. Such an enhancement in the field emission is due to the presence of sp2-graphitic sheath with a nanowire-like diamond core. This high performance flexible C-UNCD field emitter is potentially useful for the fabrication of diverse, flexible electronic devices.

  18. DEVELOPMENT OF A SCALABLE, LOW-COST, ULTRANANOCRYSTALLINE DIAMOND ELECTROCHEMICAL PROCESS FOR THE DESTRUCTION OF CONTAMINANTS OF EMERGING CONCERN (CECS) - PHASE II

    EPA Science Inventory

    This Small Business Innovation Research (SBIR) Phase II project will employ the large scale; highly reliable boron-doped ultrananocrystalline diamond (BD-UNCD) electrodes developed during Phase I project to build and test Electrochemical Anodic Oxidation process (EAOP)...

  19. DEVELOPMENT OF A SCALABLE, LOW-COST, ULTRANANOCRYSTALLINE DIAMOND ELECTROCHEMICAL PROCESS FOR THE DESTRUCTION OF CONTAMINANTS OF EMERGING CONCERN (CECS) - PHASE II

    EPA Science Inventory

    This Small Business Innovation Research (SBIR) Phase II project will employ the large scale; highly reliable boron-doped ultrananocrystalline diamond (BD-UNCD®) electrodes developed during Phase I project to build and test Electrochemical Anodic Oxidation process (EAOP)...

  20. Chemical grafting of biphenyl self-assembled monolayers on ultrananocrystalline diamond.

    PubMed

    Lud, Simon Q; Steenackers, Marin; Jordan, Rainer; Bruno, Paola; Gruen, Dieter M; Feulner, Peter; Garrido, Jose A; Stutzmann, Martin

    2006-12-27

    We have investigated the formation of self-assembled monolayers (SAMs) of 4'-nitro-1,1-biphenyl-4-diazonium tetrafluoroborate (NBD) onto ultrananocrystalline diamond (UNCD) thin films. In contrast to the common approach to modify diamond and diamond-like substrates by electrografting, the SAM was formed from the saturated solution of NBD in acetonitrile by pure chemical grafting. Atomic force microscopy (AFM), X-ray photoelectron spectroscopy (XPS), cyclic voltammetry (CV), and near edge X-ray absorption fine structure spectroscopy (NEXAFS) have been used to verify the direct covalent attachment of the 4'-nitro-1,1-biphenyl (NB) SAM on the diamond substrate via stable C-C bonds and to estimate the monolayer packing density. The results confirm the presence of a very stable, homogeneous and dense monolayer. Additionally, the terminal nitro group of the NB SAM can be readily converted into an amino group by X-ray irradiation as well as electrochemistry. This opens the possibility of in situ electrochemical modification as well as the creation of chemical patterns (chemical lithography) in the SAM on UNCD substrates and enables a variety of consecutive chemical functionalization for sensing and molecular electronics applications. PMID:17177439

  1. Transient photoresponse of nitrogen-doped ultrananocrystalline diamond electrodes in saline solution

    NASA Astrophysics Data System (ADS)

    Ahnood, Arman; Simonov, Alexandr N.; Laird, Jamie S.; Maturana, Matias I.; Ganesan, Kumaravelu; Stacey, Alastair; Ibbotson, Michael R.; Spiccia, Leone; Prawer, Steven

    2016-03-01

    Beyond conventional electrically-driven neuronal stimulation methods, there is a growing interest in optically-driven approaches. In recent years, nitrogen-doped ultrananocrystalline diamond (N-UNCD) has emerged as a strong material candidate for use in electrically-driven stimulation electrodes. This work investigates the electrochemical activity of N-UNCD in response to pulsed illumination, to assess its potential for use as an optically-driven stimulation electrode. Whilst N-UNCD in the as-grown state exhibits a weak photoresponse, the oxygen plasma treated film exhibits two orders of magnitude enhancement in its sub-bandgap open circuit photovoltage response. The enhancement is attributed to the formation of a dense network of oxygen-terminated diamond nanocrystals at the N-UNCD surface. Electrically connected to the N-UNCD bulk via sub-surface graphitic grain boundaries, these diamond nanocrystals introduce a semiconducting barrier between the sub-surface graphitic semimetal and the electrolyte solution, leading to a photovoltage under irradiation with wavelengths of λ = 450 nm and shorter. Within the safe optical exposure limit of 2 mW mm-2, charge injection capacity of 0.01 mC cm-2 is achieved using a 15 × 15 μm electrode, meeting the requirements for extracellular and intercellular stimulation. The nanoscale nature of processes presented here along with the diamond's biocompatibility and biostability open an avenue for the use of oxygen treated N-UNCD as optically driven stimulating electrodes.

  2. High Stability Electron Field Emitters Synthesized via the Combination of Carbon Nanotubes and N2-Plasma Grown Ultrananocrystalline Diamond Films.

    PubMed

    Chang, Ting-Hsun; Hsieh, Ping-Yen; Kunuku, Srinivasu; Lou, Shiu-Cheng; Manoharan, Divinah; Leou, Keh-Chyang; Lin, I-Nan; Tai, Nyan-Hwa

    2015-12-16

    An electron field emitter with superior electron field emission (EFE) properties and improved lifetime stability is being demonstrated via the combination of carbon nanotubes and the CH4/N2 plasma grown ultrananocrystalline diamond (N-UNCD) films. The resistance of the carbon nanotubes to plasma ion bombardment is improved by the formation of carbon nanocones on the side walls of the carbon nanotubes, thus forming strengthened carbon nanotubes (s-CNTs). The N-UNCD films can thus be grown on s-CNTs, forming N-UNCD/s-CNTs carbon nanocomposite materials. The N-UNCD/s-CNTs films possess good conductivity of σ = 237 S/cm and marvelous EFE properties, such as low turn-on field of (E0) = 3.58 V/μm with large EFE current density of (Je) = 1.86 mA/cm(2) at an applied field of 6.0 V/μm. Moreover, the EFE emitters can be operated under 0.19 mA/cm(2) for more than 350 min without showing any sign of degradation. Such a superior EFE property along with high robustness characteristic of these combination of materials are not attainable with neither N-UNCD films nor s-CNTs films alone. Transmission electron microscopic investigations indicated that the N-UNCD films contain needle-like diamond grains encased in a few layers of nanographitic phase, which enhanced markedly the transport of electrons in the N-UNCD films. Moreover, the needle-like diamond grains were nucleated from the s-CNTs without the necessity of forming the interlayer that facilitate the transport of electrons crossing the diamond-to-Si interface. Both these factors contributed to the enhanced EFE behavior of the N-UNCD/s-CNTs films. PMID:26600097

  3. Effects of Boron Doping on the Properties of Ultrananocrystalline Diamond Films

    NASA Astrophysics Data System (ADS)

    Yuan, Wen-Xiang; WU, Q. X.; Luo, Z. K.; Wu, H. S.

    2014-04-01

    Boron-doped ultrananocrystalline diamond (UNCD) films were fabricated on silicon substrates by microwave plasma chemical vapor deposition. UNCD films containing different concentrations of boron were prepared by using trimethylboron (B(CH3)3, TMB) as boron doping source and varying the amount of boron in the gas mixture from 0 ppm to 1000 ppm. The effects of boron doping on morphology, lattice parameter, phase composition, crystal size, and residual stress of UNCD films were investigated. No obvious change of the morphology was observed on doping with boron, and all the films had the UNCD crystal grains. Boron doping enhanced (111) growth. The preferred growth direction of the UNCD films was . Residual tensile stress was present in all the films, and increased with increasing the amount of boron in the gas mixture.

  4. Ultrananocrystalline Diamond-Coated Microporous Silicon Nitride Membranes for Medical Implant Applications

    NASA Astrophysics Data System (ADS)

    Skoog, Shelby A.; Sumant, Anirudha V.; Monteiro-Riviere, Nancy A.; Narayan, Roger J.

    2012-04-01

    Ultrananocrystalline diamond (UNCD) exhibits excellent biological and mechanical properties, which make it an appropriate choice for promoting epidermal cell migration on the surfaces of percutaneous implants. We deposited a ~150 nm thick UNCD film on a microporous silicon nitride membrane using microwave plasma chemical vapor deposition. Scanning electron microscopy and Raman spectroscopy were used to examine the pore structure and chemical bonding of this material, respectively. Growth of human epidermal keratinocytes on UNCD-coated microporous silicon nitride membranes and uncoated microporous silicon nitride membranes was compared using the 3-(4,5-dimethylthiazol-2-yl)2,5-diphenyltetrazolium bromide (MTT) assay. The results show that the UNCD coating did not significantly alter the viability of human epidermal keratinocytes, indicating potential use of this material for improving skin sealing around percutaneous implants.

  5. Method to fabricate portable electron source based on nitrogen incorporated ultrananocrystalline diamond (N-UNCD)

    DOEpatents

    Sumant, Anirudha V.; Divan, Ralu; Posada, Chrystian M.; Castano, Carlos H.; Grant, Edwin J.; Lee, Hyoung K.

    2016-03-29

    A source cold cathode field emission array (FEA) source based on ultra-nanocrystalline diamond (UNCD) field emitters. This system was constructed as an alternative for detection of obscured objects and material. Depending on the geometry of the given situation a flat-panel source can be used in tomography, radiography, or tomosynthesis. Furthermore, the unit can be used as a portable electron or X-ray scanner or an integral part of an existing detection system. UNCD field emitters show great field emission output and can be deposited over large areas as the case with carbon nanotube "forest" (CNT) cathodes. Furthermore, UNCDs have better mechanical and thermal properties as compared to CNT tips which further extend the lifetime of UNCD based FEA.

  6. Science and technology of ultrananocrystalline diamond (UNCD) thin films for multifunctional devices.

    SciTech Connect

    Auciello, O.; Gruen, D. M.; Krauss, A. R.; Jayatissa, A.; Sumant, A.; Tucek, J.; Mancini, D.; Moldovan, N.; Erdemir, A.; Ersoy, D.; Gardos, M. N.; Busmann, H. G.; Meyer, E. M.

    2000-11-15

    MEMS devices are currently fabricated primarily in silicon because of the available surface machining technology. However, Si has poor mechanical and tribological properties, and practical MEMS devices are currently limited primarily to applications involving only bending and flexural motion, such as cantilever accelerometers and vibration sensors, However, because of the poor flexural strength and fracture toughness of Si, and the tendency of Si to adhere to hydrophyllic surfaces, even these simple devices have limited dynamic range. Future MEMS applications that involve significant rolling or sliding contact will require the use of new materials with significantly improved mechanical and tribological properties, and the ability to perform well in harsh environments. Diamond is a superhard material of high mechanical strength, exceptional chemical inertness, and outstanding thermal stability. The brittle fracture strength is 23 times that of Si, and the projected wear life of diamond MEMS moving mechanical assemblies (MEMS-MMAS) is 10,000 times greater than that of Si MMAs. However, as the hardest known material, diamond is notoriously difficult to fabricate. Conventional CVD thin film deposition methods offer an approach to the fabrication of ultra-small diamond structures, but the films have large grain size, high internal stress, poor intergranular adhesion, and very rough surfaces, and are consequently ill-suited for MEMS-MMA applications. A thin film deposition process has been developed that produces phase-pure ultrananocrystalline diamond (UNCD) with morphological and mechanical properties that are ideally suited for MEMS applications in general, and MMA use in particular. We have developed lithographic techniques for the fabrication of diamond microstructure including cantilevers and multi-level devices, acting as precursors to micro-bearings and gears, making UNCD a promising material for the development of high performance MEMS devices.

  7. Development of ultrananocrystalline diamond (UNCD) coatings for multipurpose mechanical pump seals.

    SciTech Connect

    Kovalchenko, A. M.; Elam, J. W.; Erdemir, A.; Carlisle, J. A.; Auciello, O.; Libera, J. A.; Pellin, M. J.; Gruen, D. M.; Hryn, J. N.

    2011-01-01

    The reliability and performance of silicon carbide (SiC) shaft seals on multipurpose mechanical pumps are improved by applying a protective coating of ultrananocrystalline diamond (UNCD). UNCD exhibits extreme hardness (97 GPa), low friction (0.1 in air) and outstanding chemical resistance. Consequently, the application of UNCD coatings to multipurpose mechanical pump seals can reduce frictional energy losses and eliminate the downtime and hazardous emissions from seal failure and leakage. In this study, UNCD films were prepared by microwave plasma chemical vapor deposition utilizing an argon/methane gas mixture. Prior to coating, the SiC seals were subjected to mechanical polishing using different grades of micron-sized diamond powder to produce different starting surfaces with well-controlled surface roughnesses. Following this roughening process, the seals were seeded by mechanical abrasion with diamond nanopowder, and subsequently coated with UNCD. The coated seals were subjected to dynamic wear testing performed at 3600 RPM and 100 psi for up to 10 days during which the seals were periodically removed and inspected. The UNCD-coated seals were examined using Raman microanalysis, scanning electron microscopy, optical profilometry, and adhesion testing before and after the wear testing. These analyses revealed that delamination of the UNCD films was prevented when the initial SiC seal surface had an initial roughness >0.1 {micro}m. In addition, the UNCD surfaces showed no measurable wear as compared to approximately 0.2 {micro}m of wear for the untreated SiC surfaces.

  8. Nitrogen incorporated ultrananocrystalline diamond based field emitter array for a flat-panel x-ray source

    SciTech Connect

    Posada, Chrystian M.; Grant, Edwin J.; Lee, Hyoung K.; Castao, Carlos H.; Divan, Ralu; Sumant, Anirudha V.; Rosenmann, Daniel; Stan, Liliana

    2014-04-07

    A field emission based flat-panel transmission x-ray source is being developed as an alternative for medical and industrial imaging. A field emitter array (FEA) prototype based on nitrogen incorporated ultrananocrystalline diamond film has been fabricated to be used as the electron source of this flat panel x-ray source. The FEA prototype was developed using conventional microfabrication techniques. The field emission characteristics of the FEA prototype were evaluated. Results indicated that emission current densities of the order of 6?mA/cm{sup 2} could be obtained at electric fields as low as 10?V/?m to 20?V/?m. During the prototype microfabrication process, issues such as delamination of the extraction gate and poor etching of the SiO{sub 2} insulating layer located between the emitters and the extraction layer were encountered. Consequently, alternative FEA designs were investigated. Experimental and simulation data from the first FEA prototype were compared and the results were used to evaluate the performance of alternative single and double gate designs that would yield better field emission characteristics compared to the first FEA prototype. The best simulation results are obtained for the double gate FEA design, when the diameter of the collimator gate is around 2.6 times the diameter of the extraction gate.

  9. Cell adhesion and growth on ultrananocrystalline diamond and diamond-like carbon films after different surface modifications

    NASA Astrophysics Data System (ADS)

    Miksovsky, J.; Voss, A.; Kozarova, R.; Kocourek, T.; Pisarik, P.; Ceccone, G.; Kulisch, W.; Jelinek, M.; Apostolova, M. D.; Reithmaier, J. P.; Popov, C.

    2014-04-01

    Diamond and diamond-like carbon (DLC) films possess a set of excellent physical and chemical properties which together with a high biocompatibility make them attractive candidates for a number of medical and biotechnological applications. In the current work thin ultrananocrystalline diamond (UNCD) and DLC films were comparatively investigated with respect to cell attachment and proliferation after different surface modifications. The UNCD films were prepared by microwave plasma enhanced chemical vapor deposition, the DLC films by pulsed laser deposition (PLD). The films were comprehensively characterized with respect to their basic properties, e.g. crystallinity, morphology, chemical bonding nature, etc. Afterwards the UNCD and DLC films were modified applying O2 or NH3/N2 plasmas and UV/O3 treatments to alter their surface termination. The surface composition of as-grown and modified samples was studied by X-ray photoelectron spectroscopy (XPS). Furthermore the films were characterized by contact angle measurements with water, formamide, 1-decanol and diiodomethane; from the results obtained the surface energy with its dispersive and polar components was calculated. The adhesion and proliferation of MG63 osteosarcoma cells on the different UNCD and DLC samples were assessed by measurement of the cell attachment efficiency and MTT assays. The determined cell densities were compared and correlated with the surface properties of as-deposited and modified UNCD and DLC films.

  10. The influence of sterilization on nitrogen-included ultrananocrystalline diamond for biomedical applications.

    PubMed

    Tong, Wei; Tran, Phong A; Turnley, Ann M; Aramesh, Morteza; Prawer, Steven; Brandt, Milan; Fox, Kate

    2016-04-01

    Diamond has shown great potential in different biomedical applications, but the effects of sterilization on its properties have not been investigated. Here, we studied the influence of five sterilization techniques (solvent cleaning, oxygen plasma, UV irradiation, autoclave and hydrogen peroxide) on nitrogen-included ultrananocrystalline diamond. The chemical modification of the diamond surface was evaluated using X-ray photoelectron spectroscopy and water contact angle measurements. Different degrees of surface oxidation and selective sp(2) bonded carbon etching were found following all sterilization techniques, resulting in an increase of hydrophilicity. Higher viabilities of in vitro mouse 3T3 fibroblasts and rat cortical neuron cells were observed on oxygen plasma, autoclave and hydrogen peroxide sterilized diamond, which correlated with their higher hydrophilicity. By examination of apatite formation in simulated body fluid, in vivo bioactivity was predicted to be best on those surfaces which have been oxygen plasma treated and lowest on those which have been exposed to UV irradiation. The charge injection properties were also altered by the sterilization process and there appears to be a correlation between these changes and the degree of oxygen termination of the surface. We find that the modification brought by autoclave, oxygen plasma and hydrogen peroxide were most consistent with the use of N-UNCD in biological applications as compared to samples sterilized by solvent cleaning or UV exposure or indeed non-sterilized. A two-step process of sterilization by hydrogen peroxide following oxygen plasma treatment was then suggested. However, the final choice of sterilization technique will depend on the intended end application. PMID:26838856

  11. Effects of Surface Pretreatment on Nucleation and Growth of Ultra-Nanocrystalline Diamond Films

    NASA Astrophysics Data System (ADS)

    Liu, Cong; Wang, Jianhua; Liu, Sijia; Xiong, Liwei; Weng, Jun; Cui, Xiaohui

    2015-06-01

    The effects of different surface pretreatment methods on the nucleation and growth of ultra-nanocrystalline diamond (UNCD) films grown from focused microwave Ar/CH4/H2 (argon-rich) plasma were systematically studied. The surface roughness, nucleation density, microstructure, and crystallinity of the obtained UNCD films were characterized by atomic force microscope (AFM), scanning electron microscopy (SEM), X-ray diffraction (XRD), and Raman spectroscopy. The results indicate that the nucleation enhancement was found to be sensitive to the different surface pretreatment methods, and a higher initial nucleation density leads to highly smooth UNCD films. When the silicon substrate was pretreated by a two-step method, i.e., plasma treatment followed by ultrasonic vibration with diamond nanopowder, the grain size of the UNCD films was greatly decreased: about 7.5 nm can be achieved. In addition, the grain size of UNCD films depends on the substrate pretreatment methods and roughness, which indicates that the surface of substrate profile has a “genetic characteristic”. supported by National Natural Science Foundation of China (No. 11175137) and the Research Fund of Wuhan Institute of Technology, China (No. 11111051)

  12. Temperature dependence of mechanical stiffness and dissipation in ultrananocrystalline diamond films grown by the HFCVD techinque.

    SciTech Connect

    Adiga, V. P.; Sumant, A. V.; Suresh, S.; Gudeman, C.; Auciello, O.; Carlisle, J. A.; Carpick, R. W.; Materials Science Division; Univ. of Pennsylvania; Innovative Micro Tech.; Advanced Diamond Tech.

    2009-06-01

    We have characterized mechanical properties of ultrananocrystalline diamond (UNCD) thin films grown using the hot filament chemical vapor deposition (HFCVD) technique at 680 C, significantly lower than the conventional growth temperature of -800 C. The films have -4.3% sp{sup 2} content in the near-surface region as revealed by near edge x-ray absorption fine structure spectroscopy. The films, -1 {micro}m thick, exhibit a net residual compressive stress of 370 {+-} 1 MPa averaged over the entire 150 mm wafer. UNCD microcantilever resonator structures and overhanging ledges were fabricated using lithography, dry etching, and wet release techniques. Overhanging ledges of the films released from the substrate exhibited periodic undulations due to stress relaxation. This was used to determine a biaxial modulus of 838 {+-} 2 GPa. Resonant excitation and ring-down measurements in the kHz frequency range of the microcantilevers were conducted under ultrahigh vacuum (UHV) conditions in a customized UHV atomic force microscope system to determine Young's modulus as well as mechanical dissipation of cantilever structures at room temperature. Young's modulus is found to be 790 {+-} 30 GPa. Based on these measurements, Poisson's ratio is estimated to be 0.057 {+-} 0.038. The quality factors (Q) of these resonators ranged from 5000 to 16000. These Q values are lower than theoretically expected from the intrinsic properties of diamond. The results indicate that surface and bulk defects are the main contributors to the observed dissipation in UNCD resonators.

  13. Formation of Ultrananocrystalline Diamond/Amorphous Carbon Composite Films in Vacuum Using Coaxial Arc Plasma Gun

    NASA Astrophysics Data System (ADS)

    Hanada, Kenji; Yoshida, Tomohiro; Nakagawa, You; Yoshitake, Tsuyoshi

    2010-12-01

    Ultrananocrystalline diamond (UNCD)/nonhydrogenated amorphous carbon (a-C) composite films were grown in vacuum using a coaxial arc plasma gun. From the X-ray diffraction measurement, the UNCD crystallite size was estimated to be 1.6 nm. This size is dramatically reduced from that (2.3 nm) of UNCD/hydrogenated amorphous carbon (a-C:H) composite films grown in a hydrogen atmosphere. The sp3/(sp3 + sp2) value, which was estimated from the X-ray photoemission spectrum, was also reduced to be 41%. A reason for it might be the reduction in the UNCD crystallite size. From the near-edge X-ray absorption fine-structure (NEXAFS) spectrum, it was found that the ?*C=C and ?*C?C bonds are preferentially formed instead of the ?*C-H bonds in the UNCD/a-C:H films. Since the extremely small UNCD crystallites (1.6 nm) correspond to the nuclei of diamond, we consider that UNCD crystallite formation should be due predominantly to nucleation. The supersaturated condition required for nucleation is expected to be realized in the deposition using the coaxial arc plasma gun.

  14. Ultrananocrystalline diamond thin films for MEMS and moving mechanical assembly devices.

    SciTech Connect

    Krauss, A. R.; Gruen, D. M.; Jayatissa, A.; Sumant, A.; Tucek, J.; Auciello, O.; Mancini, D.; Moldovan, N.; Erdemir, A.; Ersoy, D.; Gardos, M. N.; Busmann, H. G.; Meyer, E. M.; Ding, M. Q.; Univ. of Illinois at Chicago; Raytheon Electronic Systems Comp.; Fraunhofer Inst. for Applied Materials Science; Univ. of Bremen; Beijing Inst. of Electronics

    2001-11-01

    MEMS devices are currently fabricated primarily in silicon because of the available surface machining technology. A major problem with the Si-based MEMS technology is that Si has poor mechanical and tribological properties [J.J. Sniegowski, in: B. Bushan (Ed.), Tribology Issues and Opportunities in MEMS, Kluwer Academic Publisher, The Netherlands, 1998, p. 325; A.P. Lee, A.P. Pisano, M.G. Lim, Mater. Res. Soc. Symp. Proc. 276 (1992) 67.], and practical MEMS devices are currently limited primarily to applications involving only bending and flexural motion, such as cantilever accelerometers and vibration sensors. However, because of the poor flexural strength and fracture toughness of Si, and the tendency of Si to adhere to hydrophilic surfaces, even these simple devices have limited dynamic range. Future MEMS applications that involve significant rolling or sliding contact will require the use of new materials with significantly improved mechanical and tribological properties, and the ability to perform well in harsh environments, Diamond is a superhard material of high mechanical strength, exceptional chemical inertness, and outstanding thermal stability. The brittle fracture strength is 23 times that of Si, and the projected wear life of diamond MEMS moving mechanical assemblies (MEMS MMAs) is 10 000 times greater than that of Si MMAs. However, as the hardest known material, diamond is notoriously difficult to fabricate. Conventional CVD thin film deposition methods offer an approach to the fabrication of ultra-small diamond structures, but the films have large grain size, high internal stress, poor intergranular adhesion, and very rough surfaces, and are consequently ill-suited for MEMS MMA applications. Diamond-like films are also being investigated for application to MEMS devices. However, they involve mainly physical vapor deposition methods that are not suitable for good conformal deposition on high aspect ratio features, and generally they do not exhibit the outstanding mechanical properties of diamond. We demonstrate here the application of a novel microwave plasma technique using a unique C{sub 60}/Ar or CH{sub 4}/Ar chemistry that produces phase-pure ultrananocrystalline diamond (UNCD) coatings with morphological and mechanical properties that are ideally suited for MEMS applications in general, and MMA use in particular. We have developed lithographic techniques for the fabrication of UNCD-MEMS components, including cantilevers and multi-level devices, acting as precursors to microbearings and gears, making UNCD a promising material for the development of high performance MEMS devices.

  15. Ultrathin ultrananocrystalline diamond film synthesis by direct current plasma-assisted chemical vapor deposition

    NASA Astrophysics Data System (ADS)

    Lee, Hak-Joo; Jeon, Hyeongtag; Lee, Wook-Seong

    2011-10-01

    The synthesis of ultrathin, mirror-smooth, and void-free ultra-nanocrystalline diamond (UNCD) film was investigated using DC-PACVD. The seeding process was investigated in the previously reported "two-step" seeding scheme, where the substrate was pretreated in microwave hydrocarbon plasma prior to the ultrasonic seeding to enhance seed density; in the present study, DC plasma and hot filament process were adopted for the pretreatment, instead of the conventional microwave plasma. Two types of nano-diamond seed powders of similar grain sizes but with different zeta potentials were also compared. The pretreated substrate surface and the synthesized UNCD film were characterized by near edge x-ray absorption fine structure, FTIR, AFM, high-resolution scanning electron microscope, HR-TEM, and Raman spectroscopy. The electrophoretic light scattering spectroscopy was adopted to characterize the zeta potentials of the seeding suspensions and that of the substrates, respectively. Contrary to the previous report, the pretreatments deteriorated the seed density relative to that of the non-treated substrate. By contrast, the seed density was drastically improved by using a proper type of the nano-diamond seed powder. The seed density variation according to the substrate pretreatments and the type of the seed powders was attributed to the relative values of the zeta potentials of the substrates and that of the seed powders, which indicated the electrostatic nature of the seeding process. The variation of the substrate surface zeta potentials was attributed to the variation in the surface terminations induced by the respective pretreatments. The present DC-PACVD environment ensured that the secondary nucleation was also active enough to generate the densely packed UNCD grains in the growth stage. Consequently, the ultrathin, mirror-smooth and void-free UNCD film of 30 nm in thickness was enabled.

  16. Synthesis and field emission properties of ultra-nanocrystalline diamond fibers and helices.

    PubMed

    Singh, M K; Titus, E; Willinger, M G; Grcio, J

    2010-04-01

    We propose a novel template method for large scale synthesis of Ultra-Nanocrystalline Diamond (UNCD) fibres and helices with lengths of thousands of microns and diameters ranging from 0.5 to 5 microm: (i) Large quantities of submicrometer- or nanometer-diameter silica (a-SiO2) nanostructures, with lengths in the order of 2 to 4 mm, were synthesized by Vapor-Liquid-Solid (VLS) method; (ii) UNCD coating of as-synthesized a-SiO2 micro- or nanonanostructures by Microwave Plasma Chemical Vapour Deposition (MPCVD) technique in hydrogen-deficient condition. Electron Field Emission (EFE) of as-synthesized UNCD structures was observed with a threshold field of 3.4 V/microm. These micro- or nanostructures may find potential applications in high power electronics, vertical field-effect transistors in vacuum electronics, heat sinks in microelectronics and structural materials in Micro- and Nano-Electro-Mechanical Systems (MEMS/NEMS). The successful preparation of various types of UNCD structures suggests that this templating process can be used for a wide range of materials. PMID:20355444

  17. The potential application of ultra-nanocrystalline diamond films for heavy ion irradiation detection

    SciTech Connect

    Chen, Huang-Chin; Chen, Shih-Show; Wang, Wei-Cheng; Lin, I-Nan; Chang, Ching-Lin; Lee, Chi-Young; Guo, Jinghua

    2013-06-15

    The potential of utilizing the ultra-nanocrystalline (UNCD) films for detecting the Au-ion irradiation was investigated. When the fluence for Au-ion irradiation is lower than the critical value (f{sub c}= 5.0 Multiplication-Sign 10{sup 12} ions/cm{sup 2}) the turn-on field for electron field emission (EFE) process of the UNCD films decreased systematically with the increase in fluence that is correlated with the increase in sp{sup 2}-bonded phase ({pi}{sup *}-band in EELS) due to the Au-ion irradiation. The EFE properties changed irregularly, when the fluence for Au-ion irradiation exceeds this critical value. The transmission electron microscopic microstructural examinations, in conjunction with EELS spectroscopic studies, reveal that the structural change preferentially occurred in the diamond-to-Si interface for the samples experienced over critical fluence of Au-ion irradiation, viz. the crystalline SiC phase was induced in the interfacial region and the thickness of the interface decreased. These observations implied that the UNCD films could be used as irradiation detectors when the fluence for Au-ion irradiation does not exceed such a critical value.

  18. Ultrananocrystalline diamond cantilever wide dynamic range acceleration/vibration/pressure sensor

    DOEpatents

    Krauss, Alan R.; Gruen, Dieter M.; Pellin, Michael J.; Auciello, Orlando

    2002-07-23

    An ultrananocrystalline diamond (UNCD) element formed in a cantilever configuration is used in a highly sensitive, ultra-small sensor for measuring acceleration, shock, vibration and static pressure over a wide dynamic range. The cantilever UNCD element may be used in combination with a single anode, with measurements made either optically or by capacitance. In another embodiment, the cantilever UNCD element is disposed between two anodes, with DC voltages applied to the two anodes. With a small AC modulated voltage applied to the UNCD cantilever element and because of the symmetry of the applied voltage and the anode-cathode gap distance in the Fowler-Nordheim equation, any change in the anode voltage ratio V1/N2 required to maintain a specified current ratio precisely matches any displacement of the UNCD cantilever element from equilibrium. By measuring changes in the anode voltage ratio required to maintain a specified current ratio, the deflection of the UNCD cantilever can be precisely determined. By appropriately modulating the voltages applied between the UNCD cantilever and the two anodes, or limit electrodes, precise independent measurements of pressure, uniaxial acceleration, vibration and shock can be made. This invention also contemplates a method for fabricating the cantilever UNCD structure for the sensor.

  19. Enhancement of the electron field emission properties of ultrananocrystalline diamond films via hydrogen post-treatment.

    PubMed

    Sankaran, Kamatchi Jothiramalingam; Kunuku, Srinivasu; Leou, Keh-Chyang; Tai, Nyan-Hwa; Lin, I-Nan

    2014-08-27

    Enhanced electron field emission (EFE) properties due to hydrogen post-treatment at 600 C have been observed for ultrananocrystalline diamond (UNCD) films. The EFE properties of H2-gas-treated UNCD films could be turned on at a low field of 5.3 V/?m, obtaining an EFE current density of 3.6 mA/cm(2) at an applied field of 11.7 V/?m that is superior to those of UNCD films treated with H2 plasma. Transmission electron microscopic investigations revealed that H2 plasma treatment induced amorphous carbon (a-C) (and graphitic) phases only on the surface region of the UNCD films but the interior region of the UNCD films still contained very small amounts of a-C (and graphitic) grain boundary phases, resulting in a resistive transport path and inferior EFE properties. On the other hand, H2 gas treatment induces a-C (and graphitic) phases along the grain boundary throughout the thickness of the UNCD films, resulting in creation of conduction channels for the electrons to transport from the bottom of the films to the top and hence the superior EFE properties. PMID:25093962

  20. Growth of ultrananocrystalline diamond film by DC Arcjet plasma enhanced chemical vapor deposition

    NASA Astrophysics Data System (ADS)

    Chen, G. C.; Li, B.; Yan, Z. Q.; Liu, J.; Lu, F. X.; Ye, H.

    2012-06-01

    Self-standing diamond films were grown by DC Arcjet plasma enhanced chemical vapor deposition (CVD). The feed gasses were Ar/H2/CH4, in which the flow ratio of CH4 to H2 (F/F) was varied from 5% to 20%. Two distinct morphologies were observed by scanning electron microscope (SEM), i.e. the "pineapple-like" morphology and the "cauliflower-like" morphology. It was found that the morphologies of the as-grown films are strongly dependent on the flow ratio of CH4 to H2 in the feed gasses. High resolution transmission electron microscope (HRTEM) survey results revealed that there were nanocrystalline grains within the "pineapple-like" films whilst there were ultrananocrystalline grains within "cauliflower-like" films. X-ray diffraction (XRD) results suggested that (110) crystalline plane was the dominant surface in the "cauliflower-like" films whilst (100) crystalline plane was the dominant surface in the "pineapple-like" films. Raman spectroscopy revealed that nanostructured carbon features could be observed in both types of films. Plasma diagnosis was carried out in order to understand the morphology dependent growth mechanism. It could be concluded that the film morphology was strongly influenced by the density of gas phases. The gradient of C2 radical was found to be different along the growth direction under the different growth conditions.

  1. Ultrananocrystalline Diamond Cantilever Wide Dynamic Range Acceleration/Vibration /Pressure Sensor

    DOEpatents

    Krauss, Alan R.; Gruen, Dieter M.; Pellin, Michael J.; Auciello, Orlando

    2003-09-02

    An ultrananocrystalline diamond (UNCD) element formed in a cantilever configuration is used in a highly sensitive, ultra-small sensor for measuring acceleration, shock, vibration and static pressure over a wide dynamic range. The cantilever UNCD element may be used in combination with a single anode, with measurements made either optically or by capacitance. In another embodiment, the cantilever UNCD element is disposed between two anodes, with DC voltages applied to the two anodes. With a small AC modulated voltage applied to the UNCD cantilever element and because of the symmetry of the applied voltage and the anode-cathode gap distance in the Fowler-Nordheim equation, any change in the anode voltage ratio V1/V2 required to maintain a specified current ratio precisely matches any displacement of the UNCD cantilever element from equilibrium. By measuring changes in the anode voltage ratio required to maintain a specified current ratio, the deflection of the UNCD cantilever can be precisely determined. By appropriately modulating the voltages applied between the UNCD cantilever and the two anodes, or limit electrodes, precise independent measurements of pressure, uniaxial acceleration, vibration and shock can be made. This invention also contemplates a method for fabricating the cantilever UNCD structure for the sensor.

  2. Electroplate and Lift Lithography for Patterned Micro/Nanowires Using Ultrananocrystalline Diamond (UNCD) as a Reusable Template

    PubMed Central

    2011-01-01

    A fast, simple, scalable technique is described for the controlled, solution-based, electrochemical synthesis of patterned metallic and semiconducting nanowires from reusable, nonsacrificial, ultrananocrystalline diamond (UNCD) templates. This enables the repeated fabrication of arrays of complex patterns of nanowires, potentially made of any electrochemically depositable material. Unlike all other methods of patterning nanowires, this benchtop technique quickly mass-produces patterned nanowires whose diameters are not predefined by the template, without requiring intervening vacuum or clean room processing. This technique opens a pathway for studying nanoscale phenomena with minimal equipment, allowing the process-scale development of a new generation of nanowire-based devices. PMID:21405103

  3. Electroplate and lift lithography for patterned micro/nanowires using ultrananocrystalline diamond (UNCD) as a reusable template.

    PubMed

    Seley, David B; Dissing, Daniel A; Sumant, Anirudha V; Divan, Ralu; Miller, Suzanne; Auciello, Orlando; Lepak, Lori A; Terrell, Eric A; Shogren, Tyler J; Fahrner, Daryl A; Hamilton, James P; Zach, Michael P

    2011-04-01

    A fast, simple, scalable technique is described for the controlled, solution-based, electrochemical synthesis of patterned metallic and semiconducting nanowires from reusable, nonsacrificial, ultrananocrystalline diamond (UNCD) templates. This enables the repeated fabrication of arrays of complex patterns of nanowires, potentially made of any electrochemically depositable material. Unlike all other methods of patterning nanowires, this benchtop technique quickly mass-produces patterned nanowires whose diameters are not predefined by the template, without requiring intervening vacuum or clean room processing. This technique opens a pathway for studying nanoscale phenomena with minimal equipment, allowing the process-scale development of a new generation of nanowire-based devices. PMID:21405103

  4. Toward a Boron-Doped Ultrananocrystalline Diamond Electrode-Based Dielectrophoretic Preconcentrator.

    PubMed

    Zhang, Wenli; Radadia, Adarsh D

    2016-03-01

    This paper presents results on immunobeads-based isolation of rare bacteria and their capture at a boron-doped ultrananocrystalline diamond (BD-UNCD) electrode in a microfluidic dielectrophoretic preconcentrator. We systematically vary the bead surface chemistry and the BD-UNCD surface chemistry and apply dielectrophoresis to improve the specific and the nonspecific capture of bacteria or beads. Immunobeads were synthesized by conjugating antibodies to epoxy-/sulfate, aldehyde-/sulfate, or carboxylate-modified beads with or without poly(ethylene glycol) (PEG) coimmobilization. The carboxylate-modified beads with PEG provided the highest capture efficiency (∼65%) and selectivity (∼95%) in isolating live Escherichia coli O157:H7 from cultures containing 1000 E. coli O157:H7 colony-forming units (cfu)/mL, or ∼500 E. coli O157:H7 and ∼500 E. coli K12 cfu/mL. Higher specificity was achieved with the addition of PEG to the antibody-functionalized bead surface, highest with epoxy-/sulfate beads (85-86%), followed by carboxylate-modified beads (76-78%) and aldehyde-/sulfate beads (74-76%). The bare BD-UNCD electrodes of the preconcentrator successfully withstood 240 kV/m for 100 min that was required for the microfluidic dielectrophoresis of 1 mL of sample. As expected, the application of dielectrophoresis increased the specific and the nonspecific capture of immunobeads at the BD-UNCD electrodes; however, the capture specificity remained unaltered. The addition of PEG to the antibody-functionalized BD-UNCD surface had little effect on the specificity in immunobeads capture. These results warrant the fabrication of electrical biosensors with BD-UNCD so that dielectrophoretic preconcentration can be performed directly at the biosensing electrodes. PMID:26829879

  5. Kinetics of the electrochemical mineralization of perfluorooctanoic acid on ultrananocrystalline boron doped conductive diamond electrodes.

    PubMed

    Urtiaga, Ane; Fernández-González, Carolina; Gómez-Lavín, Sonia; Ortiz, Inmaculada

    2015-06-01

    This work deals with the electrochemical degradation and mineralization of perfluorooctanoic acid (PFOA). Model aqueous solutions of PFOA (100mg/L) were electro-oxidized under galvanostatic conditions in a flow-by undivided cell provided with a tungsten cathode and an anode formed by a commercial ultrananocrystalline boron doped diamond (BDD) coating on a niobium substrate. A systematic experimental study was conducted in order to analyze the influence of the following operation variables: (i) the supporting electrolyte, NaClO4 (1.4 and 8.4g/L) and Na2SO4 (5g/L); (ii) the applied current density, japp, in the range 50-200 A/m(2) and (iii) the hydrodynamic conditions, in terms of flowrate in the range 0.4×10(-4)-1.7×10(-4)m(3)/s and temperature in the range 293-313K. After 6h of treatment and at japp 200A/m(2), PFOA removal was higher than 93% and the mineralization ratio, obtained from the decrease of the total organic carbon (TOC) was 95%. The electrochemical generation of hydroxyl radicals in the supporting electrolyte was experimentally measured based on their reaction with dimethyl sulfoxide. The enhanced formation of hydroxyl radicals at higher japp was related to the faster kinetics of PFOA removal. The fitting of experimental data to the proposed kinetic model provided the first order rate constants of PFOA degradation, kc(1) that moved from 2.06×10(-4) to 15.58×10(-4)s(-1), when japp varied from 50 to 200A/m(2). PMID:24981910

  6. Fabrication of an ultra-nanocrystalline diamond-coated silicon wire array with enhanced field-emission performance

    NASA Astrophysics Data System (ADS)

    Tzeng, Yu-Fen; Liu, Kao-Hsiang; Lee, Yen-Chih; Lin, Sue-Jian; Lin, I.-Nan; Lee, Chi-Young; Chiu, Hsin-Tien

    2007-10-01

    Large-area ultra-nanocrystalline diamond-coated silicon nanowire (UNCD/SiNW) field-emitter arrays were prepared by the deposition of ultra-nanocrystalline diamond (UNCD) on the tips of arrays of silicon nanowires (SiNWs) with uniform diameters. The electron field-emission (EFE) behavior of UNCD/SiNW arrays as well as that of the SiNW arrays has been observed. The SiNWs exhibit good electron field-emission properties with turn-on fields (E0) of about 7.6 V m-1, which is superior to the EFE properties of planar-silicon materials. The turn-on fields are related to the diameter of the SiNWs. Coating the SiNWs with a UNCD film further improves their EFE properties. The threshold field for attaining Je = 0.1 mA cm-2 EFE current density is 16.0 V m-1 for bare SiNWs and 10.2 V m-1 for UNCD/SiNWs. The improvement in EFE properties due to the UNCD coating is presumably due to the lower work function of field emission of the UNCD materials, compared to that of the silicon materials.

  7. Surface chemistry and bonding configuration of ultrananocrystalline diamond surfaces and their effects on nanotribological properties

    NASA Astrophysics Data System (ADS)

    Sumant, A. V.; Grierson, D. S.; Gerbi, J. E.; Carlisle, J. A.; Auciello, O.; Carpick, R. W.

    2007-12-01

    We present a comprehensive study of surface composition and nanotribology for ultrananocrystalline diamond (UNCD) surfaces, including the influence of film nucleation on these properties. We describe a methodology to characterize the underside of the films as revealed by sacrificial etching of the underlying substrate. This enables the study of the morphology and composition resulting from the nucleation and initial growth of the films, as well as the characterization of nanotribological properties which are relevant for applications including micro-/nanoelectromechanical systems. We study the surface chemistry, bonding configuration, and nanotribological properties of both the topside and the underside of the film with synchrotron-based x-ray absorption near-edge structure spectroscopy to identify the bonding state of the carbon atoms, x-ray photoelectron spectroscopy to determine the surface chemical composition, Auger electron spectroscopy to further verify the composition and bonding configuration, and quantitative atomic force microscopy to study the nanoscale topography and nanotribological properties. The films were grown on SiO2 after mechanically polishing the surface with detonation synthesized nanodiamond powder, followed by ultrasonication in a methanol solution containing additional nanodiamond powder. The sp2 fraction, morphology, and chemistry of the as-etched underside are distinct from the topside, exhibiting a higher sp2 fraction, some oxidized carbon, and a smoother morphology. The nanoscale single-asperity work of adhesion between a diamond nanotip and the as-etched UNCD underside is far lower than for a silicon-silicon interface ( 59.22 vs 826186mJ/m2 , respectively). Exposure to atomic hydrogen dramatically reduces nanoscale adhesion to 10.20.4mJ/m2 , at the level of van der Waals interactions and consistent with recent ab initio calculations. Friction is substantially reduced as well, demonstrating a direct link between the surface chemistry and nanoscale friction. The proposed mechanism, supported by the detailed surface spectroscopic analysis, is the elimination of reactive (e.g., C*? ), polar (e.g., C?O ), and ? -bonded (C?C) surface groups, which are replaced by fully saturated, hydrogen-terminated surface bonds to produce an inert surface that interacts minimally with the contacting counterface.

  8. Direct observation and mechanism for enhanced field emission sites in platinum ion implanted/post-annealed ultrananocrystalline diamond films

    SciTech Connect

    Panda, Kalpataru E-mail: phy.kalpa@gmail.com; Inami, Eiichi; Sugimoto, Yoshiaki; Sankaran, Kamatchi J.; Tai, Nyan Hwa; Lin, I-Nan

    2014-10-20

    Enhanced electron field emission (EFE) properties for ultrananocrystalline diamond (UNCD) films upon platinum (Pt) ion implantation and subsequent post-annealing processes is reported, viz., low turn-on field of 4.17 V/μm with high EFE current density of 5.08 mA/cm{sup 2} at an applied field of 7.0 V/μm. Current imaging tunneling spectroscopy (CITS) mode in scanning tunneling spectroscopy directly revealed the increased electron emission sites density for Pt ion implanted/post-annealed UNCD films than the pristine one. The high resolution CITS mapping and local current–voltage characteristic curves demonstrated that the electrons are dominantly emitted from the diamond grain boundaries and Pt nanoparticles.

  9. Fast Photoresponse and Long Lifetime UV Photodetectors and Field Emitters Based on ZnO/Ultrananocrystalline Diamond Films.

    PubMed

    Saravanan, Adhimoorthy; Huang, Bohr-Ran; Lin, Jun-Cheng; Keiser, Gerd; Lin, I-Nan

    2015-11-01

    We have designed photodetectors and UV field emitters based on a combination of ZnO nanowires/nanorods (ZNRs) and bilayer diamond films in a metal-semiconductor-metal (MSM) structure. The ZNRs were fabricated on different diamond films and systematic investigations showed an ultra-high photoconductive response from ZNRs prepared on ultrananocrystalline diamond (UNCD) operating at a lower voltage of 2 V. We found that the ZNRs/UNCD photodetector (PD) has improved field emission properties and a reduced turn-on field of 2.9 V μm(-1) with the highest electron field emission (EFE) by simply illuminating the sample with ultraviolet (UV) light. The photoresponse (Iphoto /Idark ) behavior of the ZNRs/UNCD PD exhibits a much higher photoresponse (912) than bare ZNRs (229), ZNRs/nanocrystalline diamond (NCD; 518), and ZNRs/microcrystalline diamond (MCD; 325) under illumination at λ=365 nm. A photodetector with UNCD films offers superior stability and a longer lifetime compared with carbon materials and bare ZNRs. The lifetime stability of the ZNRs/UNCD-based device is about 410 min, which is markedly superior to devices that use bare ZNRs (92 min). The ZNRs/UNCD PD possesses excellent photoresponse properties with improved lifetime and stability; in addition, ZNRs/UNCD-based UV emitters have great potential for applications such as cathodes in flat-panel displays and microplasma display devices. PMID:26382200

  10. Improvement on electrical conductivity and electron field emission properties of Au-ion implanted ultrananocrystalline diamond films by using Au-Si eutectic substrates

    NASA Astrophysics Data System (ADS)

    Sankaran, K. J.; Sundaravel, B.; Tai, N. H.; Lin, I. N.

    2015-08-01

    In the present work, Au-Si eutectic layer was used to enhance the electrical conductivity/electron field emission (EFE) properties of Au-ion implanted ultrananocrystalline diamond (Au-UNCD) films grown on Si substrates. The electrical conductivity was improved to a value of 230 (? cm)-1, and the EFE properties was enhanced reporting a low turn-on field of 2.1 V/?m with high EFE current density of 5.3 mA/cm2 (at an applied field of 4.9 V/?m) for the Au-UNCD films. The formation of SiC phase circumvents the formation of amorphous carbon prior to the nucleation of diamond on Si substrates. Consequently, the electron transport efficiency of the UNCD-to-Si interface increases, thereby improving the conductivity as well as the EFE properties. Moreover, the salient feature of these processes is that the sputtering deposition of Au-coating for preparing the Au-Si interlayer, the microwave plasma enhanced chemical vapor deposition process for growing the UNCD films, and the Au-ion implantation process for inducing the nanographitic phases are standard thin film preparation techniques, which are simple, robust, and easily scalable. The availability of these highly conducting UNCD films with superior EFE characteristics may open up a pathway for the development of high-definition flat panel displays and plasma devices.

  11. Detection methods of diamond diffraction peaks in ultrananocrystalline diamond/amorphous carbon composite films by X-ray diffraction measurement with semiconductor counter detector

    NASA Astrophysics Data System (ADS)

    Hara, Takeshi; Nojiri, Yoshihiro; Hanada, Kenji; Yoshitake, Tsuyoshi

    2015-10-01

    Ultrananocrystalline diamond (UNCD)/amorphous carbon (a-C) composite films were fabricated by a coaxial arc plasma deposition (CAPD) method. Hereafter, UNCD with crystallite diameters of less than 10 nm in an a-C matrix could only be unambiguously detected by powder X-ray diffraction measurement using a synchrotron radiation source (SR-XRD) or transmission electron microscopy (TEM) observation. In this study, we succeeded in detecting diffraction peaks due to diamond-111 in the film by X-ray diffraction (XRD) using a Cu-K? radiation source with a semiconductor counter detector. The obtained data were in agreement with the powder SR-XRD measurements of the deposited films.

  12. Electrical characteristics of nitrogen-doped ultrananocrystalline diamond/hydrogenated amorphous carbon composite films prepared by coaxial arc plasma deposition

    NASA Astrophysics Data System (ADS)

    Zkria, Abdelrahman; Gima, Hiroki; Shaban, Mahmoud; Yoshitake, Tsuyoshi

    2015-09-01

    Nitrogen-incorporated ultrananocrystalline diamond/hydrogenated amorphous carbon composite (UNCD/a-C:H) films were synthesized in nitrogen and hydrogen mixed gas atmospheres by coaxial arc plasma deposition. The temperature dependence of electrical resistivity implies that carriers are transported in hopping conduction. Heterojunctions comprising 3 at. % nitrogen-doped films and p-Si substrates exhibited a typical rectifying action. The expansion of a depletion region into the film side was confirmed from the capacitance-voltage characteristics, and the built-in potential and carrier concentration were estimated to be 0.51 eV and 7.5 × 1016 cm-3, respectively. It was experimentally demonstrated that nitrogen-doped UNCD/a-C:H is applicable as an n-type semiconductor.

  13. Structural and Physical Characteristics of Ultrananocrystalline Diamond/Hydrogenated Amorphous Carbon Composite Films Deposited Using a Coaxial Arc Plasma Gun

    NASA Astrophysics Data System (ADS)

    Yoshitake, Tsuyoshi; Nakagawa, You; Nagano, Akira; Ohtani, Ryota; Setoyama, Hiroyuki; Kobayashi, Eiichi; Sumitani, Kazushi; Agawa, Yoshiaki; Nagayama, Kunihito

    2010-01-01

    Ultrananocrystalline diamond (UNCD)/hydrogenated amorphous carbon (a-C:H) films were formed without initial nucleation using a coaxial arc plasma gun. The UNCD crystallite diameters estimated from the X-ray diffraction peaks were approximately 2 nm. The Fourier transform infrared absorption spectrum exhibited an intense sp3-CH peak that might originate from the grain boundaries between UNCD crystallites whose dangling bonds are terminated with hydrogen atoms. A narrow sp3 peak in the photoemission spectrum implied that the film comprises a large number of UNCD crystallites. Large optical absorption coefficients at photon energies larger than 3 eV that might be due to the grain boundaries are specific to the UNCD/a-C:H films.

  14. Synthesis of highly transparent ultrananocrystalline diamond films from a low-pressure, low-temperature focused microwave plasma jet

    NASA Astrophysics Data System (ADS)

    Liao, Wen-Hsiang; Wei, Da-Hua; Lin, Chii-Ruey

    2012-01-01

    This paper describes a new low-temperature process underlying the synthesis of highly transparent ultrananocrystalline diamond [UNCD] films by low-pressure and unheated microwave plasma jet-enhanced chemical vapor deposition with Ar-1%CH4-10%H2 gas chemistry. The unique low-pressure/low-temperature [LPLT] plasma jet-enhanced growth even with added H2 and unheated substrates yields UNCD films similar to those prepared by plasma-enhanced growth without addition of H2 and heating procedure. This is due to the focused plasma jet which effectively compensated for the sluggish kinetics associated with LPLT growth. The effects of pressure on UNCD film synthesis from the microwave plasma jet were systematically investigated. The results indicated that the substrate temperature, grain size, surface roughness, and sp 3 carbon content in the films decreased with decreasing pressure. The reason is due to the great reduction of H ? emission to lower the etching of sp 2 carbon phase, resulting from the increase of mean free path with decreasing pressure. We have demonstrated that the transition from nanocrystalline (80 nm) to ultrananocrystalline (3 to 5 nm) diamond films grown via microwave Ar-1%CH4-10%H2 plasma jets could be controlled by changing the pressure from 100 to 30 Torr. The 250-nm-thick UNCD film was synthesized on glass substrates (glass transition temperature [ T g] 557C) using the unique LPLT (30 Torr/460C) microwave plasma jet, which produced UNCD films with a high sp 3 carbon content (95.65%) and offered high optical transmittance (approximately 86% at 700 nm).

  15. Synthesis of highly transparent ultrananocrystalline diamond films from a low-pressure, low-temperature focused microwave plasma jet.

    PubMed

    Liao, Wen-Hsiang; Wei, Da-Hua; Lin, Chii-Ruey

    2012-01-01

    This paper describes a new low-temperature process underlying the synthesis of highly transparent ultrananocrystalline diamond [UNCD] films by low-pressure and unheated microwave plasma jet-enhanced chemical vapor deposition with Ar-1%CH4-10%H2 gas chemistry. The unique low-pressure/low-temperature [LPLT] plasma jet-enhanced growth even with added H2 and unheated substrates yields UNCD films similar to those prepared by plasma-enhanced growth without addition of H2 and heating procedure. This is due to the focused plasma jet which effectively compensated for the sluggish kinetics associated with LPLT growth. The effects of pressure on UNCD film synthesis from the microwave plasma jet were systematically investigated. The results indicated that the substrate temperature, grain size, surface roughness, and sp3 carbon content in the films decreased with decreasing pressure. The reason is due to the great reduction of H? emission to lower the etching of sp2 carbon phase, resulting from the increase of mean free path with decreasing pressure. We have demonstrated that the transition from nanocrystalline (80 nm) to ultrananocrystalline (3 to 5 nm) diamond films grown via microwave Ar-1%CH4-10%H2 plasma jets could be controlled by changing the pressure from 100 to 30 Torr. The 250-nm-thick UNCD film was synthesized on glass substrates (glass transition temperature [Tg] 557C) using the unique LPLT (30 Torr/460C) microwave plasma jet, which produced UNCD films with a high sp3 carbon content (95.65%) and offered high optical transmittance (approximately 86% at 700 nm). PMID:22260391

  16. Origin of a needle-like granular structure for ultrananocrystalline diamond films grown in a N2/CH4 plasma

    NASA Astrophysics Data System (ADS)

    Sankaran, K. J.; Kurian, J.; Chen, H. C.; Dong, C. L.; Y Lee, C.; Tai, N. H.; Lin, I. N.

    2012-09-01

    Microstructural evolution as a function of substrate temperature (TS) for conducting ultrananocrystalline diamond (UNCD) films is systematically studied. Variation of the sp2 graphitic and sp3 diamond content with TS in the films is analysed from the Raman and near-edge x-ray absorption fine structure spectra. Morphological and microstructural studies confirm that at TS = 700 C well-defined acicular structures evolve. These nanowire structures comprise sp3 phased diamond, encased in a sheath of sp2 bonded graphitic phase. TS causes a change in morphology and thereby the various properties of the films. For TS = 800 C the acicular grain growth ceases, while that for TS = 700 C ceases only upon termination of the deposition process. The grain-growth process for the unique needle-like granular structure is proposed such that the CN species invariably occupy the tip of the nanowire, promoting an anisotropic grain-growth process and the formation of acicular structure of the grains. The electron field emission studies substantiate that the films grown at TS = 700 C are the most conducting, with conduction mediated through the graphitic phase present in the films.

  17. Ultrananocrystalline diamond films with optimized dielectric properties for advanced RF MEMS capacitive switches

    DOEpatents

    Sumant, Anirudha V.; Auciello, Orlando H.; Mancini, Derrick C.

    2013-01-15

    An efficient deposition process is provided for fabricating reliable RF MEMS capacitive switches with multilayer ultrananocrystalline (UNCD) films for more rapid recovery, charging and discharging that is effective for more than a billion cycles of operation. Significantly, the deposition process is compatible for integration with CMOS electronics and thereby can provide monolithically integrated RF MEMS capacitive switches for use with CMOS electronic devices, such as for insertion into phase array antennas for radars and other RF communication systems.

  18. Role of carbon nanotube interlayer in enhancing the electron field emission behavior of ultrananocrystalline diamond coated Si-tip arrays.

    PubMed

    Chang, Ting-Hsun; Kunuku, Srinivasu; Kurian, Joji; Manekkathodi, Afsal; Chen, Lih-Juann; Leou, Keh-Chyang; Tai, Nyan-Hwa; Lin, I-Nan

    2015-04-15

    We improved the electron field emission properties of ultrananocrystalline diamond (UNCD) films grown on Si-tip arrays by using the carbon nanotubes (CNTs) as interlayer and post-treating the films in CH4/Ar/H2 plasma. The use of CNTs interlayer effectively suppresses the presence of amorphous carbon in the diamond-to-Si interface that enhances the transport of electrons from Si, across the interface, to diamond. The post-treatment process results in hybrid-granular-structured diamond (HiD) films via the induction of the coalescence of the ultrasmall grains in these films that enhanced the conductivity of the films. All these factors contribute toward the enhancement of the electron field emission (EFE) process for the HiDCNT/Si-tip emitters, with low turn-on field of E0 = 2.98 V/?m and a large current density of 1.68 mA/cm(2) at an applied field of 5.0 V/?m. The EFE lifetime stability under an operation current of 6.5 ?A was improved substantially to ?HiD/CNT/Si-tip = 365 min. Interestingly, these HiDCNT/Si-tip materials also show enhanced plasma illumination behavior, as well as improved robustness against plasma ion bombardment when they are used as the cathode for microplasma devices. The study concludes that the use of CNT interlayers not only increase the potential of these materials as good EFE emitters, but also prove themselves to be good microplasma devices with improved performance. PMID:25793425

  19. Fundamentals and application of materials integration for low-power piezoelectrically actuated ultra-nanocrystalline diamond MEMS/NEMS.

    SciTech Connect

    Auciello, O.; Srinivasan, S.; Hiller, J.; Kabius, B.

    2009-01-01

    Most current micro/nanoelectromechanical systems (MEMS/NEMS) are based on silicon. However, silicon exhibits relatively poor mechanical/tribological properties, compromising applications to several projected MEMS/NEMS devices, particularly those that require materials with high Young's modulus for MEMS resonators or low surface adhesion forces for MEMS/NEMS working in conditions with extensive surface contact. Diamond films with superior mechanical/tribological properties provide an excellent alternative platform material. Ultrananocrystalline diamond (UNCD{cflx W}) in film form with 2-5 nm grains exhibits excellent properties for high-performance MEMS/NEMS devices. Concurrently, piezoelectric Pb(Zr{sub x}Ti{sub 1-x})O{sub 3} (PZT) films provide high sensitivity/low electrical noise for sensing/high-force actuation at relatively low voltages. Therefore, integration of PZT and UNCD films provides a high-performance platform for advanced MEMS/NEMS devices. This paper describes the bases of such integration and demonstration of low voltage piezoactuated hybrid PZT/UNCD cantilevers.

  20. Enhancing electrical conductivity and electron field emission properties of ultrananocrystalline diamond films by copper ion implantation and annealing

    SciTech Connect

    Sankaran, K. J.; Tai, N. H. E-mail: inanlin@mail.tku.edu.tw; Panda, K.; Sundaravel, B.; Lin, I. N. E-mail: inanlin@mail.tku.edu.tw

    2014-02-14

    Copper ion implantation and subsequent annealing at 600 °C achieved high electrical conductivity of 95.0 (Ωcm){sup −1} for ultrananocrystalline diamond (UNCD) films with carrier concentration of 2.8 × 10{sup 18} cm{sup −2} and mobility of 6.8 × 10{sup 2} cm{sup 2}/V s. Transmission electron microscopy examinations reveal that the implanted Cu ions first formed Cu nanoclusters in UNCD films, which induced the formation of nanographitic grain boundary phases during annealing process. From current imaging tunneling spectroscopy and local current-voltage curves of scanning tunneling spectroscopic measurements, it is observed that the electrons are dominantly emitted from the grain boundaries. Consequently, the nanographitic phases presence in the grain boundaries formed conduction channels for efficient electron transport, ensuing in excellent electron field emission (EFE) properties for copper ion implanted/annealed UNCD films with low turn-on field of 4.80 V/μm and high EFE current density of 3.60 mA/cm{sup 2} at an applied field of 8.0 V/μm.

  1. A quantitative study of detection mechanism of a label-free impedance biosensor using ultrananocrystalline diamond microelectrode array.

    PubMed

    Siddiqui, Shabnam; Dai, Zhenting; Stavis, Courtney J; Zeng, Hongjun; Moldovan, Nicolaie; Hamers, Robert J; Carlisle, John A; Arumugam, Prabhu U

    2012-05-15

    It is well recognized that label-free biosensors are the only class of sensors that can rapidly detect antigens in real-time and provide remote environmental monitoring and point-of-care diagnosis that is low-cost, specific, and sensitive. Electrical impedance spectroscopy (EIS) based label-free biosensors have been used to detect a wide variety of antigens including bacteria, viruses, DNA, and proteins due to the simplicity of their detection technique. However, their commercial development has been hindered due to difficulty in interpreting the change in impedance upon antigen binding and poor signal reproducibility as a result of surface fouling and non-specific binding. In this study, we develop a circuit model to adequately describe the physical changes at bio functionalized surface and provide an understanding of the detection mechanism based on electron exchange between electrolyte and surface through pores surrounding antibody-antigen. The model was successfully applied to extract quantitative information about the bio surface at different stages of surface functionalization. Further, we demonstrate boron-doped ultrananocrystalline diamond (UNCD) microelectrode array (3 3 format, 200 ?m diameter) improves signal reproducibility significantly and increases sensitivity by four orders of magnitude. This study marks the first demonstration of UNCD array based biosensor that can reliably detect a model Escherichia coli K12 bacterium using EIS, positioning this technology for rapid adoption in point-of-use applications. PMID:22456097

  2. Hardness and modulus of ultrananocrystalline diamond/hydrogenated amorphous carbon composite films prepared by coaxial arc plasma deposition

    NASA Astrophysics Data System (ADS)

    Hanada, Kenji; Yoshida, Tomohiro; Nakagawa, You; Gima, Hiroki; Tominaga, Aki; Hirakawa, Masaaki; Agawa, Yoshiaki; Sugiyama, Takeharu; Yoshitake, Tsuyoshi

    2015-04-01

    Ultrananocrystalline diamond (UNCD)/hydrogenated amorphous carbon (a-C:H) composite (UNCD/a-C:H) films were deposited in hydrogen atmospheres by coaxial arc plasma deposition, and the effects of hydrogenation on the mechanical properties were studied on the basis of spectroscopic structural evaluations. The existence of UNCD grains in the films was confirmed by transmission electron microscopy and X-ray diffraction. Non-hydrogenated films prepared in no hydrogen atmosphere exhibited a 22 GPa hardness and 222 GPa Young's modulus, and the sp 3/( sp 2 + sp 3) ratio estimated from the X-ray photoemission spectra was 41 %. For the films prepared in a 53.3-Pa hydrogen atmosphere, whereas the hardness increases to 23 GPa, the modulus decreases to 184 GPa. The UNCD grain size estimated using Scherrer's equation and the sp 3/( sp 2 + sp 3) ratio were 2.3 nm and 64 %, respectively, both of which are remarkably increased as compared with those of the non-hydrogenated films. From the near-edge X-ray absorption fine structure spectra, it is considered that ?*C-H bonds are alternatively formed instead of ?*C=C, which probably results in the enhanced hardness and reduced modulus by hydrogenation. In addition, it was found that the formation of olefinic and aromatic structures remarkably softens the UNCD/a-C:H film.

  3. All diamond self-aligned thin film transistor

    DOEpatents

    Gerbi, Jennifer

    2008-07-01

    A substantially all diamond transistor with an electrically insulating substrate, an electrically conductive diamond layer on the substrate, and a source and a drain contact on the electrically conductive diamond layer. An electrically insulating diamond layer is in contact with the electrically conductive diamond layer, and a gate contact is on the electrically insulating diamond layer. The diamond layers may be homoepitaxial, polycrystalline, nanocrystalline or ultrananocrystalline in various combinations.A method of making a substantially all diamond self-aligned gate transistor is disclosed in which seeding and patterning can be avoided or minimized, if desired.

  4. Fast growth of ultrananocrystalline diamond films by bias-enhanced nucleation and growth process in CH{sub 4}/Ar plasma

    SciTech Connect

    Saravanan, A.; Huang, B. R.; Sankaran, K. J.; Tai, N. H.; Dong, C. L.; Lin, I. N.

    2014-05-05

    This letter describes the fast growth of ultrananocrystalline diamond (UNCD) films by bias-enhanced nucleation and growth process in CH{sub 4}/Ar plasma. The UNCD grains were formed at the beginning of the film's growth without the necessity of forming the amorphous carbon interlayer, reaching a thickness of ∼380 nm in 10 min. Transmission electron microscopic investigations revealed that the application of bias voltage induced the formation of graphitic phase both in the interior and at the interface regions of UNCD films that formed interconnected paths, facilitating the transport of electrons and resulting in enhanced electron field emission properties.

  5. Near-Edge X-ray Absorption Fine Structure Imaging of Spherical and Flat Counterfaces of Ultrananocrystalline Diamond Tribological Contacts: A Correlation of Surface Chemistry and Friction

    SciTech Connect

    A Konicek; C Jaye; M Hamilton; W Sawyer; D Fischer; R Carpick

    2011-12-31

    A recently installed synchrotron radiation near-edge X-ray absorption fine structure (NEXAFS) full field imaging electron spectrometer was used to spatially resolve the chemical changes of both counterfaces from an ultra-nanocrystalline diamond (UNCD) tribological contact. A silicon flat and Si{sub 3}N{sub 4} sphere were both coated with UNCD, and employed to form two wear tracks on the flat in a linear reciprocating tribometer. The first wear track was produced using a new, unconditioned sphere whose surface was thus conditioned during this first experiment. This led to faster run-in and lower friction when producing a second wear track using the conditioned sphere. The large depth of field of the magnetically guided NEXAFS imaging detector enabled rapid, large area spectromicroscopic imaging of both the spherical and flat surfaces. Laterally resolved NEXAFS data from the tribological contact area revealed that both substrates had an as-grown surface layer that contained a higher fraction of sp{sup 2}-bonded carbon and oxygen which was mechanically removed. Unlike the flat, the film on the sphere showed evidence of having graphitic character, both before and after sliding. These results show that the graphitic character of the sphere is not solely responsible for low friction and short run-in. Rather, conditioning the sphere, likely by removing asperities and passivating dangling bonds, leads to lower friction with less chemical modification of the substrate in subsequent tests. The new NEXAFS imaging spectroscopy detector enabled a more complete understanding of the tribological phenomena by imaging, for the first time, the surface chemistry of the spherical counterface which had been in continual contact during wear track formation.

  6. Science and technology of ultrananocrystalline diamond (UNCD) thin films for multifunctional devices

    SciTech Connect

    Auciello, O.; Krauss, A. R.; Gruen, D. M.; Jayatissa, A.; Sumant, A.; Tucek, J.; Mancini, D.; Molodvan, N.; Erdemir, A.; Ersoy, D.; Gardos, M. N.; Busman, H. G.; Meyer, E. M.

    2000-08-24

    MEMS devices are currently fabricated primarily in silicon because of the available surface machining technology. However, Si has poor mechanical and tribological properties, and practical MEMS devices are currently limited primarily to applications involving only bending and flexural motion, such as cantilever accelerometers and vibration sensors. However, because of the poor flexural strength and fracture toughness of Si, and the tendency of Si to adhere to hydrophyllic surfaces, even these simple devices have limited dynamic range. Future MEMS applications that involve significant rolling or sliding contact will require the use of new materials with significantly improved mechanical and tribological properties, and the ability to perform well in harsh environments. Diamond is a superhard material of high mechanical strength, exceptional chemical inertness, and outstanding thermal stability. The brittle fracture strength is 23 times that of Si, and the projected wear life of diamond MEMS moving mechanical assemblies (MEMS-MMAs) is 10,000 times greater than that of Si MMAs. However, as the hardest known material, diamond is notoriously difficult to fabricate. Conventional CVD thin film deposition methods offer an approach to the fabrication of ultra-small diamond structures, but the films have large grain size, high internal stress, poor intergranular adhesion, and very rough surfaces, and are consequently ill-suited for MEMS-MMA applications. A thin film deposition process has been developed that produces phase-pure nanocrystalline diamond with morphological and mechanical properties that are ideally suited for MEMS applications in general, and MMA use in particular. The authors have developed lithographic techniques for the fabrication of diamond microstructure including cantilevers and multi-level devices, acting as precursors to micro-bearings and gears, making nanocrystalline diamond a promising material for the development of high performance MEMS devices.

  7. High efficiency diamond solar cells

    DOEpatents

    Gruen, Dieter M.

    2008-05-06

    A photovoltaic device and method of making same. A layer of p-doped microcrystalline diamond is deposited on a layer of n-doped ultrananocrystalline diamond such as by providing a substrate in a chamber, providing a first atmosphere containing about 1% by volume CH.sub.4 and about 99% by volume H.sub.2 with dopant quantities of a boron compound, subjecting the atmosphere to microwave energy to deposit a p-doped microcrystalline diamond layer on the substrate, providing a second atmosphere of about 1% by volume CH.sub.4 and about 89% by volume Ar and about 10% by volume N.sub.2, subjecting the second atmosphere to microwave energy to deposit a n-doped ultrananocrystalline diamond layer on the p-doped microcrystalline diamond layer. Electrodes and leads are added to conduct electrical energy when the layers are irradiated.

  8. Influence of surface passivation on the friction and wear behavior of ultrananocrystalline diamond and tetrahedral amorphous carbon thin films

    NASA Astrophysics Data System (ADS)

    Konicek, A. R.; Grierson, D. S.; Sumant, A. V.; Friedmann, T. A.; Sullivan, J. P.; Gilbert, P. U. P. A.; Sawyer, W. G.; Carpick, R. W.

    2012-04-01

    Highly sp3-bonded, nearly hydrogen-free carbon-based materials can exhibit extremely low friction and wear in the absence of any liquid lubricant, but this physical behavior is limited by the vapor environment. The effect of water vapor on friction and wear is examined as a function of applied normal force for two such materials in thin film form: one that is fully amorphous in structure (tetrahedral amorphous carbon, or ta-C) and one that is polycrystalline with <10 nm grains [ultrananocrystalline diamond (UNCD)]. Tribologically induced changes in the chemistry and carbon bond hybridization at the surface are correlated with the effect of the sliding environment and loading conditions through ex situ, spatially resolved near-edge x-ray absorption fine structure (NEXAFS) spectroscopy. At sufficiently high relative humidity (RH) levels and/or sufficiently low loads, both films quickly achieve a low steady-state friction coefficient and subsequently exhibit low wear. For both films, the number of cycles necessary to reach the steady-state is progressively reduced for increasing RH levels. Worn regions formed at lower RH and higher loads have a higher concentration of chemisorbed oxygen than those formed at higher RH, with the oxygen singly bonded as hydroxyl groups (C-OH). While some carbon rehybridization from sp3 to disordered sp2 bonding is observed, no crystalline graphite formation is observed for either film. Rather, the primary solid-lubrication mechanism is the passivation of dangling bonds by OH and H from the dissociation of vapor-phase H2O. This vapor-phase lubrication mechanism is highly effective, producing friction coefficients as low as 0.078 for ta-C and 0.008 for UNCD, and wear rates requiring thousands of sliding passes to produce a few nanometers of wear.

  9. Ultrananocrystalline diamond-CMOS device integration route for high acuity retinal prostheses.

    PubMed

    Ahnood, A; Escudie, M C; Cicione, R; Abeyrathne, C D; Ganesan, K; Fox, K E; Garrett, D J; Stacey, A; Apollo, N V; Lichter, S G; Thomas, C D L; Tran, N; Meffin, H; Prawer, S

    2015-01-01

    High density electrodes are a new frontier for biomedical implants. Increasing the density and the number of electrodes used for the stimulation of retinal ganglion cells is one possible strategy for enhancing the quality of vision experienced by patients using retinal prostheses. The present work presents an integration strategy for a diamond based, high density, stimulating electrode array with a purpose built application specific integrated circuit (ASIC). The strategy is centered on flip-chip bonding of indium bumps to create high count and density vertical interconnects between the stimulator ASIC and an array of diamond neural stimulating electrodes. The use of polydimethylsiloxane (PDMS) housing prevents cross-contamination of the biocompatible diamond electrode with non-biocompatible materials, such as indium, used in the microfabrication process. Micro-imprint lithography allowed edge-to-edge micro-scale pattering of the indium bumps on non-coplanar substrates that have a form factor that can conform to body organs and thus are ideally suited for biomedical applications. Furthermore, micro-imprint lithography ensures the compatibility of lithography with the silicon ASIC and aluminum contact pads. Although this work focuses on 256 stimulating diamond electrode arrays with a pitch of 150?m, the use of indium bump bonding technology and vertical interconnects facilitates implants with tens of thousands electrodes with a pitch as low as 10?m, thus ensuring validity of the strategy for future high acuity retinal prostheses, and bionic implants in general. PMID:25877379

  10. Room-temperature hard coating of ultrananocrystalline diamond/nonhydrogenated amorphous carbon composite films on tungsten carbide by coaxial arc plasma deposition

    NASA Astrophysics Data System (ADS)

    Naragino, Hiroshi; Egiza, Mohamed; Tominaga, Aki; Murasawa, Koki; Gonda, Hidenobu; Sakurai, Masatoshi; Yoshitake, Tsuyoshi

    2016-03-01

    Ultrananocrystalline diamond (UNCD)/nonhydrogenated amorphous carbon (a-C) composite films were deposited on unheated WC containing Co by coaxial arc plasma deposition. The hardness of the film is 51.3 GPa, which is comparable with the highest values of hard a-C films deposited on nonbiased substrates. The deposited film is approximately 3 µm thick, which is one order larger than that of hard a-C films. The internal compressive stress is 4.5 GPa, which is evidently smaller than that of comparably hard a-C films. The existence of a large number of grain boundaries in the UNCD/a-C film might play a role in the release of the internal stress.

  11. Time-Resolved Spectroscopic Observation of Deposition Processes of Ultrananocrystalline Diamond/Amorphous Carbon Composite Films by Using a Coaxial Arc Plasma Gun

    NASA Astrophysics Data System (ADS)

    Hanada, Kenji; Yoshitake, Tsuyoshi; Nishiyama, Takashi; Nagayama, Kunihito

    2010-08-01

    The deposition of ultrananocrystalline diamond (UNCD)/amorphous carbon composite films using a coaxial arc plasma gun in vacuum and, for comparison, in a 53.3 Pa hydrogen atmosphere was spectroscopically observed using a high-speed camera equipped with narrow-band-pass filters. UNCD crystallites with diameters of approximately 1.6 nm were formed even in vacuum. These extremely small crystallites imply that the formation is predominantly due to nucleation without the subsequent growth. Even in vacuum, emissions from C+ ions, C atoms, and C2 dimers lasted for approximately 100 s, although the emission lifetimes of these species are generally 10 ns. We consider that the nucleation is due to the supersaturated environment containing excited carbon species with large number densities.

  12. Origin of graphitic filaments on improving the electron field emission properties of negative bias-enhanced grown ultrananocrystalline diamond films in CH{sub 4}/Ar plasma

    SciTech Connect

    Sankaran, K. J.; Tai, N. H. E-mail: nhtai@mse.nthu.edu.tw; Huang, B. R.; Saravanan, A.; Lin, I. N. E-mail: nhtai@mse.nthu.edu.tw

    2014-10-28

    Microstructural evolution of bias-enhanced grown (BEG) ultrananocrystalline diamond (UNCD) films has been investigated using microwave plasma enhanced chemical vapor deposition in gas mixtures of CH{sub 4} and Ar under different negative bias voltages ranging from ?50 to ?200?V. Scanning electron microscopy and Raman spectroscopy were used to characterize the morphology, growth rate, and chemical bonding of the synthesized films. Transmission electron microscopic investigation reveals that the application of bias voltage induced the formation of the nanographitic filaments in the grain boundaries of the films, in addition to the reduction of the size of diamond grains to ultra-nanosized granular structured grains. For BEG-UNCD films under ?200?V, the electron field emission (EFE) process can be turned on at a field as small as 4.08?V/?m, attaining a EFE current density as large as 3.19?mA/cm{sup 2} at an applied field of 8.64?V/?m. But the films grown without bias (0?V) have mostly amorphous carbon phases in the grain boundaries, possessing poorer EFE than those of the films grown using bias. Consequently, the induction of nanographitic filaments in grain boundaries of UNCD films grown in CH{sub 4}/Ar plasma due to large applied bias voltage of ?200?V is the prime factor, which possibly forms interconnected paths for facilitating the transport of electrons that markedly enhance the EFE properties.

  13. Patterning of nanocrystalline diamond films for diamond microstructures useful in MEMS and other devices

    DOEpatents

    Gruen, Dieter M. (Downers Grove, IL); Busmann, Hans-Gerd (Bremen, DE); Meyer, Eva-Maria (Bremen, DE); Auciello, Orlando (Bolingbrook, IL); Krauss, Alan R. (late of Naperville, IL); Krauss, Julie R. (Naperville, IL)

    2004-11-02

    MEMS structure and a method of fabricating them from ultrananocrystalline diamond films having average grain sizes of less than about 10 nm and feature resolution of less than about one micron . The MEMS structures are made by contacting carbon dimer species with an oxide substrate forming a carbide layer on the surface onto which ultrananocrystalline diamond having average grain sizes of less than about 10 nm is deposited. Thereafter, microfabrication process are used to form a structure of predetermined shape having a feature resolution of less than about one micron.

  14. Heterojunction Diodes Comprising p-Type Ultrananocrystalline Diamond Films Prepared by Coaxial Arc Plasma Deposition and n-Type Silicon Substrates

    NASA Astrophysics Data System (ADS)

    Katamune, Y?ki; Ohmagari, Shinya; Al-Riyami, Sausan; Takagi, Seishi; Shaban, Mahmoud; Yoshitake, Tsuyoshi

    2013-06-01

    Heterojunction diodes, which comprise boron-doped p-type ultrananocrystalline diamond/hydrogenated amorphous carbon composite (UNCD/a-C:H) films prepared by coaxial arc plasma deposition and n-type Si substrates, were electrically studied. The current-voltage characteristics showed a typical rectification action. An ideality factor of 3.7 in the forward-current implies that carrier transport is accompanied by some processes such as tunneling in addition to the generation-recombination process. From the capacitance-voltage measurements, the built-in potential was estimated to be approximately 0.6 eV, which is in agreement with that in a band diagram prepared on the assumption that carriers are transported in an a-C:H matrix in UNCD/a-C:H. Photodetection for 254 nm monochromatic light, which is predominantly attributable to photocurrents generated in UNCD grains, was evidently confirmed in heterojunctions. Since dangling bonds are detectable by electron spin resonance spectroscopy, their control might be an important key for improving the rectifying action and photodetection performance.

  15. The microstructural evolution of ultrananocrystalline diamond films due to P ion implantation process—the annealing effect

    SciTech Connect

    Lin, Sheng-Chang; Yeh, Chien-Jui; Leou, Keh-Chyang; Kurian, Joji; Lin, I.-Nan; Dong, Chung-Li; Niu, Huan

    2014-11-14

    The microstructural evolution of UNCD films which are P-ion implanted and annealed at 600 °C (or 800 °C) is systematically investigated. The difference of interaction that the UNCD content undergoes along the trajectory of the incident P-ions is reflected in the alteration of the granular structure. In regions where the P-ions reside, the “interacting zone,” which is found at about 300 nm beneath the surface of the films, coalescence of diamond grains occurs inducing nano-graphitic clusters. The annealing at 600 °C (or 800 °C) heals the defects and, in some cases, forms interconnected graphitic filaments that result in the decrease in surface resistance. However, the annealing at 600 °C (800 °C) induces marked UNCD-to-Si layers interaction. This interaction due to the annealing processes hinders the electron transport across the interface and degrades the electron field emission properties of the UNCD films. These microstructural evolution processes very well account for the phenomenon elaborating that, in spite of enhanced conductivity of the UNCD films along the film's surface due to the P-ion implantation and annealing processes, the electron field emission properties for these UNCD films do not improve.

  16. Science and technology of piezoelectric/diamond heterostructures for monolithically integrated high performance MEMS/NEMS/CMOS devices.

    SciTech Connect

    Auciello, O.; Sumant, A. V.; Hiller, J.; Kabius, B.; Ma, Z.; Srinivasan, S.

    2008-12-01

    This paper describes the fundamental and applied science performed to integrate piezoelectric PbZr{sub x}Ti{sub 1-x}O{sub 3} and AlN films with a novel mechanically robust ultrananocrystalline diamond layer to enable a new generation of low voltage/high-performance piezoactuated hybrid piezoelectric/diamond MEMS/NEMS devices.

  17. DEVELOPMENT OF A SCALABLE, LOW-COST, ULTRANANOCRYSTALLINE DIAMOND ELECTROCHEMICAL PROCESS FOR THE DESTRUCTION OF CONTAMINANTS OF EMERGING CONCERN (CECS) - PHASE I

    EPA Science Inventory

    This Small Business Innovative Research (SBIR) project will develop and ready for commercialization a scalable, low-cost process for purification of water containing Contaminants of Emerging Concern (CECs) using anodic oxidation with boron-doped ultrananocrystalline diam...

  18. Ultrananocrystalline diamond film deposition by direct-current plasma assisted chemical vapor deposition using hydrogen-rich precursor gas in the absence of the positive column

    NASA Astrophysics Data System (ADS)

    Lee, Hak-Joo; Jeon, Hyeongtag; Lee, Wook-Seong

    2011-01-01

    We have investigated the ultrananocrystalline diamond (UNCD) deposition by direct-current plasma assisted chemical vapor deposition on 4 in. Si wafer using CH4?H2 as well as CH4?Ar gas chemistry containing additive nitrogen. CH4/N2/H2 (5%/0.5%/94.5%) and CH4/N2/H2/Ar (0.5%/5%/6%/88.5%) gas mixtures were compared as the precursor gas. Molybdenum and tungsten were compared as cathode material. Discharge voltage and current were 480 V/45 A and 320 V/60 A, for respective gas chemistry. Chamber pressure and substrate temperature were 110-150 Torr and 750-850 C, respectively. The film was characterized by near edge x-ray absorption fine structure spectroscopy, x-ray diffraction, high-resolution transmission electron microscope, electron energy loss spectroscopy, and high-resolution scanning electron microscope. We have demonstrated that (1) elimination of the positive column, by adopting very small interelectrode distance, gave some important and beneficial effects; (2) the plasma stability and impurity incorporation was sensitive to the cathode material and the precursor gas; (3) using the conventional CH4/H2 precursor gas and tungsten cathode, the mirror-smooth 4 in. UNCD film of excellent phase-purity and grain size below 10 nm could be deposited even in the absence of the positive column. The high electric field in the unusually narrow interelectrode space and the consequent high electron kinetic energy, in conjunction with the unusually high electron current thereof, directed to the substrate, i.e., the anode, was proposed to be the source of the grain refinement to achieve UNCD at such high chamber pressure around 110-150 Torr, in the absence of the usual ion bombardment assistance.

  19. Effect of pretreatment bias on the nucleation and growth mechanisms of ultrananocrystalline diamond films via bias-enhanced nucleation and growth: An approach to interfacial chemistry analysis via chemical bonding mapping

    SciTech Connect

    Zhong, X. Y.; Hiller, J. M.; Chen, Y. C.; Tai, N. H.; Lin, I. N.; Auciello, O.

    2009-02-01

    The effect of pretreatment bias on the nucleation and growth mechanisms of the ultrananocrystalline diamond (UNCD) films on the Si substrate via bias-enhanced nucleation and bias-enhanced growth (BEN-BEG) was investigated using cross-sectional high-resolution transmission electron microscopy, chemical bonding mapping, and Raman spectroscopy. The mirror-polished substrate surface showed the formation of a triangular profile produced by a dominant physical sputtering mechanism induced by ion bombardment of ions from the hydrogen plasma accelerated toward the substrate due to biasing and a potential hydrogen-induced chemical reaction component before synthesizing the UNCD films. The BEN-BEG UNCD films grown on the Si substrate with biased and unbiased pretreatments in the hydrogen plasma were compared. In the case of the bias-pretreated substrate, the SiC phases were formed at the peaks of the Si surface triangular profile due to the active unsaturated Si bond and the enhanced local electrical field. The UNCD grains grew preferentially at the peaks of the triangular substrate surface profile and rapidly covered the amorphous carbon (a-C) and oriented graphite phases formed in the valley of the surface profile. In the case of the substrate with unbiased pretreatment, the SiC phases were formed via the reactions between the hydrocarbon species and the active Si atoms released from the substrate with assistance of the hydrogen plasma. The UNCD grains nucleated on the nucleating sites consisting of the SiC, a-C, and graphite phases. Growth mechanisms for the BEN-BEG UNCD films on both Si substrates were proposed to elucidate the different nucleation processes. Applying bias on the Si substrate pretreated in the hydrogen plasma optimized the nucleation sites for growth of UNCD grains, resulting in the low content of the nondiamond phases in UNCD films.

  20. UV Sensor Based on Layered Ferrite-Diamond Structure

    NASA Astrophysics Data System (ADS)

    Belyavskiy, P. Y.; Kondrashov, A. V.; Nikitin, A. A.; Vitko, V. V.; Kalinikos, B. A.; Semenov, A. A.; Ustinov, A. B.; Butler, J. E.

    2015-12-01

    Design of a UV sensor based on an yttrium-iron garnet/diamond layered cavity is presented. The operation principle of the sensor is based on the change in the spin-wave dispersion law and, consequently, in the frequency and Q-factor of eigenmodes of the cavity under study upon appearance of free carriers generated by UV light.

  1. Combined experimental and modeling studies of microwave activated CH4/H2/Ar plasmas for microcrystalline, nanocrystalline, and ultrananocrystalline diamond deposition

    NASA Astrophysics Data System (ADS)

    Richley, James C.; Fox, Oliver J. L.; Ashfold, Michael N. R.; Mankelevich, Yuri A.

    2011-03-01

    A comprehensive study of microwave (MW) activated CH4/H2/Ar plasmas used for diamond chemical vapor deposition is reported, focusing particularly on the effects of gross variations in the H2/Ar ratio in the input gas mixture (from H2/Ar mole fraction ratios of > 10:1, through to 1:99). Absolute column densities of C2(a) and CH(X) radicals and of H(n = 2) atoms have been determined by cavity ringdown spectroscopy, as functions of height (z) above a substrate and of process conditions (CH4, H2, and Ar input mole fractions, total pressure, p, and input microwave power, P). Optical emission spectroscopy has also been used to explore the relative densities of electronically excited H atoms, and CH, C2, and C3 radicals, as functions of these same process conditions. These experimental data are complemented by extensive 2D (r, z) modeling of the plasma chemistry, which provides a quantitative rationale for all of the experimental observations. Progressive replacement of H2 by Ar (at constant p and P) leads to an expanded plasma volume. Under H2-rich conditions, > 90% of the input MW power is absorbed through rovibrational excitation of H2. Reducing the H2 content (as in an Ar-rich plasma) leads to a reduction in the absorbed power density; the plasma necessarily expands in order to accommodate a given input power. The average power density in an Ar-rich plasma is much lower than that in an H2-rich plasma operating at the same p and P. Progressive replacement of H2 by Ar is shown also to result in an increased electron temperature, an increased [H]/[H2] number density ratio, but little change in the maximum gas temperature in the plasma core (which is consistently 3000 K). Given the increased [H]/[H2] ratio, the fast H-shifting (CyHx + H ? CyHx-1 + H2; y = 1-3) reactions ensure that the core of Ar-rich plasma contains much higher relative abundances of "product" species like C atoms, and C2, and C3 radicals. The effects of Ar dilution on the absorbed power dissipation pathways and the various species concentrations just above the growing diamond film are also investigated and discussed.

  2. Structural transformation of implanted diamond layers during high temperature annealing

    NASA Astrophysics Data System (ADS)

    Rubanov, S.; Fairchild, B. A.; Suvorova, A.; Olivero, P.; Prawer, S.

    2015-12-01

    In the recent years graphitization of ion-beam induced amorphous layers became the basic tool for device fabrication in diamond. The etchable graphitic layers can be removed to form free-standing membranes into which the desired structures can be sculpted using FIB milling. The optical properties of the devices fabricated using this method are assumed on the model of sharp diamond-air interface. The real quality of this interface could depend on degree of graphitization of the amorphous damage layers after annealing. In the present work the graphitization process was studied using conventional and analytical TEM. It was found that annealing at 550 C results in a partial graphitization of the implanted volume with formation of the nano-crystalline graphitic phase sandwiched between layers of tetrahedral amorphous carbon. Annealing at 1400 C resulted in complete graphitization of the amorphous layers. The average size of graphite nano-crystals did not exceed 5 nm with predominant orientation of c-planes normal to the sample surface.

  3. Diamond MEMS: wafer scale processing, devices, and technology insertion

    NASA Astrophysics Data System (ADS)

    Carlisle, J. A.

    2009-05-01

    Diamond has long held the promise of revolutionary new devices: impervious chemical barriers, smooth and reliable microscopic machines, and tough mechanical tools. Yet it's been an outsider. Laboratories have been effectively growing diamond crystals for at least 25 years, but the jump to market viability has always been blocked by the expense of diamond production and inability to integrate with other materials. Advances in chemical vapor deposition (CVD) processes have given rise to a hierarchy of carbon films ranging from diamond-like carbon (DLC) to vapor-deposited diamond coatings, however. All have pros and cons based on structure and cost, but they all share some of diamond's heralded attributes. The best performer, in theory, is the purest form of diamond film possible, one absent of graphitic phases. Such a material would capture the extreme hardness, high Young's modulus and chemical inertness of natural diamond. Advanced Diamond Technologies Inc., Romeoville, Ill., is the first company to develop a distinct chemical process to create a marketable phase-pure diamond film. The material, called UNCD (for ultrananocrystalline diamond), features grain sizes from 3 to 300 nm in size, and layers just 1 to 2 microns thick. With significant advantages over other thin films, UNCD is designed to be inexpensive enough for use in atomic force microscopy (AFM) probes, microelectromechanical machines (MEMS), cell phone circuitry, radio frequency devices, and even biosensors.

  4. Application of N- and B-doped CVD diamond layers for cyclic voltammetry measurements

    NASA Astrophysics Data System (ADS)

    Torz-Piotrowska, R.; Wrzyszczy?ski, A.; Paprocki, K.; Staryga, E.

    2009-10-01

    Conductive polycrystalline diamond layers prepared by the CVD process have received attention from electrochemists owing to such superior electrochemical properties as the wide potential window, the very low background current, the stability of chemical and physical properties. In this paper, the cyclic voltammetry application using N- and B-doped diamond electrodes was studied. Diamond layers, doped with boron and nitrogen, were synthesized on a silicon substrate in a hot-filament CVD reactor. The obtained diamond layers were characterized using Raman spectroscopy and scanning electron microscopy (SEM). The electrochemical properties of diamond layers were measured in KCl and NaCl basic solutions to gain knowledge about their potential application as an electrode material. It was found that boron doped diamond electrodes showed potential windows up to about 7 V which were almost twice wider than those observed for conventional Pt electrodes.

  5. Effects of disorder state and interfacial layer on thermal transport in copper/diamond system

    SciTech Connect

    Sinha, V.; Gengler, J. J.; Muratore, C.; Spowart, J. E.

    2015-02-21

    The characterization of Cu/diamond interface thermal conductance (h{sub c}) along with an improved understanding of factors affecting it are becoming increasingly important, as Cu-diamond composites are being considered for electronic packaging applications. In this study, ∼90 nm thick Cu layers were deposited on synthetic and natural single crystal diamond substrates. In several specimens, a Ti-interface layer of thickness ≤3.5 nm was sputtered between the diamond substrate and the Cu top layer. The h{sub c} across Cu/diamond interfaces for specimens with and without a Ti-interface layer was determined using time-domain thermoreflectance. The h{sub c} is ∼2× higher for similar interfacial layers on synthetic versus natural diamond substrate. The nitrogen concentration of synthetic diamond substrate is four orders of magnitude lower than natural diamond. The difference in nitrogen concentration can lead to variations in disorder state, with a higher nitrogen content resulting in a higher level of disorder. This difference in disorder state potentially can explain the variations in h{sub c}. Furthermore, h{sub c} was observed to increase with an increase of Ti-interface layer thickness. This was attributed to an increased adhesion of Cu top layer with increasing Ti-interface layer thickness, as observed qualitatively in the current study.

  6. Note: Laser ablation technique for electrically contacting a buried implant layer in single crystal diamond.

    PubMed

    Ray, M P; Baldwin, J W; Feygelson, T I; Butler, J E; Pate, B B

    2011-05-01

    The creation of thin, buried, and electrically conducting layers within an otherwise insulating diamond by annealed ion implantation damage is well known. Establishing facile electrical contact to the shallow buried layer has been an unmet challenge. We demonstrate a new method, based on laser micro-machining (laser ablation), to make reliable electrical contact to a buried implant layer in diamond. Comparison is made to focused ion beam milling. PMID:21639553

  7. Note: Laser ablation technique for electrically contacting a buried implant layer in single crystal diamond

    SciTech Connect

    Ray, M. P.; Baldwin, J. W.; Butler, J. E.; Pate, B. B.; Feygelson, T. I.

    2011-05-15

    The creation of thin, buried, and electrically conducting layers within an otherwise insulating diamond by annealed ion implantation damage is well known. Establishing facile electrical contact to the shallow buried layer has been an unmet challenge. We demonstrate a new method, based on laser micro-machining (laser ablation), to make reliable electrical contact to a buried implant layer in diamond. Comparison is made to focused ion beam milling.

  8. Method of forming fluorine-bearing diamond layer on substrates, including tool substrates

    DOEpatents

    Chang, R. P. H. (Glenview, IL); Grannen, Kevin J. (Evanston, IL)

    2002-01-01

    A method of forming a fluorine-bearing diamond layer on non-diamond substrates, especially on tool substrates comprising a metal matrix and hard particles, such as tungsten carbide particles, in the metal matrix. The substrate and a fluorine-bearing plasma or other gas are then contacted under temperature and pressure conditions effective to nucleate fluorine-bearing diamond on the substrate. A tool insert substrate is treated prior to the diamond nucleation and growth operation by etching both the metal matrix and the hard particles using suitable etchants.

  9. Lamb Wave Characteristics of Composite Plates Including a Diamond Layer with Distinct Electrode Arrangements

    NASA Astrophysics Data System (ADS)

    Chen, Yung-Yu

    2013-07-01

    Diamond films have been utilized to develop surface acoustic wave filters and micromechanical resonators because of the highest acoustic wave velocity and largest product of frequency and quality factor (f.Q) of diamond among all materials. A theoretical analysis of Lamb wave characteristics in multilayer piezoelectric plates including a diamond layer is presented in this paper. Formulae for effective permittivity are derived using the transfer matrix method and are further employed to calculate Lamb wave phase velocity dispersions. The electromechanical coupling coefficients (ECCs) are also calculated exactly by Green's function method. Detailed calculations are carried out for ZnO/diamond and AlN/diamond composite plates with four distinct electrode arrangements. Results show that the ZnO/diamond structure yields a phase velocity of 6420 m/s and a large ECC of 7.41%, which makes it suitable for high-frequency wideband filter applications. Moreover, in the AlN/diamond structure, the S0 mode exhibits a large phase velocity of up to 10.3 km/s and a moderate ECC of 1.97%. Such favorable characteristics are expected to contribute to the development of AlN/diamond Lamb wave oscillators operating at approximately 5-10 GHz without the need for a sub-micrometer-resolution lithographic process. Therefore, both ZnO/diamond and AlN/diamond Lamb wave devices are highly promising candidates for RF devices in modern communication systems with advantages over conventional surface acoustic wave devices.

  10. Formation of detonation diamond layers on silicon by the aerosol method

    NASA Astrophysics Data System (ADS)

    Baidakova, M. V.; Dideikin, A. T.; Pavlov, S. I.; Sokolov, R. V.; Shnitov, V. V.

    2014-09-01

    An aerosol method for deposition of nanometer-thick layers of detonation diamonds has been developed. Application of a suspension of deagglomerated diamond particles onto substrates from an aerosol provides deposition of small-size drops, with the ultrasonic spraying of the suspension precluding formation of secondary agglomerates of nanodiamond particles in the course of sample drying. The layers are promising for high-precision studies of the structure and chemical composition of the surface of isolated nanodiamond particles.

  11. Low voltage fabrication of sub-nanometer insulating layers on hydrogenated diamond

    NASA Astrophysics Data System (ADS)

    Wang, Tao; Boer-Duchemin, Elizabeth; Tranvouez, Edern; Cartwright, Richard; Comtet, Genevive; Dujardin, Grald; Mayne, Andrew J.

    2011-08-01

    A new regime of electrochemical anodic oxidation with an atomic force microscope (AFM) is introduced for producing insulating layers on a hydrogenated diamond surface. In this new regime, when a low surface voltage (VS<+2 V) is applied to the sample, an insulating layer is created without any measurable change in the topography. Insulating layers created in this fashion are shown to preserve the high sub-surface conductance of hydrogenated diamond surfaces, contrary to the oxide layers accompanied by a topographic change, which destroy sub-surface conductance.

  12. Growth and electrical characterisation of {delta}-doped boron layers on (111) diamond surfaces

    SciTech Connect

    Edgington, Robert; Jackman, Richard B.; Sato, Syunsuke; Ishiyama, Yuichiro; Kawarada, Hiroshi; Morris, Richard

    2012-02-01

    A plasma enhanced chemical vapor deposition protocol for the growth of {delta}-doping of boron in diamond is presented, using the (111) diamond plane as a substrate for diamond growth. AC Hall effect measurements have been performed on oxygen terminated {delta}-layers and desirable sheet carrier densities ({approx}10{sup 13} cm{sup -2}) for field-effect transistor application are reported with mobilities in excess of what would expected for equivalent but thicker heavily boron-doped diamond films. Temperature-dependent impedance spectroscopy and secondary ion mass spectroscopy measurements show that the grown layers have metallic-like electrical properties with high cut-off frequencies and low thermal impedance activation energies with estimated boron concentrations of approximately 10{sup 20} cm{sup -3}.

  13. Enhancement of the nucleation of smooth and dense nanocrystalline diamond films by using molybdenum seed layers

    SciTech Connect

    Buijnsters, J. G.; Vazquez, L.; Celis, J. P.

    2010-11-15

    A method for the nucleation enhancement of nanocrystalline diamond (NCD) films on silicon substrates at low temperature is discussed. A sputter deposition of a Mo seed layer with thickness 50 nm on Si substrates was applied followed by an ultrasonic seeding step with nanosized detonation diamond powders. Hot-filament chemical vapor deposition (HF-CVD) was used to nucleate and grow NCD films on substrates heated up at 550 deg. C. The nucleation of diamond and the early stages of NCD film formation were investigated at different methane percentages in methane/hydrogen gas mixtures by atomic force microscopy, micro-Raman spectroscopy, scanning electron microscopy, and grazing incidence x-ray analyses in order to gain specific insight in the nucleation process of NCD films. The nucleation kinetics of diamond on the Mo-coated Si substrates was found to be up to ten times higher than on blank Si substrates. The enhancement of the nucleation of diamond on thin Mo interlayers results from two effects, namely, (a) the nanometer rough Mo surface shows an improved embedding of ultrasonically introduced nanosized diamond seeds that act as starting points for the diamond nucleation during HF-CVD and (b) the rapid carbonization of the Mo surface causes the formation of Mo{sub 2}C onto which diamond easily nucleates. The diamond nucleation density progressively increases at increasing methane percentages and is about 5x10{sup 10} cm{sup -2} at 4.0% methane. The improved nucleation kinetics of diamond on Mo interlayers facilitates the rapid formation of NCD films possessing a very low surface roughness down to {approx}6 nm, and allows a submicron thickness control.

  14. Epitaxial synthesis of diamond layers on a monocrystalline diamond substrate in a torch microwave plasmatron

    SciTech Connect

    Sergeichev, K. F. Lukina, N. A.

    2011-12-15

    The epitaxial growth of a diamond single-crystal film in a torch microwave discharge excited by a magnetron of a domestic microwave oven with the power of {<=}1 kW in an argon-hydrogen-methane mixture with a high concentration of methane (up to 25% with respect to hydrogen) at atmospheric pressure on a sub-strate of a synthetic diamond single crystal (HPHP) with the orientation (100) and 4 Multiplication-Sign 4 mm in size is obtained. A discharge with the torch diameter of {approx}2 mm and the concentration of the microwave power absorbed in the torch volume of >10{sup 3} W/cm{sup 3} is shown to be effective for epitaxial enlargement of a single crystal of synthetic diamond. The structure of the deposited film with the thickness up to 10 {mu}m with high-quality morphology is investigated with an optical microscope as well as using the methods of the Raman scattering and scanning electron microscopy.

  15. Hybrid sensors based on colour centres in diamond and piezoactive layers.

    PubMed

    Cai, Jianming; Jelezko, Fedor; Plenio, Martin B

    2014-01-01

    The ability to measure weak signals such as pressure, force, electric field and temperature with nanoscale devices and high spatial resolution offers a wide range of applications in fundamental and applied sciences. Here we present a proposal for a hybrid device composed of thin film layers of diamond with colour centres and piezoactive elements for the transduction and measurement of physical signals. The magnetic response of a piezomagnetic layer to an external stress or a stress induced by a signal is shown to affect significantly the spin properties of nitrogen-vacancy centres in diamond. Under ambient conditions, realistic environmental noise and material imperfections, we show that this hybrid device can achieve significant improvements in sensitivity over the pure diamond-based approach in combination with nanometre-scale spatial resolution. Furthermore, the proposed hybrid architecture offers novel possibilities for engineering strong coherent couplings between nanomechanical oscillator and solid state spin qubits. PMID:24909637

  16. Weak superconductivity in the surface layer of a bulk single-crystal boron-doped diamond

    NASA Astrophysics Data System (ADS)

    Blank, Vladimir; Buga, Sergei; Bormashov, Vitaly; Denisov, Victor; Kirichenko, Alexei; Kulbachinskii, Vladimir; Kuznetsov, Michail; Kytin, Vladimir; Kytin, Gennadii; Tarelkin, Sergei; Terentiev, Sergei

    2014-12-01

    We have grown and investigated bulk single-crystal heavily boron-doped diamonds possessing superconductivity with TC{onset} =1.7\\text-3.5 \\text{K} . Only the surface layer with the thickness less than 1 ? \\text{m} showed the degenerate semiconductor behavior with transition to the superconducting state, while the bulk of the crystal was a typical doped semiconductor. The morphology of the surface layer is dendritic polycrystalline with an average boron content of 2.5-2.9 at.%. The typical Josephson junction current-voltage characteristic was observed. The degenerate semiconductor-superconductor transition as in single-crystal high-temperature superconductors and the structural data analysis of the surface layer indicate the two-dimensional character of superconductivity, and the actual superconducting structure is a set of few-nanometer thick boron carbide layers embedded in a diamond structure.

  17. Hexagonal Diamonds (Lonsdaleite) Discovered in the K/T Impact Layer in Spain and New Zealand

    NASA Astrophysics Data System (ADS)

    Bunch, T. E.; Wittke, J. H.; West, A.; Kennett, J. P.; Kennett, D. J.; Que Hee, S. S.; Wolbach, W. S.; Stich, A.; Mercer, C.; Weaver, J. C.

    2008-12-01

    We present the first evidence from Cretaceous-Tertiary (K/T) boundary clay and rock for shocked hexagonal nanodiamonds (lonsdaleite), these being found in concentrations greater than 50 ppm at Needles Point, New Zealand, and Caravaca, Spain. This is also the first evidence for K/T diamonds of any kind outside of North America. No diamonds were detected immediately above or below the impact layer. Cubic diamonds have been reported earlier from North American K/T sediments by Carlisle and Braman (1991; 45 ppm) and Hough et al. (1997; 18 ppm), but lonsdaleite was not detected. Carlisle and Braman suggested that the cubic diamonds arrived already formed within the impactor, but Hough argued that they were shock-produced by the impact with Earth. Hence, it is not yet clear that K/T cubic diamonds were formed through shock. Lonsdaleite does not co-occur with terrestrial diamonds but is found with cubic diamonds in ET impact craters (e.g., Popigai, Sudbury). Both also have been reported in the impact layer of the proposed Younger Dryas impact event at 12.9 ka. Lonsdaleite is formed by shocking carbonaceous material, e. g., graphite, under extreme conditions of pressure and temperature (more than 15 GPa at more than 1000 C), thus making this mineral an excellent impact-shock indicator (DeCarli, 2002). Although lonsdaleite is also contained in meteorites, such as ureilites, there appears to be a consensus of opinion that crater-related lonsdaleite formed during ET impact. K/T sediment samples were acquired from the boundary layer, as well as above and below. To extract the diamonds from the sediments, we utilized the protocol from Amari (1994) and Huss and Lewis (1995), but modified their methodology after determining that phosphoric and perchloric acids oxidize metastable lonsdaleite. We extracted the diamonds successfully after eliminating those acids, which may explain why lonsdaleite was not apparent in extractions by others. The extracted lonsdaleite was analyzed by transmission electron microscopy (TEM) and by selected area diffraction (SAED), which displayed characteristic reflections corresponding to lattice planar spacings of 2.18, 1.26, 1.09, and 0.82 A. A scanning electron microscope (SEM) with energy dispersive X-ray spectroscopy (EDS) confirmed their carbon composition. With exposure to long-wave ultraviolet (365 nm) radiation, clusters of lonsdaleite crystals exhibited a blue fluorescence that is characteristic of many diamonds. Individual crystals were angular to sub-rounded in shape and ranged in size from 20 to 1000 nm, with a mean size of about 50 nm. This discovery represents (1) the strongest available evidence for K/T diamond formation during the impact; (2) the first discovery of K/T diamonds outside North America; and (3) the first occurrence of any form of K/T diamonds in the Southern Hemisphere, about 12,000 km from the Chicxulub Crater in Mexico.

  18. Enhancing secondary yield of a diamond amplifier using a nitrogen layer

    SciTech Connect

    Jensen, Kevin L.; Shaw, Jonathan L.; Yater, Joan E.; Pate, Bradford B.

    2015-06-07

    A thin nitrogen-doped layer less than 4% of the total thickness in diamond thin film amplifier is shown to reduce losses of generated secondaries to the back contact, generated by a high energy primary electron beam compared to a thin film without the substitutional nitrogen layer modification. Simulation indicates that the losses due to absorption of diffusing electrons by the back contact may be considerably reduced by a factor of 2 (depending on field across the film, width of the nitrogen layer, and boron doping level), thereby mitigating undesirable effects associated with trace amounts of boron.

  19. Enhanced thermal performances of silicon-on-diamond wafers incorporating ultrathin nanocrystalline diamond and silicon layers: Raman and micro-Raman analysis

    NASA Astrophysics Data System (ADS)

    Mazellier, Jean-Paul; Mermoux, Michel; Andrieu, Francois; Widiez, Julie; Dechamp, Jrme; Saada, Samuel; Lions, Mathieu; Hasegawa, Masataka; Tsugawa, Kazuo; Bergonzo, Philippe; Faynot, Olivier

    2011-10-01

    Silicon-on-diamond (SOD) wafers potentially present thermal advantages over standard silicon-on-insulator (SOI) counterparts based on SiO2 as the buried insulating layer. This work reports the fabrication of high quality SOD wafers by the bond and etch back SOI process. One key parameter in the CVD diamond growth process is the substrate temperature. We focused here on two processes based on either high or low processing temperature to produce nanocrystalline diamond (NCD) on silicon. Both type of NCD films have been analyzed via Raman spectroscopy. Results have been correlated with scanning electron microscopy observations. In a second part, SOD wafers are fabricated and the crystalline quality of the active silicon layer is assessed via Raman measurements and high resolution transmission electron microscopy imaging. It is shown that the growth of diamond did not induce any structural defect or strain in the thin top silicon layer. Eventually, we demonstrate the efficiency of diamond integration thanks to micro-Raman spectroscopy, where the probing laser simultaneously generates Raman signal and controlled local heating. Our SOD wafers evidence a thermal resistance reduction of about 70% compared to conventional SOI materials, with heat source spatial extension in the micron range.

  20. Temperature dependent creation of nitrogen-vacancy centers in single crystal CVD diamond layers

    NASA Astrophysics Data System (ADS)

    Tallaire, A.; Lesik, M.; Jacques, V.; Pezzagna, S.; Mille, V.; Brinza, O.; Meijer, J.; Abel, B.; Roch, J. F.; Gicquel, A.; Achard, J.

    2015-01-01

    In this work, we explore the ability of plasma assisted chemical vapor deposition (PACVD) operating under high power densities to produce thin high-quality diamond layers with a controlled doping with negatively-charged nitrogen-vacancy (NV-) centers. This luminescent defect possesses specific physical characteristics that make it suitable as an addressable solid-state electron spin for measuring magnetic fields with unprecedented sensitivity. To this aim, a relatively large number of NV- centers (> 10^12 cm^-3) should ideally be located in a thin diamond layer (a few tens of nm) close to the surface which is particularly challenging to achieve with the PACVD technique. Here we show that intentional temperature variations can be exploited to tune NV- creation efficiency during growth, allowing engineering complex stacking structures with a variable doping. Because such a temperature variation can be performed quickly and without any change of the gas phase composition, thin layers can be grown. Measurements show that despite the temperature variations, the luminescent centers incorporated using this technique exhibit spin coherence properties similar to those reached in ultra-pure bulk crystals, which suggests that they could be successfully employed in magnetometry applications.

  1. Diamonds from the iridium-rich K-T boundary layer at Arroyo el Mimbral, Tamaulipas, Mexico

    NASA Astrophysics Data System (ADS)

    Hough, R. M.; Gilmour, I.; Pillinger, C. T.; Langenhorst, F.; Montanari, A.

    1997-11-01

    Diamonds, up to 30 ?m in size, were found in the iridium-rich layer from the K-T boundary site at Arroyo El Mimbral and the spherule bed from Arroyo El Peon, northeastern Mexico. Stepped heating experiments indicate two or more isotopically distinct diamond components with carbon isotopic compositions characteristic of a mixture of carbon sources. The diamonds' crystal form is cubicnot the hexagonal polymorph of diamond, lonsdaleite, which has been used previously to infer formation due to shock transformation of graphite. The size, crystallography, and mineralogic associations of K-T diamonds are similar to those of impact-produced diamonds from the Ries crater in Germany where both shock transformation of graphite and a mode of formation by condensation from a vapor plume have been inferred. The discovery of impact-produced diamonds in association with high Ir contents for these sediments supports their impact origin, K-T age, and the inference that their source was from the buried impact crater of Chicxulub on the Yucatan peninsula, Mexico.

  2. Response function measurement of layered type CVD single crystal diamond radiation detectors for 14 MeV neutrons

    SciTech Connect

    Kaneko, J.H.; Teraji, T.; Hirai, Y.; Shiraishi, M.; Kawamura, S.; Yoshizaki, S.; Ito, T.; Ochiai, K.; Nishitani, T.; Sawamura, T.

    2004-10-01

    Response function measurement of layered-type chemical vapor deposition single crystal diamond radiation detectors for 14 MeV neutrons was carried out. The detector had a layered structure that was composed of a boron-doped diamond layer of 0.5 {mu}m in thickness and a nondoped diamond layer of 20 {mu}m on an inexpensive high pressure and high temperature-type Ib diamond substrate. The detector had energy resolution of 2.6% for 5.5 MeV {alpha} particles. This experiment was mainly carried out in order to understand the present status of the detector as a 14 MeV neutron spectrometer and an extent of charge trapping. As result, a peak caused by the {sup 12}C(n,{alpha}{sub 0}){sup 9}Be reactions was clearly observed; the best energy resolution of 6% as for a synthetic diamond radiation detector was achieved. Detection efficiency was 3.2x10{sup -7} counts/unit neutron fluence. However, taking the energy resolution for {alpha} particles, etc., into account, the energy resolution for 14 MeV neutrons was not so high. Further improvement based on better crystal growth is indispensable.

  3. Assembly of a high-dielectric constant thin TiOx layer directly on H-terminated semiconductor diamond

    NASA Astrophysics Data System (ADS)

    Zhao, Jing; Liu, Jiangwei; Sang, Liwen; Liao, Meiyong; Coathup, David; Imura, Masataka; Shi, Baogui; Gu, Changzhi; Koide, Yasuo; Ye, Haitao

    2016-01-01

    A high-dielectric constant (high-k) TiOx thin layer was fabricated on hydrogen-terminated diamond (H-diamond) surface by low temperature oxidation of a thin titanium layer in ambient air. The metallic titanium layer was deposited by sputter deposition. The dielectric constant of the resultant TiOx was calculated to be around 12. The capacitance density of the metal-oxide-semiconductor (MOS) based on the TiOx/H-diamond was as high as 0.75 ?F/cm2 contributed from the high-k value and the very thin thickness of the TiOx layer. The leakage current was lower than 10-13 A at reverse biases and 10-7A at the forward bias of -2 V. The MOS field-effect transistor based on the high-k TiOx/H-diamond was demonstrated. The utilization of the high-k TiOx with a very thin thickness brought forward the features of an ideally low subthreshold swing slope of 65 mV per decade and improved drain current at low gate voltages. The advantages of the utilization high-k dielectric for diamond metal-oxide semiconductor field effect transistors are anticipated.

  4. Low temperature boron doped diamond

    NASA Astrophysics Data System (ADS)

    Zeng, Hongjun; Arumugam, Prabhu U.; Siddiqui, Shabnam; Carlisle, John A.

    2013-06-01

    Low temperature boron doped diamond (LT-BDD) film deposited under 600 C (460 C minimum) has been reported. Study reveals that the deposition temperature and boron dopant cause nanocrystalline diamond (NCD) instead of ultrananocrystalline diamond (UNCD). Unlike conventional NCD, LT-BDD has faster renucleation rate, which ensures a low surface roughness (approximately 10 nm at 0.6 ?m thickness). The overall characteristics of LT-BDD are mixed with the characteristics of conventional NCD and UNCD. Raman spectrum and electrochemical characterization prove that the quality of LT-BDD is similar to those grown under 650-900 C. LT-BDD enables diamond applications on microelectromechanical systems, bio- and optical technologies.

  5. Thermally induced defects in a polycrystalline diamond layer on a tungsten carbide substrate

    NASA Astrophysics Data System (ADS)

    Masina, B. N.; Forbes, A.; Ndwandwe, O. M.; Hearne, G.; Mwakikunga, B. W.; Katumba, G.

    2009-12-01

    In this study we make use of laser heating of HTHP industrial diamond, to study temperature induced changes to the diamond structure, both chemically and mechanically, in the absence of mechanical forces. This has relevance to the efficacy of diamond as a hard material in such applications as rock drilling and material processing. We report on the induced defects when the diamond is irradiated with high power CO 2 and Nd:YAG lasers respectively, and show that the thermal induced stresses in the diamond are sufficient to radically alter its physical properties, resulting in critical fracture. Raman spectroscopy, X-ray diffraction and scanning electron microscopy indicate that the heating does not result in graphitisation of the diamond, but rather diffusion from the non-diamond base results in cobalt and tungsten oxides forming on the diamond surface. This has a deleterious effect on the diamond performance.

  6. Tantalum as a buffer layer in diamond-like carbon coated artificial hip joints.

    PubMed

    Kiuru, Mirjami; Alakoski, Esa; Tiainen, Veli-Matti; Lappalainen, Reijo; Anttila, Asko

    2003-07-15

    The acid resistance of tantalum coated and uncoated human hip joint prostheses was studied with commercial CrCoMo acetabular cups. The samples were exposed to 10% HCl solution and the quantities of dissolved Cr, Co, and Mo were measured with proton-induced X-ray emission (PIXE). The absolute quantities were obtained with the use of Cr and Se solution standards. Tantalum coatings (thicknesses 4-6 microm) were prepared in vacuum with magnetron sputtering. Tantalum coating decreased the corrosion rate by a factor of 10(6). As a spinoff from recent wear tests on artificial hip joints it was shown that tantalum has excellent mechanical properties as an intermediate layer of diamond-like carbon (DLC) coatings. When tantalum was tested together with DLC on three metal-on-metal hip joint pairs in a hip simulator, no observable defects occurred during 15 million walking cycles with a periodic 50-300-kg load (Paul curve). PMID:12808604

  7. Polarization dependent asymmetric magneto-resistance features in nanocrystalline diamond films

    SciTech Connect

    Bhattacharyya, Somnath

    2014-08-18

    Polar angle-dependence of magneto-resistance (AMR) in heavily nitrogen-incorporated ultra-nanocrystalline diamond (UNCD) films is recorded by applying high magnetic fields, which shows strong anisotropic features at low temperatures. The temperature-dependence of MR and AMR can reveal transport in the weak-localization regime, which is explained by using a superlattice model for arbitrary values of disorder and angles. While a propagative Fermi surface model explains the negative MR features for low degree of disorder the azimuthal angle-dependent MR shows field dependent anisotropy due to the aligned conducting channels on the layers normal to film growth direction. The analysis of MR and AMR can extract the temperature dependence of dephasing time with respect to the elastic scattering time which not only establishes quasi-two dimensional features in this system but also suggests a potential application in monitoring the performance of UNCD based quantum devices.

  8. Diamond layers grown by chemical vapor deposition on NbN systems and NbN/SiO2-based devices.

    PubMed

    Orlanducci, S; Guglielmotti, V; Cianchetta, I; Lucci, M; Toschi, F; Tamburri, E; Terranova, M L

    2011-09-01

    Deposits of individual diamond grains and continuous polycrystalline diamond layers have been generated by means of a HFCVD technique onto different types of untreated or seeded NbN surfaces. To test the feasibility of using diamond layers as protective coatings for aerospace applications, we carried out diamond deposition onto the lithographically defined NbN microelectrodes of a NbN/SiO2 multifinger device. The morphological and structural features of the diamond deposits and of the substrates were characterized by FE-SEM, XRD and Raman spectroscopy. The preferential growth of diamond on the superconductive NbN enables the selective coating of the NbN microstripes sputtered on the insulating SiO2. Moreover the diamond coating procedure is able to preserve the structural integrity of the substrate material and to retain the shaped architecture of the device. For the polycrystalline diamond layers grown on NbN a residual stress of -9.8 GPa, largely due to thermal stress, has been estimated by Raman analysis. The diamond coatings of the NbN-based architectures result to be mechanically stable. PMID:22097552

  9. Presence of all Three Allotropes of Impact-Diamonds in the Younger Dryas Onset Layer (YDB) Across N America and NW Europe

    NASA Astrophysics Data System (ADS)

    West, A.; Kennett, J. P.; Kennett, D. J.; Que Hee, S. S.; Wolbach, W. S.; Stich, A.; Bunch, T. E.; Wittke, J. H.; Mercer, C.; Sellers, M.; Culleton, B. J.; Erlandson, J. M.; Johnson, J. R.; Stafford, T. W.; Weaver, J. C.; West, G.

    2008-12-01

    We report the discovery of all three diamond allotropes (cubic diamond, lonsdaleite, and n-diamond) in an extraterrestrial (ET) impact layer (the YDB), dating to the Younger Dryas onset at 12.9 ka. YDB diamonds are distributed broadly across N America and NW Europe at 15 sites spanning 9,000 km or 23 percent of Earth's circumference. N-diamonds and lonsdaleite, or hexagonal diamond, do not co-occur with terrestrial diamonds, but are found in meteorites. Lonsdaleite is found on Earth only in association with known ET impacts, and thus, is a definitive impact indicator. The diamonds were identified by transmission electron microscopy (TEM) using selected area diffraction (SAED), which display reflections corresponding to the following lattice planar spacings definitive of diamond: (1) cubic: 2.06, 1.26, 1.07, and 0.89 A; (2) lonsdaleite: 2.184, 1.261, 1.092, and 0.826 A; and (3) n-diamond: 2.06, 1.26, 1.07, and 0.89 A, plus "forbidden" reflections of 1.78, 1.04, and 0.796 A. Nanodiamonds are rounded to highly angular, and range in size from 1 to 1700 nm with most between 1 and 50 nm. Concentrations are up to 3700 ppb, equaling more than 1 billion diamonds per cm3 of sediment (comparable to K/T levels of 3600 ppb). No diamonds were detected above or below the YDB layer at any site tested. These diamonds could not have formed from volcanic activity, because they combust at temperatures above 500° C in the presence of atmospheric levels of oxygen, and micrometeoritic diamonds are similarly destroyed. Also, the diamonds could not have accumulated from the constant rain of micrometeoritic debris, because multi-billions occur in YDB layer samples, but yet none have been found in non-YDB strata dating from 55,000 RCYBP to present. YDB diamonds are associated with abundance peaks in magnetic spherules, carbon spherules, soot, and iridium, which can peak in impact layers of known ET events, such as the K/T and the 1908 airburst at Tunguska, Siberia. Furthermore, a high proportion of the nanodiamonds are found deeply embedded within spherical particles of melted plant resins, a fact inexplicable by any normal terrestrial process. Altogether, this evidence strongly suggests that the widespread and abundant nanodiamonds constrained to the thin YDB layer resulted from a major ET impact/airburst at 12.9 ka.

  10. Diamond-Like-Carbon LC-Alignment Layers for Application in LCOS Microdisplays

    SciTech Connect

    Bol,A.; Dvorak, J.; Arena, D.

    2005-01-01

    To improve the lifetime and yield of LCOS microdisplays, non-contact LC alignment techniques using inorganic materials are under investigation. This report focuses on oblique ion-beam treatment of diamond-like carbon (DLC) layers, and in particular on the influence of the ion dose on the LC alignment on DLC, keeping the ion-beam angle (40 degrees) and ion-beam energy (170 eV) the same. LC alignment on ion-milled DLC layers is uniform if the ion dose is between 3.8 x 10{sup -4} C/cm{sup 2} and 5.5x10{sup -3} C/cm{sup 2}. Above and below this ion dose range, non-uniform alignment is observed. NEXAFS experiments show that this is caused by lack of molecular anisotropy on the surface of the ion-milled DLC layers. By varying the ion dose between 3.8 x 10{sup -4} C/cm{sup 2} and 5.5 x 10{sup -3} C/cm{sup 2}, LC molecules have an average pre-tilt between 3 and 5 degrees, which is within the desired range for application in LCOS microdisplays. The lifetime of the LCOS microdisplays with ion-milled DLC for projection-TV application is, however, shorter than the lifetime of microdisplays with PI layers. Ion milling probably creates a reactive surface that is unstable under the high light fluxes used in projection TVs. A solution for this problem could be chemical passivation of the ion-milled alignment layers. Initial experiments with passivation of ion-milled PI resulted in an increase in lifetime, but the lifetime after passivation was still lower than the lifetime of rubbed PI layers (factor 0.7). Nevertheless, ion-milling of DLC or PI can be a good alternative LC alignment technique in other LCD applications. LC-alignment layers based on inorganic layers such as obliquely deposited SiO{sub 2} films would be a better option for application in LCOS microdisplays due to their higher light stability.

  11. Growth of micro- and nanocrystalline dual layer composite diamond films by microwave plasma CVD: Influence of CO2 concentration on growth of nano-layer

    NASA Astrophysics Data System (ADS)

    Liu, Cong; Wang, Jian-Hua; Weng, Jun

    2015-01-01

    The high quality and smooth micro-and nanocrystalline dual layer composite diamond films were successfully prepared using H2/CH4/Ar/CO2 plasma with a synthesis process of nucleation/MCD growth/nucleation/NCD growth. The carbon dioxide content is demonstrated to be important in controlling the NCD layer grain size and growth rate. The influences of carbon dioxide concentration on the morphology, microstructure and growth rate of the deposited NCD layer are investigated by using scanning electron microscopy (SEM), X-ray diffraction (XRD) and Raman spectroscopy. It is found that the additional carbonaceous sources supplied by CO2 are favourable to increase the growth rate, and meanwhile, the oxygen related species generated would enhance the etching effect not only to eliminate the non-diamond phase of NCD but also to decrease the growth rate. The appropriate addition of CO2 can increase the high quality and growth rate, decrease the surface roughness. It is demonstrated that adding CO2 strongly affects the contents of various reaction species in plasma, which would determine the growth features of NCD layers. The deposited highly smooth and quality micro-/nano-crystal layered diamond film is also expected to be applicable in surface aroustic wave (SAW) devices and micro-electromechanical systems (MEMS).

  12. Thin polycrystalline diamond films protecting zirconium alloys surfaces: From technology to layer analysis and application in nuclear facilities

    NASA Astrophysics Data System (ADS)

    Ashcheulov, P.; Škoda, R.; Škarohlíd, J.; Taylor, A.; Fekete, L.; Fendrych, F.; Vega, R.; Shao, L.; Kalvoda, L.; Vratislav, S.; Cháb, V.; Horáková, K.; Kůsová, K.; Klimša, L.; Kopeček, J.; Sajdl, P.; Macák, J.; Johnson, S.; Kratochvílová, I.

    2015-12-01

    Zirconium alloys can be effectively protected against corrosion by polycrystalline diamond (PCD) layers grown in microwave plasma enhanced linear antenna chemical vapor deposition apparatus. Standard and hot steam oxidized PCD layers grown on Zircaloy2 surfaces were examined and the specific impact of polycrystalline Zr substrate surface on PCD layer properties was investigated. It was found that the presence of the PCD coating blocks hydrogen diffusion into the Zircaloy2 surface and protects Zircaloy2 material from degradation. PCD anticorrosion protection of Zircaloy2 can significantly prolong life of Zircaloy2 material in nuclear reactors even at temperatures above Zr phase transition temperatures.

  13. N-type droping of nanocrystalline diamond films with nitrogen and electrodes made therefrom

    DOEpatents

    Gruen, Dieter M. (Downers Grove, IL); Krauss, Alan R. (late of Naperville, IL); Auciello, Orlando H. (Bolingbrook, IL); Carlisle, John A. (Plainfield, IL)

    2004-09-21

    An electrically conducting n-type ultrananocrystalline diamond (UNCD) having no less than 10.sup.19 atoms/cm.sup.3 of nitrogen is disclosed. A method of making the n-doped UNCD. A method for predictably controlling the conductivity is also disclosed.

  14. Characterization of tribo-layer formed during sliding wear of SiC ball against nanocrystalline diamond coatings

    SciTech Connect

    Dumpala, Ravikumar; Kumar, N.; Samji, Sunil Kumar; Dash, S.; Ramamoorthy, B.; Ramachandra Rao, M.S.

    2014-09-15

    Tribo-layer formation and frictional characteristics of the SiC ball were studied with the sliding test against nanocrystalline diamond coating under atmospheric test conditions. Unsteady friction coefficients in the range of 0.04 to 0.1 were observed during the tribo-test. Friction and wear characteristics were found to be influenced by the formation of cohesive tribo-layer (thickness ∼ 1.3 μm) in the wear track of nanocrystalline diamond coating. Hardness of the tribo-layer was measured using nanoindentation technique and low hardness of ∼ 1.2 GPa was observed. The presence of silicon and oxygen in the tribo-layer was noticed by the energy dispersive spectroscopy mapping and the chemical states of the silicon were analyzed using X-ray photoelectron spectroscopy. Large amount of oxygen content in the tribo-layer indicated tribo-oxidation wear mechanism. - Highlights: • Sliding wear and friction characteristics of SiC were studied against NCD coating. • Silicon oxide tribo-layer formation was observed in the NCD coating wear track. • Low hardness 1.2 GPa of tribo-layer was measured using nanoindentation technique. • Chemical states of silicon were analyzed using X-ray photoelectron spectroscopy.

  15. Prevention of nanoscale wear in atomic force microscopy through the use of monolithic ultrananocrystaline diamond probes.

    SciTech Connect

    Liu, J.; Grierson, D. S.; Notbohm, J.; Li, S.; O'Connor, S. D.; Turner, K. T.; Sumant, A. V.; Neelakantan, N.; Moldovan, N.; Carlisle, J. A.; Jaroenapibal, P.; Carpick, R. W.

    2010-01-01

    Nanoscale wear is a key limitation of conventional atomic force microscopy (AFM) probes that results in decreased resolution, accuracy, and reproducibility in probe-based imaging, writing, measurement, and nanomanufacturing applications. Diamond is potentially an ideal probe material due to its unrivaled hardness and stiffness, its low friction and wear, and its chemical inertness. However, the manufacture of monolithic diamond probes with consistently shaped small-radius tips has not been previously achieved. The first wafer-level fabrication of monolithic ultrananocrystalline diamond (UNCD) probes with <5-nm grain sizes and smooth tips with radii of 30-40 nm is reported, which are obtained through a combination of microfabrication and hot-filament chemical vapor deposition. Their nanoscale wear resistance under contact-mode scanning conditions is compared with that of conventional silicon nitride (SiN{sub x}) probes of similar geometry at two different relative humidity levels ({approx}15 and {approx}70%). While SiN{sub x} probes exhibit significant wear that further increases with humidity, UNCD probes show little measurable wear. The only significant degradation of the UNCD probes observed in one case is associated with removal of the initial seed layer of the UNCD film. The results show the potential of a new material for AFM probes and demonstrate a systematic approach to studying wear at the nanoscale.

  16. Single-crystal GaN/AlN layers on CVD diamond

    NASA Astrophysics Data System (ADS)

    Khrykin, O. I.; Drozdov, Yu. N.; Drozdov, M. N.; Yunin, P. A.; Shashkin, V. I.; Bogdanov, S. A.; Muchnikov, A. B.; Vikharev, A. L.; Radishev, D. B.

    2015-10-01

    Original approach to fabricating a GaN/AlN/nanocrystalline diamond structure has been suggested and implemented. The stages of deposition of a structure of this kind include the following: (a) growth of nanocrystalline CVD-diamond on single-crystal AlN (preliminarily grown on a silicon substrate), (b) etch removal of the silicon substrate, and (c) growth of single-crystal GaN on the surface of single-crystal AlN. Single-crystal gallium nitride with a width of the X-ray rocking curve for the (0002) reflection of 0.35 was obtained on a nanocrystalline-diamond substrate.

  17. Growth and properties of nanocrystalline diamond films

    NASA Astrophysics Data System (ADS)

    Williams, Oliver A.; Nesldek, Milo

    2006-10-01

    The aim of this paper is to summarise recent progress in the growth of small grain-sized Chemical Vapor Deposition (CVD) diamond often called nanocrystalline diamond, i.e., diamond with grains typically smaller than 500 nm. Nanocrystalline (NCD) and Ultrananocrystalline diamond (UNCD) films are new materials offering interesting applications to nanobioelectronics and electrochemistry. However NCD and UNCD thin films comprise of entirely different structures which is highlighted here in this paper. We discuss in detail the main differences in Raman spectra, optical properties and electrical transport properties. Finally we present a simple model of the conductivity mechanism in nitrogenated UNCD (N-UNCD) and boron doped NCD (B-NCD) films, and show the possibility of achieving the superconductive transition in B-NCD films.

  18. Transition layers between CVD diamond films and substrates of strong carbide-forming elements: vanadium, chromium, zirconium, and hafnium

    NASA Astrophysics Data System (ADS)

    Jiang, Xiang-Liu; Zhang, Fang-Qing; Zhang, Ya-Fei; Zhang, Wen-Jun; Chen, Guang-Hua

    1992-11-01

    Among the strong carbide forming elements, ten of them have melting points above 1400 degrees Centigrade. The observed transition layers between CVD diamond films and the substrates of Mo, Si, W, Ta, Nb, and Ti have been reported previously. In this paper, further research results on transition layers for the substrate elements of V, Cr, Zr, and Hf are presented. The specimens are prepared in an arc discharge plasma CVD system with the substrate temperature of 900 - 1000 degrees Centigrade and characterized by a high resolution X-ray diffusion diffraction instrument. the experimental results show that the transition layers are polycrystalline VC and V2C, Cr7C3 and HfC for the substrates of V, Cr, and Hf respectively. For the transition layers between CVD diamond films and Zr substrates, the composition of polycrystalline ZrH, ZrC, and their complex compound are verified and the content of hydride is comparable to the content of carbide in this case.

  19. Sputtered tungsten-based ternary and quaternary layers for nanocrystalline diamond deposition.

    PubMed

    Walock, Michael J; Rahil, Issam; Zou, Yujiao; Imhoff, Luc; Catledge, Shane A; Nouveau, Corinne; Stanishevsky, Andrei V

    2012-06-01

    Many of today's demanding applications require thin-film coatings with high hardness, toughness, and thermal stability. In many cases, coating thickness in the range 2-20 microm and low surface roughness are required. Diamond films meet many of the stated requirements, but their crystalline nature leads to a high surface roughness. Nanocrystalline diamond offers a smoother surface, but significant surface modification of the substrate is necessary for successful nanocrystalline diamond deposition and adhesion. A hybrid hard and tough material may be required for either the desired applications, or as a basis for nanocrystalline diamond film growth. One possibility is a composite system based on carbides or nitrides. Many binary carbides and nitrides offer one or more mentioned properties. By combining these binary compounds in a ternary or quaternary nanocrystalline system, we can tailor the material for a desired combination of properties. Here, we describe the results on the structural and mechanical properties of the coating systems composed of tungsten-chromium-carbide and/or nitride. These WC-Cr-(N) coatings are deposited using magnetron sputtering. The growth of adherent nanocrystalline diamond films by microwave plasma chemical vapor deposition has been demonstrated on these coatings. The WC-Cr-(N) and WC-Cr-(N)-NCD coatings are characterized with atomic force microscopy and SEM, X-ray diffraction, X-ray photoelectron spectroscopy, Raman spectroscopy, and nanoindentation. PMID:22905536

  20. Thermally stable diamond brazing

    DOEpatents

    Radtke, Robert P. (Kingwood, TX)

    2009-02-10

    A cutting element and a method for forming a cutting element is described and shown. The cutting element includes a substrate, a TSP diamond layer, a metal interlayer between the substrate and the diamond layer, and a braze joint securing the diamond layer to the substrate. The thickness of the metal interlayer is determined according to a formula. The formula takes into account the thickness and modulus of elasticity of the metal interlayer and the thickness of the TSP diamond. This prevents the use of a too thin or too thick metal interlayer. A metal interlayer that is too thin is not capable of absorbing enough energy to prevent the TSP diamond from fracturing. A metal interlayer that is too thick may allow the TSP diamond to fracture by reason of bending stress. A coating may be provided between the TSP diamond layer and the metal interlayer. This coating serves as a thermal barrier and to control residual thermal stress.

  1. Combination of e-beam lithography and of high velocity AIN/diamond-layered structure for SAW filters in X band.

    PubMed

    Kirsch, Philippe; Assouar, Mohamed B; Elmazria, Omar; Hakiki, M El; Mortet, Vincent; Alnot, Patrick

    2007-07-01

    In this work, we report on the fabrication results of surface acoustic wave (SAW) devices operating at frequencies up to 8 GHz. In previous work, we have shown that high acoustic velocities (9 to 12 km/s) are obtained from the layered AIN/diamond structure. The interdigital transducers (IDTs) made of aluminium with resolutions up to 250 nm were successfully patterned on AIN/diamond-layered structures with an adapted technological process. The uniformity and periodicity of IDTs were confirmed by field emission scanning electron microscopy and atomic force microscopy analyses. A highly oriented (002) piezoelectric aluminum nitride thin film was deposited on the nucleation side of the CVD diamond by magnetron sputtering technique. The X-ray diffraction effectuated on the AIN/diamond-layered structure exhibits high intensity peaks related to the (002) AIN and (111) diamond orientations. According to the calculated dispersion curves of velocity and the electromechanical coupling coefficient (K2), the AIN layer thickness was chosen in order to combine high velocity and high K2. Experimental data extracted from the fabricated SAW devices match with theoretical values quite well. PMID:17718340

  2. Diamond as a scaffold for bone growth.

    PubMed

    Fox, Kate; Palamara, Joseph; Judge, Roy; Greentree, Andrew D

    2013-04-01

    Diamond is an attractive material for biomedical implants. In this work, we investigate its capacity as a bone scaffold. It is well established that the bioactivity of a material can be evaluated by examining its capacity to form apatite-like calcium phosphate phases on its surface when exposed to simulated body fluid. Accordingly, polycrystalline diamond (PCD) and ultrananocrystalline diamond (UNCD) deposited by microwave plasma chemical vapour deposition were exposed to simulated body fluid and assessed for apatite growth when compared to the bulk silicon. Scanning electron microscopy and X-ray photoelectron spectroscopy showed that both UNCD and PCD are capable of acting as a bone scaffold. The composition of deposited apatite suggests that UNCD and PCD are suitable for in vivo implantation with UNCD possible favoured in applications where rapid osseointegration is essential. PMID:23386207

  3. High Pressure Superconductivity in Iron Based Layered Compounds Studied using Designer Diamonds

    SciTech Connect

    Vohra, Yogesh, K.

    2009-04-01

    High pressure superconductivity in Iron based superconductor FeSe0.5Te0.5 has been studied up to 15 GPa and 10 K using an eight probe designer diamond anvil in a diamond anvil cell device. Four probe electrical resistance measurements show onset of superconductivity (Tc) at 14 K at ambient pressure with Tc increasing with increasing pressure to 19 K at a pressure of 3.6 GPa. At higher pressures beyond 3.6 GPa, Tc decreases and extrapolation suggests non superconducting behavior above 10 GPa. This loss of superconductivity coincides with the pressure induced amorphization of Fe(SeTe)4 tetrahedra reported at 11 GPa in x-ray diffraction studies at ambient temperature.

  4. Band offsets of Al{sub 2}O{sub 3} and HfO{sub 2} oxides deposited by atomic layer deposition technique on hydrogenated diamond

    SciTech Connect

    Liu, J. W.; Liao, M. Y.; Imura, M.; Koide, Y.

    2012-12-17

    High-k oxide insulators (Al{sub 2}O{sub 3} and HfO{sub 2}) have been deposited on a single crystalline hydrogenated diamond (H-diamond) epilayer by an atomic layer deposition technique at temperature as low as 120 Degree-Sign C. Interfacial electronic band structures are characterized by X-ray photoelectron spectroscopy. Based on core-level binding energies and valence band maximum values, valence band offsets are found to be 2.9 {+-} 0.2 and 2.6 {+-} 0.2 eV for Al{sub 2}O{sub 3}/H-diamond and HfO{sub 2}/H-diamond heterojunctions, respectively. Band gaps of the Al{sub 2}O{sub 3} and HfO{sub 2} have been determined to be 7.2 {+-} 0.2 and 5.4 {+-} 0.2 eV by measuring O 1s energy loss spectra, respectively. Both the Al{sub 2}O{sub 3}/H-diamond and HfO{sub 2}/H-diamond heterojunctions are concluded to be type-II staggered band configurations with conduction band offsets of 1.2 {+-} 0.2 and 2.7 {+-} 0.2 eV, respectively.

  5. Direct electrochemistry of Shewanella loihica PV-4 on gold nanoparticles-modified boron-doped diamond electrodes fabricated by layer-by-layer technique.

    PubMed

    Wu, Wenguo; Xie, Ronggang; Bai, Linling; Tang, Zuming; Gu, Zhongze

    2012-05-01

    Microbial Fuel Cells (MFCs) are robust devices capable of taping biological energy, converting pollutants into electricity through renewable biomass. The fabrication of nanostructured electrodes with good bio- and electrochemical activity, play a profound role in promoting power generation of MFCs. Au nanoparticles (AuNPs)-modified Boron-Doped Diamond (BDD) electrodes are fabricated by layer-by-layer (LBL) self-assembly technique and used for the direct electrochemistry of Shewanella loihica PV-4 in an electrochemical cell. Experimental results show that the peak current densities generated on the Au/PAH multilayer-modified BDD electrodes increased from 1.25 to 2.93 microA/cm(-2) as the layer increased from 0 to 6. Different cell morphologies of S. loihica PV-4 were also observed on the electrodes and the highest density of cells was attached on the (Au/PAH)6/BDD electrode with well-formed three-dimensional nanostructure. The electrochemistry of S. loihica PV-4 was enhanced on the (Au/PAH)4/BDD electrode due to the appropriate amount of AuNPsand thickness of PAH layer. PMID:22852323

  6. Photochromism-induced amplification of critical current density in superconducting boron-doped diamond with an azobenzene molecular layer.

    PubMed

    Natsui, Keisuke; Yamamoto, Takashi; Akahori, Miku; Einaga, Yasuaki

    2015-01-14

    A key issue in molecular electronics is the control of electronic states by optical stimuli, which enables fast and high-density data storage and temporal-spatial control over molecular processes. In this article, we report preparation of a photoswitchable superconductor using a heavily boron-doped diamond (BDD) with a photochromic azobenzene (AZ) molecular layer. BDDs electrode properties allow for electrochemical immobilization, followed by copper(I)-catalyzed alkyne-azide cycloaddition (a "click" reaction). Superconducting properties were examined with magnetic and electrical transport measurements, such as field-dependent isothermal magnetization, temperature-dependent resistance, and the low-temperature voltage-current response. These measurements revealed reversible amplification of the critical current density by 55% upon photoisomerization. This effect is explained as the reversible photoisomerization of AZ inducing an inhomogeneous electron distribution along the BDD surface that renormalizes the surface pinning contribution to the critical current. PMID:25494096

  7. SAW COM-parameter extraction in AlN/diamond layered structures.

    PubMed

    Iriarte, Gonzalo F; Engelmark, Fredrik; Katardjiev, Ilia V; Plessky, Viktor; Yantchev, Ventsislav

    2003-11-01

    Highly c-axis oriented aluminum nitride (AlN) thin piezoelectric films have been grown on polycrystalline diamond substrates by pulsed direct current (DC) magnetron reactive sputter-deposition. The films were deposited at a substrate temperature below 50 degrees C (room temperature) and had a typical full width half maximum (FWHM) value of the rocking curve of the AlN-002-peak of 2.1 degrees. A variety of one-port surface acoustic wave (SAW) resonators have been designed and fabricated on top of the AlN films. The measurements indicate that various SAW modes are excited. The SAW phase velocities of up to 11.800 m/s have been measured. These results are in agreement with calculated dispersion curves of the AlN/diamond structure. Finally, the coupling of modes parameters have been extracted from S11 measurements using curve fitting for the first SAW mode, which indicate an effective coupling K2 of 0.91% and a Q factor of about 600 at a frequency of 1050 MHz. PMID:14682637

  8. Study of high-overtone bulk acoustic resonators based on the Me1/AlN/Me2/(100) diamond piezoelectric layered structure

    NASA Astrophysics Data System (ADS)

    Sorokin, B. P.; Kvashnin, G. M.; Telichko, A. V.; Gordeev, G. I.; Burkov, S. I.; Blank, V. D.

    2015-07-01

    The Me1/AlN/Me2/(100) diamond structure has been theoretically analyzed and experimentally investigated in the range 0.5-10 GHz using high-overtone bulk acoustic resonators with different electrodes topologies based on the Al/AlN/Mo/(100) diamond structure. The maximum quality parameter Q f ? 1014 Hz was obtained at f = 9.5 GHz. The layered structure has been analyzed using the developed HBAR software v. 2.3. It is demonstrated that the features in the frequency dependences of the parameters of such resonators are related to the behavior of a loaded thin-film piezoelectric transducer. The calculation results are in good agreement with the experiment. The frequency dependences of the equivalent parameters of the resonators have been calculated. It is shown that the synthetic type IIa diamond single crystal in combination with aluminum nitride is promising for implementation of high-Q acoustoelectronic microwave devices.

  9. Electrical characteristics of hydrogen-terminated diamond metal-oxide-semiconductor with atomic layer deposited HfO2 as gate dielectric

    NASA Astrophysics Data System (ADS)

    Liu, J. W.; Liao, M. Y.; Imura, M.; Oosato, H.; Watanabe, E.; Koide, Y.

    2013-03-01

    HfO2 films have been deposited on hydrogen-terminated diamond (H-diamond) by an atomic layer deposition (ALD) technique at 120 C. Effect of rapid thermal annealing treatment on electrical properties of Au/Ti/Pd/ALD-HfO2/H-diamond metal-oxide-semiconductor (MOS) diodes has been investigated. The leakage current density of the MOS diode after annealing at 300 C is as small as 10-8 A/cm2 at gate biases from -5.0 to 4.0 V. The capacitance-voltage curve in the depletion mode of the MOS diode after annealing is much sharper than that of the MOS diode before annealing and close to the theoretical dependence, which indicates the small interface state density. The annealed MOS diode is concluded to be more suitable for the fabrication of field effect transistors.

  10. Studies on distribution of element contents in transient layer at interface between boron-doped diamond film electrode and tantalum substrate

    NASA Astrophysics Data System (ADS)

    Liang, Jiachang; Gao, Chengyao; Zhang, Liping; Jiang, Lihui; Yang, Zhengquan; Wang, Zhiping; Ji, Chaohui; Le, Xiaoyun; Rong, Cuihua; Zhang, Jian

    2011-05-01

    The boron-doped diamond film (BDD) grown on tantalum (Ta) substrate as an electrode (BDD/Ta) was prepared by hot filament chemical vapor deposition method. The experimental results demonstrated that our BDD/Ta had high current efficiency, strong ability to degrade wastewater, good corrosion stability and long lifetime. These excellent characteristics of BDD/Ta have been explained in terms of Rutherford backscattering (RBS) experiments. RBS investigation revealed that the continuous transient layer at the interface between boron-doped diamond film and Ta-substrate was formed and the microstructure of the continuous transient layer given by the continuous distribution of all element contents at the interface was obtained. The thicknesses of boron-doped diamond film and the continuous transient layer were about equal to 8000 10 15 atoms/cm 2 and 5800 10 15 atoms/cm 2, respectively. The formation of the continuous transient layer at the interface can eliminate the mismatch of thermal expansion coefficients (TEC) at the interface and only lead to the slow change of TEC because of the continuous distribution of element contents of the film and substrate in the transient layer at the interface. Thus, there is no residual stress to concentrate on the interface and the stress-corrosion delamination of the film disappears. Therefore, the corrosion stability and lifetime of BDD/Ta increase and last well, that have been verified by X-ray diffraction (XRD) experiments.

  11. Investigations on diamond nanostructuring of different morphologies by the reactive-ion etching process and their potential applications.

    PubMed

    Kunuku, Srinivasu; Sankaran, Kamatchi Jothiramalingam; Tsai, Cheng-Yen; Chang, Wen-Hao; Tai, Nyan-Hwa; Leou, Keh-Chyang; Lin, I-Nan

    2013-08-14

    We report the systematic studies on the fabrication of aligned, uniform, and highly dense diamond nanostructures from diamond films of various granular structures. Self-assembled Au nanodots are used as a mask in the self-biased reactive-ion etching (RIE) process, using an O2/CF4 process plasma. The morphology of diamond nanostructures is a close function of the initial phase composition of diamond. Cone-shaped and tip-shaped diamond nanostructures result for microcrystalline diamond (MCD) and nanocrystalline diamond (NCD) films, whereas pillarlike and grasslike diamond nanostructures are obtained for Ar-plasma-based and N2-plasma-based ultrananocrystalline diamond (UNCD) films, respectively. While the nitrogen-incorporated UNCD (N-UNCD) nanograss shows the most-superior electron-field-emission properties, the NCD nanotips exhibit the best photoluminescence properties, viz, different applications need different morphology of diamond nanostructures to optimize the respective characteristics. The optimum diamond nanostructure can be achieved by proper choice of granular structure of the initial diamond film. The etching mechanism is explained by in situ observation of optical emission spectrum of RIE plasma. The preferential etching of sp(2)-bonded carbon contained in the diamond films is the prime factor, which forms the unique diamond nanostructures from each type of diamond films. However, the excited oxygen atoms (O*) are the main etching species of diamond film. PMID:23849039

  12. Rapid thermal lysis of cells using silicon-diamond microcantilever heaters.

    PubMed

    Privorotskaya, Natalya; Liu, Yi-Shao; Lee, Jungchul; Zeng, Hongjun; Carlisle, John A; Radadia, Adarsh; Millet, Larry; Bashir, Rashid; King, William P

    2010-05-01

    This paper presents the design and application of microcantilever heaters for biochemical applications. Thermal lysis of biological cells was demonstrated as a specific example. The microcantilever heaters, fabricated from selectively doped single crystal silicon, provide local resistive heating with highly uniform temperature distribution across the cantilevers. Very importantly, the microcantilever heaters were coated with a layer of 100 nm thick electrically insulating ultrananocrystalline diamond (UNCD) layer used for cell immobilization on the cantilever surface. Fibroblast cells or bacterial cells were immobilized on the UNCD/cantilever surfaces and thermal lysis was demonstrated via optical fluorescence microscopy. Upon electrical heating of the cantilever structures to 93 degrees C for 30 seconds, fibroblast cell and nuclear membrane were compromised and the cells were lysed. Over 90% of viable bacteria were also lysed after 15 seconds of heating at 93 degrees C. This work demonstrates the utility of silicon-UNCD heated microcantilevers for rapid cell lysis and forms the basis for other rapid and localized temperature-regulated microbiological experiments in cantilever-based lab on chip applications. PMID:20390131

  13. Surface damages in diamond by Ar/O{sub 2} plasma and their effect on the electrical and electrochemical characteristics of boron-doped layers

    SciTech Connect

    Denisenko, A.; Pietzka, C.; Scharpf, J.; Kohn, E.; Romanyuk, A.

    2010-10-15

    Epitaxial single crystal and boron-doped diamond layers were exposed to reactive ion etching in Ar/O{sub 2} plasma (rf power of 25 W and self-bias of 100 V); and the electrical, structural, and electrochemical characteristics of the exposed surface were investigated. Angle-resolved x-ray photoemission spectroscopy (XPS) measurements revealed a nonuniform layer of amorphous carbon at the exposed surface with an average thickness of approximately 4 nm, as confirmed also by atomic force microscopy profiling of selectively etched areas. On highly boron-doped diamond, the plasma-induced damages resulted also in a nonconductive surface layer. This damaged and insulating surface layer remained resistant to graphite-etching chemicals and to rf oxygen plasma but it was removed completely in microwave hydrogen plasma at 700 deg. C. The surface characteristics after the H-plasma process followed by wet chemical oxidation were restored back to the initial state, as confirmed by XPS. Such ''recovery'' treatment had been applied to an all-diamond submicrometer electrode array initially patterned by an Ar/O{sub 2} plasma etching. The electrochemical characteristics of this electrode array were improved by more than two orders of magnitude, approaching theoretical limit for the given geometrical configuration.

  14. Surface damages in diamond by Ar/O2 plasma and their effect on the electrical and electrochemical characteristics of boron-doped layers

    NASA Astrophysics Data System (ADS)

    Denisenko, A.; Romanyuk, A.; Pietzka, C.; Scharpf, J.; Kohn, E.

    2010-10-01

    Epitaxial single crystal and boron-doped diamond layers were exposed to reactive ion etching in Ar/O2 plasma (rf power of 25 W and self-bias of 100 V); and the electrical, structural, and electrochemical characteristics of the exposed surface were investigated. Angle-resolved x-ray photoemission spectroscopy (XPS) measurements revealed a nonuniform layer of amorphous carbon at the exposed surface with an average thickness of approximately 4 nm, as confirmed also by atomic force microscopy profiling of selectively etched areas. On highly boron-doped diamond, the plasma-induced damages resulted also in a nonconductive surface layer. This damaged and insulating surface layer remained resistant to graphite-etching chemicals and to rf oxygen plasma but it was removed completely in microwave hydrogen plasma at 700 C. The surface characteristics after the H-plasma process followed by wet chemical oxidation were restored back to the initial state, as confirmed by XPS. Such "recovery" treatment had been applied to an all-diamond submicrometer electrode array initially patterned by an Ar/O2 plasma etching. The electrochemical characteristics of this electrode array were improved by more than two orders of magnitude, approaching theoretical limit for the given geometrical configuration.

  15. Industrial diamond

    USGS Publications Warehouse

    Olson, D.W.

    2001-01-01

    An overview of the industrial diamond industry is provided. More than 90 percent of the industrial diamond consumed in the U.S. and the rest of the world is manufactured diamond. Ireland, Japan, Russia, and the U.S. produce 75 percent of the global industrial diamond output. In 2000, the U.S. was the largest market for industrial diamond. Industrial diamond applications, prices for industrial diamonds, imports and exports of industrial diamonds, the National Defense Stockpile of industrial diamonds, and the outlook for the industrial diamond market are discussed.

  16. Antibacterial efficacy of ultrahigh molecular weight polyethylene with silver containing diamond-like surface layers.

    PubMed

    Harrasser, Norbert; Jssen, Sebastian; Banke, Ingo J; Kmeth, Ralf; von Eisenhart-Rothe, Ruediger; Stritzker, Bernd; Gollwitzer, Hans; Burgkart, Rainer

    2015-12-01

    Antibacterial coating of medical devices is a promising approach to reduce the risk of infection but has not yet been achieved on wear surfaces, e.g. polyethylene (PE). We quantitatively determined the antimicrobial potency of different PE surfaces, which had been conversed to diamond-like carbon (DLC-PE) and doped with silver ions (Ag-DLC-PE). Bacterial adhesion and planktonic growth of various strains of S. epidermidis on Ag-DLC-PE were compared to untreated PE by quantification of colony forming units on the adherent surface and in the growth medium as well as semiquantitatively by determining the grade of biofilm formation by scanning electron microscopy. (1) A significant (p<0.05) antimicrobial effect could be found for Ag-DLC-PE. (2) The antimicrobial effect was positively correlated with the applied fluences of Ag (fivefold reduced bacterial surface growth and fourfold reduced bacterial concentration in the surrounding medium with fluences of 1נ10(17) vs. 1נ10(16)cm(-2) under implantation energy of 10keV). (3) A low depth of Ag penetration using low ion energies (10 or 20 vs. 100keV) led to evident antimicrobial effects (fourfold reduced bacterial surface growth and twofold reduced bacterial concentration in the surrounding medium with 10 or 20keV and 1נ10(17) cm(-2) vs. no reduction of growth with 100keV and 1נ10(17)cm(-2)). (4) Biofilm formation was decreased by Ag-DLC-PE surfaces. The results obtained in this study suggest that PE-surfaces can be equipped with antibacterial effects and may provide a promising platform to finally add antibacterial coatings on wear surfaces of joint prostheses. PMID:26391393

  17. Microstructural evolution of diamond growth during HFCVD

    NASA Technical Reports Server (NTRS)

    Singh, J.

    1994-01-01

    High resolution transmission electron microscopy (HRTEM) was used to study the nucleation and growth mechanism of diamond by hot filament chemical vapor deposition (HFCVD) process. A novel technique has shown a direct evidence for the formation of the diamond-like carbon layer 8-14 nm thick in which small diamond micro-crystallites were embedded. These diamond micro-crystallites were formed as a result of transformation of diamond-like carbon into diamond. The diamond micro-crystallites present in the amorphous diamond-like carbon layer provided nucleation sites for diamond growth. Large diamond crystallites were observed to grow from these micro-crystallites. The mechanism of diamond growth will be presented based on experimental findings.

  18. Diamond-Cutter Drill Bits

    SciTech Connect

    1995-11-01

    Geothermal Energy Program Office of Geothermal and Wind Technologies Diamond-Cutter Drill Bits Diamond-cutter drill bits cut through tough rock quicker, reducing the cost of drilling for energy resources The U.S. Department of Energy (DOE) contributed markedly to the geothermal, oil, and gas industries through the development of the advanced polycrystalline diamond compact (PDC) drill bit. Introduced in the 1970s by General Electric Company (GE), the PDC bit uses thin, diamond layers bonded to t

  19. Characterization of microparticles and oxide layers generated by laser irradiation of diamond-machined silicon wafers

    NASA Astrophysics Data System (ADS)

    Yan, Jiwang; Sakai, Shin; Isogai, Hiromichi; Izunome, Koji

    2011-02-01

    Nanosecond-pulsed laser irradiation is a potential method for removing machining-induced subsurface damage from silicon wafers. In this study, the material compositions and microstructures of microparticles and oxide layers generated during laser irradiation were investigated by atomic force microscopy, energy-dispersive x-ray spectroscopy, cross-sectional transmission electron microscopy, electron energy-loss spectroscopy and Auger electron spectroscopy. The oxide layer was found to be approximately 5 nm thick, which is significantly thicker than the native oxide layer of silicon at room temperature in air (~1 nm). The microparticles have a low-density amorphous structure and are mainly composed of silicon oxide, while a few particles contain silicon. The particles are attached to the substrate, but are distinct from it. The results indicate that silicon boiled during the laser pulse and that the particles are recondensed and oxidized liquid silicon boiled away from the wafer surface. The microparticles can be completely removed from the wafer surface by hydrofluoric acid etching.

  20. Ohmic contact properties of p-type surface conductive layer on H-terminated diamond films prepared by DC arc jet CVD

    NASA Astrophysics Data System (ADS)

    Liu, Jin-long; Li, Cheng-ming; Zhu, Rui-hua; Chen, Liang-xian; Wang, Jing-jing; Feng, Zhi-hong

    2013-08-01

    With the advantages of high deposition rate and large deposition area, polycrystalline diamond films prepared by direct current (DC) arc jet chemical vapor deposition (CVD) are considered to be one of the most promising materials for high-frequency and high-power electronic devices. In this paper, high-quality self-standing polycrystalline diamond films with the diameter of 100 mm were prepared by DC arc jet CVD, and then, the p-type surface conductive layer with the sheet carrier density of 1011-1013 cm-2 on the H-terminated diamond film was obtained by micro-wave hydrogen plasma treatment for 40 min. Ti/Au and Au films were deposited on the H-terminated diamond surface as the ohmic contact electrode, respectively, afterwards, they were treated by rapid vacuum annealing at different temperatures. The properties of these two types of ohmic contacts were investigated by measuring the specific contact resistance using the transmission line method (TLM). Due to the formation of Ti-related carbide at high temperature, the specific contact resistance of Ti/Au contact gradually decreases to 9.95 10-5 ?cm2 as the temperature increases to 820C. However, when the annealing temperature reaches 850C, the ohmic contact for Ti/Au is degraded significantly due to the strong diffusion and reaction between Ti and Au. As for the as-deposited Au contact, it shows an ohmic contact. After annealing treatment at 550C, low specific contact resistance was detected for Au contact, which is derived from the enhancement of interdiffusion between Au and diamond films.

  1. Industrial diamond

    USGS Publications Warehouse

    Olson, D.W.

    2003-01-01

    Statistics on the production, consumption, cost, trade, and government stockpile of natural and synthetic industrial diamond are provided. The outlook for the industrial diamond market is also considered.

  2. On interlayer stability and high-cycle simulator performance of diamond-like carbon layers for articulating joint replacements.

    PubMed

    Thorwarth, Kerstin; Thorwarth, Gtz; Figi, Renato; Weisse, Bernhard; Stiefel, Michael; Hauert, Roland

    2014-01-01

    Diamond like carbon (DLC) coatings have been proven to be an excellent choice for wear reduction in many technical applications. However, for successful adaption to the orthopaedic field, layer performance, stability and adhesion in physiologically relevant setups are crucial and not consistently investigated. In vitro wear testing as well as adequate corrosion tests of interfaces and interlayers are of great importance to verify the long term stability of DLC coated load bearing implants in the human body. DLC coatings were deposited on articulating lumbar spinal disks made of CoCr28Mo6 biomedical implant alloy using a plasma-activated chemical vapor deposition (PACVD) process. As an adhesion promoting interlayer, tantalum films were deposited by magnetron sputtering. Wear tests of coated and uncoated implants were performed in physiological solution up to a maximum of 101 million articulation cycles with an amplitude of 2 and -3/+6 in successive intervals at a preload of 1200 N. The implants were characterized by gravimetry, inductively coupled plasma optical emission spectrometry (ICP-OES) and cross section scanning electron microscopy (SEM) analysis. It is shown that DLC coated surfaces with uncontaminated tantalum interlayers perform very well and no corrosive or mechanical failure could be observed. This also holds true in tests featuring overload and third-body wear by cortical bone chips present in the bearing pairs. Regarding the interlayer tolerance towards interlayer contamination (oxygen), limits for initiation of potential failure modes were established. It was found that mechanical failure is the most critical aspect and this mode is hypothetically linked to the ?-? tantalum phase switch induced by increasing oxygen levels as observed by X-ray diffraction (XRD). It is concluded that DLC coatings are a feasible candidate for near zero wear articulations on implants, potentially even surpassing the performance of ceramic vs. ceramic. PMID:24921709

  3. On Interlayer Stability and High-Cycle Simulator Performance of Diamond-Like Carbon Layers for Articulating Joint Replacements

    PubMed Central

    Thorwarth, Kerstin; Thorwarth, Götz; Figi, Renato; Weisse, Bernhard; Stiefel, Michael; Hauert, Roland

    2014-01-01

    Diamond like carbon (DLC) coatings have been proven to be an excellent choice for wear reduction in many technical applications. However, for successful adaption to the orthopaedic field, layer performance, stability and adhesion in physiologically relevant setups are crucial and not consistently investigated. In vitro wear testing as well as adequate corrosion tests of interfaces and interlayers are of great importance to verify the long term stability of DLC coated load bearing implants in the human body. DLC coatings were deposited on articulating lumbar spinal disks made of CoCr28Mo6 biomedical implant alloy using a plasma-activated chemical vapor deposition (PACVD) process. As an adhesion promoting interlayer, tantalum films were deposited by magnetron sputtering. Wear tests of coated and uncoated implants were performed in physiological solution up to a maximum of 101 million articulation cycles with an amplitude of ±2° and −3/+6° in successive intervals at a preload of 1200 N. The implants were characterized by gravimetry, inductively coupled plasma optical emission spectrometry (ICP-OES) and cross section scanning electron microscopy (SEM) analysis. It is shown that DLC coated surfaces with uncontaminated tantalum interlayers perform very well and no corrosive or mechanical failure could be observed. This also holds true in tests featuring overload and third-body wear by cortical bone chips present in the bearing pairs. Regarding the interlayer tolerance towards interlayer contamination (oxygen), limits for initiation of potential failure modes were established. It was found that mechanical failure is the most critical aspect and this mode is hypothetically linked to the α-β tantalum phase switch induced by increasing oxygen levels as observed by X-ray diffraction (XRD). It is concluded that DLC coatings are a feasible candidate for near zero wear articulations on implants, potentially even surpassing the performance of ceramic vs. ceramic. PMID:24921709

  4. Diamond Smoothing Tools

    NASA Technical Reports Server (NTRS)

    Voronov, Oleg

    2007-01-01

    Diamond smoothing tools have been proposed for use in conjunction with diamond cutting tools that are used in many finish-machining operations. Diamond machining (including finishing) is often used, for example, in fabrication of precise metal mirrors. A diamond smoothing tool according to the proposal would have a smooth spherical surface. For a given finish machining operation, the smoothing tool would be mounted next to the cutting tool. The smoothing tool would slide on the machined surface left behind by the cutting tool, plastically deforming the surface material and thereby reducing the roughness of the surface, closing microcracks and otherwise generally reducing or eliminating microscopic surface and subsurface defects, and increasing the microhardness of the surface layer. It has been estimated that if smoothing tools of this type were used in conjunction with cutting tools on sufficiently precise lathes, it would be possible to reduce the roughness of machined surfaces to as little as 3 nm. A tool according to the proposal would consist of a smoothing insert in a metal holder. The smoothing insert would be made from a diamond/metal functionally graded composite rod preform, which, in turn, would be made by sintering together a bulk single-crystal or polycrystalline diamond, a diamond powder, and a metallic alloy at high pressure. To form the spherical smoothing tip, the diamond end of the preform would be subjected to flat grinding, conical grinding, spherical grinding using diamond wheels, and finally spherical polishing and/or buffing using diamond powders. If the diamond were a single crystal, then it would be crystallographically oriented, relative to the machining motion, to minimize its wear and maximize its hardness. Spherically polished diamonds could also be useful for purposes other than smoothing in finish machining: They would likely also be suitable for use as heat-resistant, wear-resistant, unlubricated sliding-fit bearing inserts.

  5. Formation of Graphene-on-Diamond Structure by Graphitization of Atomically Flat Diamond (111) Surface

    NASA Astrophysics Data System (ADS)

    Tokuda, Norio; Fukui, Makoto; Makino, Toshiharu; Takeuchi, Daisuke; Yamsaki, Satoshi; Inokuma, Takao

    2013-11-01

    We succeeded in the formation of a graphene-on-diamond (GOD) structure by the graphitization of a diamond (111) surface. Before the graphitization, atomically flat diamond (111) surfaces were formed by homoepitaxial lateral growth. The graphene layers, which were formed on the atomically flat diamond (111) surfaces horizontally, were observed by cross-sectional high-resolution transmission electron microscopy.

  6. Diamond-based MEMS devices for biosensing based on electrochemical and gravimetric

    NASA Astrophysics Data System (ADS)

    Carlisle, John

    2005-03-01

    Diamond offers several potential advantages as a platform material for bioinorganic interfaces, including chemical and bio-inertness, electrochemistry, and high acoustic velocity. Ultrananocrystalline diamond (UNCD), with a unique combination of physical, chemical and electrical properties, is attractive for a variety of biochemical/biomedical applications such as hermetic bio-inert coatings, MEMS compatible biosensors, and electrochemical biointerfaces. Over the past several years we have worked on both the fundamental and applied science related to enabling UNCD-based bioMEMS devices, which has encompassed both the development of UNCD surface functionalization strategies that allow fine control of surface hydrophobicity and bioactivity, as well as the development of material integration strategies and surface micromachining techniques to enable the microfabrication of UNCD structural layers (e.g. cantilevers) that incorporate these functionalized surfaces into MEMS devices which are back-end compatible with CMOS electronics. These devices could thus combine the electrochemical and gravimetric transduction of the selective adsorption of target analytes in MEMS structures fabricated directly on top of a silicon microchip.. In the past year we have successfully demonstrated the use of conducting UNCD thin films as electrochemical biointerfaces, via the successful attachment of a redox enzyme onto the UNCD surface, Glucose oxidase (GOD). The procedure to achieve GOD immobilization involved the electrochemical immobilization of nitrophenyl groups to the UNCD surface and transformation of nitrophenyl to aminophenyl groups and the covalent bonding of GOD to the carboxyl groups using the diisopropylcarbodiimide/ N-hydroxysuccinimide (DCC/NHS) as the catalyst. After immobilization, the activity of the enzyme was demonstrated via the direct electrochemical detection of hydrogen peroxide. We have also developed CMOS-compatible UNCD MEMS cantilevers and fixed-fixed beam structures, using both traditional photolithography and e-beam lithography techniques.

  7. Boron-doped diamond electrode: synthesis, characterization, functionalization and analytical applications.

    PubMed

    Luong, John H T; Male, Keith B; Glennon, Jeremy D

    2009-10-01

    In recent years, conductive diamond electrodes for electrochemical applications have been a major focus of research and development. The impetus behind such endeavors could be attributed to their wide potential window, low background current, chemical inertness, and mechanical durability. Several analytes can be oxidized by conducting diamond compared to other carbon-based materials before the breakdown of water in aqueous electrolytes. This is important for detecting and/or identifying species in solution since oxygen and hydrogen evolution do not interfere with the analysis. Thus, conductive diamond electrodes take electrochemical detection into new areas and extend their usefulness to analytes which are not feasible with conventional electrode materials. Different types of diamond electrodes, polycrystalline, microcrystalline, nanocrystalline and ultrananocrystalline, have been synthesized and characterized. Of particular interest is the synthesis of boron-doped diamond (BDD) films by chemical vapor deposition on various substrates. In the tetrahedral diamond lattice, each carbon atom is covalently bonded to its neighbors forming an extremely robust crystalline structure. Some carbon atoms in the lattice are substituted with boron to provide electrical conductivity. Modification strategies of doped diamond electrodes with metallic nanoparticles and/or electropolymerized films are of importance to impart novel characteristics or to improve the performance of diamond electrodes. Biofunctionalization of diamond films is also feasible to foster several useful bioanalytical applications. A plethora of opportunities for nanoscale analytical devices based on conducting diamond is anticipated in the very near future. PMID:19768202

  8. Method and article of manufacture corresponding to a composite comprised of ultra nonacrystalline diamond, metal, and other nanocarbons useful for thermoelectric and other applications

    DOEpatents

    Gruen, Dieter M.

    2010-05-18

    One provides (101) disperse ultra-nanocrystalline diamond powder material that comprises a plurality of substantially ordered crystallites that are each sized no larger than about 10 nanometers. One then reacts (102) these crystallites with a metallic component. The resultant nanowire is then able to exhibit a desired increase with respect to its ability to conduct electricity while also substantially preserving the thermal conductivity behavior of the disperse ultra-nanocrystalline diamond powder material. The reaction process can comprise combining (201) the crystallites with one or more metal salts in an aqueous solution and then heating (203) that aqueous solution to remove the water. This heating can occur in a reducing atmosphere (comprising, for example, hydrogen and/or methane) to also reduce the salt to metal.

  9. Isotope analysis of diamond-surface passivation effect of high-temperature H2O-grown atomic layer deposition-Al2O3 films

    NASA Astrophysics Data System (ADS)

    Hiraiwa, Atsushi; Saito, Tatsuya; Matsumura, Daisuke; Kawarada, Hiroshi

    2015-06-01

    The Al2O3 film formed using an atomic layer deposition (ALD) method with trimethylaluminum as Al precursor and H2O as oxidant at a high temperature (450 °C) effectively passivates the p-type surface conduction (SC) layer specific to a hydrogen-terminated diamond surface, leading to a successful operation of diamond SC field-effect transistors at 400 °C. In order to investigate this excellent passivation effect, we carried out an isotope analysis using D2O instead of H2O in the ALD and found that the Al2O3 film formed at a conventional temperature (100 °C) incorporates 50 times more CH3 groups than the high-temperature film. This CH3 is supposed to dissociate from the film when heated afterwards at a higher temperature (550 °C) and causes peeling patterns on the H-terminated surface. The high-temperature film is free from this problem and has the largest mass density and dielectric constant among those investigated in this study. The isotope analysis also unveiled a relatively active H-exchange reaction between the diamond H-termination and H2O oxidant during the high-temperature ALD, the SC still being kept intact. This dynamic and yet steady H termination is realized by the suppressed oxidation due to the endothermic reaction with H2O. Additionally, we not only observed the kinetic isotope effect in the form of reduced growth rate of D2O-oxidant ALD but found that the mass density and dielectric constant of D2O-grown Al2O3 films are smaller than those of H2O-grown films. This is a new type of isotope effect, which is not caused by the presence of isotopes in the films unlike the traditional isotope effects that originate from the presence of isotopes itself. Hence, the high-temperature ALD is very effective in forming Al2O3 films as a passivation and/or gate-insulation layer of high-temperature-operation diamond SC devices, and the knowledge of the aforementioned new isotope effect will be a basis for further enhancing ALD technologies in general.

  10. Nanocrystalline Diamond Films for Biosensor Applications

    NASA Astrophysics Data System (ADS)

    Popov, Cyril; Kulisch, Wilhelm

    Diamond is a material with quite a number of excellent properties, like extreme hardness, high elastic modulus, high wear resistance, optical transparency in a broad spectral range, resistivity controllable by the level of dopants, etc. which make it a promising candidate for different sensor applications, e.g. for X-ray detection. Due to its outstanding electrochemical properties, superior chemical inertness and biocompatibility, artificially grown diamond has been recognised as an extremely attractive material for both (bio-)chemical sensing and as an interface to biological systems. This holds for all forms of diamond: monocrystalline (natural or artificial) and poly- (PCD), nano- (NCD) and ultrananocrystalline (UNCD) films. This paper is devoted to possible biosensor application of NCD and UNCD films. The first part will briefly introduce UNCD films (composed of diamond nanocrystallites of 3-5 nm diameter embedded in an amorphous carbon matrix with a grain boundary thickness of 1.0-1.5 nm), their deposition by microwave plasma chemical vapour deposition, their growth mechanisms and the characterization of their bulk properties, comparing them with other types of diamond films. The second part deals with surface modifications of UNCD films, which is the first step towards preparation of a biosensor, including different plasma and chemical processes, the thorough characterization of the resulting surfaces by a variety of techniques (AFM, XPS, ToF-SIMS, contact angle measurements, etc.) and the possibility to pattern the surface properties. The third part will describe possible pathways for the immobilization of biomolecules (proteins, DNA) on UNCD surfaces and the techniques for the characterization of this step, including force measurements, AFM and spectroscopic analyses. In the final part, different examples of biosensors based on UNCD as well as on NCD will be demonstrated in order to reveal the potential of diamond (films) in this field.

  11. Diamond-based capacitive micromachined ultrasonic transducers in immersion.

    PubMed

    Cetin, Ahmet M; Bayram, Baris

    2013-02-01

    Diamond is a superior membrane material for capacitive micromachined ultrasonic transducers (CMUTs). By using ultrananocrystalline diamond (UNCD) membrane and plasma-activated wafer bonding technology, a single diamond-based circular CMUT is demonstrated and operated in immersion for the first time. The diamond-based CMUT, biased at 100 V, is excited with a 10-cycle burst of 36 V(p-p) sine signal at 3.5 MHz. Pressure generated on a 2-D plane coincident with the normal of the CMUT is measured using a broadband hydrophone. Peak-to-peak hydrophone voltage measurements along the scan area clearly indicate the main lobe and the side lobes, as theoretically predicted by our directivity function calculations. The peak-to-peak hydrophone voltage on the axial direction of the CMUT is found to be in agreement with our theoretical calculations in the Fraunhofer region (-45 mm diamond-based CMUT is measured for a dc bias of 100 V, and ac excitation with 30-cycle bursts of 9, 36, and 54 V(p-p) sine signal. A peak response at 5.6 MHz is measured for all ac amplitudes. Overall, diamond is shown to be an applicable membrane for CMUT devices and applications. PMID:23357916

  12. Characterization of single-crystal diamond grown from the vapor phase on substrates of natural diamond

    SciTech Connect

    Altukhov, A. A.; Vikharev, A. L.; Gorbachev, A. M.; Dukhnovsky, M. P.; Zemlyakov, V. E.; Ziablyuk, K. N.; Mitenkin, A. V.; Muchnikov, A. B. Radishev, D. B.; Ratnikova, A. K.; Fedorov, Yu. Yu.

    2011-03-15

    The results of studies of single-crystal diamond layers with orientation (100) grown on substrates of IIa-type natural diamond by chemical-vapor deposition and of semiconductor diamond obtained subsequently by doping by implantation of boron ions are reported. Optimal conditions of postimplantation annealing of diamond that provide the hole mobility of 1150 cm{sup 2} V{sup -1} s{sup -1} (the highest mobility obtained so far for semiconductor diamond after ion implantation) are given.

  13. Surface transfer doping of diamond

    NASA Astrophysics Data System (ADS)

    Strobel, P.; Riedel, M.; Ristein, J.; Ley, L.

    2004-07-01

    The electronic properties of many materials can be controlled by introducing appropriate impurities into the bulk crystal lattice in a process known as doping. In this way, diamond (a well-known insulator) can be transformed into a semiconductor, and recent progress in thin-film diamond synthesis has sparked interest in the potential applications of semiconducting diamond. However, the high dopant activation energies (in excess of 0.36eV) and the limitation of donor incorporation to (111) growth facets only have hampered the development of diamond-based devices. Here we report a doping mechanism for diamond, using a method that does not require the introduction of foreign atoms into the diamond lattice. Instead, C60 molecules are evaporated onto the hydrogen-terminated diamond surface, where they induce a subsurface hole accumulation and a significant rise in two-dimensional conductivity. Our observations bear a resemblance to the so-called surface conductivity of diamond seen when hydrogenated diamond surfaces are exposed to air, and support an electrochemical model in which the reduction of hydrated protons in an aqueous surface layer gives rise to a hole accumulation layer. We expect that transfer doping by C60 will open a broad vista of possible semiconductor applications for diamond.

  14. Nanofabrication of sharp diamond tips by e-beam lithography and inductively coupled plasma reactive ion etching.

    SciTech Connect

    Moldovan, N.; Divan, R.; Zeng, H.; Carlisle, J. A.; Advanced Diamond Tech.

    2009-12-07

    Ultrasharp diamond tips make excellent atomic force microscopy probes, field emitters, and abrasive articles due to diamond's outstanding physical properties, i.e., hardness, low friction coefficient, low work function, and toughness. Sharp diamond tips are currently fabricated as individual tips or arrays by three principal methods: (1) focused ion beam milling and gluing onto a cantilever of individual diamond tips, (2) coating silicon tips with diamond films, or (3) molding diamond into grooves etched in a sacrificial substrate, bonding the sacrificial substrate to another substrate or electrodepositing of a handling chip, followed by dissolution of the sacrificial substrate. The first method is tedious and serial in nature but does produce very sharp tips, the second method results in tips whose radius is limited by the thickness of the diamond coating, while the third method involves a costly bonding and release process and difficulties in thoroughly filling the high aspect ratio apex of molding grooves with diamond at the nanoscale. To overcome the difficulties with these existing methods, this article reports on the feasibility of the fabrication of sharp diamond tips by direct etching of ultrananocrystalline diamond (UNCD{reg_sign}) as a starting and structural material. The UNCD is reactive ion etched using a cap-precursor-mask scheme. An optimized etching recipe demonstrates the formation of ultrasharp diamond tips ({approx} 10 nm tip radius) with etch rates of 650 nm/min.

  15. Diamond-like carbon (DLC) thin film bioelectrodes: effect of thermal post-treatments and the use of Ti adhesion layer.

    PubMed

    Laurila, Tomi; Rautiainen, Antti; Sintonen, Sakari; Jiang, Hua; Kaivosoja, Emilia; Koskinen, Jari

    2014-01-01

    The effect of thermal post-treatments and the use of Ti adhesion layer on the performance of thin film diamond like carbon bioelectrodes (DLC) have been investigated in this work. The following results were obtained: (i) The microstructure of the DLC layer after the deposition was amorphous and thermal annealing had no marked effect on the structure, (ii) formation of oxygen containing SiOx and Ti[O,C] layers were detected at the Si/Ti and Ti/DLC interfaces with the help of transmission electron microscope (TEM), (iii) thermal post-treatments increased the polar fraction of the surface energy, (iv) cyclic voltammetry (CV) measurements showed that the DLC films had wide water windows and were stable in contact with dilute sulphuric acid and phosphate buffered saline (PBS) solutions, (v) use of Ti interlayer between Pt(Ir) microwire and DLC layer was crucial for the electrodes to survive the electrochemical measurements without the loss of adhesion of the DLC layer, (vi) DLC electrodes with small exposed Pt areas were an order of magnitude more sensitive towards dopamine than Pt electrodes and (vii) thermal post-treatments did not markedly change the electrochemical behavior of the electrodes despite the significant increase in the polar nature of the surfaces. It can be concluded that thin DLC bioelectrodes are stable under physiological conditions and can detect dopamine in micro molar range, but their sensitivity must be further improved. PMID:24268281

  16. Industrial diamond

    USGS Publications Warehouse

    Olson, D.W.

    2012-01-01

    Estimated 2011 world production of natural and synthetic industrial diamond was about 4.45 billion carats. During 2011, natural industrial diamonds were produced in more than 20 countries, and synthetic industrial diamond was produced in at least 13 countries. About 98 percent of the combined natural and synthetic global output was produced in China, Ireland, Japan, Russia, South Africa and the United States. China is the world's leading producer of synthetic industrial diamond followed by Russia and the United States.

  17. Industrial diamond

    USGS Publications Warehouse

    Olson, D.W.

    2011-01-01

    Estimated world production of natural and synthetic industrial diamond was about 4.44 billion carats in 2010. Natural industrial diamond deposits have been found in more than 35 countries, and synthetic industrial diamond is produced in at least 15 countries.

  18. Industrial diamond

    USGS Publications Warehouse

    Olson, D.W.

    2006-01-01

    In 2005, estimated world production of natural and synthetic industrial diamond was 630 million carats. Natural industrial diamond deposits were found in more than 35 countries. Synthetic industrial diamond is produced in at least 15 countries. More than 81% of the combined natural and synthetic global output was produced in Ireland, Japan, Russia, South Africa and the United States.

  19. Industrial diamond

    USGS Publications Warehouse

    Olson, D.W.

    2013-01-01

    Estimated 2012 world production of natural and synthetic industrial diamond was about 4.45 billion carats. During 2012, natural industrial diamonds were produced in at least 20 countries, and synthetic industrial diamond was produced in at least 12 countries. About 99 percent of the combined natural and synthetic global output was produced in Belarus, China, Ireland, Japan, Russia, South Africa and the United States. During 2012, China was the world’s leading producer of synthetic industrial diamond followed by the United States and Russia. In 2012, the two U.S. synthetic producers, one in Pennsylvania and the other in Ohio, had an estimated output of 103 million carats, valued at about $70.6 million. This was an estimated 43.7 million carats of synthetic diamond bort, grit, and dust and powder with a value of $14.5 million combined with an estimated 59.7 million carats of synthetic diamond stone with a value of $56.1 million. Also in 2012, nine U.S. firms manufactured polycrystalline diamond (PCD) from synthetic diamond grit and powder. The United States government does not collect or maintain data for either domestic PCD producers or domestic chemical vapor deposition (CVD) diamond producers for quantity or value of annual production. Current trade and consumption quantity data are not available for PCD or for CVD diamond. For these reasons, PCD and CVD diamond are not included in the industrial diamond quantitative data reported here.

  20. Spacetime diamonds

    NASA Astrophysics Data System (ADS)

    Su, Daiqin; Ralph, T. C.

    2016-02-01

    We show that the particle-number distribution of diamond modes, modes that are localized in a finite spacetime region, are thermal for the Minkowski vacuum state of a massless scalar field, an analogue to the Unruh effect. The temperature of the diamond is inversely proportional to its size. An inertial observer can detect this thermal radiation by coupling to the diamond modes using an appropriate energy-scaled detector. We further investigate the correlations between various diamonds and find that entanglement between adjacent diamonds dominates.

  1. Industrial diamond

    USGS Publications Warehouse

    Olson, D.W.

    2000-01-01

    Part of the 1999 Industrial Minerals Review. A review of the state of the global industrial diamond industry in 1999 is presented. World consumption of industrial diamond has increased annually in recent years, with an estimated 500 million carats valued between $650 million and $800 million consumed in 1999. In 1999, the U.S. was the world's largest market for industrial diamond and was also one of the world's main producers; the others were Ireland, Russia, and South Africa. Uses of industrial diamonds are discussed, and prices of natural and synthetic industrial diamond are reported.

  2. The induction of nanographitic phase on Fe coated diamond films for the enhancement in electron field emission properties

    NASA Astrophysics Data System (ADS)

    Panda, Kalpataru; Sundaravel, B.; Panigrahi, B. K.; Chen, H.-C.; Huang, P.-C.; Shih, W.-C.; Lo, S.-C.; Lin, L.-J.; Lee, C.-Y.; Lin, I.-N.

    2013-03-01

    A thin layer of iron coating and subsequent post-annealing (Fe-coating/post-annealing) is seen to significantly enhance the electron field emission (EFE) properties of ultrananocrystalline diamond (UNCD) films. The best EFE properties, with a turn on field (E0) of 1.98 V/?m and current density (Je) of 705 ?A/cm2 at 7.5 V/?m, are obtained for the films, which were Fe-coated/post-annealed at 900 C in H2 atmosphere. The mechanism behind the enhanced EFE properties of Fe coated/post-annealed UNCD films are explained by the microstructural analysis which shows formation of nanographitic phase surrounding the Fe (or Fe3C) nanoparticles. The role of the nanographitic phase in improving the emission sites of Fe coated/post-annealed UNCD films is clearly revealed by the current imaging tunneling spectroscopy (CITS) images. The CITS images clearly show significant increase in emission sites in Fe-coated/post-annealed UNCD films than the as-deposited one. Enhanced emission sites are mostly seen around the boundaries of the Fe (or Fe3C) nanoparticles which were formed due to the Fe-coating/post-annealing processes. Moreover, the Fe-coating/post-annealing processes enhance the EFE properties of UNCD films more than that on the microcrystalline diamond films. The authentic factor, resulting in such a phenomenon, is attributed to the unique granular structure of the UNCD films. The nano-sized and uniformly distributed grains of UNCD films, resulted in markedly smaller and densely populated Fe-clusters, which, in turn, induced more finer and higher populated nano-graphite clusters.

  3. Diamond detector - material science, design and application

    NASA Astrophysics Data System (ADS)

    Gaowei, Mengjia

    Modern synchrotrons, such as the NSLS-II, will enable unprecedented science by having extremely high brightness and flux with exceptional beam stability. These capabilities create a harsh and demanding environment for measuring the characteristics of the x-ray beam. In many cases, existing measurement techniques fail completely, requiring the development of new detectors which can meet the demands of the synchrotron. The combination of diamond properties ranked diamond an appealing candidate in the field of radiation detection in extreme conditions and it has been used as x-ray sensor material for decades. However, only until the development of chemical vapor deposition (CVD) process in the synthesis of diamond that has it been considered for wider applications in the state-of-art synchrotron light sources as part of beamline diagnostics, including the detection of x-ray beam flux and position. While defects and dislocations in CVD grown single crystal diamonds are inevitable, there are solutions in other aspects of a device fabrication to compensate this technological downside, including improving device performance in engineering diamond surface electrode materials and patterns and slicing and polishing diamond plates into thinner pieces. The content of this dissertation summarizes our effort in addressing several problems we encounter in the process of design and fabrication of single crystal CVD diamond based electronic devices. In order to study the generation of post-anneal photoconductive gain in our devices we have discussed in section 3 and 4 the two criteria for the observation of photoconductive current. In section 3 we reveal the correlation between structural defects in diamond and the post-anneal photoconductive regions. Section 4 introduces the measurements of hard x-ray photoelectron spectroscopy (HAXPES) we applied to investigate the diamond-metal Schottky barrier height for several metals and diamond surface terminations. The position of the diamond valence-band maximum was determined by theoretically calculating the diamond density of states and applying cross section corrections. The diamond-platinum Schottky barrier height was lowered by 0.2 eV after thermal annealing, indicating annealing may increase carrier injection in diamond devices leading to photoconductive gain. In order to adapt our device to soft x-ray applications, efforts are made to develop a thin diamond position monitor for lowering device absorption. In section 5 we have discussed the fabrication and testing of thin diamond x-ray monitors made from diamond plates with nominal thickness of 30microm, which is 1/10th of the thickness of the diamonds we previously used. Calibration results of this detector are presented and discussed in comparison with thicker diamond sensors. Section 6 introduces our effort on the investigation of carrier loss mechanism in diamond detectors. Near edge responsivity in diamond x-ray detectors has been used to confirm the carrier loss mechanism as recombination due to diffusion into the incident electrode. We present a detailed study of the bias dependence of the diamond responsivity across the carbon k-edge. The carrier loss is modeled by incorporating a characteristic recombination length into the absorption model and is shown to agree well with Monte Carlo simulated carrier losses. In addition, nitrogen doped ultrananocrystalline diamond (nUNCD) grown on the surface of a CVD single crystal diamond as an alternative contact to metal is tested in the similar measurements as the metal contact diamond. nUNCD has a much lower x-ray absorption than metal contacts and is designed to improve the performance of our device. This diamond is calibrated over a wide photon energy range from 0.2 keV to 28 keV, and compared with platinum coated diamond. Results of these studies will be presented and discussed in section 7. Future work has been proposed in the last section in improving the design and fabrication of diamond based electronics as well as in the investigation to enhance our understanding of its material and

  4. Diamond Electronic Devices

    SciTech Connect

    Isberg, J.

    2010-11-01

    For high-power and high-voltage applications, silicon is by far the dominant semiconductor material. However, silicon has many limitations, e.g. a relatively low thermal conductivity, electric breakdown occurs at relatively low fields and the bandgap is 1.1 eV which effectively limits operation to temperatures below 175 deg.n C. Wide-bandgap materials, such as silicon carbide (SiC), gallium nitride (GaN) and diamond offer the potential to overcome both the temperature and power handling limitations of silicon. Diamond is the most extreme in this class of materials. By the fundamental material properties alone, diamond offers the largest benefits as a semiconductor material for power electronic applications. On the other hand, diamond has a problem with a large carrier activation energy of available dopants which necessitates specialised device concepts to allow room temperature (RT) operation. In addition, the role of common defects on the charge transport properties of diamond is poorly understood. Notwithstanding this, many proof-of-principle two-terminal and three-terminal devices have been made and tested. Two-terminal electronic diamond devices described in the literature include: p-n diodes, p-i-n diodes, various types of radiation detectors, Schottky diodes and photoconductive or electron beam triggered switches. Three terminal devices include e.g. MISFETs and JFETs. However, the development of diamond devices poses great challenges for the future. A particularly interesting way to overcome the doping problem, for which there has been some recent progress, is to make so-called delta doped (or pulse-doped) devices. Such devices utilise very thin ({approx}1 nm) doped layers in order to achieve high RT activation.

  5. Diamond Electronic Devices

    NASA Astrophysics Data System (ADS)

    Isberg, J.

    2010-11-01

    For high-power and high-voltage applications, silicon is by far the dominant semiconductor material. However, silicon has many limitations, e.g. a relatively low thermal conductivity, electric breakdown occurs at relatively low fields and the bandgap is 1.1 eV which effectively limits operation to temperatures below 175° C. Wide-bandgap materials, such as silicon carbide (SiC), gallium nitride (GaN) and diamond offer the potential to overcome both the temperature and power handling limitations of silicon. Diamond is the most extreme in this class of materials. By the fundamental material properties alone, diamond offers the largest benefits as a semiconductor material for power electronic applications. On the other hand, diamond has a problem with a large carrier activation energy of available dopants which necessitates specialised device concepts to allow room temperature (RT) operation. In addition, the role of common defects on the charge transport properties of diamond is poorly understood. Notwithstanding this, many proof-of-principle two-terminal and three-terminal devices have been made and tested. Two-terminal electronic diamond devices described in the literature include: p-n diodes, p-i-n diodes, various types of radiation detectors, Schottky diodes and photoconductive or electron beam triggered switches. Three terminal devices include e.g. MISFETs and JFETs. However, the development of diamond devices poses great challenges for the future. A particularly interesting way to overcome the doping problem, for which there has been some recent progress, is to make so-called delta doped (or pulse-doped) devices. Such devices utilise very thin (˜1 nm) doped layers in order to achieve high RT activation.

  6. Diamond optics IV; Proceedings of the Meeting, San Diego, CA, July 22, 23, 1991

    NASA Astrophysics Data System (ADS)

    Feldman, Albert; Holly, Sandor

    1991-12-01

    The proceedings on diamond optics include topics on diamond film growth, growth mechanisms, optical properties, diamondlike carbon and bulk diamond, growth mechanisms and diamond composites, and deposition processes and characterizations. Papers are presented on pressure effects in the microwave plasma growth of polycrystalline diamond, diagnostics of a DC plasma torch, effects of interfacial modifications on diamond film adhesion, polishing of filament-assisted CVD diamond films, diamond growth on the (110) surface, and critical-point phonons of diamond. Other papers include those on optical properties of amorphous hydrogenated carbon layers, fundamental studies of chemical-vapor-deposition diamond growth processes, optical properties of ZnS/diamond composites, a study of impurities in CVD diamond using cathodoluminescence, smooth diamond films by reactive ion-beam polishing, and morphological phenomena of CVD diamond.

  7. Diamond pixel modules

    NASA Astrophysics Data System (ADS)

    Rd42 Collaboration; Asner, D.; Barbero, M.; Bellini, V.; Belyaev, V.; Brom, J.-M.; Bruzzi, M.; Chren, D.; Cindro, V.; Claus, G.; Cristinziani, M.; Costa, S.; D'Alessandro, R.; de Boer, W.; Dobos, D.; Dolenc, I.; Dulinski, W.; Duris, J.; Eremin, V.; Eusebi, R.; Frais-Klbl, H.; Furgeri, A.; Gan, K. K.; Goffe, M.; Goldstein, J.; Golubev, A.; Goriek, A.; Griesmayer, E.; Grigoriev, E.; Hits, D.; Hgging, F.; Kagan, H.; Kass, R.; Kramberger, G.; Kuleshov, S.; Lagomarsino, S.; La Rosa, A.; Lo Giudice, A.; Mandic, I.; Manfredotti, C.; Manfredotti, C.; Martemyanov, A.; Mathes, M.; Menichelli, D.; Miku, M.; Mishina, M.; Moss, J.; Mueller, S.; Oakham, G.; Olivero, P.; Parrini, G.; Pernegger, H.; Potenza, R.; Randrianarivony, K.; Robichaud, A.; Roe, S.; Schaffner, D.; Schnetzer, S.; Schreiner, T.; Sciortino, S.; Smith, S.; Sopko, B.; Stone, R.; Sutera, C.; Trischuk, W.; Tsung, J.-W.; Tuve, C.; Velthuis, J.; Vittone, E.; Wallny, R.; Weilhammer, P.; Wermes, N.; RD42 Collaboration

    2011-04-01

    With the commissioning of the LHC in 2010 and upgrades expected in 2015, ATLAS and CMS are planning to upgrade their innermost tracking layers with radiation hard technologies. Chemical Vapor Deposition diamond has been used extensively in beam conditions monitors as the innermost detectors in the highest radiation areas of BaBar, Belle, CDF and all LHC experiments. This material is now being considered as a sensor material for use very close to the interaction region where the most extreme radiation conditions exist. Recently the RD42 collaboration constructed, irradiated and tested polycrystalline and single-crystal chemical vapor deposition diamond sensors to the highest fluences expected at the super-LHC. We present beam test results of chemical vapor deposition diamond up to fluences of 1.81016 protons/cm2 illustrating that both polycrystalline and single-crystal chemical vapor deposition diamonds follow a single damage curve. We also present beam test results of irradiated complete diamond pixel modules.

  8. High-reliability passivation of hydrogen-terminated diamond surface by atomic layer deposition of Al{sub 2}O{sub 3}

    SciTech Connect

    Daicho, Akira Saito, Tatsuya; Kurihara, Shinichiro; Kawarada, Hiroshi; Hiraiwa, Atsushi

    2014-06-14

    Although the two-dimensional hole gas (2DHG) of a hydrogen-terminated diamond surface provides a unique p-type conducting layer for high-performance transistors, the conductivity is highly sensitive to its environment. Therefore, the surface must be passivated to preserve the 2DHG, especially at high temperature. We passivated the surface at high temperature (450 °C) without the loss of C-H surface bonds by atomic layer deposition (ALD) and investigated the thermal reliability of the Al{sub 2}O{sub 3} film. As a result, C-H bonds were preserved, and the hole accumulation effect appeared after the Al{sub 2}O{sub 3} deposition by ALD with H{sub 2}O as an oxidant. The sheet resistivity and hole density were almost constant between room temperature and 500 °C by the passivation with thick Al{sub 2}O{sub 3} film thicker than 38 nm deposited by ALD at 450 °C. After the annealing at 550 °C in air The sheet resistivity and hole density were preserved. These results indicate the possibility of high-temperature application of the C-H surface diamond device in air. In the case of lower deposition temperatures, the sheet resistivity increased after air annealing, suggesting an insufficient protection capability of these films. Given the result of sheet resistivity after annealing, the increase in the sheet resistivity of these samples was not greatly significant. However, bubble like patterns were observed in the Al{sub 2}O{sub 3} films formed from 200 to 400 °C by air annealing at 550 °C for 1 h. On the other hand, the patterns were no longer observed at 450 °C deposition. Thus, this 450 °C deposition is the sole solution to enabling power device application, which requires high reliability at high temperatures.

  9. Diamond Coatings

    NASA Technical Reports Server (NTRS)

    1990-01-01

    Advances in materials technology have demonstrated that it is possible to get the advantages of diamond in a number of applications without the cost penalty, by coating and chemically bonding an inexpensive substrate with a thin film of diamond-like carbon (DLC). Diamond films offer tremendous technical and economic potential in such advances as chemically inert protective coatings; machine tools and parts capable of resisting wear 10 times longer; ball bearings and metal cutting tools; a broad variety of optical instruments and systems; and consumer products. Among the American companies engaged in DLC commercialization is Diamonex, Inc., a diamond coating spinoff of Air Products and Chemicals, Inc. Along with its own proprietary technology for both polycrystalline diamond and DLC coatings, Diamonex is using, under an exclusive license, NASA technology for depositing DLC on a substrate. Diamonex is developing, and offering commercially, under the trade name Diamond Aegis, a line of polycrystalline diamond-coated products that can be custom tailored for optical, electronic and engineering applications. Diamonex's initial focus is on optical products and the first commercial product is expected in late 1990. Other target applications include electronic heat sink substrates, x-ray lithography masks, metal cutting tools and bearings.

  10. Generation of microdischarges in diamond substrates

    NASA Astrophysics Data System (ADS)

    Mitea, S.; Zeleznik, M.; Bowden, M. D.; May, P. W.; Fox, N. A.; Hart, J. N.; Fowler, C.; Stevens, R.; StJ Braithwaite, N.

    2012-04-01

    We report the generation of microdischarges in devices composed of microcrystalline diamond. Discharges were generated in device structures with microhollow cathode discharge geometries. One structure consisted of an insulating diamond wafer coated with boron-doped diamond layers on both sides. A second structure consisted of an insulating diamond wafer coated with metal layers on both sides. In each case, a single sub-millimetre hole was machined through the conductor-insulator-conductor structure. The discharges were generated in a helium atmosphere. Breakdown voltages were around 500 V and discharge currents in the range 0.1-2.5 mA were maintained by a sustaining dc voltage of 300 V.

  11. Industrial diamond

    USGS Publications Warehouse

    Olson, D.W.

    2007-01-01

    World production of natural and synthetic industrial diamond was about 648 million carats in 2006, with 79 percent of the production coming from Ireland, Japan, Russia, South Africa, and the U.S. U.S. consumption was was an estimated 602 million carats, imports were over 391 million carats, and exports were about 83 million carats. About 87 percent of the industrial diamonds market uses synthetic diamonds, which are expected to become less expensive as technology improves and competition from low-cost producers increases.

  12. Shock consolidation of diamond and graphite mixtures to fused polycrystalline diamond

    NASA Astrophysics Data System (ADS)

    Potter, David K.; Ahrens, Thomas J.

    1988-02-01

    The production of fused compacts of polycrystalline diamond was achieved by subjecting porous (35%-49% porosity) mixtures of diamond crystals plus graphite (13-16 wt. %) to dynamic shock pressures of 10-18 GPa. The recovered material from an initial mixture of 4-8-μm diamond crystals plus graphite revealed a very homogeneous texture with little evidence of original grain boundaries. The preconsolidation addition of graphite also allowed ultrafine (<5 μm) diamond crystals to be consolidated; this was not previously possible with the use of diamond crystals alone. The results are consistent with calculations which suggest that a thin layer of graphite surrounding a diamond crystal delays thermal equilibrium between the surface and interior of the diamond crystal, thus allowing greater surface heating. Consolidation is also probably enhanced by conversion of graphite to diamond, possibly via the liquid state.

  13. A novel radial anode layer ion source for inner wall pipe coating and materials modificationHydrogenated diamond-like carbon coatings from butane gas

    NASA Astrophysics Data System (ADS)

    Murmu, Peter P.; Markwitz, Andreas; Suschke, Konrad; Futter, John

    2014-08-01

    We report a new ion source development for inner wall pipe coating and materials modification. The ion source deposits coatings simultaneously in a 360 radial geometry and can be used to coat inner walls of pipelines by simply moving the ion source in the pipe. Rotating parts are not required, making the source ideal for rough environments and minimizing maintenance and replacements of parts. First results are reported for diamond-like carbon (DLC) coatings on Si and stainless steel substrates deposited using a novel 360 ion source design. The ion source operates with permanent magnets and uses a single power supply for the anode voltage and ion acceleration up to 10 kV. Butane (C4H10) gas is used to coat the inner wall of pipes with smooth and homogeneous DLC coatings with thicknesses up to 5 ?m in a short time using a deposition rate of 70 10 nm min-1. Rutherford backscattering spectrometry results showed that DLC coatings contain hydrogen up to 30 3% indicating deposition of hydrogenated DLC (a-C:H) coatings. Coatings with good adhesion are achieved when using a multiple energy implantation regime. Raman spectroscopy results suggest slightly larger disordered DLC layers when using low ion energy, indicating higher sp3 bonds in DLC coatings. The results show that commercially interesting coatings can be achieved in short time.

  14. A novel radial anode layer ion source for inner wall pipe coating and materials modification--hydrogenated diamond-like carbon coatings from butane gas.

    PubMed

    Murmu, Peter P; Markwitz, Andreas; Suschke, Konrad; Futter, John

    2014-08-01

    We report a new ion source development for inner wall pipe coating and materials modification. The ion source deposits coatings simultaneously in a 360° radial geometry and can be used to coat inner walls of pipelines by simply moving the ion source in the pipe. Rotating parts are not required, making the source ideal for rough environments and minimizing maintenance and replacements of parts. First results are reported for diamond-like carbon (DLC) coatings on Si and stainless steel substrates deposited using a novel 360° ion source design. The ion source operates with permanent magnets and uses a single power supply for the anode voltage and ion acceleration up to 10 kV. Butane (C4H10) gas is used to coat the inner wall of pipes with smooth and homogeneous DLC coatings with thicknesses up to 5 μm in a short time using a deposition rate of 70 ± 10 nm min(-1). Rutherford backscattering spectrometry results showed that DLC coatings contain hydrogen up to 30 ± 3% indicating deposition of hydrogenated DLC (a-C:H) coatings. Coatings with good adhesion are achieved when using a multiple energy implantation regime. Raman spectroscopy results suggest slightly larger disordered DLC layers when using low ion energy, indicating higher sp(3) bonds in DLC coatings. The results show that commercially interesting coatings can be achieved in short time. PMID:25173323

  15. Multi-layer haemocompatible diamond-like carbon coatings obtained by combined radio frequency plasma enhanced chemical vapor deposition and magnetron sputtering.

    PubMed

    Popa, A C; Stan, G E; Husanu, M A; Pasuk, I; Popescu, I D; Popescu, A C; Mihailescu, I N

    2013-12-01

    Radio-frequency Plasma Enhanced Chemical Vapour Deposition (in different methane dilutions) was used to synthesize adherent and haemocompatible diamond-like carbon (DLC) films on medical grade titanium substrates. The improvement of the adherence has been achieved by interposing a functional buffer layer with graded composition TixTiC1-x (x = 0-1) synthesized by magnetron co-sputtering. Bonding strength values of up to ~67 MPa have been measured by pull-out tests. Films with different sp(3)/sp(2) ratio have been obtained by changing the methane concentration in the deposition chamber. Raman spectroscopy, X-ray photoelectron spectroscopy and X-ray diffraction were employed for the physical-chemical characterization of the samples. The highest concentration of sp(3)-C (~87 %), corresponding to a lower DLC surface energy (28.7 mJ/m(2) ), was deposited in a pure methane atmosphere. The biological response of the DLC films was assayed by a state-of-the-art biological analysis method (surface enhanced laser desorption/ionization-time of flight mass spectroscopy), in conjunction with other dedicated testing techniques: Western blot and partial thromboplastin time. The data support a cause-effect relationship between sp(3)-C content, surface energy and coagulation time, as well as between platelet-surface adherence properties and protein adsorption profiles. PMID:23943017

  16. Diamond nanophotonics

    PubMed Central

    Beha, Katja; Wolfer, Marco; Becker, Merle C; Siyushev, Petr; Jamali, Mohammad; Batalov, Anton; Hinz, Christopher; Hees, Jakob; Kirste, Lutz; Obloh, Harald; Gheeraert, Etienne; Naydenov, Boris; Jakobi, Ingmar; Dolde, Florian; Pezzagna, Sbastien; Twittchen, Daniel; Markham, Matthew; Dregely, Daniel; Giessen, Harald; Meijer, Jan; Jelezko, Fedor; Nebel, Christoph E; Bratschitsch, Rudolf; Leitenstorfer, Alfred; Wrachtrup, Jrg

    2012-01-01

    Summary We demonstrate the coupling of single color centers in diamond to plasmonic and dielectric photonic structures to realize novel nanophotonic devices. Nanometer spatial control in the creation of single color centers in diamond is achieved by implantation of nitrogen atoms through high-aspect-ratio channels in a mica mask. Enhanced broadband single-photon emission is demonstrated by coupling nitrogenvacancy centers to plasmonic resonators, such as metallic nanoantennas. Improved photon-collection efficiency and directed emission is demonstrated by solid immersion lenses and micropillar cavities. Thereafter, the coupling of diamond nanocrystals to the guided modes of micropillar resonators is discussed along with experimental results. Finally, we present a gas-phase-doping approach to incorporate color centers based on nickel and tungsten, in situ into diamond using microwave-plasma-enhanced chemical vapor deposition. The fabrication of siliconvacancy centers in nanodiamonds by microwave-plasma-enhanced chemical vapor deposition is discussed in addition. PMID:23365803

  17. Industrial diamond

    USGS Publications Warehouse

    Olson, D.W.

    2004-01-01

    Part of the 2003 industrial minerals review. Supply and demand data for industrial diamond are provided. Topics discussed are consumption, prices, imports and exports, government stockpiles, and the outlook for 2004.

  18. Diamond nanophotonics.

    PubMed

    Beha, Katja; Fedder, Helmut; Wolfer, Marco; Becker, Merle C; Siyushev, Petr; Jamali, Mohammad; Batalov, Anton; Hinz, Christopher; Hees, Jakob; Kirste, Lutz; Obloh, Harald; Gheeraert, Etienne; Naydenov, Boris; Jakobi, Ingmar; Dolde, Florian; Pezzagna, Sbastien; Twittchen, Daniel; Markham, Matthew; Dregely, Daniel; Giessen, Harald; Meijer, Jan; Jelezko, Fedor; Nebel, Christoph E; Bratschitsch, Rudolf; Leitenstorfer, Alfred; Wrachtrup, Jrg

    2012-01-01

    We demonstrate the coupling of single color centers in diamond to plasmonic and dielectric photonic structures to realize novel nanophotonic devices. Nanometer spatial control in the creation of single color centers in diamond is achieved by implantation of nitrogen atoms through high-aspect-ratio channels in a mica mask. Enhanced broadband single-photon emission is demonstrated by coupling nitrogen-vacancy centers to plasmonic resonators, such as metallic nanoantennas. Improved photon-collection efficiency and directed emission is demonstrated by solid immersion lenses and micropillar cavities. Thereafter, the coupling of diamond nanocrystals to the guided modes of micropillar resonators is discussed along with experimental results. Finally, we present a gas-phase-doping approach to incorporate color centers based on nickel and tungsten, in situ into diamond using microwave-plasma-enhanced chemical vapor deposition. The fabrication of silicon-vacancy centers in nanodiamonds by microwave-plasma-enhanced chemical vapor deposition is discussed in addition. PMID:23365803

  19. Nanocrystalline diamond for medicine

    NASA Astrophysics Data System (ADS)

    Mitura, Stanislaw

    1997-06-01

    The unique properties of thin amorphous diamond layers make them perspective candidates for producing advanced micro- electronic devices, coatings for cutting tools and optics. Moreover, due to the highest bicompatibility of carbon resulting from the presence of this element in human body, it appears to be a potential biomaterial. Until present the amorphous diamond has found industrial applications in some areas. One of the applications of the carbon layers are coatings for medical implants. The studies of carbon films as coatings for implants in surgery were aimed on the investigations of biological resistance of implants, histopathological investigations on laboratory animals, tests of corrosion resistance, measurements of mechanical properties and a breakdown test in Tyrod solution. The current state of published work in the subject is reviewed in the paper together with a discussion concerning classification of this material.

  20. Diamond fiber field emitters

    DOEpatents

    Blanchet-Fincher, Graciela B. (Wilmington, DE); Coates, Don M. (Santa Fe, NM); Devlin, David J. (Los Alamos, NM); Eaton, David F. (Wilmington, DE); Silzars, Aris K. (Landenburg, PA); Valone, Steven M. (Santa Fe, NM)

    1996-01-01

    A field emission electron emitter comprising an electrode formed of at least one diamond, diamond-like carbon or glassy carbon composite fiber, said composite fiber having a non-diamond core and a diamond, diamond-like carbon or glassy carbon coating on said non-diamond core, and electronic devices employing such a field emission electron emitter.

  1. Diamond and biology.

    PubMed

    Nebel, Christoph E; Shin, Dongchan; Rezek, Bohuslav; Tokuda, Norio; Uetsuka, Hiroshi; Watanabe, Hideyuki

    2007-06-22

    A summary of photo- and electrochemical surface modifications applied on single-crystalline chemical vapour deposition diamond films is given. The covalently bonded formation of amine and phenyl linker molecular layers is characterized using X-ray photoelectron spectroscopy, atomic force microscopy (AFM), cyclic voltammetry and field-effect transistor characterization experiments. Amine and phenyl layers are very different with respect to formation, growth, thickness and molecular arrangement. We deduce a sub-monolayer of amine linker molecules on diamond with approximately 10% coverage of 1.510(15) cm(-2) carbon bonds. Amine is bonded only on initially H-terminated surface areas. In the case of electrochemical deposition of phenyl layers, multilayer properties are detected with three-dimensional nitrophenyl growth properties. This leads to the formation of typically 25 A thick layers. The electrochemical bonding to boron-doped diamond works on H-terminated and oxidized surfaces. After reacting such films with heterobifunctional cross-linker molecules, thiol-modified ss-DNA markers are bonded to the organic system. Application of fluorescence and AFM on hybridized DNA films shows dense arrangements with densities up to 10(13) cm(-2). The DNA is tilted by an angle of approximately 35 degrees with respect to the diamond surface. Shortening the bonding time of thiol-modified ss-DNA to 10 min causes a decrease in DNA density to approximately 10(12) cm(-2). Application of AFM scratching experiments shows threshold removal forces of approximately 75 and 45 nN for the DNA bonded to the phenyl and the amine linker molecules, respectively. First, DNA sensor applications using Fe(CN6) 3-/4- mediator redox molecules and DNA field-effect transistor devices are introduced and discussed. PMID:17251162

  2. Boron concentration profiling by high angle annular dark field-scanning transmission electron microscopy in homoepitaxial δ-doped diamond layers

    SciTech Connect

    Araújo, D.; Alegre, M. P.; Piñero, J. C.; Fiori, A.; Bustarret, E.; Jomard, F.

    2013-07-22

    To develop further diamond related devices, the concentration and spatial location of dopants should be controlled down to the nanometer scale. Scanning transmission electron microscopy using the high angle annular dark field mode is shown to be sensitive to boron doping in diamond epilayers. An analytical procedure is described, whereby local boron concentrations above 10{sup 20} cm{sup −3} were quantitatively derived down to nanometer resolution from the signal dependence on thickness and boron content. Experimental boron local doping profiles measured on diamond p{sup −}/p{sup ++}/p{sup −} multilayers are compared to macroscopic profiles obtained by secondary ion mass spectrometry, avoiding reported artefacts.

  3. Advanced Diamond Anvil Techniques (Customized Diamond Anvils)

    SciTech Connect

    Weir, S

    2009-02-11

    A complete set of diamond-based fabrication tools now exists for making a wide range of different types of diamond anvils which are tailored for various high-P applications. Current tools include: CVD diamond deposition (making diamond); Diamond polishing, laser drilling, plasma etching (removal of diamond); and Lithography, 3D laser pantography (patterning features onto diamond); - Metal deposition (putting electrical circuits and metal masks onto diamond). Current applications include the following: Electrical Conductivity; Magnetic Susceptibility; and High-P/High-T. Future applications may include: NMR; Hall Effect; de Haas - Shubnikov (Fermi surface topology); Calorimetry; and thermal conductivity.

  4. Diamond-modified AFM probes: from diamond nanowires to atomic force microscopy-integrated boron-doped diamond electrodes.

    PubMed

    Smirnov, Waldemar; Kriele, Armin; Hoffmann, Ren; Sillero, Eugenio; Hees, Jakob; Williams, Oliver A; Yang, Nianjun; Kranz, Christine; Nebel, Christoph E

    2011-06-15

    In atomic force microscopy (AFM), sharp and wear-resistant tips are a critical issue. Regarding scanning electrochemical microscopy (SECM), electrodes are required to be mechanically and chemically stable. Diamond is the perfect candidate for both AFM probes as well as for electrode materials if doped, due to diamond's unrivaled mechanical, chemical, and electrochemical properties. In this study, standard AFM tips were overgrown with typically 300 nm thick nanocrystalline diamond (NCD) layers and modified to obtain ultra sharp diamond nanowire-based AFM probes and probes that were used for combined AFM-SECM measurements based on integrated boron-doped conductive diamond electrodes. Analysis of the resonance properties of the diamond overgrown AFM cantilevers showed increasing resonance frequencies with increasing diamond coating thicknesses (i.e., from 160 to 260 kHz). The measured data were compared to performed simulations and show excellent correlation. A strong enhancement of the quality factor upon overgrowth was also observed (120 to 710). AFM tips with integrated diamond nanowires are shown to have apex radii as small as 5 nm and where fabricated by selectively etching diamond in a plasma etching process using self-organized metal nanomasks. These scanning tips showed superior imaging performance as compared to standard Si-tips or commercially available diamond-coated tips. The high imaging resolution and low tip wear are demonstrated using tapping and contact mode AFM measurements by imaging ultra hard substrates and DNA. Furthermore, AFM probes were coated with conductive boron-doped and insulating diamond layers to achieve bifunctional AFM-SECM probes. For this, focused ion beam (FIB) technology was used to expose the boron-doped diamond as a recessed electrode near the apex of the scanning tip. Such a modified probe was used to perform proof-of-concept AFM-SECM measurements. The results show that high-quality diamond probes can be fabricated, which are suitable for probing, manipulating, sculpting, and sensing at single digit nanoscale. PMID:21534601

  5. 'Diamond' in 3-D

    NASA Technical Reports Server (NTRS)

    2004-01-01

    This 3-D, microscopic imager mosaic of a target area on a rock called 'Diamond Jenness' was taken after NASA's Mars Exploration Rover Opportunity ground into the surface with its rock abrasion tool for a second time.

    Opportunity has bored nearly a dozen holes into the inner walls of 'Endurance Crater.' On sols 177 and 178 (July 23 and July 24, 2004), the rover worked double-duty on Diamond Jenness. Surface debris and the bumpy shape of the rock resulted in a shallow and irregular hole, only about 2 millimeters (0.08 inch) deep. The final depth was not enough to remove all the bumps and leave a neat hole with a smooth floor. This extremely shallow depression was then examined by the rover's alpha particle X-ray spectrometer.

    On Sol 178, Opportunity's 'robotic rodent' dined on Diamond Jenness once again, grinding almost an additional 5 millimeters (about 0.2 inch). The rover then applied its Moessbauer spectrometer to the deepened hole. This double dose of Diamond Jenness enabled the science team to examine the rock at varying layers. Results from those grindings are currently being analyzed.

    The image mosaic is about 6 centimeters (2.4 inches) across.

  6. Amorphous-diamond electron emitter

    DOEpatents

    Falabella, Steven (Livermore, CA)

    2001-01-01

    An electron emitter comprising a textured silicon wafer overcoated with a thin (200 .ANG.) layer of nitrogen-doped, amorphous-diamond (a:D-N), which lowers the field below 20 volts/micrometer have been demonstrated using this emitter compared to uncoated or diamond coated emitters wherein the emission is at fields of nearly 60 volts/micrometer. The silicon/nitrogen-doped, amorphous-diamond (Si/a:D-N) emitter may be produced by overcoating a textured silicon wafer with amorphous-diamond (a:D) in a nitrogen atmosphere using a filtered cathodic-arc system. The enhanced performance of the Si/a:D-N emitter lowers the voltages required to the point where field-emission displays are practical. Thus, this emitter can be used, for example, in flat-panel emission displays (FEDs), and cold-cathode vacuum electronics.

  7. Diamond-coated ZnS for improved erosion resistance

    NASA Astrophysics Data System (ADS)

    Korenstein, Ralph; Goldman, Lee M.; Hallock, Robert B.; Ondercin, Robert J.; Kelly, Eron S.

    1997-06-01

    Durable coatings are used to improve the erosion resistance of high performance optical materials such ZnS. Diamond is the hardest and stiffest of all LWIR transparent materials and would make an excellent protective coating for ZnS. Direct deposition of diamond on ZnS by microwave plasma CVD has proved to be very difficult. Atomic hydrogen used in the diamond deposition process attacks and destroys ZnS very rapidly. In order to protect ZnS during the diamond deposition process protective IR transparent interlayers were developed. These layers encapsulate the ZnS and provide a nucleating surface for diamond deposition. Two different methods of nucleating diamond on these interlayers were developed to produce fully dense diamond films several microns thick. The sand erosion resistance of diamond coated ZnS was found to improve when the diamond was deposited on patterned ZnS substrates.

  8. Superconducting nanowire single photon detector on diamond

    SciTech Connect

    Atikian, Haig A.; Burek, Michael J.; Choy, Jennifer T.; Lončar, Marko; Eftekharian, Amin; Jafari Salim, A.; Hamed Majedi, A.

    2014-03-24

    Superconducting nanowire single photon detectors are fabricated directly on diamond substrates and their optical and electrical properties are characterized. Dark count performance and photon count rates are measured at varying temperatures for 1310 nm and 632 nm photons. A multi-step diamond surface polishing procedure is reported, involving iterative reactive ion etching and mechanical polishing to create a suitable diamond surface for the deposition and patterning of thin film superconducting layers. Using this approach, diamond substrates with less than 300 pm Root Mean Square surface roughness are obtained.

  9. Superconducting nanowire single photon detector on diamond

    NASA Astrophysics Data System (ADS)

    Atikian, Haig A.; Eftekharian, Amin; Jafari Salim, A.; Burek, Michael J.; Choy, Jennifer T.; Hamed Majedi, A.; Lon?ar, Marko

    2014-03-01

    Superconducting nanowire single photon detectors are fabricated directly on diamond substrates and their optical and electrical properties are characterized. Dark count performance and photon count rates are measured at varying temperatures for 1310 nm and 632 nm photons. A multi-step diamond surface polishing procedure is reported, involving iterative reactive ion etching and mechanical polishing to create a suitable diamond surface for the deposition and patterning of thin film superconducting layers. Using this approach, diamond substrates with less than 300 pm Root Mean Square surface roughness are obtained.

  10. Epitaxial growth of europium monoxide on diamond

    NASA Astrophysics Data System (ADS)

    Melville, A.; Mairoser, T.; Schmehl, A.; Fischer, M.; Gsell, S.; Schreck, M.; Awschalom, D. D.; Heeg, T.; Holländer, B.; Schubert, J.; Schlom, D. G.

    2013-11-01

    We report the epitaxial integration of phase-pure EuO on both single-crystal diamond and on epitaxial diamond films grown on silicon utilizing reactive molecular-beam epitaxy. The epitaxial orientation relationship is (001) EuO ‖ (001) diamond and [110] EuO ‖ [100] diamond. The EuO layer is nominally unstrained and ferromagnetic with a transition temperature of 68 ± 2 K and a saturation magnetization of 5.5 ± 0.1 Bohr magnetons per europium ion on the single-crystal diamond, and a transition temperature of 67 ± 2 K and a saturation magnetization of 2.1 ± 0.1 Bohr magnetons per europium ion on the epitaxial diamond film.

  11. Epitaxial growth of europium monoxide on diamond

    SciTech Connect

    Melville, A.; Heeg, T.; Mairoser, T.; Schmehl, A.; Fischer, M.; Gsell, S.; Schreck, M.; Awschalom, D. D.; Holländer, B.; Schubert, J.; Schlom, D. G.; Kavli Institute at Cornell for Nanoscale Science, Ithaca, New York 14853

    2013-11-25

    We report the epitaxial integration of phase-pure EuO on both single-crystal diamond and on epitaxial diamond films grown on silicon utilizing reactive molecular-beam epitaxy. The epitaxial orientation relationship is (001) EuO ‖ (001) diamond and [110] EuO ‖[100] diamond. The EuO layer is nominally unstrained and ferromagnetic with a transition temperature of 68 ± 2 K and a saturation magnetization of 5.5 ± 0.1 Bohr magnetons per europium ion on the single-crystal diamond, and a transition temperature of 67 ± 2 K and a saturation magnetization of 2.1 ± 0.1 Bohr magnetons per europium ion on the epitaxial diamond film.

  12. Method to grow carbon thin films consisting entirely of diamond grains 3-5 nm in size and high-energy grain boundaries

    DOEpatents

    Carlisle, John A.; Auciello, Orlando; Birrell, James

    2006-10-31

    An ultrananocrystalline diamond (UNCD) having an average grain size between 3 and 5 nanometers (nm) with not more than about 8% by volume diamond having an average grain size larger than 10 nm. A method of manufacturing UNCD film is also disclosed in which a vapor of acetylene and hydrogen in an inert gas other than He wherein the volume ratio of acetylene to hydrogen is greater than 0.35 and less than 0.85, with the balance being an inert gas, is subjected to a suitable amount of energy to fragment at least some of the acetylene to form a UNCD film having an average grain size of 3 to 5 nm with not more than about 8% by volume diamond having an average grain size larger than 10 nm.

  13. Design and production of diamond devices

    SciTech Connect

    Haenni, W.; Dan, J.P.; Perret, A.

    1995-12-31

    The outstanding properties of thin diamond films (hardness, chemical inertness, high thermal conductivity, high transparency, etc.) make them a good candidate for sensors, electronic or micromechanical devices, either self-standing or as part of microsystems. The structuring of diamond films and production of devices based on their properties has been described several times in the literature. Intrinsic as well as p-type doped diamond layers are now routinely deposited by different suppliers. To make full use of these layers in microtechnical products, it is necessary to further master suitable structuring techniques. Two methods have been developed and tested namely, selective area deposition (SAD) and direct etching of blanket-deposited diamond films. Both of these complementary approaches are described here, aiming at the production of thin diamond film structures suitable for example, to manufacture chemical sensors, cantilever beams or electrodes.

  14. Large-area low-temperature ultrananocrystaline diamond (UNCD) films and integration with CMOS devices for monolithically integrated diamond MEMD/NEMS-CMOS systems.

    SciTech Connect

    Sumant, A.V.; Auciello, O.; Yuan, H.-C; Ma, Z.; Carpick, R. W.; Mancini, D. C.; Univ. of Wisconsin; Univ. of Pennsylvania

    2009-05-01

    Because of exceptional mechanical, chemical, and tribological properties, diamond has a great potential to be used as a material for the development of high-performance MEMS and NEMS such as resonators and switches compatible with harsh environments, which involve mechanical motion and intermittent contact. Integration of such MEMS/NEMS devices with complementary metal oxide semiconductor (CMOS) microelectronics will provide a unique platform for CMOS-driven commercial MEMS/NEMS. The main hurdle to achieve diamond-CMOS integration is the relatively high substrate temperatures (600-800 C) required for depositing conventional diamond thin films, which are well above the CMOS operating thermal budget (400 C). Additionally, a materials integration strategy has to be developed to enable diamond-CMOS integration. Ultrananocrystalline diamond (UNCD), a novel material developed in thin film form at Argonne, is currently the only microwave plasma chemical vapor deposition (MPCVD) grown diamond film that can be grown at 400 C, and still retain exceptional mechanical, chemical, and tribological properties comparable to that of single crystal diamond. We have developed a process based on MPCVD to synthesize UNCD films on up to 200 mm in diameter CMOS wafers, which will open new avenues for the fabrication of monolithically integrated CMOS-driven MEMS/NEMS based on UNCD. UNCD films were grown successfully on individual Si-based CMOS chips and on 200 mm CMOS wafers at 400 C in a MPCVD system, using Ar-rich/CH4 gas mixture. The CMOS devices on the wafers were characterized before and after UNCD deposition. All devices were performing to specifications with very small degradation after UNCD deposition and processing. A threshold voltage degradation in the range of 0.08-0.44V and transconductance degradation in the range of 1.5-9% were observed.

  15. Diamond Tours

    NASA Technical Reports Server (NTRS)

    2007-01-01

    On April 24, a group traveling with Diamond Tours visited StenniSphere, the visitor center at NASA John C. Stennis Space Center in South Mississippi. The trip marked Diamond Tours' return to StenniSphere since Hurricane Katrina struck the Gulf Coast on Aug. 29, 2005. About 25 business professionals from Georgia enjoyed the day's tour of America's largest rocket engine test complex, along with the many displays and exhibits at the museum. Before Hurricane Katrina, the nationwide company brought more than 1,000 visitors to StenniSphere each month. That contributed to more than 100,000 visitors from around the world touring the space center each year. In past years StenniSphere's visitor relations specialists booked Diamond Tours two or three times a week, averaging 40 to 50 people per visit. SSC was established in the 1960s to test the huge engines for the Saturn V moon rockets. Now 40 years later, the center tests every main engine for the space shuttle. SSC will soon begin testing the rocket engines that will power spacecraft carrying Americans back to the moon and on to Mars. For more information or to book a tour, visit http://www.nasa.gov/centers/stennis/home/index.html and click on the StenniSphere logo; or call 800-237-1821 or 228-688-2370.

  16. Isotope analysis of diamond-surface passivation effect of high-temperature H{sub 2}O-grown atomic layer deposition-Al{sub 2}O{sub 3} films

    SciTech Connect

    Hiraiwa, Atsushi E-mail: qs4a-hriw@asahi-net.or.jp; Saito, Tatsuya; Matsumura, Daisuke; Kawarada, Hiroshi

    2015-06-07

    The Al{sub 2}O{sub 3} film formed using an atomic layer deposition (ALD) method with trimethylaluminum as Al precursor and H{sub 2}O as oxidant at a high temperature (450 °C) effectively passivates the p-type surface conduction (SC) layer specific to a hydrogen-terminated diamond surface, leading to a successful operation of diamond SC field-effect transistors at 400 °C. In order to investigate this excellent passivation effect, we carried out an isotope analysis using D{sub 2}O instead of H{sub 2}O in the ALD and found that the Al{sub 2}O{sub 3} film formed at a conventional temperature (100 °C) incorporates 50 times more CH{sub 3} groups than the high-temperature film. This CH{sub 3} is supposed to dissociate from the film when heated afterwards at a higher temperature (550 °C) and causes peeling patterns on the H-terminated surface. The high-temperature film is free from this problem and has the largest mass density and dielectric constant among those investigated in this study. The isotope analysis also unveiled a relatively active H-exchange reaction between the diamond H-termination and H{sub 2}O oxidant during the high-temperature ALD, the SC still being kept intact. This dynamic and yet steady H termination is realized by the suppressed oxidation due to the endothermic reaction with H{sub 2}O. Additionally, we not only observed the kinetic isotope effect in the form of reduced growth rate of D{sub 2}O-oxidant ALD but found that the mass density and dielectric constant of D{sub 2}O-grown Al{sub 2}O{sub 3} films are smaller than those of H{sub 2}O-grown films. This is a new type of isotope effect, which is not caused by the presence of isotopes in the films unlike the traditional isotope effects that originate from the presence of isotopes itself. Hence, the high-temperature ALD is very effective in forming Al{sub 2}O{sub 3} films as a passivation and/or gate-insulation layer of high-temperature-operation diamond SC devices, and the knowledge of the aforementioned new isotope effect will be a basis for further enhancing ALD technologies in general.

  17. Study of diamond film growth and properties

    NASA Technical Reports Server (NTRS)

    Albin, Sacharial

    1990-01-01

    The objective was to study diamond film growth and its properties in order to enhance the laser damage threshold of substrate materials. Calculations were performed to evaluate laser induced thermal stress parameter, R(sub T) of diamond. It is found that diamond has several orders of magnitude higher in value for R(sub T) compared to other materials. Thus, the laser induced damage threshold (LIDT) of diamond is much higher. Diamond films were grown using a microwave plasma enhanced chemical vapor deposition (MPECVD) system at various conditions of gas composition, pressure, temperature, and substrate materials. A 0.5 percent CH4 in H2 at 20 torr were ideal conditions for growing of high quality diamond films on substrates maintained at 900 C. The diamond films were polycrystalline which were characterized by scanning electron microscopy (SEM) and Raman scattering spectroscopy. The top surface of the growing film is always rough due to the facets of polycrystalline film while the back surface of the film replicates the substrate surface. An analytical model based on two dimensional periodic heat flow was developed to calculate the effective in-plane (face parallel) diffusivity of a two layer system. The effective diffusivity of diamond/silicon samples was measured using a laser pulse technique. The thermal conductivity of the films was measured to be 13.5 W/cm K, which is better than that of a type Ia natural diamond. Laser induced damage experiments were performed on bare Si substrates, diamond film coated Si, and diamond film windows. Significant improvements in the LIDT were obtained for diamond film coated Si compared to the bare Si.

  18. Below-Band-Gap Laser Ablation Of Diamond For TEM

    NASA Technical Reports Server (NTRS)

    George, Thomas; Foote, Marc C.; Vasquez, Richard P.; Fortier, Edward P.; Posthill, John B.

    1995-01-01

    Thin, electron-transparent layers of diamond for examination in transmission electron microscope (TEM) fabricated from thicker diamond substrates by using laser beam to ablate surface of substrate. Involves use of photon energy below band gap. Growing interest in use of diamond as bulk substrate and as coating material in variety of applications has given rise to increasing need for TEM for characterization of diamond-based materials. Below-band-gap laser ablation method helps to satisfy this need. Also applied in general to cutting and etching of diamonds.

  19. Research on the diamond MISFET

    NASA Astrophysics Data System (ADS)

    Jianjun, Zhou; Song, Bai; Cen, Kong; Xijiao, Geng; Haiyan, Lu; Yuechan, Kong; Tangsheng, Chen

    2013-03-01

    Based on the hydrogen-terminated surface channel diamond material, a 1 ?m gate length diamond metalinsulatorsemiconductor field-effect transistor (MISFET) was fabricated. The gate dielectric A12O3 was formed by naturally oxidated thin Al metal layer, and a less than 2 pA gate leakage current was obtained at gate bias between -4 V and 4 V. The DC characteristic of the diamond MISFET showed a drain-current density of 80 mA/mm at drain voltage of -5 V, and a maximum transconductance of 22 mS/mm at gatesource voltage of -3 V. With the small signal measurement, a current gain cutoff frequency of 2.1 GHz was also obtained.

  20. Nanostructured Diamond Device for Biomedical Applications.

    PubMed

    Fijalkowski, M; Karczemska, A; Lysko, J M; Zybala, R; KozaneckI, M; Filipczak, P; Ralchenko, V; Walock, M; Stanishevsky, A; Mitura, S

    2015-02-01

    Diamond is increasingly used in biomedical applications because of its unique properties such as the highest thermal conductivity, good optical properties, high electrical breakdown voltage as well as excellent biocompatibility and chemical resistance. Diamond has also been introduced as an excellent substrate to make the functional microchip structures for electrophoresis, which is the most popular separation technique for the determination of analytes. In this investigation, a diamond electrophoretic chip was manufactured by a replica method using a silicon mold. A polycrystalline 300 micron-thick diamond layer was grown by the microwave plasma-assisted CVD (MPCVD) technique onto a patterned silicon substrate followed by the removal of the substrate. The geometry of microstructure, chemical composition, thermal and optical properties of the resulting free-standing diamond electrophoretic microchip structure were examined by CLSM, SFE, UV-Vis, Raman, XRD and X-ray Photoelectron Spectroscopy, and by a modified laser flash method for thermal property measurements. PMID:26353606

  1. Surface structure of cubic diamond nanowires

    NASA Astrophysics Data System (ADS)

    Barnard, A. S.; Russo, S. P.; Snook, I. K.

    2003-07-01

    Presented are results of our ab initio study of the surface reconstruction and relaxation of (1 0 0) surfaces on diamond nanowires. We have used a density function theory within the generalized-gradient approximation using the Vienna ab initio simulation package, to consider dehydrogenated and hydrogenated surfaces. Edges of nanowires offer a new challenge in the determination of surface structure. We have applied the methodology for stepped diamond (1 0 0) surfaces to this problem, and consider it useful in describing diamond nanowire edges to first approximation. We have found that dimer lengths and atomic layer depths of the C(1 0 0)(2 1) and C(1 0 0)(2 1):H nanowire surfaces differ slightly from those of bulk diamond and nanodiamond surfaces. The aim of this study is provide a better understanding of the effects of nano-scale surfaces on the stability of diamond nanostructures.

  2. Plasma spraying method for forming diamond and diamond-like coatings

    DOEpatents

    Holcombe, C.E.; Seals, R.D.; Price, R.E.

    1997-06-03

    A method and composition is disclosed for the deposition of a thick layer of diamond or diamond-like material. The method includes high temperature processing wherein a selected composition including at least glassy carbon is heated in a direct current plasma arc device to a selected temperature above the softening point, in an inert atmosphere, and is propelled to quickly quenched on a selected substrate. The softened or molten composition crystallizes on the substrate to form a thick deposition layer comprising at least a diamond or diamond-like material. The selected composition includes at least glassy carbon as a primary constituent and may include at least one secondary constituent. Preferably, the secondary constituents are selected from the group consisting of at least diamond powder, boron carbide (B{sub 4}C) powder and mixtures thereof. 9 figs.

  3. Plasma spraying method for forming diamond and diamond-like coatings

    DOEpatents

    Holcombe, Cressie E. (Farragut, TN); Seals, Roland D. (Oak Ridge, TN); Price, R. Eugene (Knoxville, TN)

    1997-01-01

    A method and composition for the deposition of a thick layer (10) of diamond or diamond-like material. The method includes high temperature processing wherein a selected composition (12) including at least glassy carbon is heated in a direct current plasma arc device to a selected temperature above the softening point, in an inert atmosphere, and is propelled to quickly quenched on a selected substrate (20). The softened or molten composition (18) crystallizes on the substrate (20) to form a thick deposition layer (10) comprising at least a diamond or diamond-like material. The selected composition (12) includes at least glassy carbon as a primary constituent (14) and may include at least one secondary constituent (16). Preferably, the secondary constituents (16) are selected from the group consisting of at least diamond powder, boron carbide (B.sub.4 C) powder and mixtures thereof.

  4. The mechanical properties of various chemical vapor deposition diamond structures compared to the ideal single crystal

    NASA Astrophysics Data System (ADS)

    Hess, Peter

    2012-03-01

    The structural and electronic properties of the diamond lattice, leading to its outstanding mechanical properties, are discussed. These include the highest elastic moduli and fracture strength of any known material. Its extreme hardness is strongly connected with the extreme shear modulus, which even exceeds the large bulk modulus, revealing that diamond is more resistant to shear deformation than to volume changes. These unique features protect the ideal diamond lattice also against mechanical failure and fracture. Besides fast heat conduction, the fast vibrational movement of carbon atoms results in an extreme speed of sound and propagation of crack tips with comparable velocity. The ideal mechanical properties are compared with those of real diamond films, plates, and crystals, such as ultrananocrystalline (UNC), nanocrystalline, microcrystalline, and homo- and heteroepitaxial single-crystal chemical vapor deposition (CVD) diamond, produced by metastable synthesis using CVD. Ultrasonic methods have played and continue to play a dominant role in the determination of the linear elastic properties, such as elastic moduli of crystals or the Young's modulus of thin films with substantially varying impurity levels and morphologies. A surprising result of these extensive measurements is that even UNC diamond may approach the extreme Young's modulus of single-crystal diamond under optimized deposition conditions. The physical reasons for why the stiffness often deviates by no more than a factor of two from the ideal value are discussed, keeping in mind the large variety of diamond materials grown by various deposition conditions. Diamond is also known for its extreme hardness and fracture strength, despite its brittle nature. However, even for the best natural and synthetic diamond crystals, the measured critical fracture stress is one to two orders of magnitude smaller than the ideal value obtained by ab initio calculations for the ideal cubic lattice. Currently, fracture is studied mainly by indentation or mechanical breaking of freestanding films, e.g., by bending or bursting. It is very difficult to study the fracture mechanism, discriminating between tensile, shear, and tearing stress components (mode I-III fracture) with these partly semiquantitative methods. A novel ultrasonic laser-based technique using short nonlinear surface acoustic wave pulses, developing shock fronts during propagation, has recently been employed to study mode-resolved fractures of single-crystal silicon. This method allows the generation of finite cracks and the evaluation of the fracture strength for well-defined crystallographic configurations. Laser ultrasonics reaches the critical stress at which real diamond fails and therefore can be employed as a new tool for mechanistic studies of the fracture behavior of CVD diamond in the future.

  5. Stand-alone diamond binary phase transmission gratings for the EUV band

    NASA Astrophysics Data System (ADS)

    Braig, C.; Ksebier, T.; Kley, E.-B.; Tnnermann, A.

    2011-07-01

    We report on the development of true free-standing phase transmission gratings for the extreme ultraviolet band. An ultra-nanocrystalline, 300 nm thin diamond film on a backside etched silicon wafer is structured by electron-beam lithography to periods of 1 ?m. In this way, flat and stable gratings of 400 ?m in diameter are fabricated. First-order net efficiencies up to 28% are obtained from measurements at a synchrotron beamline within a wavelength range from 5.0 nm to 8.3 nm, whereas the 0th order is suppressed to 1% near 6.8 nm. Higher diffraction orders up to the 3rd one contribute less than 7% in sum to the far-field pattern.

  6. Physical and Tribological Characteristics of Ion-Implanted Diamond Films

    NASA Technical Reports Server (NTRS)

    Miyoshi, K.; Heidger, S.; Korenyi-Both, A. L.; Jayne, D. T.; Herrera-Fierro, P.; Shogrin, B.; Wilbur, P. J.; Wu, R. L. C.; Garscadden, A.; Barnes, P. N.

    1994-01-01

    Unidirectional sliding friction experiments were conducted with a natural, polished diamond pin in contact with both as-deposited and carbon-ion-implanted diamond films in ultrahigh vacuum. Diamond films were deposited on silicon, silicon carbide, and silicon nitride by microwave-plasma-assisted chemical vapor deposition. The as-deposited diamond films were impacted with carbon ions at an accelerating energy of 60 keV and a current density of 50 micron A/cm(exp 2) for approximately 6 min, resulting in a dose of 1.2 x 10(exp 17) carbon ions/cm(exp 2). The results indicate that the carbon ion implantation produced a thin surface layer of amorphous, nondiamond carbon. The nondiamond carbon greatly decreased both friction and wear of the diamond films. The coefficients of friction for the carbon-ion-implanted, fine-grain diamond films were less than 0.1, factors of 20 to 30 lower than those for the as-deposited, fine-grain diamond films. The coefficients of friction for the carbon-ion-implanted, coarse-grain diamond films were approximately 0.35, a factor of five lower than those for the as-deposited, coarse-grain diamond films. The wear rates for the carbon-ion-implanted, diamond films were on the order of 10(exp -6) mm(exp 3)/Nm, factors of 30 to 80 lower than that for the as-deposited diamond films, regardless of grain size. The friction of the carbon-ion-implanted diamond films was greatly reduced because the amorphous, nondiamond carbon, which had a low shear strength, was restricted to the surface layers (less than 0.1 micron thick) and because the underlying diamond materials retained their high hardness. In conclusion, the carbon-ion-implanted, fine-grain diamond films can be used effectively as wear resistant, self-lubricating coatings for ceramics, such as silicon nitride and silicon carbide, in ultrahigh vacuum.

  7. Diamond Sheet: A new diamond tool material

    NASA Technical Reports Server (NTRS)

    Mackey, C. R.

    1982-01-01

    Diamond sheet is termed a diamond tool material because it is not a cutting tool, but rather a new material from which a variety of different tools may be fabricated. In appearance and properties, it resembles a sheet of copper alloy with diamond abrasive dispersed throughout it. It is capable of being cut, formed, and joined by conventional methods, and subsequently used for cutting as a metal bonded diamond tool. Diamond sheet is normally made with industrial diamond as the abrasive material. The metal matrix in diamond sheet is a medium hard copper alloy which has performed well in most applications. This alloy has the capability of being made harder or softer if specific cutting conditions require it. Other alloys have also been used including a precipitation hardened aluminum alloy with very free cutting characteristics. The material is suitable for use in a variety of cutting, surfacing, and ring type tools, as well as in such mundane items as files and sandpaper. It can also be used as a bearing surface (diamond to diamond) and in wear resistant surfaces.

  8. One step deposition of highly adhesive diamond films on cemented carbide substrates via diamond/?-SiC composite interlayers

    NASA Astrophysics Data System (ADS)

    Wang, Tao; Zhuang, Hao; Jiang, Xin

    2015-12-01

    Deposition of adherent diamond films on cobalt-cemented tungsten carbide substrates has been realized by application of diamond/beta-silicon carbide composite interlayers. Diamond top layers and the interlayers were deposited in one single process by hot filament chemical vapor deposition technique. Two different kinds of interlayers have been employed, namely, gradient interlayer and interlayer with constant composition. The distribution of diamond and beta-silicon carbide phases was precisely controlled by manipulating the gas phase composition. X-ray diffraction and Raman spectroscopy were employed to determine the existence of diamond, beta-silicon carbide and cobalt silicides (Co2Si, CoSi) phases, as well as the quality of diamond crystal and the residual stress in the films. Rockwell-C indentation tests were carried out to evaluate the film adhesion. It is revealed that the adhesion of the diamond film is drastically improved by employing the interlayer. This is mainly influenced by the residual stress in the diamond top layer, which is induced by the different thermal expansion coefficient of the film and the substrate. It is even possible to further suppress the stress by manipulating the distribution of diamond and beta-silicon carbide in the interlayer. The most adhesive diamond film on cemented carbide is thus obtained by employing a gradient composite interlayer.

  9. Effects of high energy Au-ion irradiation on the microstructure of diamond films

    SciTech Connect

    Chen, Shih-Show; Chen, Huang-Chin; Wang, Wei-Cheng; Lin, I-Nan; Chang, Ching-Lin; Lee, Chi-Young; Guo Jinghua

    2013-03-21

    The effects of 2.245 GeV Au-ion irradiation and subsequent annealing processes on the evolution of microstructure of diamond films with microcrystalline (MCD) or ultra-nanocrystalline (UNCD) granular structure were investigated, using near edge x-ray absorption fine structure and electron energy loss spectroscopy in transmission electron microscopy. For MCD films, the Au-ion irradiation disintegrated some of the diamond grains, resulting in the formation of nano-sized carbon clusters embedded in a matrix of amorphous carbon (a-C). The annealing process recrystallized the diamond grains and converted the a-C into nano-sized graphite particulates and, at the same time, induced the formation of nano-sized i-carbon clusters, the bcc structured carbon with a{sub 0} = 0.432 nm. In contrast, for UNCD films, the Au-ion irradiation transformed the grain boundary phase into nano-sized graphite, but insignificantly altered the crystallinity of the grains of the UNCD films. The annealing process recrystallized the materials. In some of the regions, the residual a-C phases were transformed into nano-sized graphites, whereas in other regions i-carbon nanoclusters were formed. The difference in irradiation-induced microstructural transformation behavior between the MCD and the UNCD films is ascribed to the different granular structures of the two types of films.

  10. Migration behaviour of carbon atoms on clean diamond (0 0 1) surface: A first principle study

    NASA Astrophysics Data System (ADS)

    Liu, Xuejie; Xia, Qing; Li, Wenjuan; Luo, Hao; Ren, Yuan; Tan, Xin; Sun, Shiyang

    2016-01-01

    The adsorption and migration energies of a single carbon atom and the configuration evolution energies of two carbon atoms on a clean diamond (0 0 1) surface were calculated using the first principle method based on density functional theory to investigate the formation of ultra-nanocrystalline diamond (UNCD) film. The activation energy of a single atom diffusing along a dimer row is 1.96 eV, which is almost the same as that of a CH2 migrating along a dimer row under hydrogen-rich conditions. However, the activation energy of a single atom diffusing along a dimer chain is 2.66 eV, which is approximately 1.55 times greater than that of a CH2 migrating along a dimer chain in a hydrogen-rich environment. The configuration evolution of the two carbon atoms is almost impossible at common diamond film deposition temperatures (700-900 °C) because the activation energies reach 4.46 or 5.90 eV. Therefore, the high-energy barrier could result in insufficient migration of adatoms, leading to the formation of amorphous in UNCD films in hydrogen-poor CVD environment.

  11. Effects of high energy Au-ion irradiation on the microstructure of diamond films

    NASA Astrophysics Data System (ADS)

    Chen, Shih-Show; Chen, Huang-Chin; Wang, Wei-Cheng; Lee, Chi-Young; Lin, I.-Nan; Guo, Jinghua; Chang, Ching-Lin

    2013-03-01

    The effects of 2.245 GeV Au-ion irradiation and subsequent annealing processes on the evolution of microstructure of diamond films with microcrystalline (MCD) or ultra-nanocrystalline (UNCD) granular structure were investigated, using near edge x-ray absorption fine structure and electron energy loss spectroscopy in transmission electron microscopy. For MCD films, the Au-ion irradiation disintegrated some of the diamond grains, resulting in the formation of nano-sized carbon clusters embedded in a matrix of amorphous carbon (a-C). The annealing process recrystallized the diamond grains and converted the a-C into nano-sized graphite particulates and, at the same time, induced the formation of nano-sized i-carbon clusters, the bcc structured carbon with a0 = 0.432 nm. In contrast, for UNCD films, the Au-ion irradiation transformed the grain boundary phase into nano-sized graphite, but insignificantly altered the crystallinity of the grains of the UNCD films. The annealing process recrystallized the materials. In some of the regions, the residual a-C phases were transformed into nano-sized graphites, whereas in other regions i-carbon nanoclusters were formed. The difference in irradiation-induced microstructural transformation behavior between the MCD and the UNCD films is ascribed to the different granular structures of the two types of films.

  12. 'Diamond Jenness': A Tough Grind

    NASA Technical Reports Server (NTRS)

    2004-01-01

    This microscopic imager mosaic of the target area called 'Diamond Jenness' was taken after NASA's Mars Exploration Rover Opportunity ground into the surface with its rock abrasion tool for a second time.

    Opportunity has bored nearly a dozen holes into the inner walls of 'Endurance Crater.' On sols 177 and 178 (July 23 and July 24, 2004), the rover worked double-duty on Diamond Jenness. Surface debris and the bumpy shape of the rock resulted in a shallow and irregular hole, only about 2 millimeters (0.08 inch) deep. The final depth was not enough to remove all the bumps and leave a neat hole with a smooth floor. This extremely shallow depression was then examined by the rover's alpha particle X-ray spectrometer.

    On Sol 178, Opportunity's 'robotic rodent' dined on Diamond Jenness once again, grinding almost an additional 5 millimeters (about 0.2 inch). The rover then applied its Moessbauer spectrometer to the deepened hole. This double dose of Diamond Jenness enabled the science team to examine the rock at varying layers. Results from those grindings are currently being analyzed.

    The image mosaic is about 6 centimeters (2.4 inches) across.

  13. 'Diamond Jenness': Before the Grind

    NASA Technical Reports Server (NTRS)

    2004-01-01

    This microscopic imager mosaic of the rock called 'Diamond Jenness' was snapped on sol 177 before NASA's Mars Exploration Rover Opportunity ground into the surface with its rock abrasion tool, or 'Rat.'

    Opportunity has bored nearly a dozen holes into the inner walls of 'Endurance Crater.' On sols 177 and 178 (July 23 and July 24, 2004), the rover worked double-duty on Diamond Jenness. Surface debris and the bumpy shape of the rock resulted in a shallow and irregular hole, only about 2 millimeters (0.08 inch) deep. The final depth was not enough to remove all the bumps and leave a neat hole with a smooth floor. This extremely shallow depression was then examined by the rover's alpha particle X-ray spectrometer. On Sol 178, Opportunity's 'robotic rodent' dined on Diamond Jenness once again, grinding almost an additional 5 millimeters (about 0.2 inch). The rover then applied its Moessbauer spectrometer to the deepened hole. This double dose of Diamond Jenness enabled the science team to examine the rock at varying layers. Results from those grindings are currently being analyzed.

    The image mosaic is about 6 centimeters (2.4 inches) across.

  14. 'Diamond Jenness': After the Grind

    NASA Technical Reports Server (NTRS)

    2004-01-01

    This microscopic imager mosaic taken by NASA's Mars Exploration Rover Opportunity shows the rock dubbed 'Diamond Jenness.' It was taken on sol 177 (July 23, 2004) after the rover first ground into the rock with its rock abrasion tool, or 'Rat.' The rover later ground into the rock a second time. A sliced spherule, or 'blueberry,' is visible in the upper left corner of the hole.

    Opportunity has bored nearly a dozen holes into the inner walls of 'Endurance Crater.' On sols 177 and 178 (July 23 and July 24, 2004), the rover worked double-duty on Diamond Jenness. Surface debris and the bumpy shape of the rock resulted in a shallow and irregular hole, only about 2 millimeters (0.08 inch) deep. The final depth was not enough to remove all the bumps and leave a neat hole with a smooth floor. This extremely shallow depression was then examined by the rover's alpha particle X-ray spectrometer.

    On Sol 178, Opportunity's 'robotic rodent' dined on Diamond Jenness once again, grinding almost an additional 5 millimeters (about 0.2 inch). The rover then applied its Moessbauer spectrometer to the deepened hole. This double dose of Diamond Jenness enabled the science team to examine the rock at varying layers. Results from those grindings are currently being analyzed.

    The image mosaic is about 6 centimeters (2.4 inches) across.

  15. Surface doping: a special feature of diamond

    NASA Astrophysics Data System (ADS)

    Ristein, J.; Riedel, M.; Maier, F.; Mantel, B. F.; Stammler, M.; Ley, L.

    2001-10-01

    A unique feature of diamond surfaces is a highly conductive p-type layer, which is usually observed when the surfaces are hydrogen terminated. This phenomenon has recently attracted a lot of interest since a number of electronic applications proposed for diamond are based on the effect. Nevertheless, its microscopic origin is still a matter of debate. In this paper we propose an electron transfer from the diamond valence band to adsorbates at the surface to be the effective doping mechanism. These adsorbates act not as isolated species but as components of a mildly acidic aqueous surface layer and thus charge exchange has to be described by electrochemical arguments. The model is supported by experiments, which show that the hydrogenation of the surface is necessary but not sufficient for inducing the hole accumulation layer at the surface.

  16. Composite and diamond cold cathode materials

    SciTech Connect

    Worthington, M.S.; Wheeland, C.L.; Ramacher, K.; Doyle, E.

    1996-12-31

    Cold-cathode technology for Crossed-Field Amplifiers (CFAs) has not changed significantly over the last thirty years. The material typically used for cold cathode CFAs is either platinum (Pt) or beryllium (Be), although numerous other materials with higher secondary electron emission ratios have been tested. Beryllium cathodes display higher secondary emission ratios, {approximately} 3.4, than Pt, but require a partial pressure of oxygen to maintain a beryllium oxide (BeO) surface layer. These dispensers limit the life of the CFA, both directly, due to oxygen-source filament burnout, and indirectly, by the production of undesirable gases which adversely affect the performance of the CFA. In an attempt to reduce or eliminate the required oxygen dispenser output level, cathodes were constructed from three varieties of Be/BeO composite material and tested in L-4808s, standard forward-wave AEGIS CFAs. Diamond and diamond-like carbons are desirable as cathode materials because of their extremely high secondary electron emission ratio, greater than 20, but their use has previously been prohibitive because of cost, available, and physical characteristics. Because of recent advances in diamond growth technology it is now possible to deposit thin layers of diamond on a variety of geometric objects. In coordination with Penn State University four annular diamond emitters have been fabricated. The diamond emitters will be tested in a standard AEGIS CFA, both under vacuum and with a partial pressure of hydrogen.

  17. Germanium: a new catalyst for diamond synthesis and a new optically active impurity in diamond

    NASA Astrophysics Data System (ADS)

    Palyanov, Yuri N.; Kupriyanov, Igor N.; Borzdov, Yuri M.; Surovtsev, Nikolay V.

    2015-10-01

    Diamond attracts considerable attention as a versatile and technologically useful material. For many demanding applications, such as recently emerged quantum optics and sensing, it is important to develop new routes for fabrication of diamond containing defects with specific optical, electronic and magnetic properties. Here we report on successful synthesis of diamond from a germanium-carbon system at conditions of 7?GPa and 1,500-1,800?C. Both spontaneously nucleated diamond crystals and diamond growth layers on seeds were produced in experiments with reaction time up to 60?h. We found that diamonds synthesized in the Ge-C system contain a new optical centre with a ZPL system at 2.059?eV, which is assigned to germanium impurities. Photoluminescence from this centre is dominated by zero-phonon optical transitions even at room temperature. Our results have widened the family of non-metallic elemental catalysts for diamond synthesis and demonstrated the creation of germanium-related optical centres in diamond.

  18. Germanium: a new catalyst for diamond synthesis and a new optically active impurity in diamond

    PubMed Central

    Palyanov, Yuri N.; Kupriyanov, Igor N.; Borzdov, Yuri M.; Surovtsev, Nikolay V.

    2015-01-01

    Diamond attracts considerable attention as a versatile and technologically useful material. For many demanding applications, such as recently emerged quantum optics and sensing, it is important to develop new routes for fabrication of diamond containing defects with specific optical, electronic and magnetic properties. Here we report on successful synthesis of diamond from a germanium-carbon system at conditions of 7 GPa and 1,500–1,800 °C. Both spontaneously nucleated diamond crystals and diamond growth layers on seeds were produced in experiments with reaction time up to 60 h. We found that diamonds synthesized in the Ge-C system contain a new optical centre with a ZPL system at 2.059 eV, which is assigned to germanium impurities. Photoluminescence from this centre is dominated by zero-phonon optical transitions even at room temperature. Our results have widened the family of non-metallic elemental catalysts for diamond synthesis and demonstrated the creation of germanium-related optical centres in diamond. PMID:26435400

  19. Germanium: a new catalyst for diamond synthesis and a new optically active impurity in diamond.

    PubMed

    Palyanov, Yuri N; Kupriyanov, Igor N; Borzdov, Yuri M; Surovtsev, Nikolay V

    2015-01-01

    Diamond attracts considerable attention as a versatile and technologically useful material. For many demanding applications, such as recently emerged quantum optics and sensing, it is important to develop new routes for fabrication of diamond containing defects with specific optical, electronic and magnetic properties. Here we report on successful synthesis of diamond from a germanium-carbon system at conditions of 7 GPa and 1,500-1,800 C. Both spontaneously nucleated diamond crystals and diamond growth layers on seeds were produced in experiments with reaction time up to 60 h. We found that diamonds synthesized in the Ge-C system contain a new optical centre with a ZPL system at 2.059 eV, which is assigned to germanium impurities. Photoluminescence from this centre is dominated by zero-phonon optical transitions even at room temperature. Our results have widened the family of non-metallic elemental catalysts for diamond synthesis and demonstrated the creation of germanium-related optical centres in diamond. PMID:26435400

  20. Homoepitaxial Boron Doped Diamond Anvils as Heating Elements in a Diamond Anvil Cell

    NASA Astrophysics Data System (ADS)

    Montgomery, Jeffrey; Samudrala, Gopi; Smith, Spencer; Tsoi, Georgiy; Vohra, Yogesh; Weir, Samuel

    2013-03-01

    Recent advances in designer-diamond technology have allowed for the use of electrically and thermally conducting homoepitaxially-grown layers of boron-doped diamond (grown at 1200 °C with a 2% mixture of CH4 in H, resulting in extremely high doping levels ~ 1020/cm3) to be used as heating elements in a diamond anvil cell (DAC). These diamonds allow for precise control of the temperature inside of the diamond anvil itself, particularly when coupled with a cryostat. Furthermore, the unmatched thermally conducting nature of diamond ensures that no significant lateral gradient in temperature occurs across the culet area. Since a thermocouple can easily be attached anywhere on the diamond surface, we can also measure diamond temperatures directly. With two such heaters, one can raise sample temperatures uniformly, or with any desired gradient along the pressure axis while preserving optical access. In our continuing set of benchmark experiments, we use two newly created matching heater anvils with 500 μm culets to analyze the various fluorescence emission lines of ruby microspheres, which show more complicated behavior than traditional ruby chips. We also report on the temperature dependence of the high-pressure Raman modes of paracetamol (C8H9NO2) up to 20 GPa.

  1. Electrically conductive diamond electrodes

    DOEpatents

    Swain, Greg (East Lansing, MI); Fischer, Anne (Arlington, VA),; Bennett, Jason (Lansing, MI); Lowe, Michael (Holt, MI)

    2009-05-19

    An electrically conductive diamond electrode and process for preparation thereof is described. The electrode comprises diamond particles coated with electrically conductive doped diamond preferably by chemical vapor deposition which are held together with a binder. The electrodes are useful for oxidation reduction in gas, such as hydrogen generation by electrolysis.

  2. Diamond-Bronze Coatings for Grinding Applications

    NASA Astrophysics Data System (ADS)

    Tillmann, W.; Vogli, E.; Nebel, J.

    2008-12-01

    Grinding applications for the machining of stone and concrete require composite tools where large diamonds are perfectly embedded into a metallic matrix. With the detonation flame spraying process, it is possible to manufacture these super abrasive composites. Excellent embedment of the voluminous super abrasive particles into the matrix coating material can be realized to produce high quality composite layers for grinding applications of stone and concrete. In this paper, different diamond gradings as well as different volume contents of diamond in matrix are compared. Especially, the influence of particle size on its implantation efficiency is investigated and the influence of process and substrate temperature is analyzed. The thermal sprayed grinding tools are evaluated with respect to their microstructure as well as their grinding abilities. Compared to sintered diamond-bronze samples, the results of an adaptively designed grinding test for the machining of concrete are presented and analyzed.

  3. Minimal graphene thickness for wear protection of diamond

    NASA Astrophysics Data System (ADS)

    van Wijk, M. M.; Fasolino, A.

    2015-01-01

    We show, by means of molecular dynamics simulations, that the transformation from diamond to amorphous carbon occurring while sliding under pressure can be prevented by having at least two graphene layers between the diamond slabs. The resulting reduction of wear makes this combination of materials suitable for new coatings and micro- and nanoelectromechanical devices. Grain boundaries, vacancies and steps on the diamond surface do not change this prediction. We attribute this behavior to the bonding in layered materials like graphene. The strong in-plane bonding and the weak interlayer interaction that evolves to a strong interlayer repulsion under pressure prevent the transition to amorphous carbon when more than one layer is present.

  4. Electronic properties of graphene-single crystal diamond heterostructures

    SciTech Connect

    Zhao, Fang; Thuong Nguyen, Thuong; Golsharifi, Mohammad; Amakubo, Suguru; Jackman, Richard B.; Loh, K. P.

    2013-08-07

    Single crystal diamond has been used as a substrate to support single layer graphene grown by chemical vapor deposition methods. It is possible to chemically functionalise the diamond surface, and in the present case H-, F-, O-, and N-group have been purposefully added prior to graphene deposition. The electronic properties of the resultant heterostructures vary strongly; a p-type layer with good mobility and a band gap of ?0.7?eV is created when H-terminated diamond layers are used, whilst a layer with more metallic-like character (high carrier density and low carrier mobility) arises when N(O)-terminations are introduced. Since it is relatively easy to pattern these functional groups on the diamond surface, this suggests that this approach may offer an exciting route to 2D device structures on single layer graphene sheets.

  5. Diamond bio electronics.

    PubMed

    Linares, Robert; Doering, Patrick; Linares, Bryant

    2009-01-01

    The use of diamond for advanced applications has been the dream of mankind for centuries. Until recently this dream has been realized only in the use of diamond for gemstones and abrasive applications where tons of diamonds are used on an annual basis. Diamond is the material system of choice for many applications, but its use has historically been limited due to the small size, high cost, and inconsistent (and typically poor) quality of available diamond materials until recently. The recent development of high quality, single crystal diamond crystal growth via the Chemical Vapor Deposition (CVD) process has allowed physcists and increasingly scientists in the life science area to think beyond these limitations and envision how diamond may be used in advanced applications ranging from quantum computing, to power generation and molecular imaging, and eventually even diamond nano-bots. Because of diamond's unique properties as a bio-compatible material, better understanding of diamond's quantum effects and a convergence of mass production, semiconductor-like fabrication process, diamond now promises a unique and powerful key to the realization of the bio-electronic devices being envisioned for the new era of medical science. The combination of robust in-the-body diamond based sensors, coupled with smart bio-functionalized diamond devices may lead to diamond being the platform of choice for bio-electronics. This generation of diamond based bio-electronic devices would contribute substantially to ushering in a paradigm shift for medical science, leading to vastly improved patient diagnosis, decrease of drug development costs and risks, and improved effectiveness of drug delivery and gene therapy programs through better timed and more customized solutions. PMID:19745488

  6. Diamond/aluminium nitride composites for efficient thermal management applications

    NASA Astrophysics Data System (ADS)

    Cervenka, J.; Dontschuk, N.; Ladouceur, F.; Duvall, S. G.; Prawer, S.

    2012-07-01

    Synthetic diamond/AlN composite materials have been fabricated by a combination of microwave plasma-assisted chemical vapor deposition and molecular beam epitaxy. These wide band gap semiconductor heterojunctions show promises for many applications, including thermal management, deep ultraviolet light emitting devices, and high power and high temperature electronics. Here, we report results of an interface study of polycrystalline diamond layers grown on single crystal AlN(0001). High resolution transmission microscopy revealed atomically sharp interfaces between diamond and AlN. Temperature dependent Raman spectroscopy measurements showed reduced thermal resistance on diamond-coated AlN substrates compared to uncoated AlN at temperatures above 330 K.

  7. Diamond/aluminium nitride composites for efficient thermal management applications

    SciTech Connect

    Cervenka, J.; Dontschuk, N.; Prawer, S.; Ladouceur, F.; Duvall, S. G.

    2012-07-30

    Synthetic diamond/AlN composite materials have been fabricated by a combination of microwave plasma-assisted chemical vapor deposition and molecular beam epitaxy. These wide band gap semiconductor heterojunctions show promises for many applications, including thermal management, deep ultraviolet light emitting devices, and high power and high temperature electronics. Here, we report results of an interface study of polycrystalline diamond layers grown on single crystal AlN(0001). High resolution transmission microscopy revealed atomically sharp interfaces between diamond and AlN. Temperature dependent Raman spectroscopy measurements showed reduced thermal resistance on diamond-coated AlN substrates compared to uncoated AlN at temperatures above 330 K.

  8. Diamond Synthesis Employing Nanoparticle Seeds

    NASA Technical Reports Server (NTRS)

    Uppireddi, Kishore (Inventor); Morell, Gerardo (Inventor); Weiner, Brad R. (Inventor)

    2014-01-01

    Iron nanoparticles were employed to induce the synthesis of diamond on molybdenum, silicon, and quartz substrates. Diamond films were grown using conventional conditions for diamond synthesis by hot filament chemical vapor deposition, except that dispersed iron oxide nanoparticles replaced the seeding. This approach to diamond induction can be combined with dip pen nanolithography for the selective deposition of diamond and diamond patterning while avoiding surface damage associated to diamond-seeding methods.

  9. Diamonds for beam instrumentation

    SciTech Connect

    Griesmayer, Erich

    2013-04-19

    Diamond is perhaps the most versatile, efficient and radiation tolerant material available for use in beam detectors with a correspondingly wide range of applications in beam instrumentation. Numerous practical applications have demonstrated and exploited the sensitivity of diamond to charged particles, photons and neutrons. In this paper, a brief description of a generic diamond detector is given and the interaction of the CVD diamond detector material with protons, electrons, photons and neutrons is presented. Latest results of the interaction of sCVD diamond with 14 MeV mono-energetic neutrons are shown.

  10. The Nature of Diamonds

    NASA Astrophysics Data System (ADS)

    Harlow, George E.

    1997-10-01

    The paragon of physical perfection and a sparkling example of Earth's forces at work, the diamond has fascinated all realms of society, from starlets to scientists. The Nature of Diamonds is a comprehensive look at nature's most coveted gem. A handsome, large-format book, The Nature of Diamonds is an authoritative and richly-illustrated tribute to the diamond. Leading geologists, gemologists, physicists, and cultural observers cover every facet of the stone, from its formation in the depths of the Earth, its ascent to the surface, and its economic, regal, social, and technological roles. Cutting-edge research takes the reader to the frontiers of diamond exploration and exploitation, from the Arctic wastes to the laboratories where diamonds are created for massive road shredders that rip up and then re-create superhighways. Here also is an overview of cutting, from the rough stones in Roman rings to the highly-faceted stones we see today, and a glimpse into the business of diamonds. Finally, The Nature of Diamonds chronicles scientific and cultural history and explores the diamond as both a sacred and a social symbol, including a picture history of betrothal rings. Wide-ranging illustrations explain the geology of diamonds, chart the history of mining from its origins in India and Brazil through the diamond rush in South Africa and today's high-tech enterprises, and capture the brilliance and beauty of this extraordinary gem. _

  11. Diamond particle detectors systems in high energy physics

    NASA Astrophysics Data System (ADS)

    Oh, A.

    2015-04-01

    With the first three years of the LHC running complete, ATLAS and CMS are planning to upgrade their innermost tracking layers with more radiation hard technologies. Chemical Vapor Deposition (CVD) diamond is one such technology. CVD diamond has been used extensively in beam condition monitors as the innermost detectors in the highest radiation areas of BaBar, Belle, CDF and all LHC experiments. The lessons learned in constructing the ATLAS Beam Conditions Monitor (BCM), Diamond Beam Monitor (DBM) and the CMS Pixel Luminosity Telescope (PLT) all of which are based on CVD diamond with the goal of elucidating the issues that should be addressed for future diamond based detector systems. The first beam test results of prototype diamond devices with 3D detector geometry should further enhance the radiation tolerance of this material.

  12. Protein-modified nanocrystalline diamond thin films for biosensor applications.

    PubMed

    Hrtl, Andreas; Schmich, Evelyn; Garrido, Jose A; Hernando, Jorge; Catharino, Silvia C R; Walter, Stefan; Feulner, Peter; Kromka, Alexander; Steinmller, Doris; Stutzmann, Martin

    2004-10-01

    Diamond exhibits several special properties, for example good biocompatibility and a large electrochemical potential window, that make it particularly suitable for biofunctionalization and biosensing. Here we show that proteins can be attached covalently to nanocrystalline diamond thin films. Moreover, we show that, although the biomolecules are immobilized at the surface, they are still fully functional and active. Hydrogen-terminated nanocrystalline diamond films were modified by using a photochemical process to generate a surface layer of amino groups, to which proteins were covalently attached. We used green fluorescent protein to reveal the successful coupling directly. After functionalization of nanocrystalline diamond electrodes with the enzyme catalase, a direct electron transfer between the enzyme's redox centre and the diamond electrode was detected. Moreover, the modified electrode was found to be sensitive to hydrogen peroxide. Because of its dual role as a substrate for biofunctionalization and as an electrode, nanocrystalline diamond is a very promising candidate for future biosensor applications. PMID:15359341

  13. Protein-modified nanocrystalline diamond thin films for biosensor applications

    NASA Astrophysics Data System (ADS)

    Hrtl, Andreas; Schmich, Evelyn; Garrido, Jose A.; Hernando, Jorge; Catharino, Silvia C. R.; Walter, Stefan; Feulner, Peter; Kromka, Alexander; Steinmller, Doris; Stutzmann, Martin

    2004-10-01

    Diamond exhibits several special properties, for example good biocompatibility and a large electrochemical potential window, that make it particularly suitable for biofunctionalization and biosensing. Here we show that proteins can be attached covalently to nanocrystalline diamond thin films. Moreover, we show that, although the biomolecules are immobilized at the surface, they are still fully functional and active. Hydrogen-terminated nanocrystalline diamond films were modified by using a photochemical process to generate a surface layer of amino groups, to which proteins were covalently attached. We used green fluorescent protein to reveal the successful coupling directly. After functionalization of nanocrystalline diamond electrodes with the enzyme catalase, a direct electron transfer between the enzyme's redox centre and the diamond electrode was detected. Moreover, the modified electrode was found to be sensitive to hydrogen peroxide. Because of its dual role as a substrate for biofunctionalization and as an electrode, nanocrystalline diamond is a very promising candidate for future biosensor applications.

  14. The polycrystalline diamond (100)/amorphous carbon heterostructure

    NASA Astrophysics Data System (ADS)

    Reinke, P.; Oelhafen, P.; Locher, R.

    1999-09-01

    In this study the interaction of the diamond surface with carbon is examined. Carbon, supplied by electron beam evaporation, is deposited on a polycrystalline diamond film of (100) orientation. The interface formation and carbon film growth are monitored by photoelectron spectroscopy in the ultraviolet (UPS) and X-ray (XPS) regime. The deposition of small amounts of carbon triggers changes in the surface structure of diamond, evidenced by an increase in the intensity of peaks located below 4 eV binding energy. Subsequently the deposition of amorphous carbon (a-C) leads to an abrupt interface. The analysis of the XPS data indicates a growth mode of the overlayer close to a layer-by-layer growth. The microscopic structure of the boundary layer between diamond and a-C is still a subject of discussion and several models are suggested. The diamond/amorphous carbon heterostructure is an example of a crystalline-amorphous heterostructure where both components are formed by the same element.

  15. Diamond For Optical Material

    NASA Astrophysics Data System (ADS)

    Clay, Robert D.; Clay, John P.

    1984-12-01

    Clay Engineering Inc. currently has a proposal before DARPA to manufacture large optical quality diamond for use as optical material. The manufactured diamond will be approximately 100 mm in diameter by 100 mm long. The cost of producing the diamond is expected to be three dollars per carat. It is expected that total impurities of a few parts per billion can readily be obtained. A study of diamond is a study of the effects of impurities. The elements boron and nitrogen can replace carbon atoms in the lattice structure, making diamond a "P" or "N" type semiconductor. Diamonds which are not semiconductors are classified as type IIa. The presence of B or N in the lattice causes diamond to photoconduct in ultraviolet light. All type I and III) and most type IIa diamonds photoconduct. The manufactured diamond will not photoconduct and will have an electrical resistivity greater than 1018 ohm*m. All non-lattice impurities are in the form of inclusions which dramatically affect the mechanical properties of diamond. High purity diamond has a coefficient of absorption of order 10-3 cm-1 at wavelengths of 8 to 12 micro metres, which makes it useful for infrared applications. It also has a low coefficient of absorption at wavelengths greater than 12 micro metres. For missile and aircraft applications, diamond is relatively immune to erosion or pitting damage by sand and rain. Diamond will readily withstand the stagnation temperature of Mach 3 flight and will go to Mach 4.8 with an anti-reflective coating to protect it from oxygen attack. Diamond is highly resistant to thermal shock, which makes it valuable for high energy laser applications. Using R = St (1-)) k/Ea as a measure of thermal shock resistance, diamond is 107 w/m vs "sapphire" and Zerodur at 104 and fused quartz at 1.45x103. Diamond does not perform well in the 2.5-7.5 micro metres and less than 0.4 micro metres wavelengths. Intense beams of less than 0.4 micro metres energy can create color centers in diamond. For laser pulses of such short duration that thermal shock is not a problem, diamond will take less peak power than some competing materials, such as quartz. One could take advantage of the superior strength of diamond and use a thinner slice to obtain equal peak power capacity.

  16. A micro-scale hot wire anemometer based on low stress (Ni/W) multi-layers deposited on nano-crystalline diamond for air flow sensing

    NASA Astrophysics Data System (ADS)

    Talbi, A.; Gimeno, L.; Gerbedoen, J.-C.; Viard, R.; Soltani, A.; Mortet, V.; Preobrazhensky, V.; Merlen, A.; Pernod, P.

    2015-12-01

    A linear array of microscale thermal anemometers has been designed, fabricated and characterized. The sensitive element consists of a self-compensated-stress multilayer (Ni/W) patterned to form a wire with length, width, and thickness close to 200 μm, 5 μm and 2 μm respectively. The wire is deposited and supported by prongs made of nano-crystalline diamond (NCD) of about 2 μm in thickness. Due to its high Young’s modulus, NCD allows a very high mechanical toughness without the need for thicker support for the hot wire. Also, depending on grain size, the NCD is able to present thermal conductivity smaller than 10 W mK‑1, providing good thermal insulation from the substrate and less conductive end losses to the prongs. The sensor was characterized experimentally. Its electrical and thermal properties were obtained first in the absence of fluid flow. The results confirm the effectiveness of thermal insulation and the mechanical robustness of the structure. The fluidic characterizations were performed and analysed in the case of an airflow with velocities of up to 30 m s‑1.

  17. Ultrafast transformation of graphite to diamond: an ab initio study of graphite under shock compression.

    PubMed

    Mundy, Christopher J; Curioni, Alessandro; Goldman, Nir; Will Kuo, I-F; Reed, Evan J; Fried, Laurence E; Ianuzzi, Marcella

    2008-05-14

    We report herein ab initio molecular dynamics simulations of graphite under shock compression in conjunction with the multiscale shock technique. Our simulations reveal that a novel short-lived layered diamond intermediate is formed within a few hundred of femtoseconds upon shock loading at a shock velocity of 12 kms (longitudinal stress>130 GPa), followed by formation of cubic diamond. The layered diamond state differs from the experimentally observed hexagonal diamond intermediate found at lower pressures and previous hydrostatic calculations in that a rapid buckling of the graphitic planes produces a mixture of hexagonal and cubic diamond (layered diamond). Direct calculation of the x-ray absorption spectra in our simulations reveals that the electronic structure of the final state closely resembles that of compressed cubic diamond. PMID:18532830

  18. Diamond tool machining of materials which react with diamond

    DOEpatents

    Lundin, R.L.; Stewart, D.D.; Evans, C.J.

    1992-04-14

    An apparatus is described for the diamond machining of materials which detrimentally react with diamond cutting tools in which the cutting tool and the workpiece are chilled to very low temperatures. This chilling halts or retards the chemical reaction between the workpiece and the diamond cutting tool so that wear rates of the diamond tool on previously detrimental materials are comparable with the diamond turning of materials which do not react with diamond. 1 figs.

  19. Diamond tool machining of materials which react with diamond

    DOEpatents

    Lundin, Ralph L. (Los Alamos, NM); Stewart, Delbert D. (Los Alamos, NM); Evans, Christopher J. (Gaithersburg, MD)

    1992-01-01

    Apparatus for the diamond machining of materials which detrimentally react with diamond cutting tools in which the cutting tool and the workpiece are chilled to very low temperatures. This chilling halts or retards the chemical reaction between the workpiece and the diamond cutting tool so that wear rates of the diamond tool on previously detrimental materials are comparable with the diamond turning of materials which do not react with diamond.

  20. Subnanosecond scintillations in diamond

    SciTech Connect

    Gavrilov, V.; Aluker, E.; Chernov, S.

    1994-12-31

    Diamond is known as a prospective material for the detection of ionizing radiation. At present current detectors are widely used. But data about the kinetics of the fast luminescence are not known sufficiently for diamond. Data about fast luminescence of natural and synthetic diamonds are presented. Analysis of the luminescence spectra and the kinetics of both the luminescence and pulse conductivity leads to the conclusion that these processes are determined by the band electron lifetime.

  1. Diamond anvil technology

    NASA Astrophysics Data System (ADS)

    Seal, Michael

    This paper is largely a review of the techniques used in making diamond anvils and the constraints these put on the shapes of anvil. Techniques available for shaping diamonds include cleaving, sawing, polishing, laser cutting, and bruting. At present the shapes most commonly used for anvils are a modification of the brilliant cut derived from the gem industry, and a design based on an octagonal prism with truncated pyramidal top and base, known as the "Drukker standard design". Diamond orientation and material selection are considered as are future possibilities for the attainment of still higher pressures through modifications of the diamond anvil material or design.

  2. Characterization of diamond thin films: Diamond phase identification, surface morphology, and defect structures

    SciTech Connect

    Williams, B.E.; Glass, J.T.

    1989-03-01

    Thin carbon films grown from a low pressure methane-hydrogen gas mixture by microwave plasma enhanced CVD have been examined by Auger electron spectroscopy, secondary ion mass spectrometry, electron and x-ray diffraction, electron energy loss spectroscopy, and electron microscopy. They were determined to be similar to natural diamond in terms of composition, structure, and bonding. The surface morphology of the diamond films was a function of position on the sample surface and the methane concentration in the feedgas. Well-faceted diamond crystals were observed near the center of the sample whereas a less faceted, cauliflower texture was observed near the edge of the sample, presumably due to variations in temperature across the surface of the sample. Regarding methane concentration effects, threefold /111/ faceted diamond crystals were predominant on a film grown at 0.3% CH/sub 4/ in H/sub 2/ while fourfold /100/ facets were observed on films grown in 1.0% and 2.0% CH/sub 4/ in H/sub 2/. Transmission electron microscopy of the diamond films has shown that the majority of diamond crystals have a very high defect density comprised of /111/ twins, /111/ stacking faults, and dislocations. In addition, cross-sectional TEM has revealed a 50 A epitaxial layer of ..beta..--SiC at the diamond-silicon interface of a film grown with 0.3% CH/sub 4/ in H/sub 2/ while no such layer was observed on a diamond film grown in 2.0% CH/sub 4/ in H/sub 2/.

  3. ZnO nanowire and amorphous diamond nanocomposites and field emission enhancement

    NASA Astrophysics Data System (ADS)

    Yang, Y. H.; Wang, C. X.; Wang, B.; Xu, N. S.; Yang, G. W.

    2005-02-01

    ZnO nanowires were fabricated on the amorphous diamond thin layer on silicon substrates using thermal chemical vapor transport and condensation (CVTC) without any metal catalysts. The remarkable enhancement of the field emission of the nanocomposites by ZnO nanowires covered amorphous diamond was found compared to that of the intrinsic amorphous diamond, suggesting the probability of decorating amorphous diamond by fabricating one-dimensional nanostructures on its surface, which could largely improve the field emission by modifying surface microstructures. Associated with surface chemical reactions, a vapor-solid mechanism of ZnO nanowires nucleation and growth on amorphous diamond was established.

  4. Diamond films: Historical perspective

    SciTech Connect

    Messier, R.

    1993-01-01

    This section is a compilation of notes and published international articles about the development of methods of depositing diamond films. Vapor deposition articles are included from American, Russian, and Japanese publications. The international competition to develop new deposition methodologies is stressed. The current status of chemical vapor deposition of diamond is assessed.

  5. Diamond nucleation using polyethene

    DOEpatents

    Morell, Gerardo; Makarov, Vladimir; Varshney, Deepak; Weiner, Brad

    2013-07-23

    The invention presents a simple, non-destructive and non-abrasive method of diamond nucleation using polyethene. It particularly describes the nucleation of diamond on an electrically viable substrate surface using polyethene via chemical vapor deposition (CVD) technique in a gaseous environment.

  6. Diamond Nucleation Using Polyethene

    NASA Technical Reports Server (NTRS)

    Morell, Gerardo (Inventor); Makarov, Vladimir (Inventor); Varshney, Deepak (Inventor); Weiner, Brad (Inventor)

    2013-01-01

    The invention presents a simple, non-destructive and non-abrasive method of diamond nucleation using polyethene. It particularly describes the nucleation of diamond on an electrically viable substrate surface using polyethene via chemical vapor deposition (CVD) technique in a gaseous environment.

  7. Superconductivity in diamond.

    PubMed

    Ekimov, E A; Sidorov, V A; Bauer, E D; Mel'nik, N N; Curro, N J; Thompson, J D; Stishov, S M

    2004-04-01

    Diamond is an electrical insulator well known for its exceptional hardness. It also conducts heat even more effectively than copper, and can withstand very high electric fields. With these physical properties, diamond is attractive for electronic applications, particularly when charge carriers are introduced (by chemical doping) into the system. Boron has one less electron than carbon and, because of its small atomic radius, boron is relatively easily incorporated into diamond; as boron acts as a charge acceptor, the resulting diamond is effectively hole-doped. Here we report the discovery of superconductivity in boron-doped diamond synthesized at high pressure (nearly 100,000 atmospheres) and temperature (2,500-2,800 K). Electrical resistivity, magnetic susceptibility, specific heat and field-dependent resistance measurements show that boron-doped diamond is a bulk, type-II superconductor below the superconducting transition temperature T(c) approximately 4 K; superconductivity survives in a magnetic field up to Hc2(0) > or = 3.5 T. The discovery of superconductivity in diamond-structured carbon suggests that Si and Ge, which also form in the diamond structure, may similarly exhibit superconductivity under the appropriate conditions. PMID:15057827

  8. All-diamond microelectrode array device.

    PubMed

    Pagels, Markus; Hall, Clive E; Lawrence, Nathan S; Meredith, Andrew; Jones, Timothy G J; Godfried, Herman P; Pickles, C S James; Wilman, Jonathan; Banks, Craig E; Compton, Richard G; Jiang, Li

    2005-06-01

    We report the development of all-diamond microelectrochemical devices, namely, a microelectrode array (MEA), in which a periodic array structure with well-defined diameters, distance, and hexagonal unit cell pattern is micromachined using a combination of state-of-the-art microwave-induced plasma growth and laser ablation shaping techniques to prepare and coat a patterned boron-doped diamond (BDD) substrate with an intrinsic diamond insulating layer. The active BDD element can be tuned to between 10 and 50 microm in diameter with a 10 times diameter center-to-center distance between two adjacent conducting elements, which are exactly coplanar to the dielectric surroundings. This type of device should enable applications in harsh conditions such as high temperature, high pressure, and resistive media under dynamic flow regimes. PMID:15924409

  9. Raman Characterisation of Diamond Coatings Using Different Laser Wavelengths

    NASA Astrophysics Data System (ADS)

    Haubner, Roland; Rudigier, Moritz

    Diamond layers can show different morphologies, i.e. well-facetted, fine-grained and ballas diamond. Additionally, the types NCD (nanocrystalline diamond), UNCD (ultra nanocrystalline diamond) and various types of amorphous carbon (a- C, a-CH ) are known. To characterise the various carbon deposits Raman spectroscopy is most common, because this technique is simple to handle. With a modern Raman spectrometer, provided with three different laser units (wavelengths 472,681 nm/ blue, 532,1 nm/ green, 632,81 nm/ red), the same spot of a sample can be measured several times. A set of diamond coatings, representing the different morphologies, and moreover, boron doped levels were selected for Raman characterisation. Varying the laser wavelength, highly different Raman spectra were obtained and their interpretation is quite difficult.

  10. On diamond surface properties and interactions with neurons.

    PubMed

    Ariano, P; Budnyk, O; Dalmazzo, S; Lovisolo, D; Manfredotti, Ch; Rivolo, P; Vittone, E

    2009-10-01

    In this paper we report about the role the diamond surface morphology and atomic termination plays in the survival and viability of neuronal cells, which represent an appropriate experimental model for the development of cell-based biosensors. The samples we have investigated were both CVD homoepitaxial diamond films and nanocrystalline diamond layers deposited on quartz substrates. Different surface terminations were induced through exposure to atomic hydrogen and to intense UV irradiation. GT1-7 cells, a neuronal line of hypothalamic origin, were plated directly onto the diamond surfaces without exogenous adhesion molecules, in order to correlate the surface topography and chemistry to cell growth and viability. The cell density on nanocrystalline diamonds after 48 h from plating was approximately 55% of the control on plastic dishes, whatever is the atomic termination of the surface, whereas the performances of homoepitaxial samples in terms of cell growth depend on surface termination and were significantly lower, 30%. PMID:19821130

  11. On diamond surface properties and interactions with neurons

    NASA Astrophysics Data System (ADS)

    Ariano, P.; Budnyk, O.; Dalmazzo, S.; Lovisolo, D.; Manfredotti, Ch.; Rivolo, P.; Vittone, E.

    2009-10-01

    In this paper we report about the role the diamond surface morphology and atomic termination plays in the survival and viability of neuronal cells, which represent an appropriate experimental model for the development of cell-based biosensors. The samples we have investigated were both CVD homoepitaxial diamond films and nanocrystalline diamond layers deposited on quartz substrates. Different surface terminations were induced through exposure to atomic hydrogen and to intense UV irradiation. GT1-7 cells, a neuronal line of hypothalamic origin, were plated directly onto the diamond surfaces without exogenous adhesion molecules, in order to correlate the surface topography and chemistry to cell growth and viability. The cell density on nanocrystalline diamonds after 48h from plating was approximately 55% of the control on plastic dishes, whatever is the atomic termination of the surface, whereas the performances of homoepitaxial samples in terms of cell growth depend on surface termination and were significantly lower, 30%.-1

  12. Size distribution analyses for estimating diamond grade and value

    NASA Astrophysics Data System (ADS)

    Chapman, J. G.; Boxer, G. L.

    2004-09-01

    Analysing the size frequency distributions (SFDs) of both micro diamonds and macro diamonds from primary deposits shows that the distributions are continuous across all sizes and that there are two regions of different character with a transition about 1-2 mm. Using log axes, the frequency curve is linear for the smaller sizes allowing slope and intercept parameters to be determined which are less ambiguous than stone counts and ratios of macro to micro populations that are generally reported. Modelling a diamond population that has undergone removal of a uniform thickness of the outer layer transforms a linear frequency curve into a quadratic form, which is also the form of the frequency curve for macro diamonds. Diamonds grown synthetically also display a linear distribution across a smaller fraction of their size distribution curve.

  13. Growth optimization of columnar nanostructured diamond films with high electrical performances for SOD applications

    NASA Astrophysics Data System (ADS)

    Lions, M.; Saada, S.; Pinault, M.-A.; Andrieu, F.; Faynot, O.; Bergonzo, P.

    2010-11-01

    In today's nanoelectronics devices, thermal management is a major issue to miniaturization. Because of its high thermal conductivity, diamond is an extremely interesting material for heat spreading. SOI (Silicon-On-Insulator) technology suffers of the poor thermal dissipation due to the silicon oxide buried layer. Thus, SOD (Silicon-On-Diamond) based on dielectrical diamond layer is seen as a promising candidate for future bulk solution. Polycrystalline diamond layers of extreme insulating properties (>1014??cm) are successfully synthesis with thickness under 150 nm on 2 inches silicon wafer. However, defects due to the growth and the polycrystal structure are responsible for the detrimental current stimulate by alternative electrical field. The defects activation energies were measured on columnar nanostructured diamond grown under different conditions. Values of 0.56 to 1.56 eV were found for defects in these films and were correlated to the growth parameters as well as the diamond morphology.

  14. The use of thin diamond films in fiber-optic low-coherence interferometers

    NASA Astrophysics Data System (ADS)

    Milewska, D.; Karpienko, K.

    2016-01-01

    In this paper we present the use of thin diamond films in fiber-optic low-coherence interferometers. Two kinds of diamond surfaces were used: undoped diamond film and boron- doped diamond film. They were deposited on glass plates as well as silicon layers. A conventionally used mirror was used as a reference layer. Diamond films were deposited using Microwave Plasma Enhanced Chemical Vapour Deposition (μPE CVD) system. Measurements were performed using two superluminescent diodes (SLD) with wavelengths of 1300 mm and 1550 mm. The optimal conditions for each layers were examined: the required wavelength of the light source and the length of Fabry-Perot interferometer cavity. Metrological parameters of Fabry-Perot interferometer with different mirrors were compared. The presented thin diamond films may be an interesting alternative to the commonly used reflective surfaces.

  15. Diamond and diamond-like carbon films for advanced electronic applications

    SciTech Connect

    Siegal, M.P.; Friedmann, T.A.; Sullivan, J.P.

    1996-03-01

    Aim of this laboratory-directed research and development (LDRD) project was to develop diamond and/or diamond-like carbon (DLC) films for electronic applications. Quality of diamond and DLC films grown by chemical vapor deposition (CVD) is not adequate for electronic applications. Nucleation of diamond grains during growth typically results in coarse films that must be very thick in order to be physically continuous. DLC films grown by CVD are heavily hydrogenated and are stable to temperatures {le} 400{degrees}C. However, diamond and DLC`s exceptional electronic properties make them candidates for integration into a variety of microelectronic structures. This work studied new techniques for the growth of both materials. Template layers have been developed for the growth of CVD diamond films resulting in a significantly higher nucleation density on unscratched or unprepared Si surfaces. Hydrogen-free DLC with temperature stability {le} 800{degrees}C has been developed using energetic growth methods such as high-energy pulsed-laser deposition. Applications with the largest system impact include electron-emitting materials for flat-panel displays, dielectrics for interconnects, diffusion barriers, encapsulants, and nonvolatile memories, and tribological coatings that reduce wear and friction in integrated micro-electro-mechanical devices.

  16. Diamonds in detonation soot

    NASA Technical Reports Server (NTRS)

    Greiner, N. Roy; Phillips, Dave; Johnson, J. D.; Volk, Fred

    1990-01-01

    Diamonds 4 to 7 nm in diameter have been identified and partially isolated from soot formed in detonations of carbon-forming composite explosives. The morphology of the soot has been examined by transmission electron microscopy (TEM), and the identity of the diamond has been established by the electron diffraction pattern of the TEM samples and by the X-ray diffraction (XRD) pattern of the isolated solid. Graphite is also present in the form of ribbons of turbostatic structure with a thickness of 2 to 4 nm. A fraction, about 25 percent of the soot by weight, was recovered from the crude soot after oxidation of the graphite with fuming perchloric acid. This fraction showed a distinct XRD pattern of diamond and the diffuse band of amorphous carbon. The IR spectrum of these diamonds closely matches that of diamonds recovered from meteorites (Lewis et al., 1987), perhaps indicating similar surface properties after the oxidation. If these diamonds are produced in the detonation itself or during the initial expansion, they exhibit a phenomenal crystal growth rate (5 nm/0.00001 s equal 1.8 m/hr) in a medium with a very low hydrogen/carbon ratio. Because the diamonds will be carried along with the expanding gases, they will be accelerated to velocities approaching 8 km/s.

  17. Fundamentals of ultrananocrystallie diamond (UNCD) thin films as biomaterials for developmental biology : embryonic fibroblasts growth on the surface of (UNCD) films.

    SciTech Connect

    Shi, B.; Jin, Q.; Chen, L.; Auciello, O.

    2008-09-13

    Ultrananocrystalline diamond (UNCD) films possess numerous valuable good physical, chemical and mechanical properties, making UNCD an excellent material for implantable biodevices. However, one very important property required for biomaterials i.e., biocompatibility has not been studied for UNCD. In this research, biocompatible UNCD films were synthesized. It was found that UNCD film coated substrates can dramatically promote the growth of mouse embryonic fibroblasts (MEFs), while the uncoated substrates inhabit cell attachment. Through analyzing the microstructure and the surface chemistry of UNCD, the mechanisms of cell growth on UNCD were investigated. Given the unique properties of UNCD on inertness and toughness, the results consolidate UNCD film as the leading coating candidate for the next generation of medical implanted devices.

  18. Electrostatic grafting of diamond nanoparticles: a versatile route to nanocrystalline diamond thin films.

    PubMed

    Girard, Hugues A; Perruchas, Sandrine; Gesset, Cline; Chaigneau, Marc; Vieille, Laetitia; Arnault, Jean-Charles; Bergonzo, Philippe; Boilot, Jean-Pierre; Gacoin, Thierry

    2009-12-01

    Nanodiamond (ND) seeding is a well-established route toward the CVD (chemical vapor deposition) synthesis of diamond ultrathin films. This method is based on the deposition onto a substrate of diamond nanoparticles which act as pre-existing sp(3) seeds. Here, we report on a straightforward method to disperse diamond nanoparticles on a substrate by taking advantage of the electrostatic interactions between the nanodiamonds and the substrate surface coated with a cationic polymer. This layer-by-layer deposition technique leads to reproducible and homogeneous large-scale nanoparticle deposits independent of the substrate's nature and shape. No specific functionalization of the nanoparticles is required, and low concentrated solutions can be used. The density of NDs on the substrate can be controlled, as shown by in situ ATR-FTIR (attenuated total reflection Fourier transform infrared) analysis and QCM (quartz crystal microbalance) measurements. Highly dense and compact ND deposits can be obtained, allowing CVD growth of nanocrystalline diamond ultrathin films (70 nm) on various substrates. The synthesis of 3D structured and patterned diamond thin films has also been demonstrated with this method. PMID:20356151

  19. Mechanical stresses and amorphization of ion-implanted diamond

    NASA Astrophysics Data System (ADS)

    Khmelnitsky, R. A.; Dravin, V. A.; Tal, A. A.; Latushko, M. I.; Khomich, A. A.; Khomich, A. V.; Trushin, A. S.; Alekseev, A. A.; Terentiev, S. A.

    2013-06-01

    Scanning white light interferometry and Raman spectroscopy were used to investigate the mechanical stresses and structural changes in ion-implanted natural diamonds with different impurity content. The uniform distribution of radiation defects in implanted area was obtained by the regime of multiple-energy implantation of keV He+ ions. A modification of Bosia's et al. (Nucl. Instrum. Meth. B 268 (2010) 2991) method for determining the internal stresses and the density variation in an ion-implanted diamond layer was proposed that suggests measuring, in addition to the surface swelling of a diamond plate, the radius of curvature of the plate. It is shown that, under multiple-energy implantation of He+, mechanical stresses in the implanted layer may be as high as 12 GPa. It is shown that radiation damage reaches saturation for the implantation fluence characteristic of amorphization of diamond but is appreciably lower than the graphitization threshold.

  20. Metal oxynitride and diamond hard coatings for infrared windows

    NASA Astrophysics Data System (ADS)

    Miller, Andrew J.; Hudson, Martin D.; Dennis, Paul V.; Wilson, Anthony E. J.

    1999-07-01

    The protection of IR windows in airborne FLIR sensor systems against erosion resulting from raindrop and particle impact is accomplished by means of a front surface coating. The wavelength ranges required are 8-14 micrometers , where diamond competes with boron phosphide based coatings for the protection of multispectral zinc sulphide used as a window for multiple detectors. This paper describes progress in the development of diamond coatings for germanium windows, including selection and deposition of durable front surface antireflection layers. The diamond layers are deposited by microwave plasma CVD techniques at 500 degrees C. For the multispectral application, hard oxynitride coatings have been developed both as stand-alone coatings and as interlayers for diamond coatings. The multispectral coatings and the antireflection coatings are deposited by a sputtering process, applicable to flats and domes. In both cases, structured surfaces at appropriate scales are used to improve optical transmission and mechanical adhesion.

  1. Diamond at 800 GPa

    SciTech Connect

    Bradley, D. K.; Eggert, J. H.; Smith, R. F.; Prisbrey, S. T.; Hicks, D. G.; Braun, D. G.; Biener, J.; Hamza, A. V.; Rudd, R. E.; Collins, G. W.

    2009-02-20

    A new compression technique, which enables the study of solids into the TPa regime, is described and used to ramp (or quasi-isentropically) compress diamond to a peak pressure of 1400 GPa. Diamond stress versus density data are reported to 800 GPa and suggest that the diamond phase is stable and has significant material strength up to at least this stress level. Data presented here are the highest ramp compression pressures by more than a factor of 5 and the highest-pressure solid equation-of-state data ever reported.

  2. Software optimization for electrical conductivity imaging in polycrystalline diamond cutters

    NASA Astrophysics Data System (ADS)

    Bogdanov, G.; Wiggins, J.; Bertagnolli, K.; Ludwig, R.

    2014-02-01

    We previously reported on an electrical conductivity imaging instrument developed for measurements on polycrystalline diamond cutters. These cylindrical cutters for oil and gas drilling feature a thick polycrystalline diamond layer on a tungsten carbide substrate. The instrument uses electrical impedance tomography to profile the conductivity in the diamond table. Conductivity images must be acquired quickly, on the order of 5 sec per cutter, to be useful in the manufacturing process. This paper reports on successful efforts to optimize the conductivity reconstruction routine, porting major portions of it to NVIDIA GPUs, including a custom CUDA kernel for Jacobian computation.

  3. Instrumentation development for electrical conductivity imaging in polycrystalline diamond cutters

    NASA Astrophysics Data System (ADS)

    Bogdanov, G.; Wiggins, J.; Rhodes, J.; Bertagnolli, K.; Ludwig, R.

    2013-01-01

    We previously reported on an electrical conductivity non-destructive inspection methodology for polycrystalline diamond cutters. These cylindrical cutters for oil and gas drilling feature a thick polycrystalline diamond layer on a tungsten carbide substrate. We use electrical impedance tomography to image the conductivity in the diamond table. In this paper we report on progress in preparing this instrument for factory deployment. Instrument enhancements include an adjustable part holder, a field-swappable sensor and GPU-enabled software capable of rapidly acquiring images.

  4. Software optimization for electrical conductivity imaging in polycrystalline diamond cutters

    SciTech Connect

    Bogdanov, G.; Ludwig, R.; Wiggins, J.; Bertagnolli, K.

    2014-02-18

    We previously reported on an electrical conductivity imaging instrument developed for measurements on polycrystalline diamond cutters. These cylindrical cutters for oil and gas drilling feature a thick polycrystalline diamond layer on a tungsten carbide substrate. The instrument uses electrical impedance tomography to profile the conductivity in the diamond table. Conductivity images must be acquired quickly, on the order of 5 sec per cutter, to be useful in the manufacturing process. This paper reports on successful efforts to optimize the conductivity reconstruction routine, porting major portions of it to NVIDIA GPUs, including a custom CUDA kernel for Jacobian computation.

  5. Metal oxide semiconductor structure using oxygen-terminated diamond

    NASA Astrophysics Data System (ADS)

    Chicot, G.; Marchal, A.; Motte, R.; Muret, P.; Gheeraert, E.; Pernot, J.

    2013-06-01

    Metal-oxide-semiconductor structures with aluminum oxide as insulator and p-type (100) mono-crystalline diamond as semiconductor have been fabricated and investigated by capacitance versus voltage and current versus voltage measurements. The aluminum oxide dielectric was deposited using low temperature atomic layer deposition on an oxygenated diamond surface. The capacitance voltage measurements demonstrate that accumulation, depletion, and deep depletion regimes can be controlled by the bias voltage, opening the route for diamond metal-oxide-semiconductor field effect transistor. A band diagram is proposed and discussed.

  6. Diamond diode-based chemical gas sensors

    NASA Astrophysics Data System (ADS)

    Gurbuz, Yasar

    The successful utilization of microelectronic-based gas sensors (MOS Capacitor, MOSFET, MS, and MIS diodes) in many practical applications such as automotive, aeronautical, commercial, and environmental has not been achieved due to the limited operating temperature range of Si and GaAs semiconductors (less than 200sp°C). Present development in the diamond technology provides an opportunity to address this problem. Along with its well known physical and optical properties, the superior semiconductor properties of diamond over Si, GaAs, and SiC (higher breakdown voltage, energy band gap, carrier mobility, and thermal conductivity) are useful for gas sensor applications. We have developed a novel family of diamond-based chemical gas sensors for the detection of hydrogen, oxygen and carbon monoxide at a higher operating temperature range than currently possible with Si- and GaAs-based microelectronic gas sensors. The new devices were fabricated in the form of a Pd/i-diamond/psp+-diamond MIS structure for the detection hydrogen and a Pt/SnOsb{x}/i-diamond/psp+-diamond CAIS structure for the detection of oxygen and carbon monoxide. Sensor performances have been investigated over a wide temperature range (22sp° C{-}400sp° C). The gas sensitivity of the devices have been found to be large, fast, selective, repeatable, and reproducible. Detection mechanisms of the sensors have been developed. The hydrogen detection mechanism of the diamond-based MIS device is due to hydrogen dipole formation at the Pd/i-diamond interface and a subsequent change in the voltage distribution across the junction. The oxygen and carbon monoxide sensitivity of the CAIS device is attributed to the modification of the oxygen vacancies in the SnOsb{x} layer and the subsequent change in the voltage drop across the oxide. The current transport mechanisms of the sensors have been studied and gas adsorption effects on sensor parameters have been modeled. The current conduction mechanism of the sensors is Space Charge Limited, distinctively different from Si- and GaAs-based diodes. While no significant change was observed on the ideality factor, a change in the barrier height and tunneling factor of the sensors was found upon gas adsorption. The findings of this study form the basis for the utilization of microelectronic devices in wide range of gas sensor applications, requiring large sensitivity, fast, repeatable, and reproducible response, wider operating temperature range, and stability in harsh environments. Furthermore, this study contributes a fundamental knowledge in the operating principles and sensing mechanisms of the high temperature-tolerant microelectronic gas sensors.

  7. Diamond Ranch High School.

    ERIC Educational Resources Information Center

    Betsky, Aaron

    2000-01-01

    Highlights award-winning Diamond Ranch High School (California) that was designed and built on a steep site around Los Angeles considered unsatisfactory for building due to its unstable soils. Building organization is discussed, and photos are provided. (GR)

  8. Amorphous diamond films

    DOEpatents

    Falabella, S.

    1998-06-09

    Amorphous diamond films having a significant reduction in intrinsic stress are prepared by biasing a substrate to be coated and depositing carbon ions thereon under controlled temperature conditions. 1 fig.

  9. The 3D-tomography of the nano-clusters formed by Fe-coating and annealing of diamond films for enhancing their surface electron field emitters

    NASA Astrophysics Data System (ADS)

    Chen, Huang-Chin; Lo, Shen-Chuan; Lin, Li-Jiaun; Huang, Pin-Chang; Shih, Wen-Ching; Lin, I.-Nan; Lee, Chi-Young

    2012-09-01

    The Fe-coating and H2-annealed processes markedly increased the conductivity and enhanced the surface electron field emission (s-EFE) properties for the diamond films. The enhancement on the s-EFE properties for the diamond films is presumably owing to the formation of nano-graphite clusters on the surface of the films via the Fe-to-diamond interaction. However, the extent of enhancement varied with the granular structure of the diamond films. For the microcrystalline (MCD) films, the s-EFE process can be turned on at (E0)MCD = 1.9 V/?m, achieving a large s-EFE current density of (Je)MCD = 315 ?A/cm2 at an applied field of 8.8 V/?m. These s-EFE properties are markedly better than those for Fe-coated/annealed ultrananocrystalline diamond (UNCD) films with (E0)UNCD = 2.0 V/?m and (Je)UNCD = 120 ?A/cm2. The transmission electron microscopy showed that the nano-graphite clusters formed an interconnected network for MCD films that facilitated the electron transport more markedly, as compared with the isolated nano-graphitic clusters formed at the surface of the UNCD films. Therefore, the Fe-coating/annealing processes improved the s-EFE properties for the MCD films more markedly than that for the UNCD films. The understanding on the distribution of the nano-clusters is of critical importance in elucidating the authentic factor that influences the s-EFE properties of the diamond films. Such an understanding is possible only through the 3D-tomographic investigations.

  10. Near-ultraviolet micro-Raman study of diamond grown on GaN

    NASA Astrophysics Data System (ADS)

    Nazari, M.; Hancock, B. L.; Anderson, J.; Savage, A.; Piner, E. L.; Graham, S.; Faili, F.; Oh, S.; Francis, D.; Twitchen, D.; Holtz, M.

    2016-01-01

    Ultraviolet (UV) micro-Raman measurements are reported of diamond grown on GaN using chemical vapor deposition. UV excitation permits simultaneous investigation of the diamond (D) and disordered carbon (DC) comprising the polycrystalline layer. From line scans of a cross-section along the diamond growth direction, the DC component of the diamond layer is found to be highest near the GaN-on-diamond interface and diminish with characteristic length scale of 3.5 ?m. Transmission electron microscopy (TEM) of the diamond near the interface confirms the presence of DC. Combined micro-Raman and TEM are used to develop an optical method for estimating the DC volume fraction.

  11. High-mobility diamond

    NASA Astrophysics Data System (ADS)

    Landstrass, Maurice I.

    1994-04-01

    Recent improvements in the CVD diamond deposition process have made possible the fabrication of diamond photoconductive diodes with carrier mobility and lifetime exceeding the values typical of natural gemstones. One of the more surprising recent results is that the best room-temperature carrier properties have been measured on polycrystalline diamond films. The combined electron- hole mobility, as measured by transient photoconductivity at low carrier densities, is 4000 square centimeters per volt per second at electric field of 200 volts per centimeter and is comparable to that of the best single-crystal IIa natural diamonds. Carrier lifetimes measured under the same conditions are 150 picoseconds for the CVD diamond films. The collection distance within the diamond films, at the highest applied fields, is comparable to the average film grain size, indicative of little or no carrier scattering at grain boundaries. A comparison of SIMS measurements with electrical results suggest that impurity incorporation in the near grain boundary regions are responsible for controlling the carrier mobility.

  12. Diamond nanoimprint lithography

    NASA Astrophysics Data System (ADS)

    Taniguchi, Jun; Tokano, Yuji; Miyamoto, Iwao; Komuro, Masanori; Hiroshima, Hiroshi

    2002-10-01

    Electron beam (EB) lithography using polymethylmethacrylate (PMMA) and oxygen gas reactive ion etching (RIE) were used to fabricate fine patterns in a diamond mould. To prevent charge-up during EB lithography, thin conductive polymer was spin-coated over the PMMA resist, yielding dented line patterns 2 ? m wide and 270 nm deep. The diamond mould was pressed into PMMA on a silicon substrate heated to 130, 150 and 170C at 43.6, 65.4 and 87.2 MPa. All transferred PMMA convex line patterns were 2 ? m wide. Imprinted pattern depth increased with rising temperature and pressure. PMMA patterns on diamond were transferred by the diamond mould at 150C and 65.4 MPa, yielding convex line patterns 2 ? m wide and 200 nm high. Direct aluminium and copper patterns were obtained using the diamond mould at room temperature and 130.8 MPa. The diamond mould is thus useful for replicating patterns on PMMA and metals.

  13. Diamond micro-optics

    NASA Astrophysics Data System (ADS)

    Nikolajeff, Fredrik K.; Karlsson, Mikael

    2003-11-01

    We have developed a method for fabricating almost any type of optical surfaces in diamond. The method consists of the following steps: First, a polymer film, spun onto diamond substrates of optical quality, is patterned by lithographic processes. Next, the surface relief is transferred into the underlying diamond by use of inductively coupled plasma dry etching in an oxygen/argon chemistry. Using this technique, we have successfully demonstrated the fabrication of diamond spherical microlenses, blazed gratings, Fresnel lenses, subwavelength gratings and diffractive fan-out elements. The spherical microlenses had apertures of 90 ?m and f-number of 4. The phase error, measured with a Twyman-Green interferometer at 633 nm, was found to be less than 31 nm. The diffraction efficiency for the blazed grating was measured to be 68% at 400 nm, with a theoretical maximum of 71%. The subwavelength grating was designed for reducing surface reflections at a wavelength of 10.6 ?m. Spectrophotometric results show that the optical transmission was increased from 70%, using a non-structured diamond substrate, to 97%, using our subwavelength structured diamond. Finally, the fan-out element has been tested with a 6 kW carbon-dioxide laser, to microstructure pieces of PMMA. The results are excellent, showing diffraction limited spots.

  14. Enhancement of oxidation resistance via a self-healing boron carbide coating on diamond particles

    NASA Astrophysics Data System (ADS)

    Sun, Youhong; Meng, Qingnan; Qian, Ming; Liu, Baochang; Gao, Ke; Ma, Yinlong; Wen, Mao; Zheng, Weitao

    2016-02-01

    A boron carbide coating was applied to diamond particles by heating the particles in a powder mixture consisting of H3BO3, B and Mg. The composition, bond state and coverage fraction of the boron carbide coating on the diamond particles were investigated. The boron carbide coating prefers to grow on the diamond (100) surface than on the diamond (111) surface. A stoichiometric B4C coating completely covered the diamond particle after maintaining the raw mixture at 1200 °C for 2 h. The contribution of the boron carbide coating to the oxidation resistance enhancement of the diamond particles was investigated. During annealing of the coated diamond in air, the priory formed B2O3, which exhibits a self-healing property, as an oxygen barrier layer, which protected the diamond from oxidation. The formation temperature of B2O3 is dependent on the amorphous boron carbide content. The coating on the diamond provided effective protection of the diamond against oxidation by heating in air at 1000 °C for 1 h. Furthermore, the presence of the boron carbide coating also contributed to the maintenance of the static compressive strength during the annealing of diamond in air.

  15. Enhancement of oxidation resistance via a self-healing boron carbide coating on diamond particles.

    PubMed

    Sun, Youhong; Meng, Qingnan; Qian, Ming; Liu, Baochang; Gao, Ke; Ma, Yinlong; Wen, Mao; Zheng, Weitao

    2016-01-01

    A boron carbide coating was applied to diamond particles by heating the particles in a powder mixture consisting of H3BO3, B and Mg. The composition, bond state and coverage fraction of the boron carbide coating on the diamond particles were investigated. The boron carbide coating prefers to grow on the diamond (100) surface than on the diamond (111) surface. A stoichiometric B4C coating completely covered the diamond particle after maintaining the raw mixture at 1200?C for 2?h. The contribution of the boron carbide coating to the oxidation resistance enhancement of the diamond particles was investigated. During annealing of the coated diamond in air, the priory formed B2O3, which exhibits a self-healing property, as an oxygen barrier layer, which protected the diamond from oxidation. The formation temperature of B2O3 is dependent on the amorphous boron carbide content. The coating on the diamond provided effective protection of the diamond against oxidation by heating in air at 1000?C for 1?h. Furthermore, the presence of the boron carbide coating also contributed to the maintenance of the static compressive strength during the annealing of diamond in air. PMID:26831205

  16. Enhancement of oxidation resistance via a self-healing boron carbide coating on diamond particles

    PubMed Central

    Sun, Youhong; Meng, Qingnan; Qian, Ming; Liu, Baochang; Gao, Ke; Ma, Yinlong; Wen, Mao; Zheng, Weitao

    2016-01-01

    A boron carbide coating was applied to diamond particles by heating the particles in a powder mixture consisting of H3BO3, B and Mg. The composition, bond state and coverage fraction of the boron carbide coating on the diamond particles were investigated. The boron carbide coating prefers to grow on the diamond (100) surface than on the diamond (111) surface. A stoichiometric B4C coating completely covered the diamond particle after maintaining the raw mixture at 1200 °C for 2 h. The contribution of the boron carbide coating to the oxidation resistance enhancement of the diamond particles was investigated. During annealing of the coated diamond in air, the priory formed B2O3, which exhibits a self-healing property, as an oxygen barrier layer, which protected the diamond from oxidation. The formation temperature of B2O3 is dependent on the amorphous boron carbide content. The coating on the diamond provided effective protection of the diamond against oxidation by heating in air at 1000 °C for 1 h. Furthermore, the presence of the boron carbide coating also contributed to the maintenance of the static compressive strength during the annealing of diamond in air. PMID:26831205

  17. Fundamentals and technology for monolithically integrated RF MEMS switches with ultra-nanocrystaline diamond dielectric/CMOS devices.

    SciTech Connect

    Auciello, O.; Sumant, A.; Goldsmith, C.; O'Brien, S.; Sampath, S.; Gudeman, C; Wang, W.; Hwang, J.; Swonger, J.; Carlisle, J.; Balachandran, S.; MEMtronics Corp.; Innovative Micro Technology; Lehigh Univ.; Peregrine Semiconductor; Advanced Diamond Technologies

    2010-01-01

    Most current capacitive RF-MEMS switch technology is based on conventional dielectric materials such as SiO{sub 2} and Si{sub 3}N{sub 4}. However, they suffer not only from charging problems but also stiction problems leading to premature failure of an RF-MEMS switch. Ultrananocrystalline diamond (UNCD{sup (R)}) (2-5 nm grains) and nanocrystalline diamond (NCD) (10-100 nm grains) films exhibit one of the highest Young's modulus ({approx} 980-1100 GPa) and demonstrated MEMS resonators with the highest quality factor (Q {ge} 10,000 in air for NCD) today, they also exhibit the lowest force of adhesion among MEMS/NEMS materials ({approx}10 mJ/m{sup 2}-close to van der Waals attractive force for UNCD) demonstrated today. Finally, UNCD exhibits dielectric properties (fast discharge) superior to those of Si and SiO{sub 2}, as shown in this paper. Thus, UNCD and NCD films provide promising platform materials beyond Si for a new generation of important classes of high-performance MEMS/NEMS devices.

  18. Ion-Implanted Diamond Films and Their Tribological Properties

    NASA Technical Reports Server (NTRS)

    Wu, Richard L. C.; Miyoshi, Kazuhisa; Korenyi-Both, Andras L.; Garscadden, Alan; Barnes, Paul N.

    1993-01-01

    This paper reports the physical characterization and tribological evaluation of ion-implanted diamond films. Diamond films were produced by microwave plasma, chemical vapor deposition technique. Diamond films with various grain sizes (0.3 and 3 microns) and roughness (9.1 and 92.1 nm r.m.s. respectively) were implanted with C(+) (m/e = 12) at an ion energy of 160 eV and a fluence of 6.72 x 10(exp 17) ions/sq cm. Unidirectional sliding friction experiments were conducted in ultrahigh vacuum (6.6 x 10(exp -7)Pa), dry nitrogen and humid air (40% RH) environments. The effects of C(+) ion bombardment on fine and coarse-grained diamond films are as follows: the surface morphology of the diamond films did not change; the surface roughness increased (16.3 and 135.3 nm r.m.s.); the diamond structures were damaged and formed a thin layer of amorphous non-diamond carbon; the friction coefficients dramatically decreased in the ultrahigh vacuum (0.1 and 0.4); the friction coefficients decreased slightly in the dry nitrogen and humid air environments.

  19. Facts about Diamond Blackfan Anemia

    MedlinePLUS

    ... NCBDDD Cancel Submit Search The CDC Diamond Blackfan Anemia (DBA) Note: Javascript is disabled or is not ... Recommend on Facebook Tweet Share Compartir Diamond Blackfan anemia (DBA) is a rare blood disorder that is ...

  20. Effect of Metal Matrix Alloying on Mechanical Strength of Diamond Particle-Reinforced Aluminum Composites

    NASA Astrophysics Data System (ADS)

    Zhang, Hailong; Wu, Jianhua; Zhang, Yang; Li, Jianwei; Wang, Xitao

    2015-06-01

    Diamond particle-reinforced Al matrix (Al/diamond) composites were produced by a gas pressure infiltration method, where 0.5-4.0 wt.% Ti was added to Al matrix. An interfacial TiC layer of about 2 ?m thickness was formed between Al and diamond at 4.0 wt.% Ti addition. The mechanical properties of the Al/diamond composites were enhanced by both the formation of interfacial layer and the strengthening of the matrix. The mechanical strength increased with increasing alloying Ti content, and a tensile strength of 153 MPa was obtained at 4.0 wt.% Ti addition. The tensile flow stress of the composites was found to be in broad agreement with the prediction of the Mori-Tanaka model. The effect of interfacial layer on mechanical properties provides guideline for the production of mechanically reliable Al/diamond composites.

  1. New diamond science and technology

    SciTech Connect

    Messier, R.; Roy, R. ); Glass, J.T. ); Butler, J.E. )

    1991-01-01

    This book covers the following topics: Vapor phase diamonds; General, theory, modeling; Natural and synthetic HP/HT diamond; Gas phase and surface measurements; Gas phase and surface chemistry; Properties: Mechanical, chemical, thermal; Properties: Electrical; Diamond-like materials; and Cubic boron nitride.

  2. Diamond collecting in northern Colorado.

    USGS Publications Warehouse

    Collins, D.S.

    1982-01-01

    The discovery of numerous diamond-bearing kimberlite diatremes in the N Front Range of Colorado and Wyoming is of both scientific and economic interest. Species recovered from heavy-mineral concentrates include Cr-diopside, spinel, Mg-ilmenite, pyrope and diamond. A nodule tentatively identified as a graphite-diamond eclogite was also found. -G.W.R.

  3. Making Diamond in the Laboratory

    ERIC Educational Resources Information Center

    Strong, Herbert

    1975-01-01

    Discusses the graphite to diamond transformation and a phase diagram for carbon. Describes high temperature-higher pressure experimental apparatus and growth of diamonds from seed crystals. Reviews properties of the diamond which suggest uses for the synthetic product. Illustrations with text. (GH)

  4. Repulsive effects of hydrophobic diamond thin films on biomolecule detection

    NASA Astrophysics Data System (ADS)

    Ruslinda, A. Rahim; Ishiyama, Y.; Penmatsa, V.; Ibori, S.; Kawarada, H.

    2015-02-01

    The repulsive effect of hydrophobic diamond thin film on biomolecule detection, such as single-nucleotide polymorphisms and human immunodeficiency virus type 1 trans-activator of transcription peptide protein detection, was investigated using a mixture of a fluorine-, amine-, and hydrogen-terminated diamond surfaces. These chemical modifications lead to the formation of a surface that effectively resists the nonspecific adsorption of proteins and other biomolecules. The effect of fluorine plasma treatment on elemental composition was also investigated via X-ray photoelectron spectroscopy (XPS). XPS results revealed a fluorocarbon layer on the diamond thin films. The contact angle measurement results indicated that the fluorine-treated diamond thin films were highly hydrophobic with a surface energy value of ?25 mN/m.

  5. Studies of mono-crystalline CVD diamond pixel detectors

    NASA Astrophysics Data System (ADS)

    Bugg, W.; Hollingsworth, M.; Spanier, S.; Yang, Z.; Bartz, E.; Doroshenko, J.; Hits, D.; Schnetzer, S.; Stone, R.; Atramentov, O.; Patel, R.; Barker, A.; Hall-Wilton, R.; Ryjov, V.; Farrow, C.; Pernicka, M.; Steininger, H.; Johns, W.; Halyo, V.; Harrop, B.; Hunt, A.; Marlow, D.; Hebda, P.

    2011-09-01

    The Pixel Luminosity Telescope (PLT) is a dedicated luminosity monitor, presently under construction, for the Compact Muon Solenoid (CMS) experiment at the Large Hadron Collider (LHC). It measures the particle flux in several three layered pixel diamond detectors that are aligned precisely with respect to each other and the beam direction. At a lower rate it also performs particle track position measurements. The PLT's mono-crystalline CVD diamonds are bump-bonded to the same readout chip used in the silicon pixel system in CMS. Mono-crystalline diamond detectors have many attributes that make them desirable for use in charged particle tracking in radiation hostile environments such as the LHC. In order to further characterize the applicability of diamond technology to charged particle tracking we performed several tests with particle beams that included a measurement of the intrinsic spatial resolution with a high resolution beam telescope.

  6. Laser Patterning of Diamond. Part II. Surface Nondiamond Carbon Formation and its Removal

    SciTech Connect

    Smedley, J.; Jaye, C; Bohon, J; Rao, T; Fischer, D

    2009-01-01

    As diamond becomes more prevalent for electronic and research applications, methods of patterning diamond will be required. One such method, laser ablation, has been investigated in a related work. We report on the formation of surface nondiamond carbon during laser ablation of both polycrystalline and single-crystal synthetic diamonds. Near edge x-ray absorption fine structure spectroscopy was used to confirm that the nondiamond carbon layer formed during the ablation was amorphous, and Fourier transform infrared absorption spectroscopy (FTIR) was used to estimate the thickness of this layer to be {approx} 60 nm. Ozone cleaning was used to remove the nondiamond carbon layer.

  7. Experimental study of diamond resorption during mantle metasomatism

    NASA Astrophysics Data System (ADS)

    Fedorchuk, Yana; Schmidt, Max W.; Liebske, Christian

    2014-05-01

    Many of kimberlite-derived diamonds are partially dissolved to various degree but show similar resorption style. This resorption style has been observed in experiments with aqueous fluid at the conditions corresponding to kimberlite emplacement (1-2 GPa). At the same time, each diamond population has more than ten percent of diamond crystals with several drastically different resorption styles, which have not been observed in experiments, and may represent partial dissolution of diamonds during metasomatism in different mantle domains. Metasomatic processes modify the composition of subcratonic mantle, may trigger the formation of kimberlite magma, and result in the growth and partial dissolution of diamonds. Composition of metasomatic agents as constrained from studies of the reaction rims on mantle minerals (garnet, clinopyroxene) and experimental studies vary between carbonatitic melt, aqueous silicate melt, and CHO fluid. However, complex chemical pattern of mantle minerals and estimates of redox regime in subcratonic mantle allow different interpretations. Here we explore diamond dissolution morphology as an indicator of the composition of mantle metasomatic agents. Towards this end we examine diamond dissolution morphologies developed in experiments at the conditions of mantle metasomatism in different reacting media and compare them to the mantle-derived dissolution features of natural diamonds. The experiments were conducted in multi-anvil (Walker-Type) apparatus at 6 GPa and 1200-1500oC. Dissolution morphology of natural octahedral diamond crystals (0.5 mg) was examined in various compositions in synthetic system MgO-CaO- SiO2-CO2-H2O. The runs had the following phases present: solid crystals with fluid (various ratio of H2O-CO2-SiO2, and in the air), carbonate melt, carbonate-silicate melt, and carbonate melt with CHO fluid. Experiments produced three different styles of diamond resorption. In the presence of a fluid phase with variable proportions of H2O and CO2 diamond crystals develop ditrigonal outline of {111} faces, striation or hillocks along the edges, and shallow negatively oriented trigonal etch pits with flat or pointed bottom. Presence of SiO2 in the fluid resulted in multi-corner morphology, layering and / or more intensive etching of {111} faces. Dissolution in carbonate melt in the absence of water produced deep stepped-wall hexagonal and trigonal etch pits with negative orientation. The three resorption styles show strong resemblance to the secondary morphology of natural diamonds. This suggests that CHO fluid, aqueous silicate melt, and carbonatatitic melt are metasomatic agents reacting with natural diamonds in subcratonic mantle. The comparison of the experimentally-induced resorption styles to those on natural diamonds show that mantle metasomatism induced by CHO fluid develop morphologies similar to those developed in kimberlite magma. This indicates that significant proportion of kimberlite-hosted diamonds may show resorption features of mantle origin. Aqueous silicate melt induces step-faced multi-corner resorption morphology, similar to natural diamonds with nitrogen aggregation corresponding to eclogitic diamonds. Dissolution in carbonatitic melt results in complex morphologies with deep hexagonal pits similar to natural diamonds with nitrogen data corresponding to peridotitic diamonds.

  8. Peculiarities of boron distribution in as-grown boron-doped diamond

    NASA Astrophysics Data System (ADS)

    Blank, V. D.; Kulnitskiy, B. A.; Perezhogin, I. A.; Terentiev, S. A.; Nosukhin, S. A.; Kuznetsov, M. S.

    2014-09-01

    Boron doped diamond (BDD) single crystals have been grown under conditions of high isostatic pressure by the temperature gradient method. Numerous equilateral triangles were found on the fluorescence images of {111}-diamond facets. Structural peculiarities of BDD were investigated by JEM-2010 transmission electron microscope with GIF Quantum attachment for electron energy loss spectroscopy (EELS). High resolution image of diamond lattice revealed some distorted {111}-layers. EELS testifies the presence of boron in distorted regions of diamond lattice. The crystallographic features of BDD and their connection with the superconductivity are discussed.

  9. Dosimetry with diamond detectors

    NASA Astrophysics Data System (ADS)

    Gervino, G.; Marino, C.; Silvestri, F.; Lavagno, A.; Truc, F.

    2010-05-01

    In this paper we present the dosimetry analysis in terms of stability and repeatability of the signal and dose rate dependence of a synthetic single crystal diamond grown by Chemical Vapor Deposition (CVD) technique. The measurements carried out by 5 MeV X-ray photons beam show very promising results, even if the dose rate detector response points out that the charge trapping centers distribution is not uniform inside the crystal volume. This handicap that affects the detectors performances, must be ascribed to the growing process. Synthetic single crystal diamonds could be a valuable alternative to air ionization chambers for quality beam control and for intensity modulated radiation therapy beams dosimetry.

  10. Process for making diamonds

    NASA Technical Reports Server (NTRS)

    Rasquin, J. R.; Estes, M. F. (Inventor)

    1973-01-01

    A description is given of a device and process for making industrial diamonds. The device is composed of an exponential horn tapering from a large end to a small end, with a copper plate against the large end. A magnetic hammer abuts the copper plate. The copper plate and magnetic hammer function together to create a shock wave at the large end of the horn. As the wave propagates to the small end, the extreme pressure and temperature caused by the wave transforms the graphite, present in an anvil pocket at the small end, into diamonds.

  11. Diamond/AlN Thin Films for Optical Applications

    SciTech Connect

    Knoebber, F.; Bludau, O.; Williams, O. A.; Sah, R. E.; Kirste, L.; Baeumler, M.; Nebel, C. E.; Ambacher, O.; Cimalla, V.; Lebedev, V.; Leopold, S.; Paetz, D.

    2010-11-01

    In this work we report on membranes made of nanocrystalline diamond (NCD) and AlN for the use in tunable micro-optics. For the growth of the AlN and NCD thin films, magnetron sputtering and chemical vapor deposition techniques have been used, respectively. A chemical-mechanical polishing process of NCD layers has been introduced, which is crucial for the growth of c-oriented, fiber textured AlN films. AlN layers deposited on as grown and polished nanocrystalline diamond along with free standing membranes have been compared by studying microstructure, surface morphology, piezoelectrical response as well as optical properties.

  12. Fluidized bed deposition of diamond

    DOEpatents

    Laia, Jr., Joseph R. (Los Alamos, NM); Carroll, David W. (Los Alamos, NM); Trkula, Mitchell (Los Alamos, NM); Anderson, Wallace E. (Los Alamos, NM); Valone, Steven M. (Santa Fe, NM)

    1998-01-01

    A process for coating a substrate with diamond or diamond-like material including maintaining a substrate within a bed of particles capable of being fluidized, the particles having substantially uniform dimensions and the substrate characterized as having different dimensions than the bed particles, fluidizing the bed of particles, and depositing a coating of diamond or diamond-like material upon the substrate by chemical vapor deposition of a carbon-containing precursor gas mixture, the precursor gas mixture introduced into the fluidized bed under conditions resulting in excitation mechanisms sufficient to form the diamond coating.

  13. Photo-stimulated low electron temperature high current diamond film field emission cathode

    DOEpatents

    Shurter; Roger Philips , Devlin; David James , Moody; Nathan Andrew , Taccetti; Jose Martin , Russell; Steven John

    2012-07-24

    An electron source includes a back contact surface having a means for attaching a power source to the back contact surface. The electron source also includes a layer comprising platinum in direct contact with the back contact surface, a composite layer of single-walled carbon nanotubes embedded in platinum in direct contact with the layer comprising platinum. The electron source also includes a nanocrystalline diamond layer in direct contact with the composite layer. The nanocrystalline diamond layer is doped with boron. A portion of the back contact surface is removed to reveal the underlying platinum. The electron source is contained in an evacuable container.

  14. Loss of electrical conductivity in boron-doped diamond due to ion-induced damage

    SciTech Connect

    Kalish, R.; Uzan-Saguy, C.; Philosoph, B.; Richter, V.; Prawer, S.

    1997-02-01

    The response of B-ion-implanted type-IIa diamond to light ion (H, He) irradiation is investigated by monitoring the sample resistance as a function of dose. It is found that the resistivity of the layer increases rapidly with increasing dose, and reaches the resistivity of the undoped diamond for irradiation doses much less than those required for the onset of damage related electrical conductivity in pristine diamond. It is shown that defects created by the nuclear stopping process act as compensating centers for the B acceptors. The present findings are of importance for the design of radiation hard diamond based electronic devices and suggests a method for the isolation of B-doped devices on a diamond chip. The results of the present work also explain why the collection distance in intrinsic nondoped diamond radiation detectors actually increases with increasing ion dose. {copyright} {ital 1997 American Institute of Physics.}

  15. Heteroepitaxial CVD diamond film growth

    NASA Astrophysics Data System (ADS)

    Dai, Zhongning; Bednarski-Meinke, Connie; Golding, Brage

    2003-03-01

    We have studied the conditions necessary for growth of (001) oriented CVD diamond films on iridium films grown epitaxially on sapphire substrates. Using sequential interrupted growth experiments, we have followed the coalescence of individual crystallites by interface annihilation at an early growth stage. After one-hour growth, an extremely smooth, continuous film of single crystal diamond covers the entire surface of the substrate, an area of 10 mm^2. By growing for extended periods, to a maximum of 48 hr, diamond plates of thickness 35 ?m were produced. XRD, Raman, AFM, EBSD, and SEM analyses were used to characterize the crystallographic and surface quality of the diamond film. Freestanding crystals exhibited (111) cleavage surfaces, the same as natural diamond, and were transparent in visible light. The discovery that (001) Ir on sapphire can be used as a substrate to grow diamond promises to lead to improvements in diamond quality and will enable scale-up to large-area crystals.

  16. Fracture of synthetic diamond

    SciTech Connect

    Drory, M.D.; Dauskardt, R.H.; Kant, A.; Ritchie, R.O.

    1995-09-01

    The fracture behavior of synthetic diamond has been investigated using indentation methods and by the tensile testing of pre-notched fracture-mechanics type samples. Specifically, the fracture toughness of free-standing diamond plates, grown by chemically-vapor deposited (CVD) methods, was measured using Vickers indentations and by the use of disk-shaped compact-tension specimens; the latter method provides an evaluation of the through-thickness fracture properties, whereas the indentation method was performed on the nucleation surface of the sample. Measured fracture toughness ({ital K}{sub c}) values were found to be approximately 5--6 MPa{radical}m by both methods, indicating that the fracture resistance of CVD diamond does not vary appreciably with grain size (within the certainty of the testing procedures). Complications, however, arose with the fracture-mechanics testing regarding crack initiation from a relatively blunt notch; further work is needed to develop pre-cracking methods to permit more reliable fracture toughness testing of diamond. {copyright} {ital 1995} {ital American} {ital Institute} {ital of} {ital Physics}.

  17. Multiplying Electrons With Diamond

    NASA Technical Reports Server (NTRS)

    2003-01-01

    As researchers in the Space Communications Division of NASA s Glenn Research Center in 1992, Dr. Gerald Mearini, Dr. Isay Krainsky, and Dr. James Dayton made a secondary electron emission discovery that became the foundation for Mearini s company, GENVAC AeroSpace Corporation. Even after Mearini departed Glenn, then known as Lewis Research Center, his contact with NASA remained strong as he was awarded Small Business Innovation Research (SBIR) contracts to further develop his work. Mearini s work for NASA began with the investigation of diamond as a material for the suppression of secondary electron emissions. The results of his research were the opposite of what was expected diamond proved to be an excellent emitter rather than absorber. Mearini, Krainsky, and Dayton discovered that laboratory-grown diamond films can produce up to 45 electrons from a single incident electron. Having built an electron multiplier prototype at NASA, Mearini decided to start his own company to develop diamond structures usable in electron beam devices.

  18. CVD diamond - fundamental phenomena

    SciTech Connect

    Yarbrough, W.A.

    1993-01-01

    This compilation of figures and diagrams addresses the basic physical processes involved in the chemical vapor deposition of diamond. Different methods of deposition are illustrated. For each method, observations are made of the prominent advantages and disadvantages of the technique. Chemical mechanisms of nucleation are introduced.

  19. ELECTRON AMPLIFICATION IN DIAMOND.

    SciTech Connect

    SMEDLEY, J.; BEN-ZVI, I.; BURRILL, A.; CHANG, X.; GRIMES, J.; RAO, T.; SEGALOV, Z.; WU, Q.

    2006-07-10

    We report on recent progress toward development of secondary emission ''amplifiers'' for photocathodes. Secondary emission gain of over 300 has been achieved in transmission mode and emission mode for a variety of diamond samples. Techniques of sample preparation, including hydrogenation to achieve negative electron affinity (NEA), have been adapted to this application.

  20. DIAMOND AMPLIFIED PHOTOCATHODES.

    SciTech Connect

    SMEDLEY,J.; BEN-ZVI, I.; BOHON, J.; CHANG, X.; GROVER, R.; ISAKOVIC, A.; RAO, T.; WU, Q.

    2007-11-26

    High-average-current linear electron accelerators require photoinjectors capable of delivering tens to hundreds of mA average current, with peak currents of hundreds of amps. Standard photocathodes face significant challenges in meeting these requirements, and often have short operational lifetimes in an accelerator environment. We report on recent progress toward development of secondary emission amplifiers for photocathodes, which are intended to increase the achievable average current while protecting the cathode from the accelerator. The amplifier is a thin diamond wafer which converts energetic (few keV) primary electrons into hundreds of electron-hole pairs via secondary electron emission. The electrons drift through the diamond under an external bias and are emitted into vacuum via a hydrogen-terminated surface with negative electron affinity (NEA). Secondary emission gain of over 200 has been achieved. Two methods of patterning diamond, laser ablation and reactive-ion etching (RIE), are being developed to produce the required geometry. A variety of diagnostic techniques, including FTIR, SEM and AFM, have been used to characterize the diamonds.

  1. Development of Designer Diamond Anvils for High Pressure-High-Temperature Experiments in Support of the Stockpile Stewardship Program

    SciTech Connect

    Yogesh K. Vohra

    2005-05-12

    The focus of this program at the University of Alabama at Birmingham (UAB) is to develop the next generation of designer diamond anvils that can perform simultaneous joule heating and temperature profile measurements in a diamond anvil cell. A series of tungsten-rhenium thermocouples will be fabricated onto to the anvil and encapsulated by a chemical vapor deposited diamond layer to allow for a complete temperature profile measurement across the anvil. The tip of the diamond anvil will be engineered to reduce the thermal conductivity so that the tungsten-heating coils can be deposited on top of this layer. Several different approaches will be investigated to engineer the tip of the diamond anvil for reduction in thermal conductivity (a) isotopic mixture of 12C and 13C in the diamond layer, (b) doping of diamond with impurities (nitrogen and/or boron), and (c) growing diamond in a higher concentration of methane in hydrogen plasma. Under this academic alliance with Lawrence Livermore National Laboratory (LLNL), PI and his graduate students will use the lithographic and diamond polishing facility at LLNL. This proposed next generation of designer diamond anvils will allow multi-tasking capability with the ability to measure electrical, magnetic, structural and thermal data on actinide materials with unparallel sensitivity in support of the stockpile stewardship program.

  2. A multilayer innovative solution to improve the adhesion of nanocrystalline diamond coatings

    NASA Astrophysics Data System (ADS)

    Poulon-Quintin, A.; Faure, C.; Teul-Gay, L.; Manaud, J. P.

    2015-03-01

    Nano-crystalline diamond (NCD) films grown under negative biased substrates by chemical vapor deposition (CVD) are widely used as surface overlay coating onto cermet WC-Co cutting tools to get better performances. To improve the diamond adhesion to the cermet substrate, suitable multi-layer systems have been added. They are composed of a cobalt diffusion barrier close to the substrate (single and sequenced nitrides layers) coated with a nucleation extra layer to improve the nucleus density of diamond during CVD processing. For all systems, before and after diamond deposition, transmission electron microscopy (TEM) has been performed for a better understanding of the diffusion phenomena occurring at the interfaces and to evaluate the presence of graphitic species at the interface with the diamond. Innovative multilayer system dedicated to the regulation of cobalt diffusion coated with a bilayer system optimized for the carbon diffusion control, is shown as an efficient solution to significantly reduce the graphite layer formation at the interface with the diamond down to 10 nm thick and to increase the adhesion of NCD diamond layer as scratch-tests confirm.

  3. REMEDIATION OF OIL CONTAMINATED GROUND AND SURFACE WATER USING SULFATE NANOFILTRATION COMBINED WITH HIGH EFFICIENCY ON-SITE GENERATION OF PEROXODISULFATE USING ULTRANANOCRYSTALLINE DIAMOND ELECTRODES - PHASE I

    EPA Science Inventory

    This Small Business Innovation Research (SBIR) project will employ nanofiltration to generate sulfate ion feedstocks and high current density on-site generation (synthesis) of the powerful oxidant...

  4. Lower pressure synthesis of diamond material

    DOEpatents

    Lueking, Angela (State College, PA); Gutierrez, Humberto (State College, PA); Narayanan, Deepa (Redmond, WA); Burgess Clifford, Caroline E. (State College, PA); Jain, Puja (King Of Prussia, PA)

    2010-07-13

    Methods of synthesizing a diamond material, particularly nanocrystalline diamond, diamond-like carbon and bucky diamond are provided. In particular embodiments, a composition including a carbon source, such as coal, is subjected to addition of energy, such as high energy reactive milling, producing a milling product enriched in hydrogenated tetrahedral amorphous diamond-like carbon compared to the coal. A milling product is treated with heat, acid and/or base to produce nanocrystalline diamond and/or crystalline diamond-like carbon. Energy is added to produced crystalline diamond-like carbon in particular embodiments to produce bucky diamonds.

  5. 31 CFR 592.310 - Rough diamond.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... 31 Money and Finance:Treasury 3 2013-07-01 2013-07-01 false Rough diamond. 592.310 Section 592.310... ASSETS CONTROL, DEPARTMENT OF THE TREASURY ROUGH DIAMONDS CONTROL REGULATIONS General Definitions § 592.310 Rough diamond. The term rough diamond means any diamond that is unworked or simply sawn,...

  6. 31 CFR 592.310 - Rough diamond.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... 31 Money and Finance:Treasury 3 2011-07-01 2011-07-01 false Rough diamond. 592.310 Section 592.310... ASSETS CONTROL, DEPARTMENT OF THE TREASURY ROUGH DIAMONDS CONTROL REGULATIONS General Definitions § 592.310 Rough diamond. The term rough diamond means any diamond that is unworked or simply sawn,...

  7. 31 CFR 592.310 - Rough diamond.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... 31 Money and Finance: Treasury 3 2010-07-01 2010-07-01 false Rough diamond. 592.310 Section 592... FOREIGN ASSETS CONTROL, DEPARTMENT OF THE TREASURY ROUGH DIAMONDS CONTROL REGULATIONS General Definitions § 592.310 Rough diamond. The term rough diamond means any diamond that is unworked or simply...

  8. 31 CFR 592.310 - Rough diamond.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... 31 Money and Finance:Treasury 3 2014-07-01 2014-07-01 false Rough diamond. 592.310 Section 592.310... ASSETS CONTROL, DEPARTMENT OF THE TREASURY ROUGH DIAMONDS CONTROL REGULATIONS General Definitions § 592.310 Rough diamond. The term rough diamond means any diamond that is unworked or simply sawn,...

  9. 31 CFR 592.310 - Rough diamond.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... 31 Money and Finance:Treasury 3 2012-07-01 2012-07-01 false Rough diamond. 592.310 Section 592.310... ASSETS CONTROL, DEPARTMENT OF THE TREASURY ROUGH DIAMONDS CONTROL REGULATIONS General Definitions § 592.310 Rough diamond. The term rough diamond means any diamond that is unworked or simply sawn,...

  10. A charge transport study in diamond, surface passivated by high-k dielectric oxides

    SciTech Connect

    Kovi, Kiran Kumar Majdi, Saman; Gabrysch, Markus; Isberg, Jan

    2014-11-17

    The recent progress in the growth of high-quality single-crystalline diamond films has sparked interest in the realization of efficient diamond power electronic devices. However, finding a suitable passivation is essential to improve the reliability and electrical performance of devices. In the current work, high-k dielectric materials such as aluminum oxide and hafnium oxide were deposited by atomic layer deposition on intrinsic diamond as a surface passivation layer. The hole transport properties in the diamond films were evaluated and compared to unpassivated films using the lateral time-of-flight technique. An enhancement of the near surface hole mobility in diamond films of up to 27% is observed when using aluminum oxide passivation.

  11. Surface Design and Engineering Toward Wear-Resistant, Self-Lubricant Diamond Films and Coatings. Chapter 10

    NASA Technical Reports Server (NTRS)

    Miyoshi, Kazuhisa

    1999-01-01

    This chapter describes three studies on the surface design, surface engineering, and tribology of chemical-vapor-deposited (CVD) diamond films and coatings toward wear-resistant, self-lubricating diamond films and coatings. Friction mechanisms and solid lubrication mechanisms of CVD diamond are stated. Effects of an amorphous hydrogenated carbon on CVD diamond, an amorphous, nondiamond carbon surface layer formed on CVD diamond by carbon and nitrogen ion implantation, and a materials combination of cubic boron nitride and CVD diamond on the adhesion, friction, and wear behaviors of CVD diamond in ultrahigh vacuum are described. How surface modification and the selected materials couple improved the tribological functionality of coatings, giving low coefficient of friction and good wear resistance, is explained.

  12. South Africa, Namibia Diamond Deposits

    NASA Technical Reports Server (NTRS)

    1998-01-01

    This radar image covers a portion of the Richtersveld National Park and Orange River (top of image) in the Northern Cape Province of the Republic of South Africa. The Orange River marks the boundary between South Africa to the south and Namibia to the north. This is an area of active mining for diamonds, which were washed downstream from the famous Kimberley Diamond Area, millions of years ago when the river was much larger. The mining is focused on ancient drainages of the Orange River which are currently buried by think layers of sand and gravel. Scientists are investigating whether these ancient drainages can be seen with the radar's ability to penetrate sand cover in extremely dry regions. A mine, shown in yellow, is on the southern bank of the river in an abandoned bend which is known as an 'oxbow.' The small bright circular areas (left edge of image) west of the mine circles are fields of a large ostrich farm that are being watered with pivot irrigation. The large dark area in the center of the image is the Kubus Pluton, a body of granite rock that broke through the surrounding rocks about 550 million years ago. North is toward the upper right. The area shown is about 55 by 60 kilometers (34 by 37 miles) centered at 28.4 degrees south latitude, 16.8 degrees east longitude. Colors are assigned to different radar frequencies and polarizations as follows: red is L-band horizontally transmitted and horizontally received; green is L-band horizontally transmitted and vertically received; blue is C-band horizontally transmitted and vertically received. The image was acquired on April 18, 1994 by the Spaceborne Imaging Radar-C/X-band Synthetic Aperture (SIR-C/X-SAR) imaging radar when it flew aboard the space shuttle Endeavour. SIR-C/X-SAR is a joint mission of the U.S./German and Italian space agencies.

  13. Progress on Diamond-Based Cylindrical Dielectric Accelerating Structures

    SciTech Connect

    Kanareykin, A.; Schoessow, P.; Conde, M.; Gai, W.

    2006-11-27

    The development of a high gradient diamond-based cylindrical dielectric loaded accelerator (DLA) is presented. A diamond-loaded DLA can potentially sustain accelerating gradients far in excess of the limits experimentally observed for conventional metallic accelerating structures. The electrical and mechanical properties of diamond make it an ideal candidate material for use in dielectric accelerators: high rf breakdown level, extremely low dielectric losses and the highest available thermoconductive coefficient. We used the hot-filament Chemical Vapor Deposition (CVD) process to produce high quality 5-10 cm long cylindrical diamond layers. Our collaboration has also been developing a new method of CVD diamond surface preparation that reduces the secondary electron emission coefficient below unity. Special attention was paid to the numerical optimization of the waveguide to structure rf coupling section, where the surface magnetic and electric fields were minimized relative to the accelerating gradient and within known metal surface breakdown limits. We conclude with a brief overview of the use of diamond microstructures for use in compact rf sources.

  14. Raman investigation of diamond films

    SciTech Connect

    Feng, Li-Ming

    1993-12-31

    Extensive Raman investigations were conducted on a wide range of diamond films whose structures were dilineated by optical and confocal microscopy. The Raman Spectra from one extreme of this range indicates a very intense 1331 cm{sup {minus}1} line diagnostic of bulk crystalline diamond. Microscopy of the corresponding film shows the presence of many large true diamond crystallite. The 1331 cm{sup {minus}1} Raman line at the other extreme of the range, however, is virtually absent. It is replaced, at this extreme, by a very broad Raman contour whose maxima occur near 1355 cm{sup {minus}1} and 1575 cm{sup {minus}1}. Optical microscopy now reveals a complete lack of diamond crystallites. The ratio of the integrated Raman intensity of the 1331 cm{sup {minus}1} diamond line to the integral of the entire broad contour extending from {approx}1200 cm{sup {minus}1} to 1800 cm{sup {minus}1}, with maxima near 1355 cm{sup {minus}1} and 1575 cm{sup {minus}1}, was determined. This ratio rises with increasing diamond crystallite size, and it decreases as true diamond crystallites are replaced by diamond-like, but amorphous, hard carbon, which produces the broad Raman contour. The measured intensity ratio was analyzed in terms of a differential equation related to phonon coupling. The increase of the intensity ratio of the 1331 cm{sup {minus}1} diagnostic diamond peak is due to phono-phonon coupling between the diamond crystallites, as the concentration of the amorphous diamond-like carbon decreases. Confocal microscopy indicates many amorphous-like regions interspersed between diamond crystallites which account for the intensity loss, and agree with the Raman intensity measurements. These Raman measurements crystallinity versus amorphous hard-carbon character of thin diamond film.

  15. Catalytic effect of ultrananocrystalline Fe3O4 on algal bio-crude production via HTL process

    NASA Astrophysics Data System (ADS)

    Rojas-Pérez, Arnulfo; Diaz-Diestra, Daysi; Frias-Flores, Cecilia B.; Beltran-Huarac, Juan; Das, K. C.; Weiner, Brad R.; Morell, Gerardo; Díaz-Vázquez, Liz M.

    2015-10-01

    We report a comprehensive quantitative study of the production of refined bio-crudes via a controlled hydrothermal liquefaction (HTL) process using Ulva fasciata macroalgae (UFMA) as biomass and ultrananocrystalline Fe3O4 (UNCFO) as catalyst. X-ray diffraction and electron microscopy were applied to elucidate the formation of the high-quality nanocatalysts. Gas chromatography-mass spectroscopy (GC-MS) and CHNS analyses showed that the bio-crude yield and carbon/oxygen ratios increase as the amount of UNCFO increases, reaching a peak value of 32% at 1.25 wt% (a 9% increase when compared to the catalyst-free yield). The bio-crude is mainly composed of fatty acids, alcohols, ketones, phenol and benzene derivatives, and hydrocarbons. Their relative abundance changes as a function of catalyst concentration. FTIR spectroscopy and vibrating sample magnetometry revealed that the as-produced bio-crudes are free of iron species, which accumulate in the generated bio-chars. Our findings also indicate that the energy recovery values via the HTL process are sensitive to the catalyst loading, with a threshold loading of 1.25 wt%. GC-MS studies show that the UNCFO not only influences the chemical nature of the resulting bio-crudes and bio-chars, but also the amount of fixed carbons in the solid residues. The detailed molecular characterization of the bio-crudes and bio-chars catalyzed by UNCFO represents the first systematic study reported using UFMA. This study brings forth new avenues to advance the highly-pure bio-crude production employing active, heterogeneous catalyst materials that are recoverable and recyclable for continuous thermochemical reactions.We report a comprehensive quantitative study of the production of refined bio-crudes via a controlled hydrothermal liquefaction (HTL) process using Ulva fasciata macroalgae (UFMA) as biomass and ultrananocrystalline Fe3O4 (UNCFO) as catalyst. X-ray diffraction and electron microscopy were applied to elucidate the formation of the high-quality nanocatalysts. Gas chromatography-mass spectroscopy (GC-MS) and CHNS analyses showed that the bio-crude yield and carbon/oxygen ratios increase as the amount of UNCFO increases, reaching a peak value of 32% at 1.25 wt% (a 9% increase when compared to the catalyst-free yield). The bio-crude is mainly composed of fatty acids, alcohols, ketones, phenol and benzene derivatives, and hydrocarbons. Their relative abundance changes as a function of catalyst concentration. FTIR spectroscopy and vibrating sample magnetometry revealed that the as-produced bio-crudes are free of iron species, which accumulate in the generated bio-chars. Our findings also indicate that the energy recovery values via the HTL process are sensitive to the catalyst loading, with a threshold loading of 1.25 wt%. GC-MS studies show that the UNCFO not only influences the chemical nature of the resulting bio-crudes and bio-chars, but also the amount of fixed carbons in the solid residues. The detailed molecular characterization of the bio-crudes and bio-chars catalyzed by UNCFO represents the first systematic study reported using UFMA. This study brings forth new avenues to advance the highly-pure bio-crude production employing active, heterogeneous catalyst materials that are recoverable and recyclable for continuous thermochemical reactions. Electronic supplementary information (ESI) available. See DOI: 10.1039/c5nr04404a

  16. Metastable carbon allotropes in picosecond-laser-modified diamond

    NASA Astrophysics Data System (ADS)

    Pimenov, Sergei M.; Khomich, Andrey A.; Vlasov, Igor I.; Zavedeev, Evgeny V.; Khomich, Alexander V.; Neuenschwander, Beat; Jggi, Beat; Romano, Valerio

    2014-08-01

    In this paper, we report on the bulk modifications of type IIa single-crystal diamond with visible 10-ps pulses (at ? = 532 nm) and microstructural changes characterized by the appearance of several `unidentifiable' vibrational modes in the frequency range of 1000-1400 cm-1 in the Raman spectra of laser-modified diamond. It is found that the new Raman modes are strongly pronounced in the spectra of high-stress regions in immediate proximity to the bulk microstructures in the absence of the G mode at ~1580 cm-1 characteristic of the sp2 phase. The high internal stresses are determined from the splitting of the triply degenerate diamond Raman line. The revealed structure transformation is localized within a narrow bulk layer near the bulk microstructures formed, and the stress relaxation is found to result in disappearance of the detected vibrational modes in the spectra. It is suggested that the formation of bulk regions with a sp3 carbon structure consisting of Z-carbon and hexagonal diamond is responsible for the appearance of new Raman modes in the spectra of laser-modified diamond. These findings evidence that the stress-assisted formation of novel metastable carbon phases or defect structures occur in the course of bulk modification of diamond with ps-laser pulses. In addition, we report the results of simulations of internal stresses in the system `graphitized cylinder-in-diamond' to show (1) the effect of the mechanical properties of laser-modified diamond on the resulting stresses and (2) formation of bulk microscopic regions with high stresses of >10 GPa, i.e., the conditions at which various sp3 carbon allotropes and defect structures become more stable than graphite.

  17. Self-assembled ultra-nanocrystalline silicon films with preferred <2 2 0> crystallographic orientation for solar cell applications

    NASA Astrophysics Data System (ADS)

    Banerjee, Amit; Das, Debajyoti

    2015-03-01

    Using low-pressure planar inductively coupled plasma CVD at 87% H2-dilution to the SiH4 plasma, nc-Si:H films are prepared that possess preferential growth along <2 2 0> crystallographic orientation with I220/I111 > 1.2, bonded H-content of ?5.5 at.%, a low microstructure factor of ?0.56, along with a reasonably high ?D ? 5.2 10-4 S cm-1, ?E ? 143 meV and ?Ph ? 1.4 10-3 S cm-1. The growth of the nc-Si:H network has been optimized to a moderately high nanocrystallinity (?68%), with an average grain size of ?8 nm. The overall network comprises a significant fraction of ultra-nanocrystalline component, Xunc/Xnc ? 0.47, which are dominantly inhabited by the thermodynamically preferred <2 2 0> crystallographic orientation that provides convenient electrical transport perpendicular to the film surface and subsequently could facilitate photovoltaic performance. The cross-sectional view of the fracture surface demonstrates columnar structures, closely correlated to the favored growth of the nanocrystallites along <2 2 0> crystallographic orientation that retains direction perpendicular to the substrate surface. The underlying phenomena could be demonstrated as a consequence of preferential growth induced by high atomic H density present in the planar inductively coupled SiH4 plasma obtained via much lower H2-dilution compared to that realized in conventional capacitively coupled plasma-CVD. The nc-Si:H films with precise material properties as well as the allied low-pressure ICP-CVD growth process could be of significant use in further progress of nc-Si solar cells.

  18. Catalytic effect of ultrananocrystalline Fe3O4 on algal bio-crude production via HTL process.

    PubMed

    Rojas-Prez, Arnulfo; Diaz-Diestra, Daysi; Frias-Flores, Cecilia B; Beltran-Huarac, Juan; Das, K C; Weiner, Brad R; Morell, Gerardo; Daz-Vzquez, Liz M

    2015-11-14

    We report a comprehensive quantitative study of the production of refined bio-crudes via a controlled hydrothermal liquefaction (HTL) process using Ulva fasciata macroalgae (UFMA) as biomass and ultrananocrystalline Fe3O4 (UNCFO) as catalyst. X-ray diffraction and electron microscopy were applied to elucidate the formation of the high-quality nanocatalysts. Gas chromatography-mass spectroscopy (GC-MS) and CHNS analyses showed that the bio-crude yield and carbon/oxygen ratios increase as the amount of UNCFO increases, reaching a peak value of 32% at 1.25 wt% (a 9% increase when compared to the catalyst-free yield). The bio-crude is mainly composed of fatty acids, alcohols, ketones, phenol and benzene derivatives, and hydrocarbons. Their relative abundance changes as a function of catalyst concentration. FTIR spectroscopy and vibrating sample magnetometry revealed that the as-produced bio-crudes are free of iron species, which accumulate in the generated bio-chars. Our findings also indicate that the energy recovery values via the HTL process are sensitive to the catalyst loading, with a threshold loading of 1.25 wt%. GC-MS studies show that the UNCFO not only influences the chemical nature of the resulting bio-crudes and bio-chars, but also the amount of fixed carbons in the solid residues. The detailed molecular characterization of the bio-crudes and bio-chars catalyzed by UNCFO represents the first systematic study reported using UFMA. This study brings forth new avenues to advance the highly-pure bio-crude production employing active, heterogeneous catalyst materials that are recoverable and recyclable for continuous thermochemical reactions. PMID:26465090

  19. Structure and properties of diamond and diamond-like films

    SciTech Connect

    Clausing, R.E.

    1993-01-01

    This section is broken into four parts: (1) introduction, (2) natural IIa diamond, (3) importance of structure and composition, and (4) control of structure and properties. Conclusions of this discussion are that properties of chemical vapor deposited diamond films can compare favorably with natural diamond, that properties are anisotropic and are a strong function of structure and crystal perfection, that crystal perfection and morphology are functions of growth conditions and can be controlled, and that the manipulation of texture and thereby surface morphology and internal crystal perfection is an important step in optimizing chemically deposited diamond films for applications.

  20. Surface damage on diamond membranes fabricated by ion implantation and lift-off

    SciTech Connect

    Drumm, V. S.; Alves, A. D. C.; Fairchild, B. A.; Ganesan, K.; McCallum, J. C.; Jamieson, D. N.; Prawer, S.; Rubanov, S.; Kalish, R.; Feldman, L. C.

    2011-06-06

    Thin membranes with excellent optical properties are essential elements in diamond based photonic systems. Due to the chemical inertness of diamond, ion beam processing must be employed to carve photonic structures. One method to realize such membranes is ion-implantation graphitization followed by chemical removal of the sacrificial graphite. The interface revealed when the sacrificial layer is removed has interesting properties. To investigate this interface, we employed the surface sensitive technique of grazing angle channeled Rutherford backscattering spectroscopy. Even after high temperature annealing and chemical etching a thin layer of damaged diamond remains, however, it is removed by hydrogen plasma exposure.

  1. Diamond Film Gas Sensors for Leak Detection of Semiconductor Doping Gases

    NASA Astrophysics Data System (ADS)

    Hayashi, Kazushi; Yokota, Yoshihiro; Tachibana, Takeshi; Miyata, Koichi; Kobashi, Koji; Fukunaga, Tetsuya; Takada, Tadashi

    2000-01-01

    Gas sensors for leak detection of toxic semiconductor doping gases such as PH3, B2H6, and AsH3 were fabricated using diamond films. The sensors have a double-layered structure composed of undoped and B-doped polycrystalline diamond layers with Pt electrodes. The relative changes in the resistance of the sensors were typically 10-20% for 0.2 ppm PH3 in air, and the highest value was over 100%. It was concluded that the diamond film gas sensors fabricated in the present work would be practically applicable as compact solid-state sensors with an advantage over the conventional aqueous electrolyte sensors.

  2. Low Temperature Growth of Nanostructured Diamond Films on Metals

    NASA Technical Reports Server (NTRS)

    Baker, Paul A.; Catledge, Shane A.; Vohra, Yogesh K.

    2001-01-01

    The field of nanocrystalline diamond and tetrahedral amorphous carbon films has been the focus of intense experimental activity in the last few years for applications in field emission display devices, optical windows, and tribological coatings, The choice of substrate used in most studies has typically been silicon. For metals, however, the thermal expansion mismatch between the diamond film and substrate gives rise to thermal stress that often results in delamination of the film. To avoid this problem in conventional CVD deposition low substrate temperatures (less than 700 C) have been used, often with the incorporation of oxygen or carbon monoxide to the feedgas mixture. Conventionally grown CVD diamond films are also rough and would require post-deposition polishing for most applications. Therefore, there is an obvious need to develop techniques for deposition of well-adhered, smooth nano-structured diamond films on metals for various tribological applications. In our work, nanostructured diamond films are grown on a titanium alloy substrate using a two-step deposition process. The first step is performed at elevated temperature (820 C) for 30 minutes using a H2/CH4/N2 gas mixture in order to grow a thin (approx. 600 nm) nanostructured diamond layer and improve film adhesion. The remainder of the deposition involves growth at low temperature (less than 600 C) in a H2/CH4/O2 gas mixture. Laser reflectance Interferometry (LRI) pattern during growth of a nanostructured diamond film on Ti-6Al-4V alloy. The first 30 minutes are at a high temperature of 820 C and the rest of the film is grown at a low temperature of 580 T. The fringe pattern is observed till the very end due to extremely low surface roughness of 40 nm. The continuation of the smooth nanostructured diamond film growth during low temperature deposition is confirmed by in-situ laser reflectance interferometry and by post-deposition micro-Raman spectroscopy and surface profilometry. Similar experiments performed without the starting nanostructured diamond layer resulted in poorly adhered films with a more crystalline appearance and a higher surface roughness. This low temperature deposition of nanostructured diamond films on metals offers advantages in cases where high residual thermal stress leads to delamination at high temperatures.

  3. Conversion of fullerenes to diamond

    DOEpatents

    Gruen, Dieter M. (1324 59th St., Downers Grove, IL 60515)

    1993-01-01

    A method of forming synthetic diamond on a substrate is disclosed. The method involves providing a substrate surface covered with a fullerene or diamond coating, positioning a fullerene in an ionization source, creating a fullerene vapor, ionizing fullerene molecules, accelerating the fullerene ions to energies above 250 eV to form a fullerene ion beam, impinging the fullerene ion beam on the substrate surface and continuing these steps to obtain a diamond thickness on the substrate.

  4. Diamond films for laser hardening

    NASA Technical Reports Server (NTRS)

    Albin, S.; Watkins, L.; Ravi, K.; Yokota, S.

    1989-01-01

    Laser-damage experiments were performed on free-standing polycrystalline diamond films prepared by plasma-enhanced CVD. The high laser-induced stress resistance found for this material makes it useful for thin-film coatings for laser optics. Results for diamond-coated silicon substrates demonstrate the enhanced damage threshold imparted by diamond thin-film coatings to materials susceptible to laser damage.

  5. Conversion of fullerenes to diamond

    DOEpatents

    Gruen, Dieter M. (1324 59th St., Downers Grove, IL 60515)

    1994-01-01

    A method of forming synthetic diamond on a substrate. The method involves providing a substrate surface covered with a fullerene or diamond coating, positioning a fullerene in an ionization source, creating a fullerene vapor, ionizing fullerene molecules, accelerating the fullerene ions to energies above 250 eV to form a fullerene ion beam, impinging the fullerene ion beam on the substrate surface and continuing these steps to obtain a diamond film thickness on the substrate.

  6. Hexagonal diamonds in meteorites: implications.

    PubMed

    Hanneman, R E; Strong, H M; Bundy, F P

    1967-02-24

    A new polymorph of carbon, hexagonal diamond, has been discovered in the Canyon Diablo and Goalpara meteorites. This phase had been synthesized recently under specific high-pressure conditions in the laboratory. Our results: provide strong evidence that diamonds found in these meteorites were produced by intense shock pressures acting on crystalline graphite inclusions present within the meteorite before impact, rather than by disintegration of larger, statically grown diamonds, as some theories propose. PMID:17830485

  7. DIAMOND SECONDARY EMITTER

    SciTech Connect

    BEN-ZVI, I.; RAO, T.; BURRILL, A.; CHANG, X.; GRIMES, J.; RANK, J.; SEGALOV, Z.; SMEDLEY, J.

    2005-10-09

    We present the design and experimental progress on the diamond secondary emitter as an electron source for high average power injectors. The design criteria for average currents up to 1 A and charge up to 20 nC are established. Secondary Electron Yield (SEY) exceeding 200 in transmission mode and 50 in emission mode have been measured. Preliminary results on the design and fabrication of the self contained capsule with primary electron source and secondary electron emitter will also be presented.

  8. DIAMOND PEAK WILDERNESS, OREGON.

    USGS Publications Warehouse

    Sherrod, David R.; Moyle, Phillip R.

    1984-01-01

    No metallic mineral resources were identified during a mineral survey of the Diamond Peak Wilderness in Oregon. Cinder cones within the wilderness contain substantial cinder resources, but similar deposits that are more accessible occur outside the wilderness. The area could have geothermal resources, but available data are insufficient to evaluate their potential. Several deep holes could be drilled in areas of the High Cascades outside the wilderness, from which extrapolations of the geothermal potential of the several Cascade wilderness could be made.

  9. Diamond turning of glass

    SciTech Connect

    Blackley, W.S.; Scattergood, R.O.

    1988-12-01

    A new research initiative will be undertaken to investigate the critical cutting depth concepts for single point diamond turning of brittle, amorphous materials. Inorganic glasses and a brittle, thermoset polymer (organic glass) are the principal candidate materials. Interrupted cutting tests similar to those done in earlier research are Ge and Si crystals will be made to obtain critical depth values as a function of machining parameters. The results will provide systematic data with which to assess machining performance on glasses and amorphous materials

  10. Conversion of fullerenes to diamonds

    DOEpatents

    Gruen, Dieter M. (1324 59th St., Downers Grove, IL 60515)

    1995-01-01

    A method of forming synthetic diamond or diamond-like films on a substrate surface. The method involves the steps of providing a vapor selected from the group of fullerene molecules or an inert gas/fullerene molecule mixture, providing energy to the fullerene molecules consisting of carbon-carbon bonds, the energized fullerene molecules breaking down to form fragments of fullerene molecules including C.sub.2 molecules and depositing the energized fullerene molecules with C.sub.2 fragments onto the substrate with farther fragmentation occurring and forming a thickness of diamond or diamond-like films on the substrate surface.

  11. The Diamond STING server

    PubMed Central

    Neshich, Goran; Borro, Luiz C.; Higa, Roberto H.; Kuser, Paula R.; Yamagishi, Michel E. B.; Franco, Eduardo H.; Krauchenco, Joao N.; Fileto, Renato; Ribeiro, Andr A.; Bezerra, George B. P.; Velludo, Thiago M.; Jimenez, Toms S.; Furukawa, Noboru; Teshima, Hirofumi; Kitajima, Koji; Bava, Abdulla; Sarai, Akinori; Togawa, Roberto C.; Mancini, Adauto L.

    2005-01-01

    Diamond STING is a new version of the STING suite of programs for a comprehensive analysis of a relationship between protein sequence, structure, function and stability. We have added a number of new functionalities by both providing more structure parameters to the STING Database and by improving/expanding the interface for enhanced data handling. The integration among the STING components has also been improved. A new key feature is the ability of the STING server to handle local files containing protein structures (either modeled or not yet deposited to the Protein Data Bank) so that they can be used by the principal STING components: JavaProtein Dossier (JPD) and STING Report. The current capabilities of the new STING version and a couple of biologically relevant applications are described here. We have provided an example where Diamond STING identifies the active site amino acids and folding essential amino acids (both previously determined by experiments) by filtering out all but those residues by selecting the numerical values/ranges for a set of corresponding parameters. This is the fundamental step toward a more interesting endeavorthe prediction of such residues. Diamond STING is freely accessible at and . PMID:15980473

  12. DIAMOND AMPLIFIER FOR PHOTOCATHODES.

    SciTech Connect

    RAO,T.; BEN-ZVI,I.; BURRILL,A.; CHANG,X.; HULBERT,S.; JOHNSON,P.D.; KEWISCH,J.

    2004-06-21

    We report a new approach to the generation of high-current, high-brightness electron beams. Primary electrons are produced by a photocathode (or other means) and are accelerated to a few thousand electron-volts, then strike a specially prepared diamond window. The large Secondary Electron Yield (SEY) provides a multiplication of the number of electrons by about two orders of magnitude. The secondary electrons drift through the diamond under an electric field and emerge into the accelerating proper of the ''gun'' through a Negative Electron Affinity surface of the diamond. The advantages of the new approach include the following: (1) Reduction of the number of primary electrons by the large SEY, i.e. a very low laser power in a photocathode producing the primaries. (2) Low thermal emittance due to the NEA surface and the rapid thermalization of the electrons. (3) Protection of the cathode from possible contamination from the gun, allowing the use of large quantum efficiency but sensitive cathodes. (4) Protection of the gun from possible contamination by the cathode, allowing the use of superconducting gun cavities. (5) Production of high average currents, up to ampere class. (6) Encapsulated design, making the ''load-lock'' systems unnecessary. This paper presents the criteria that need to be taken into account in designing the amplifier.

  13. Monolithic diamond Raman laser.

    PubMed

    Reilly, Sean; Savitski, Vasili G; Liu, Hangyu; Gu, Erdan; Dawson, Martin D; Kemp, Alan J

    2015-03-15

    A monolithic diamond Raman laser is reported. It utilizes a 13-mm radius of curvature lens etched onto the diamond surface and dielectric mirror coatings to form a stable resonator. The performance is compared to that of a monolithic diamond Raman laser operating in a plane-plane cavity. On pumping with a compact Q-switched laser at 532nm (16?J pulse energy; 1.5ns pulse duration; 10kHz repetition-rate; M2<1.5), laser action was observed at the first, second, and third Stokes wavelengths (573nm, 620nm and 676nm, respectively) in both cases. For the microlens cavity, a conversion efficiency of 84% was achieved from the pump to the total Raman output power, with a slope efficiency of 88%. This compares to a conversion efficiency of 59% and a slope efficiency of 74% for the plane-plane case. Total Raman output powers of 134 and 96mW were achieved for the microlens and plane-plane cavities, respectively. PMID:25768149

  14. Diamonds in ophiolites: Contamination or a new diamond growth environment?

    NASA Astrophysics Data System (ADS)

    Howell, D.; Griffin, W. L.; Yang, J.; Gain, S.; Stern, R. A.; Huang, J.-X.; Jacob, D. E.; Xu, X.; Stokes, A. J.; O'Reilly, S. Y.; Pearson, N. J.

    2015-11-01

    For more than 20 years, the reported occurrence of diamonds in the chromites and peridotites of the Luobusa massif in Tibet (a complex described as an ophiolite) has been widely ignored by the diamond research community. This skepticism has persisted because the diamonds are similar in many respects to high-pressure high-temperature (HPHT) synthetic/industrial diamonds (grown from metal solvents), and the finding previously has not been independently replicated. We present a detailed examination of the Luobusa diamonds (recovered from both peridotites and chromitites), including morphology, size, color, impurity characteristics (by infrared spectroscopy), internal growth structures, trace-element patterns, and C and N isotopes. A detailed comparison with synthetic industrial diamonds shows many similarities. Cubo-octahedral morphology, yellow color due to unaggregated nitrogen (C centres only, Type Ib), metal-alloy inclusions and highly negative δ13C values are present in both sets of diamonds. The Tibetan diamonds (n = 3) show an exceptionally large range in δ15N (-5.6 to + 28.7 ‰) within individual crystals, and inconsistent fractionation between {111} and {100} growth sectors. This in contrast to large synthetic HPHT diamonds grown by the temperature gradient method, which have with δ15N = 0 ‰ in {111} sectors and + 30 ‰ in {100} sectors, as reported in the literature. This comparison is limited by the small sample set combined with the fact the diamonds probably grew by different processes. However, the Tibetan diamonds do have generally higher concentrations and different ratios of trace elements; most inclusions are a NiMnCo alloy, but there are also some small REE-rich phases never seen in HPHT synthetics. These characteristics indicate that the Tibetan diamonds grew in contact with a C-saturated Ni-Mn-Co-rich melt in a highly reduced environment. The stable isotopes indicate a major subduction-related contribution to the chemical environment. The unaggregated nitrogen, combined with the lack of evidence for resorption or plastic deformation, suggests a short (geologically speaking) residence in the mantle. Previously published models to explain the occurrence of the diamonds, and other phases indicative of highly reduced conditions and very high pressures, have failed to take into account the characteristics of the diamonds and the implications for their formation. For these diamonds to be seriously considered as the result of a natural growth environment requires a new understanding of mantle conditions that could produce them.

  15. Congenital Anomalies in Diamond Blackfan Anemia (DBA)

    MedlinePLUS

    Congenital Anomalies In Diamond Blackfan Anemia (DBA) CS217857 National Center on Birth Defects and Developmental Disabilities Division of Blood Disorders Congenital Anomalies In Diamond Blackfan Anemia (DBA) ...

  16. Microstructure evolution and the modification of the electron field emission properties of diamond films by gigaelectron volt Au-ion irradiation

    NASA Astrophysics Data System (ADS)

    Teng, Kuang-Yau; Chen, Huang-Chin; Tang, Chen-Yau; Sundaravel, Balakrishnan; Amirthapandian, Sankarakumar; Lin, I.-Nan

    2011-12-01

    The effect of 2.245 GeV Au-ion irradiation and post-annealing processes on the microstructure and electron field emission (EFE) properties of diamond films was investigated. For the microcrystalline diamond (MCD) films, Au-ion irradiation with a fluence of approximately 8.41013 ions/cm2 almost completely suppressed the EFE properties of the films. Post-annealing the Au-ion irradiated MCD films at 1000C for 1 h effectively restored these properties. In contrast, for ultra-nanocrystalline diamond (UNCD) films, the Au-ion irradiation induced a large improvement in the EFE properties, and the post-annealing process slightly degraded the EFE properties of the films. The resulting EFE behavior was still better than that of pristine UNCD films. TEM examination indicated that the difference in Au-ion irradiation/post-annealing effects on the EFE properties of the MCD and UNCD films is closely related to the different phase transformation process involved. This difference is dependent on the different granular structures of these films. The MCD films with large-grain microstructure contain very few grain boundaries of negligible thickness, whereas the UNCD films with ultra-small-grain granular structure contain abundant grain boundaries of considerable thickness. Au-ion irradiation disintegrated the large grains in the MCD films into small diamond clusters embedded in an amorphous carbon (a-C) matrix that suppressed the EFE properties of the MCD films. In contrast, the Au-ion irradiation insignificantly altered the crystallinity of the grains of the UNCD films but transformed the grain boundary phase into nano-graphite, enhancing the EFE properties. The post-annealing process recrystallized the residual a-C phase into nano-graphites for both films.

  17. Combustion growth of large diamond crystals

    NASA Astrophysics Data System (ADS)

    Wang, X. H.; Zhu, W.; von Windheim, J.; Glass, J. T.

    1993-03-01

    This paper reports the successful growth of optically transparent, individual diamond crystals up to millimeter diameters on silicon substrates by oxygen-acetylene combustion flames at atmospheric pressure. The growth process consisted of three steps: (i) achieve a suitable nucleation density by pretreating the as-received Si substrate in an acetylene-rich flame (oxygen-to-acetylene ratio Rf = 0.95) for about 30 min at a downstream position (7-10 mm away from the tip of the flame inner cone); (ii) grow crystals up to 200 ?m in diameter in an annular area on the substrate at Rf = 0.98 and a substrate-to-tip of the flame inner cone distance of 2 mm; (iii) move the preferred crystals from the annular region into either the central core region of the flame feather or near the edge of the flame feather for further growth up to millimeter diameters under carefully controlled conditions. The final step of moving the crystals into a different growth region was necessary to avoid extensive secondary nucleation and structural defects. The key factor for diamond crystals to grow up to millimeter diameters was to maintain the growth conditions at the growing surface constant throughout the process. It was found that the crystal surface temperature, which was the most sensitive and also one of the most critical parameters, could be effectively maintained constant by decreasing the total gas flow rate as growth continued. Both the crystal growth orientations and the amount of nitrogen impurity incorporated in the diamond lattice were closely related to the crystal surface temperature. It is believed that the gas flow dynamics, or more specifically, the boundary layer thickness, played an important role in the growth and morphological development of large diamond crystals.

  18. Nanocrystalline tungsten carbide: As incompressible as diamond

    SciTech Connect

    Lin, Zhijun; Wang, Lin; Zhang, Jianzhong; Mao, Ho-kwang; Zhao, Yusheng

    2009-12-10

    We investigate the compressibility of nanocrystalline tungsten carbide (nano-WC) using synchrotron x-ray diffraction. Nano-WC displays a bulk modulus (452 GPa) comparable to that of diamond; it is 10%-15% larger than previously reported values for bulk WC. This finding is consistent with a generalized model of nanocrystal with a compressed surface layer. The linear bulk moduli of nano-WC along a- and c-axes were determined to be 407 and 546 GPa, respectively. First-principles density functional theory (DFT) calculations confirm the experimental observations of an anisotropic linear compressibility and a lower bulk modulus for microsized WC.

  19. Stable metallization for diamond and other materials

    NASA Technical Reports Server (NTRS)

    Bachli, Andreas (Inventor); Kolawa, Elzbieta (Inventor); Nicolet, Marc-Aurele (Inventor); Vandersande, Jan W. (Inventor)

    2000-01-01

    An adherent and metallurgically stable metallization system for diamond is presented. The big improvement in metallurgical stability is attributed to the use of a ternary, amorphous Ti--Si--N diffusion barrier. No diffusion between the layers and no delamination of the metallization was observed after annealing the schemes at 400.degree. C. for 100 hours and at 900.degree. C. for 30 minutes. Thermal cycling experiments in air from -65 to 155.degree. C. and adhesion tests were performed. Various embodiments are disclosed.

  20. Raman and conductivity studies of boron doped microcrystalline diamond, facetted nanocrystalline diamond and cauliflower diamond films

    NASA Astrophysics Data System (ADS)

    May, P. W.; Ludlow, W. J.; Hannaway, M.; Heard, P. J.; Smith, J. A.; Rosser, K. N.

    2007-09-01

    We present data showing how the electrical conductivity and Raman spectra of boron-doped CVD diamond films vary with both B content and crystallite size, for microcrystalline diamond (MCD), facetted nanocrystalline diamond (f-NCD) and 'cauliflower' diamond (c-NCD). The position of the Lorentzian contribution to the 500 cm -1 Raman feature was used to estimate the B content. This underestimated the SIMS concentration of B by a factor of 5 for the f-NCD and c-NCD films, but remained reasonably accurate for MCD films. One explanation for this is that most of the B incorporates at the grain boundaries and not in substitutional sites.

  1. Influence of diamond surface termination on thermal boundary conductance between Al and diamond

    SciTech Connect

    Monachon, Christian; Weber, Ludger

    2013-05-14

    The effect of diamond surface treatment on the Thermal Boundary Conductance (TBC) between Al and diamond is investigated. The treatments consist in either of the following: exposition to a plasma of pure Ar, Ar:H and Ar:O, and HNO{sub 3}:H{sub 2}SO{sub 4} acid dip for various times. The surface of diamond after treatment is analyzed by X-ray Photoelectron Spectroscopy, revealing hydrogen termination for the as-received and Ar:H plasma treated samples, pure sp{sup 2} termination for Ar treated ones and oxygen (keton-like) termination for the other treatments. At ambient, all the specific treatments improve the TBC between Al and diamond from 23 {+-} 2 MW m{sup -2} K{sup -1} for the as-received to 65 {+-} 5, 125 {+-} 20, 150 {+-} 20, 180 {+-} 20 MW m{sup -2} K{sup -1} for the ones treated by Ar:H plasma, acid, pure Ar plasma, and Ar:O plasma with an evaporated Al layer on top, respectively. The effect of these treatments on temperature dependence are also observed and compared with the most common models available in the literature as well as experimental values in the same system. The results obtained show that the values measured for an Ar:O plasma treated diamond with Al sputtered on top stay consistently higher than the values existing in the literature over a temperature range from 78 to 290 K, probably due a lower sample surface roughness. Around ambient, the TBC values measured lay close to or even somewhat above the radiation limit, suggesting that inelastic or electronic processes may influence the transfer of heat at this metal/dielectric interface.

  2. Influence of diamond surface termination on thermal boundary conductance between Al and diamond

    NASA Astrophysics Data System (ADS)

    Monachon, Christian; Weber, Ludger

    2013-05-01

    The effect of diamond surface treatment on the Thermal Boundary Conductance (TBC) between Al and diamond is investigated. The treatments consist in either of the following: exposition to a plasma of pure Ar, Ar:H and Ar:O, and HNO3:H2SO4 acid dip for various times. The surface of diamond after treatment is analyzed by X-ray Photoelectron Spectroscopy, revealing hydrogen termination for the as-received and Ar:H plasma treated samples, pure sp2 termination for Ar treated ones and oxygen (keton-like) termination for the other treatments. At ambient, all the specific treatments improve the TBC between Al and diamond from 23 2 MW m-2 K-1 for the as-received to 65 5, 125 20, 150 20, 180 20 MW m-2 K-1 for the ones treated by Ar:H plasma, acid, pure Ar plasma, and Ar:O plasma with an evaporated Al layer on top, respectively. The effect of these treatments on temperature dependence are also observed and compared with the most common models available in the literature as well as experimental values in the same system. The results obtained show that the values measured for an Ar:O plasma treated diamond with Al sputtered on top stay consistently higher than the values existing in the literature over a temperature range from 78 to 290 K, probably due a lower sample surface roughness. Around ambient, the TBC values measured lay close to or even somewhat above the radiation limit, suggesting that inelastic or electronic processes may influence the transfer of heat at this metal/dielectric interface.

  3. Boron-doped superlattices and Bragg mirrors in diamond

    NASA Astrophysics Data System (ADS)

    Fiori, A.; Bousquet, J.; Eon, D.; Omns, F.; Bellet-Amalric, E.; Bustarret, E.

    2014-08-01

    A periodic modulation of the boron doping level of single crystal diamond multilayers over more than three orders of magnitude during epitaxial growth by microwave plasma-enhanced chemical vapor deposition is shown to yield Bragg mirrors in the visible. The thicknesses and doping level of the individual layers were controlled by in situ spectroscopic ellipsometry, enabling to tune the reflectance peak to the wavelength range of diamond color centers, such as NV0 or NV-. The crystalline quality, periodicity, and sharpness of the doping transitions in these doping superlattices over tens of periods were confirmed by high resolution X-ray diffraction.

  4. Boron-doped superlattices and Bragg mirrors in diamond

    SciTech Connect

    Fiori, A.; Bousquet, J.; Eon, D.; Omnès, F.; Bustarret, E.; Bellet-Amalric, E.

    2014-08-25

    A periodic modulation of the boron doping level of single crystal diamond multilayers over more than three orders of magnitude during epitaxial growth by microwave plasma-enhanced chemical vapor deposition is shown to yield Bragg mirrors in the visible. The thicknesses and doping level of the individual layers were controlled by in situ spectroscopic ellipsometry, enabling to tune the reflectance peak to the wavelength range of diamond color centers, such as NV{sup 0} or NV{sup −}. The crystalline quality, periodicity, and sharpness of the doping transitions in these doping superlattices over tens of periods were confirmed by high resolution X-ray diffraction.

  5. Photo- and thermionic emission of MWPECVD nanocrystalline diamond films

    NASA Astrophysics Data System (ADS)

    Cicala, G.; Magaletti, V.; Valentini, A.; Nitti, M. A.; Bellucci, A.; Trucchi, D. M.

    2014-11-01

    Nanocrystalline diamond (NCD) films with and without a diamond buffer layer (BL) have been grown on p-type silicon substrates by microwave plasma enhanced chemical vapor deposition technique at different values of deposition temperature (652-884 C). The photo- and thermionic electron emission properties of NCD films have been investigated, illustrated and explained by analyzing the surface morphology and the grain shape determined by atomic force microscopy, the chemical-structural properties by Raman spectroscopy and nanocrystallites size by X-ray diffraction. The NCD films with BL grown at the highest deposition temperature have shown the highest photo- and thermionic emission currents.

  6. Observation of higher stiffness in nanopolycrystal diamond than monocrystal diamond

    NASA Astrophysics Data System (ADS)

    Tanigaki, Kenichi; Ogi, Hirotsugu; Sumiya, Hitoshi; Kusakabe, Koichi; Nakamura, Nobutomo; Hirao, Masahiko; Ledbetter, Hassel

    2013-08-01

    Diamond is the stiffest known material. Here we report that nanopolycrystal diamond synthesized by direct-conversion method from graphite is stiffer than natural and synthesized monocrystal diamonds. This observation departs from the usual thinking that nanocrystalline materials are softer than their monocrystals because of a large volume fraction of soft grain-boundary region. The direct conversion causes the nondiffusional phase transformation to cubic diamond, producing many twins inside diamond grains. We give an ab initio-calculation twinned model that confirms the stiffening. We find that shorter interplane bonds along [111] are significantly strengthened near the twinned region, from which the superstiff structure originates. Our discovery provides a novel step forward in the search for superstiff materials.

  7. Epitaxial overgrowth of 13C diamond films on diamond substrates predamaged by ion implantation

    NASA Astrophysics Data System (ADS)

    Behr, D.; Locher, R.; Wagner, J.; Koidl, P.; Richter, V.; Kalish, R.

    1997-02-01

    Homoepitaxial chemical vapor deposited (CVD) 13C diamond films were grown on <100> diamond substrates predamaged by implantation with 620 keV Xe ions. The structural quality of the overgrown films was analyzed by plain-view and cross-sectional micro-Raman spectroscopy. Implantation doses below 21014 cm-2, for which no damage detectable by Raman spectroscopy was observed in the substrate, had no effect on the quality of the overgrown films. For doses around 41014 cm-2, a pronounced predamage of the diamond substrate was found which had a strong degrading effect on the quality of the overgrown layer resulting in a drastic increase of the width of the optic zone-center phonon and in the appearance of Raman scattering from sp2-bonded carbon. Higher implantation doses up to 11015 cm-2 resulted in a complete etch removal of the predamaged graphitic surface layer during the initial phase of CVD growth, which thus had no effect on the quality of the film produced by the subsequent overgrowth.

  8. Conversion of p-type to n-type diamond by exposure to a deuterium plasma

    SciTech Connect

    Kalish, R.; Saguy, C.; Cytermann, C.; Chevallier, J.; Teukam, Z.; Jomard, F.; Kociniewski, T.; Ballutaud, D.; Butler, J.E.; Baron, C.; Deneuville, A.

    2004-12-15

    The lack of a shallow donor in diamond with reasonable room temperature conductivity has been a major obstacle, until now, for the realization of many diamond based electronic devices. Most recently it has been shown that exposure of p-type (B doped) homoepitaxial diamond layers to a deuterium plasma can result in the formation of n-type diamond with a shallow donor state (E{sub a}=0.34 eV) and high room temperature mobility (430 cm{sup 2}/V s) [Z. Teukam et al., Nat. Mater. 2, 482 (2003); C. Saguy et al., Diamond Relat. Mater. 13, 700 (2004)]. Experimental results, based on the comparison of secondary ion mass spectrometry profiles of B and D and Hall effect measurements at different temperatures are presented. They confirm the previous speculation that some deuterium related complex is responsible for the donor activity in diamond. These donors are shown to be formed in a two-step process. First, deuterium diffuses into the entire B containing layer rather slowly, being trapped by the boron acceptors and passivating them. Once all B have formed complexes, further exposure to a D plasma results in the formation of a layer that contains about twice as many D atoms as the B content. This step is the one that gives rise to the excellent n-type features observed. The most recent theoretical attempts to explain the donor state by simulations of various boron-hydrogen complexes in diamond are reviewed.

  9. Stress engineering of high-quality single crystal diamond by heteroepitaxial lateral overgrowth

    NASA Astrophysics Data System (ADS)

    Tang, Y.-H.; Golding, B.

    2016-02-01

    A method for lateral overgrowth of low-stress single crystal diamond by chemical vapor deposition (CVD) is described. The process is initiated by deposition of a thin (550 nm) (001) diamond layer on Ir-buffered a-plane sapphire. The diamond is partially masked by periodic thermally evaporated Au stripes using photolithography. Lateral overgrowth of the Au occurs with extremely effective filtering of threading dislocations. Thermal stress resulting from mismatch of the low thermal expansion diamond and the sapphire substrate is largely accommodated by the ductile Au layer. The stress state of the diamond is investigated by Raman spectroscopy for two thicknesses: at 10 μm where the film has just overgrown the Au mask and at 180 μm where the film thickness greatly exceeds the scale of the masking. For the 10-μm film, the Raman linewidth shows spatial oscillations with the period of the Au stripes with a factor of 2 to 3 reduction relative to the unmasked region. In a 180-μm thick diamond film, the overall surface stress was extremely low, 0.00 ± 0.16 GPa, obtained from the Raman shift averaged over the 7.5 mm diameter of the crystal at its surface. We conclude that the metal mask protects the overgrown diamond layer from substrate-induced thermal stress and cracking. It is also responsible for low internal stress by reducing dislocation density by several orders of magnitude.

  10. Preparation of Diamond Mold Using Electron Beam Lithography for Application to Nanoimprint Lithography

    NASA Astrophysics Data System (ADS)

    Taniguchi, Jun; Tokano, Yuji; Miyamoto, Iwao; Komuro, Masanori; Hiroshima, Hiroshi; Kobayashi, Kazuhiko; Miyazaki, Takeshi; Ohyi, Hideyuki

    2000-12-01

    Diamond molds were fabricated by two types of fabrication processes, both of which use a conductive intermediate layer between the diamond surface and polymethylmethacrylate (PMMA) resist to prevent surface charge-up. Using a PtPd intermediate layer, electron beam lithography and ion beam etching, a denting line pattern of 600 nm width and 70 nm depth was fabricated. Using a carbon intermediate layer, electron beam lithography, PtPd lift-off and oxygen ion beam etching, a convex line pattern of 600 nm width and 110 nm height was fabricated. These diamond molds were pressed into PMMA on a silicon substrate that was heated to a temperature of 150^\\circC and kept at a pressure of 23.5 MPa until the temperature dropped below 90^\\circC, and then the diamond mold was released from the PMMA@. The convex line pattern of 600 nm width and 150 nm height was imprinted using a denting diamond mold. The denting pattern of 1100 nm width and 180 nm height was imprinted using a convex diamond mold. PMMA patterns were transferred well over the imprinted area by the diamond molds.

  11. Diamond and other forms of elemental carbon in Saturns deep atmosphere

    NASA Astrophysics Data System (ADS)

    Delitsky, M. L.; Baines, K. H.

    2013-10-01

    The energetic lightning storms in the Saturn atmosphere will dissociate molecules into atoms, ions and plasma. Specifically, methane will be dissociated into elemental carbon, most probably in an amorphous form, such as fluffy turbostratic carbon or irregular soot particles. Once formed, this non-crystalline carbon sinks down through the atmosphere reaching an altitude of similar density. Amorphous carbon is converted to graphite under pressure. Graphite has a density of ~2.2 g/cc at room temperature. The density of diamond is ~3.3 g/cc at STP. However, at much higher pressures, the density of diamond increases dramatically, up to 9 grams/cm3 at P=1500 GPa (15 Mbar). As carbon descends through the atmosphere, amorphous carbon becomes graphite which then is converted into diamond, creating various strata of carbon allotropes according to their densities. Densities of the planets increase with depth. Eventually, at great depths, diamond will melt, forming liquid diamond. The melting point of diamond varies with pressure, reaching a high of ~ 8000 K at 500 GPa (5 Mbar). Using updated adiabats and equation-of-state data from Nettelmann et al. (2011), we determined the altitude at which diamond reaches its melting point on each planet. Combining these adiabats with new data for the carbon phase diagram from high-pressure shockwave experiments indicates that diamond may be a stable layer in the atmospheres of Jupiter and Saturn. Previously, only Uranus and Neptune were thought to have conditions in their interiors that would allow the formation of diamond at their cores. It appears that the interior of Jupiter gets hot enough to reach the liquid diamond region of the carbon phase diagram, whereas the interior of Saturn includes regions of temperature and pressure where carbon could exist as solid diamond. At the boundaries (locations of sharp increases in density) on Jupiter and Saturn, there may be diamond rain or diamond oceans sitting as a layer. However, in Uranus and Neptune, the temperatures never reach as high as 8000 K. The cores are ~5000K, too cold for diamond to melt on these planets. Therefore, it appears that diamonds are forever on Uranus and Neptune but not on Jupiter and Saturn.

  12. Friction and Wear Properties of As-Deposited and Carbon Ion-Implanted Diamond Films

    NASA Technical Reports Server (NTRS)

    Miyoshi, Kazuhisa

    1996-01-01

    Recent work on the friction and wear properties of as-deposited and carbon ion-implanted diamond films was reviewed. Diamond films were produced by the microwave plasma chemical vapor deposition (CVD) technique. Diamond films with various grain sizes and surface roughnesses were implanted with carbon ions at 60 keV ion energy, resulting in a dose of 1.2 x 10(exp 17) carbon ions per cm(exp 2). Various analytical techniques, including Raman spectroscopy, proton recoil analysis, Rutherford backscattering, transmission and scanning electron microscopy, X-ray photoelectron spectroscopy, and X-ray diffraction, were utilized to characterize the diamond films. Sliding friction experiments were conducted with a polished natural diamond pin in contact with diamond films in the three environments: humid air (40% relative humidity), dry nitrogen (less than 1 percent relative humidity), and ultrahigh vacuum (10(exp -7) Pa). The CVD diamond films indeed have friction and wear properties similar to those of natural diamond in the three environments. The as-deposited, fine-grain diamond films can be effectively used as self-lubricating, wear-resistant coatings that have low coefficients of friction (0.02 to 0.04) and low wear rates (10(exp -7) to lO(exp -8) mm(exp 3) N(exp -1) m(exp -1)) in both humid air and dry nitrogen. However, they have high coefficients of friction (1.5 to 1.7) and a high wear rate (10(exp -4) mm(exp 7) N(exp -1) m(exp -1)) in ultrahigh vacuum. The carbon ion implantation produced a thin surficial layer (less than 0.1 micron thick) of amorphous, non-diamond carbon on the diamond films. In humid air and dry nitrogen, the ion-implanted, fine and coarse-grain diamond films have a low coefficient of friction (around 0.1) and a low wear rate (10(exp -7) mm(exp 3) N(exp -1) m(exp-1)). Even in ultrahigh vacuum, the presence of the non-diamond carbon layer reduced the coefficient of friction of fine-grain diamond films to 0.1 or lower and the wear rate to 10(exp -6) mm(exp 3) N(exp -1) m(exp -1). Thus, the carbon ion-implanted, fine-grain diamond films can be effectively used as wear-resistant, self-lubricating coatings not only in air and dry nitrogen, but also in ultrahigh vacuum.

  13. Deposition of diamond and diamond-like carbon nuclei by electrolysis of alcohol solutions

    NASA Astrophysics Data System (ADS)

    Tosin, M. C.; Peterlevitz, A. C.; Surdutovich, G. I.; Baranauskas, V.

    1999-04-01

    We show that nuclei and aggregates of diamond, diamond-like carbon (DLC) and crystalline graphite may be deposited by the electrolysis of heated methanol. The structures were characterized by micro-Raman spectroscopy, optical microscopy and scanning electron microscopy (SEM). It is observed that bubble formation inhibits the film deposition in DLC form on the immersed substrate but enhances the formation of carbon nuclei on the wetted capillary area of the substrate. We observed experimentally an inhomogeneity in the film thickness in the vertical direction and explain this effect by relating it to an inhomogeneous turbulent `boiling layer' present near the cathode. In addition, we observed that the film growth rate on the wetted capillary area is much higher than the average growth rate on the immersed cathode.

  14. Improving nanocrystalline diamond coatings for micro end mills

    NASA Astrophysics Data System (ADS)

    Heaney, Patrick J.

    A new method is presented for coating 300 mum diameter tungsten carbide (WC) micro end mills with diamond using a hot filament chemical vapor deposition (HF-CVD) method. This method has been developed to create uniform, conformal and continuous diamond coatings. Initial work is shown to prove the feasibility and concept of the project. This was the first work known to coat and evaluate the machining performance WC micro end mills. The performance of uncoated and coated micro end mills was evaluated by dry machining channels in 6061-T6 aluminum. The test results showed a 75% and 90% decrease in both cutting and trust forces for machining, respectfully. The coated tools produced a more predictable surface finish with no burring. These improved results are due to the superior tribological properties of diamond against aluminum. Initial results indicated severe problems with coating delamination causing complete tool failure. After proving the initial concept, new methods for optimizing the coating and improving performance were studied. Each optimization step is monitored through surface analysis techniques to monitor changes in coating morphology and diamond quality. Nucleation density was increased by improving the seed method, using ultra dispersed diamond (UDD) seed. The increase in nucleation density allowed the synthesis of coatings as thin as 60 nm. The adhesion of the coating to the tool was improved through carbon ion implantation (CII). CII is a different surface preparation technique that deactivates the effect of Co, while not weakening the tool. CII also creates a great nucleation layer which diamond can directly grow from, allowing the diamond coating to chemically bond to the substrate improving adhesion and eliminating the need for a seed layer. These thin coatings were shown to be of high quality sp3 trigonaly bonded diamond that resulted in lower machining forces with less delamination. The 90% reduction in machining forces that thin conformal diamond coatings can achieve for micro end mills directly influences the accuracy of parts and the speed with which they can be made. A 50% reduction in forces could be used to double the material removal rate, cutting the part machining cost in half.

  15. Electric-field-driven hole carriers and superconductivity in diamond

    NASA Astrophysics Data System (ADS)

    Nakamura, K.; Rhim, S. H.; Sugiyama, A.; Sano, K.; Akiyama, T.; Ito, T.; Weinert, M.; Freeman, A. J.

    2013-06-01

    First-principles calculations of electric-field-driven superconductivity at the hydrogenated diamond (110) surface are presented. While the hydrogens on the surface effectively maintain the intrinsic sp3 covalent nature of diamond, the hole carriers induced by an external negative electric field (E-field) lead to a metallic surface region. Importantly, the concentration of hole carriers, confined within a few carbon layers of thickness 5-10 below the surface, exceeds 1021 cm-3, which is larger than the critical hole density responsible for superconductivity in the boron-doped diamond, while the calculated electron-phonon coupling constants are comparable in magnitude, suggesting the possibility of superconductivity with enhanced critical field.

  16. Deuterium-induced passivation of boron acceptors in polycrystalline diamond

    NASA Astrophysics Data System (ADS)

    Habka, N.; Chikoidze, E.; Jomard, F.; Dumont, Y.; Chevallier, J.; Barjon, J.; Mer, C.; Bergonzo, P.

    2010-12-01

    In monocrystalline boron-doped diamond (BDD), the diffusion of deuterium induces an electrical passivation of acceptors by the formation of (B,D) complexes. However, device applications based on this process are presently limited by the small size of available monocrystalline substrates. In this work, we show that the grain size of polycrystalline diamond is a key parameter in order to achieve efficient deuterium diffusion by trapping on boron atoms. As a result, we present the first clear evidences of the electrical passivation of boron acceptors in the case of polycrystalline diamond layers with an average grain size of 50 ?m. We show that, for a boron concentration of 21019 cm-3, the room temperature hole mobility increases from 70 to 120 cm2 V-1 s-1 after deuteration. More surprisingly, the compensation ratio keeps the same order of magnitude which suggests a passivation effect on both acceptors and donors.

  17. Ab initio structure determination of n-diamond

    NASA Astrophysics Data System (ADS)

    Li, Da; Tian, Fubo; Chu, Binhua; Duan, Defang; Sha, Xiaojing; Lv, Yunzhou; Zhang, Huadi; Lu, Nan; Liu, Bingbing; Cui, Tian

    2015-08-01

    A systematic computational study on the crystal structure of n-diamond has been performed using first-principle methods. A novel carbon allotrope with hexagonal symmetry R32 space group has been predicted. We name it as HR-carbon. HR-carbon composed of lonsdaleite layers and unique C3 isosceles triangle rings, is stable over graphite phase above 14.2?GPa. The simulated x-ray diffraction pattern, Raman, and energy-loss near-edge spectrum can match the experimental results very well, indicating that HR-carbon is a likely candidate structure for n-diamond. HR-carbon has an incompressible atomic arrangement because of unique C3 isosceles triangle rings. The hardness and bulk modulus of HR-carbon are calculated to be 80?GPa and 427?GPa, respectively, which are comparable to those of diamond. C3 isosceles triangle rings are very important for the stability and hardness of HR-carbon.

  18. Ab initio structure determination of n-diamond.

    PubMed

    Li, Da; Tian, Fubo; Chu, Binhua; Duan, Defang; Sha, Xiaojing; Lv, Yunzhou; Zhang, Huadi; Lu, Nan; Liu, Bingbing; Cui, Tian

    2015-01-01

    A systematic computational study on the crystal structure of n-diamond has been performed using first-principle methods. A novel carbon allotrope with hexagonal symmetry R32 space group has been predicted. We name it as HR-carbon. HR-carbon composed of lonsdaleite layers and unique C3 isosceles triangle rings, is stable over graphite phase above 14.2?GPa. The simulated x-ray diffraction pattern, Raman, and energy-loss near-edge spectrum can match the experimental results very well, indicating that HR-carbon is a likely candidate structure for n-diamond. HR-carbon has an incompressible atomic arrangement because of unique C3 isosceles triangle rings. The hardness and bulk modulus of HR-carbon are calculated to be 80?GPa and 427?GPa, respectively, which are comparable to those of diamond. C3 isosceles triangle rings are very important for the stability and hardness of HR-carbon. PMID:26299905

  19. Interfaces in nano-/microcrystalline multigrade CVD diamond coatings.

    PubMed

    Almeida, Flvia A; Salgueiredo, Ermelinda; Oliveira, Filipe J; Silva, Rui F; Baptista, Daniel L; Peripolli, Suzana B; Achete, Carlos A

    2013-11-27

    The interfaces of multilayered CVD diamond films grown by the hot-filament technique were characterized with high detail using HRTEM, STEM-EDX, and EELS. The results show that at the transition from micro- (MCD) to nanocrystalline diamond (NCD), a thin precursor graphitic film is formed, irrespectively of the NCD gas chemistry used (with or without argon). On the contrary, the transition of the NCD to MCD grade is free of carbon structures other than diamond, the result of a higher substrate temperature and more abundant atomic H in the gas chemistry. At those transitions WC nanoparticles could be found due to contamination from the filament, being also present at the first interface of the MCD layer with the silicon nitride substrate. PMID:24164667

  20. Ab initio structure determination of n-diamond

    PubMed Central

    Li, Da; Tian, Fubo; Chu, Binhua; Duan, Defang; Sha, Xiaojing; Lv, Yunzhou; Zhang, Huadi; Lu, Nan; Liu, Bingbing; Cui, Tian

    2015-01-01

    A systematic computational study on the crystal structure of n-diamond has been performed using first-principle methods. A novel carbon allotrope with hexagonal symmetry R32 space group has been predicted. We name it as HR-carbon. HR-carbon composed of lonsdaleite layers and unique C3 isosceles triangle rings, is stable over graphite phase above 14.2?GPa. The simulated x-ray diffraction pattern, Raman, and energy-loss near-edge spectrum can match the experimental results very well, indicating that HR-carbon is a likely candidate structure for n-diamond. HR-carbon has an incompressible atomic arrangement because of unique C3 isosceles triangle rings. The hardness and bulk modulus of HR-carbon are calculated to be 80?GPa and 427?GPa, respectively, which are comparable to those of diamond. C3 isosceles triangle rings are very important for the stability and hardness of HR-carbon. PMID:26299905

  1. Fabrication of UV Photodetector on TiO2/Diamond Film

    NASA Astrophysics Data System (ADS)

    Liu, Zhangcheng; Li, Fengnan; Li, Shuoye; Hu, Chao; Wang, Wei; Wang, Fei; Lin, Fang; Wang, Hongxing

    2015-09-01

    The properties of ultraviolet (UV) photodetector fabricated on TiO2/diamond film were investigated. Single crystal diamond layer was grown on high-pressure-high-temperature Ib-type diamond substrate by microwave plasma chemical vapor deposition method, upon which TiO2 film was prepared directly using radio frequency magnetron sputtering technique in Ar and O2 mixing atmosphere. Tungsten was used as electrode material to fabricate metal-semiconductor-metal UV photodetector. The dark current is measured to be 1.12 pA at 30 V. The photo response of the device displays an obvious selectivity between UV and visible light, and the UV-to-visible rejection ratio can reach 2 orders of magnitude. Compared with that directly on diamond film, photodetector on TiO2/diamond film shows higher responsivity.

  2. Fabrication of UV Photodetector on TiO2/Diamond Film.

    PubMed

    Liu, Zhangcheng; Li, Fengnan; Li, Shuoye; Hu, Chao; Wang, Wei; Wang, Fei; Lin, Fang; Wang, Hongxing

    2015-01-01

    The properties of ultraviolet (UV) photodetector fabricated on TiO2/diamond film were investigated. Single crystal diamond layer was grown on high-pressure-high-temperature Ib-type diamond substrate by microwave plasma chemical vapor deposition method, upon which TiO2 film was prepared directly using radio frequency magnetron sputtering technique in Ar and O2 mixing atmosphere. Tungsten was used as electrode material to fabricate metal-semiconductor-metal UV photodetector. The dark current is measured to be 1.12 pA at 30 V. The photo response of the device displays an obvious selectivity between UV and visible light, and the UV-to-visible rejection ratio can reach 2 orders of magnitude. Compared with that directly on diamond film, photodetector on TiO2/diamond film shows higher responsivity. PMID:26399514

  3. Modelling wafer bow in silicon-polycrystalline CVD diamond substrates for GaN-based devices

    NASA Astrophysics Data System (ADS)

    Edwards, M. J.; Bowen, C. R.; Allsopp, D. W. E.; Dent, A. C. E.

    2010-09-01

    Composite silicon-polycrystalline chemical vapour deposition (CVD) diamond wafers are potential substrates for GaN-based devices for use in harsh environments due to their high thermal conductivity and chemical stability. When cooled from a typical diamond deposition temperature of approximately 800 to 25 C wafer bowing arises from a mismatch in the coefficients of thermal expansion of silicon and polycrystalline diamond. In this paper 100 mm diameter silicon-polycrystalline diamond wafers have been modelled using ANSYS finite element software to investigate their bowing behaviour as a function of temperature and geometry. The maximum bow of a wafer occurred where the thicknesses of both the silicon and polycrystalline diamond layers was almost identical; this has been confirmed using analytical methods. Strategies are discussed for reducing wafer bow.

  4. A new hydrogen sensor using a polycrystalline diamond-based Schottky diode

    SciTech Connect

    Kang, W.P.; Gurbuz, Y.; Davidson, J.L.; Kerns, D.V. . Dept. of Applied and Engineering Sciences)

    1994-08-01

    A new hydrogen sensor utilizing plasma-enhanced chemical vapor deposited diamond in conjunction with palladium (Pd) metal has been developed. The device is fabricated in a layered Pd/Undoped diamond/p-doped diamond Schottky diode configuration. Hydrogen sensing characteristics of the device have been examined in terms of sensitivity, linearity, response rate, and response time as a function of temperature and hydrogen partial pressure. Hydrogen adsorption activation energy is investigated in the temperature range from 27 to 85 C. Analysis of the steady-state reaction kinetics using the I-V method confirm that the hydrogen adsorption process is responsible for the barrier height change in the diamond Schottky diode. The ability to fabricate diamond-based hydrogen sensor on a variety of substrates makes the device very versatile for gas sensing.

  5. Fabrication of UV Photodetector on TiO2/Diamond Film

    PubMed Central

    Liu, Zhangcheng; Li, Fengnan; Li, Shuoye; Hu, Chao; Wang, Wei; Wang, Fei; Lin, Fang; Wang, Hongxing

    2015-01-01

    The properties of ultraviolet (UV) photodetector fabricated on TiO2/diamond film were investigated. Single crystal diamond layer was grown on high-pressure-high-temperature Ib-type diamond substrate by microwave plasma chemical vapor deposition method, upon which TiO2 film was prepared directly using radio frequency magnetron sputtering technique in Ar and O2 mixing atmosphere. Tungsten was used as electrode material to fabricate metal-semiconductor-metal UV photodetector. The dark current is measured to be 1.12 pA at 30 V. The photo response of the device displays an obvious selectivity between UV and visible light, and the UV-to-visible rejection ratio can reach 2 orders of magnitude. Compared with that directly on diamond film, photodetector on TiO2/diamond film shows higher responsivity. PMID:26399514

  6. Amorphous Diamond for MEMS

    NASA Astrophysics Data System (ADS)

    Sullivan, J. P.

    2002-03-01

    Pure carbon films can exhibit surprising complexity in structure and properties. Amorphous diamond (tetrahedrally-coordinated amorphous carbon) is an amorphous quasi-two phase mixture of four-fold and three-fold coordinated carbon which is produced by pulsed excimer laser deposition, an energetic deposition process that leads to film growth by sub-surface carbon implantation and the creation of local metastability in carbon bonding. Modest annealing, < 900K, produces significant irreversible strain relaxation which is thermally activated with activation energies ranging from < 1 eV to > 2 eV. During annealing the material remains amorphous, but there is a detectable increase in medium-range order as measured by fluctuation microscopy. The strain relaxation permits the residual strain in the films to be reduced to < 0.00001, which is a critical requirement for the fabrication of microelectromechanical systems (MEMS). Amorphous diamond MEMS have been fabricated in order to evaluate the mechanical properties of this material under tension and flexure, and this has enabled the determination of elastic modulus (800 GPa), tensile strength (8 GPa), and fracture toughness (8 MPa m^1/2). In addition, amorphous diamond MEMS structures have been fabricated to measure internal dissipation and surface adhesion. The high hardness and strength and hydrophobic nature of the surface makes this material particularly suitable for the fabrication of high wear resistance and low stiction MEMS. Sandia is a multiprogram laboratory operated by Sandia Corp., a Lockheed Martin Co., for the U.S. Dept. of Energy under contract DE-AC04-94AL85000.

  7. The effect of surface treatment on the electrical properties of metal contacts to boron-doped homoepitaxial diamond film

    SciTech Connect

    Grot, S.A.; Gildenblat, G.S.; Hatfield, C.W.; Wronski, C.R. . Dept. of Electrical Engineering); Badzian, A.R.; Badzian, T.; Messier, R. . Materials Research Lab.)

    1990-02-01

    Both doped and undoped homoepitaxial diamond films were fabricated using microwave plasma-enhanced chemical vapor deposition (CVD). The conductivity of the diamond film is strongly affected by the surface treatment. In particular, exposure of film surface to a hydrogen plasma results in the formation of a conductive layer which can be used to obtain linear (ohmic) {ital I-V} characteristics of the Au/diamond contacts, regardless of the doping level. The proper chemical cleaning of the boron-doped homoepitaxial diamond surface allows the fabrication of Au-gate Schottky diodes with excellent rectifying characteristics at temperatures of at least 400{degrees}C.

  8. Microwave plasma enhanced chemical vapor deposition of nanocrystalline diamond films by bias-enhanced nucleation and bias-enhanced growth

    SciTech Connect

    Chu, Yueh-Chieh; Tzeng, Yonhua; Auciello, Orlando

    2014-01-14

    Effects of biasing voltage-current relationship on microwave plasma enhanced chemical vapor deposition of ultrananocrystalline diamond (UNCD) films on (100) silicon in hydrogen diluted methane by bias-enhanced nucleation and bias-enhanced growth processes are reported. Three biasing methods are applied to study their effects on nucleation, growth, and microstructures of deposited UNCD films. Method A employs 320 mA constant biasing current and a negative biasing voltage decreasing from −490 V to −375 V for silicon substrates pre-heated to 800 °C. Method B employs 400 mA constant biasing current and a decreasing negative biasing voltage from −375 V to −390 V for silicon pre-heated to 900 °C. Method C employs −350 V constant biasing voltage and an increasing biasing current up to 400 mA for silicon pre-heated to 800 °C. UNCD nanopillars, merged clusters, and dense films with smooth surface morphology are deposited by the biasing methods A, B, and C, respectively. Effects of ion energy and flux controlled by the biasing voltage and current, respectively, on nucleation, growth, microstructures, surface morphologies, and UNCD contents are confirmed by scanning electron microscopy, high-resolution transmission-electron-microscopy, and UV Raman scattering.

  9. Chemical Vapor-Deposited (CVD) Diamond Films for Electronic Applications

    NASA Technical Reports Server (NTRS)

    1995-01-01

    Diamond films have a variety of useful applications as electron emitters in devices such as magnetrons, electron multipliers, displays, and sensors. Secondary electron emission is the effect in which electrons are emitted from the near surface of a material because of energetic incident electrons. The total secondary yield coefficient, which is the ratio of the number of secondary electrons to the number of incident electrons, generally ranges from 2 to 4 for most materials used in such applications. It was discovered recently at the NASA Lewis Research Center that chemical vapor-deposited (CVD) diamond films have very high secondary electron yields, particularly when they are coated with thin layers of CsI. For CsI-coated diamond films, the total secondary yield coefficient can exceed 60. In addition, diamond films exhibit field emission at fields orders of magnitude lower than for existing state-of-the-art emitters. Present state-of-the-art microfabricated field emitters generally require applied fields above 5x10^7 V/cm. Research on field emission from CVD diamond and high-pressure, high-temperature diamond has shown that field emission can be obtained at fields as low as 2x10^4 V/cm. It has also been shown that thin layers of metals, such as gold, and of alkali halides, such as CsI, can significantly increase field emission and stability. Emitters with nanometer-scale lithography will be able to obtain high-current densities with voltages on the order of only 10 to 15 V.

  10. Investigation of the shape transferability of nanoscale multi-tip diamond tools in the diamond turning of nanostructures

    NASA Astrophysics Data System (ADS)

    Luo, Xichun; Tong, Zhen; Liang, Yingchun

    2014-12-01

    In this article, the shape transferability of using nanoscale multi-tip diamond tools in the diamond turning for scale-up manufacturing of nanostructures has been demonstrated. Atomistic multi-tip diamond tool models were built with different tool geometries in terms of the difference in the tip cross-sectional shape, tip angle, and the feature of tool tip configuration, to determine their effect on the applied forces and the machined nano-groove geometries. The quality of machined nanostructures was characterized by the thickness of the deformed layers and the dimensional accuracy achieved. Simulation results show that diamond turning using nanoscale multi-tip tools offers tremendous shape transferability in machining nanostructures. Both periodic and non-periodic nano-grooves with different cross-sectional shapes can be successfully fabricated using the multi-tip tools. A hypothesis of minimum designed ratio of tool tip distance to tip base width (L/Wf) of the nanoscale multi-tip diamond tool for the high precision machining of nanostructures was proposed based on the analytical study of the quality of the nanostructures fabricated using different types of the multi-tip tools. Nanometric cutting trials using nanoscale multi-tip diamond tools (different in L/Wf) fabricated by focused ion beam (FIB) were then conducted to verify the hypothesis. The investigations done in this work imply the potential of using the nanoscale multi-tip diamond tool for the deterministic fabrication of period and non-periodic nanostructures, which opens up the feasibility of using the process as a versatile manufacturing technique in nanotechnology.

  11. GaN heterostructures with diamond and graphene

    NASA Astrophysics Data System (ADS)

    Pcz, B.; Tth, L.; Tsiakatouras, G.; Adikimenakis, A.; Kovcs, A.; Duchamp, M.; Dunin-Borkowski, R. E.; Yakimova, R.; Neumann, P. L.; Behmenburg, H.; Foltynski, B.; Giesen, C.; Heuken, M.; Georgakilas, A.

    2015-11-01

    The full performance of GaN devices for high power applications is not exploited due to their self-heating. Possible solutions are the integration of materials with high heat conductivity i.e., single crystalline diamond and graphene layers. We report the growth of single crystalline (0001)-oriented GaN thin films on (100), (110) and (111) diamond single crystals studied by transmission electron microscopy (TEM) in cross-sections. As for graphene, we show a high quality GaN layer that was deposited on patterned graphene layers and 6H-SiC. The atomic structures of the interfaces in the heterostructure are studied using aberration-corrected scanning TEM combined with energy dispersive x-ray and electron energy-loss spectroscopy.

  12. Photochemical functionalization of diamond surfaces

    NASA Astrophysics Data System (ADS)

    Nichols, Beth Marie

    Diamond surfaces are excellent substrates for potential applications in fields such as biotechnology, molecular sensing, and molecular electronics. In order to develop new diamond-based technologies, it is important to develop a fundamental understanding of diamond surface chemistry. Previous work in the Hamers group has demonstrated covalent functionalization of hydrogen-terminated diamond surfaces with molecules bearing a terminal vinyl group via a photochemical process using sub-bandgap light at 254 nm. While the reaction was shown to occur reproducibly with self-terminating monolayer surface coverage, the mechanism was never fully understood. This thesis investigates the photochemical modification of hydrogen-terminated surfaces of diamond. The results show that this reaction is a surface-mediated radical process initiated by the UV-assisted photoejection of electrons from the diamond surfaces into the liquid phase. To develop a better understanding of the photochemical mechanism, an electrical bias was applied to the diamond samples during the photochemical reaction. Applying a 1 volt potential between two diamond electrodes significantly increases the rate of functionalization of the negative electrode. Cyclic voltammetry and electrochemical impedance measurements show that the applied potential induces downward band-bending within the negative diamond film electrode. At higher voltages a Faradaic current is observed, with no further acceleration of the functionalization rate. The bias-dependent changes in rate are attributed to a field effect; the applied potential induces a downward band-bending on the negative electrode and facilitates electron ejection into the adjacent organic fluid. The ability to directly organically photopattern the surface on length scales of <25 microns has also been demonstrated using simple photomasking techniques. Techniques for the functionalization of diamond may be applied to other 'unreactive' surfaces. The activation of a gallium nitride surface with a hydrogen plasma treatment has been achieved; this hydrogen-treated surface has been shown to be photochemically reactive under 254 nm light. Preliminary studies into the use of diamond as a photocatalytic substrate suggest that diamond can be used for the photo-induced breakdown of small organics. The stability of the diamond surfaces in these environments remains to be examined.

  13. Diamond microstructures fabricated using silicon molds

    SciTech Connect

    Salvadori, M.C.; Martins, D.R.; Mansano, R.D.; Verdonck, P.; Brown, I.G.

    2005-11-15

    We have fabricated diamond microstructures using silicon molds into which microcrystalline diamond was deposited by plasma assisted chemical vapor deposition. Prior to diamond deposition the silicon molds were seeded with the diamond powder of two different grain sizes (1/4) and 1 {mu}m. Scanning electron microscopy and atomic force microscopy were used to view and characterize the resultant diamond microstructures. Analysis of the diamond replicas indicates better reproduction fidelity for the (1/4) {mu}m diamond powder, and a surface roughness of 20 nm.

  14. Electron energy loss spectrometry of interstellar diamonds

    NASA Technical Reports Server (NTRS)

    Bernatowicz, Thomas J.; Gibbons, Patrick C.; Lewis, Roy S.

    1990-01-01

    The results are reported of electron energy loss spectra (EELS) measurements on diamond residues from carbonaceous meteorites designed to elucidate the structure and composition of interstellar diamonds. Dynamic effective medium theory is used to model the dielectric properties of the diamonds and in particular to synthesize the observed spectra as mixtures of diamond and various pi-bonded carbons. The results are shown to be quantitatively consistent with the idea that diamonds and their surfaces are the only contributors to the electron energy loss spectra of the diamond residues and that these peculiar spectra are the result of the exceptionally small grain size and large specific surface area of the interstellar diamonds.

  15. Subpicotesla Diamond Magnetometry

    NASA Astrophysics Data System (ADS)

    Wolf, Thomas; Neumann, Philipp; Nakamura, Kazuo; Sumiya, Hitoshi; Ohshima, Takeshi; Isoya, Junichi; Wrachtrup, Jörg

    2015-10-01

    Nitrogen-vacancy (NV) defect centers in diamond are promising solid-state magnetometers. Single centers allow for high-spatial-resolution field imaging but are limited in their magnetic field sensitivity. Using defect-center ensembles, sensitivity can be scaled with √{N } when N is the number of defects. In the present work, we use an ensemble of N ˜1011 defect centers within an effective sensor volume of 8.5 ×10-4 mm3 for sensing at room temperature. By carefully eliminating noise sources and using high-quality diamonds with large NV concentrations, we demonstrate, for such sensors, a sensitivity scaling as 1 /√{t } , where t is the total measurement time. The associated photon-shot-noise-limited magnetic-field sensitivity for ac signals of f =20 kHz is 0.9 pT /√{Hz } . For a total measurement time of 100 s, we reach a standard deviation of about 100 fT. Further improvements using decoupling sequences and material optimization could lead to fT /√{Hz } sensitivity.

  16. REVIEW ARTICLE: Diamond for bio-sensor applications

    NASA Astrophysics Data System (ADS)

    Nebel, Christoph E.; Rezek, Bohuslav; Shin, Dongchan; Uetsuka, Hiroshi; Yang, Nianjun

    2007-10-01

    A summary of photo- and electrochemical surface modifications applied on single-crystalline chemical vapour deposition (CVD) diamond films is given. The covalently bonded formation of amine- and phenyl-linker molecule layers is characterized using x-ray photoelectron spectroscopy, atomic force microscopy (AFM), cyclic voltammetry and field-effect transistor characterization experiments. Amine- and phenyl-layers are very different with respect to formation, growth, thickness and molecule arrangement. We detect a single-molecular layer of amine-linker molecules on diamond with a density of about 1014 cm-2 (10% of carbon bonds). Amine molecules are bonded only on initially H-terminated surface areas to carbon. In the case of electrochemical deposition of phenyl-layers, multi-layer formation is detected due to three-dimensional (3D) growths. This gives rise to the formation of typically 25 thick layers. The electrochemical grafting of boron-doped diamond works on H-terminated and oxidized surfaces. After reacting such films with hetero-bifunctional crosslinker molecules, thiol-modified ss-DNA markers are bonded to the organic system. Application of fluorescence and AFM on hybridized DNA films shows dense arrangements with densities of up to 1013 cm-2. The DNA is tilted by an angle of about 35 with respect to the diamond surface. Shortening the bonding time of thiol-modified ss-DNA to 10 min causes a decrease of DNA density to about 1012 cm-2. Application of AFM scratching experiments shows threshold removal forces of around 75 nN for DNA bonded on phenyl-linker molecules and of about 45 nN for DNA bonded to amine-linker molecules. DNA sensor applications using Fe(CN6)3-/4- mediator redox molecules, impedance spectroscopy and DNA-field effect transistor devices performances are introduced and discussed.

  17. Direct coating adherent diamond films on Fe-based alloy substrate: the roles of Al, Cr in enhancing interfacial adhesion and promoting diamond growth.

    PubMed

    Li, X J; He, L L; Li, Y S; Yang, Q; Hirose, A

    2013-08-14

    Direct CVD deposition of dense, continuous, and adherent diamond films on conventional Fe-based alloys has long been considered impossible. The current study demonstrates that such a deposition can be realized on Al, Cr-modified Fe-based alloy substrate (FeAl or FeCrAl). To clarify the fundamental mechanism of Al, Cr in promoting diamond growth and enhancing interfacial adhesion, fine structure and chemical analysis around the diamond film-substrate interface have been comprehensively characterized by transmission electron microscopy. An intermediate graphite layer forms on those Al-free substrates such as pure Fe and FeCr, which significantly deteriorates the interfacial adhesion of diamond. In contrast, such a graphite layer is absent on the FeAl and FeCrAl substrates, whereas a very thin Al-rich amorphous oxide sublayer is always identified between the diamond film and substrate interface. These comparative results indicate that the Al-rich interfacial oxide layer acts as an effective barrier to prevent the formation of graphite phase and consequently enhance diamond growth and adhesion. The adhesion of diamond film formed on FeCrAl is especially superior to that formed on FeAl substrate. This can be further attributed to a synergetic effect including the reduced fraction of Al and the decreased substrate thermal-expansion coefficient on FeCrAl in comparison with FeAl, and a mechanical interlocking effect due to the formation of interfacial chromium carbides. Accordingly, a mechanism model is proposed to account for the different interfacial adhesion of diamond grown on the various Fe-based substrates. PMID:23829602

  18. Friction and Wear Properties of As-deposited and Carbon Ion-implanted Diamond Films

    NASA Technical Reports Server (NTRS)

    Miyoshi, Kazuhisa

    1994-01-01

    Recent work on the friction and wear properties of as-deposited and carbon ion-implanted diamond films was reviewed. Diamond films were produced by the microwave plasma chemical vapor deposition (CVD) technique. Diamond films with various grain sizes and surface roughnesses were implanted with carbon ions at 60 ke V ion energy, resulting in a dose of 1.2310(exp 17) carbon ions/cm(exp 2). Various analytical techniques, including Raman spectroscopy, proton recoil analysis, Rutherford backscattering, transmission and scanning electron microscopy, x-ray photoelectron spectroscopy, and x-ray diffraction, were utilized to characterize the diamond films. Sliding friction experiments were conducted with a polished natural diamond pin in contact with diamond films in the three environments: humid air (40 percent relative humidity), dry nitrogen (less than 1 percent relative humidity), and ultrahigh vacuum (10(exp -7) Pa). The CVD diamond films indeed have friction and were properties similar to those of natural diamond in the three environments. The as-deposited, fine-grain diamond films can be effectively used as self-lubricating, wear-resistant coatings that have low coefficients of friction (0.02 to 0.04) and low wear rates (10(exp -7) to 10(exp -8)mm(exp 3)/N-m) in both humid air and dry nitrogen. However, they have high coefficients of friction (1.5 to 1.7) and a high wear rate (10(exp -4)mm(exp 3/N-m) in ultrahigh vacuum. The carbon ion implanation produced a thin surficial layer (less than 0.1 micron thick) of amorphous, nondiamond carbon on the diamond films. In humid air and dry nitrogen, the ion-implanted, fine- and coarse-grain diamond films have a low coefficient of friction (around 0.1) and a low wear rate (10(exp -7)mm(exp 3/N-m). Even in ultrahigh vacuum, the presence of the nondiamond carbon layer reduced the coefficient of friction of fine-grain diamond films to 0.1 or lower and the wear rate to 10(exp -6)mm(exp 3)/N-m. Thus, the carbon ion-implanted, fine-grain diamond films can be effectively used as wear-resistant, self-lubricating coatings not only in air and dry nitrogen, but also in ultrahigh vacuum. The wear mechanism of diamond films is that of small fragments chipping off the surface. The size of wear particles is related to the extent of wear rates.

  19. Reducing GaN-on-diamond interfacial thermal resistance for high power transistor applications

    NASA Astrophysics Data System (ADS)

    Sun, Huarui; Simon, Roland B.; Pomeroy, James W.; Francis, Daniel; Faili, Firooz; Twitchen, Daniel J.; Kuball, Martin

    2015-03-01

    Integration of chemical vapor deposited polycrystalline diamond offers promising thermal performance for GaN-based high power radio frequency amplifiers. One limiting factor is the thermal barrier at the GaN to diamond interface, often referred to as the effective thermal boundary resistance (TBReff). Using a combination of transient thermoreflectance measurement, finite element modeling and microstructural analysis, the TBReff of GaN-on-diamond wafers is shown to be dominated by the SiNx interlayer for diamond growth seeding, with additional impacts from the diamond nucleation surface. By decreasing the SiNx layer thickness and minimizing the diamond nucleation region, TBReff can be significantly reduced, and a TBReff as low as 12 m2K/GW is demonstrated. This enables a major improvement in GaN-on-diamond transistor thermal resistance with respect to GaN-on-SiC wafers. A further reduction in TBReff towards the diffuse mismatch limit is also predicted, demonstrating the full potential of using diamond as the heat spreading substrate.

  20. Chemical-Vapor-Deposited Diamond Film

    NASA Technical Reports Server (NTRS)

    Miyoshi, Kazuhisa

    1999-01-01

    This chapter describes the nature of clean and contaminated diamond surfaces, Chemical-vapor-deposited (CVD) diamond film deposition technology, analytical techniques and the results of research on CVD diamond films, and the general properties of CVD diamond films. Further, it describes the friction and wear properties of CVD diamond films in the atmosphere, in a controlled nitrogen environment, and in an ultra-high-vacuum environment.

  1. Investigation of nucleation and growth processes of diamond films by atomic force microscopy

    NASA Technical Reports Server (NTRS)

    George, M. A.; Burger, A.; Collins, Warren E.; Hu, Z.

    1995-01-01

    The nucleation and growth of plasma enhanced chemical vapor deposited (PECVD) polycrystalline diamond films were studied using atomic force microscopy (AFM). AFM images were obtained for: (1) nucleated diamond films produced from depositions that were terminated during the initial stages of growth, (2) the silicon substrate-diamond film interface side of diamond films (1-4 micrometers thick) removed from the original surface of the substrate, and (3) cross-sectional fracture surface of the film, including the Si/diamond interface. Pronounced tip effects were observed for early-stage diamond nucleation attributed to tip convolution in the AFM images. AFM images of the films cross-section and interface however were not affected by tip convolution, and the images indicate that the surface of the silicon substrate is initially covered by small grained polycrystalline-like film and the formation of this precursor film is followed by nucleation of the diamond film on top of this layer. X-ray photoelectron spectroscoy (XPS) spectra indicates that some silicon carbide is present in the precursor layer.

  2. Investigation of nucleation and growth processes of diamond films by atomic force microscopy

    NASA Technical Reports Server (NTRS)

    George, M. A.; Burger, A.; Collins, W. E.; Davidson, J. L.; Barnes, A. V.; Tolk, N. H.

    1994-01-01

    The nucleation and growth of plasma-enhanced chemical-vapor deposited polycrystalline diamond films were studied using atomic force microscopy (AFM). AFM images were obtained for (1) nucleated diamond films produced from depositions that were terminated during the initial stages of growth, (2) the silicon substrate-diamond film interface side of diamond films (1-4 micrometers thick) removed from the original surface of the substrate, and (3) the cross-sectional fracture surface of the film, including the Si/diamond interface. Pronounced tip effects were observed for early-stage diamond nucleation attributed to tip convolution in the AFM images. AFM images of the film's cross section and interface, however, were not highly affected by tip convolution, and the images indicate that the surface of the silicon substrate is initially covered by a small grained polycrystalline-like film and the formation of this precursor film is followed by nucleation of the diamond film on top of this layer. X-ray photoelectron spectroscopy spectra indicate that some silicon carbide is present in the precursor layer.

  3. Electrochemically grafted polypyrrole changes photoluminescence of electronic states inside nanocrystalline diamond

    SciTech Connect

    Galář, P. Malý, P.; Čermák, J.; Kromka, A.; Rezek, B.

    2014-12-14

    Hybrid diamond-organic interfaces are considered attractive for diverse applications ranging from electronics and energy conversion to medicine. Here we use time-resolved and time-integrated photoluminescence spectroscopy in visible spectral range (380–700 nm) to study electronic processes in H-terminated nanocrystalline diamond films (NCD) with 150 nm thin, electrochemically deposited polypyrrole (PPy) layer. We observe changes in dynamics of NCD photoluminescence as well as in its time-integrated spectra after polymer deposition. The effect is reversible. We propose a model where the PPy layer on the NCD surface promotes spatial separation of photo-generated charge carriers both in non-diamond carbon phase and in bulk diamond. By comparing different NCD thicknesses we show that the effect goes as much as 200 nm deep inside the NCD film.

  4. Electrochemically grafted polypyrrole changes photoluminescence of electronic states inside nanocrystalline diamond

    NASA Astrophysics Data System (ADS)

    Gal?, P.; ?ermk, J.; Mal, P.; Kromka, A.; Rezek, B.

    2014-12-01

    Hybrid diamond-organic interfaces are considered attractive for diverse applications ranging from electronics and energy conversion to medicine. Here we use time-resolved and time-integrated photoluminescence spectroscopy in visible spectral range (380-700 nm) to study electronic processes in H-terminated nanocrystalline diamond films (NCD) with 150 nm thin, electrochemically deposited polypyrrole (PPy) layer. We observe changes in dynamics of NCD photoluminescence as well as in its time-integrated spectra after polymer deposition. The effect is reversible. We propose a model where the PPy layer on the NCD surface promotes spatial separation of photo-generated charge carriers both in non-diamond carbon phase and in bulk diamond. By comparing different NCD thicknesses we show that the effect goes as much as 200 nm deep inside the NCD film.

  5. CVD Diamond Dielectric Accelerating Structures

    SciTech Connect

    Schoessow, P.; Kanareykin, A.; Gat, R.

    2009-01-22

    The electrical and mechanical properties of diamond make it an ideal candidate material for use in dielectric accelerating structures: high RF breakdown field, extremely low dielectric losses and the highest available thermoconductive coefficient. Using chemical vapor deposition (CVD) cylindrical diamond structures have been manufactured with dimensions corresponding to fundamental TM{sub 01} mode frequencies in the GHz to THz range. Surface treatments are being developed to reduce the secondary electron emission (SEE) coefficient below unity to reduce the possibility of multipactor. The diamond CVD cylindrical waveguide technology developed here can be applied to a variety of other high frequency, large-signal applications.

  6. Tailoring nanocrystalline diamond film properties

    DOEpatents

    Gruen, Dieter M. (Downers Grove, IL); McCauley, Thomas G. (Somerville, MA); Zhou, Dan (Orlando, FL); Krauss, Alan R. (Naperville, IL)

    2003-07-15

    A method for controlling the crystallite size and growth rate of plasma-deposited diamond films. A plasma is established at a pressure in excess of about 55 Torr with controlled concentrations of hydrogen up to about 98% by volume, of unsubstituted hydrocarbons up to about 3% by volume and an inert gas of one or more of the noble gases and nitrogen up to about 98% by volume. The volume ratio of inert gas to hydrogen is preferably maintained at greater than about 4, to deposit a diamond film on a suitable substrate. The diamond film is deposited with a predetermined crystallite size and at a predetermined growth rate.

  7. Conversion of fullerenes to diamond

    DOEpatents

    Gruen, Dieter M. (1324 59th St., Downers Grove, IL 60515)

    1994-01-01

    A method of forming synthetic hydrogen defect free diamond or diamond like films on a substrate. The method involves providing vapor containing fullerene molecules with or without an inert gas, providing a device to impart energy to the fullerene molecules, fragmenting at least in part some of the fullerene molecules in the vapor or energizing the molecules to incipient fragmentation, ionizing the fullerene molecules, impinging ionized fullerene molecules on the substrate to assist in causing fullerene fragmentation to obtain a thickness of diamond on the substrate.

  8. Diamond and Diamond-Like Materials as Hydrogen Isotope Barriers

    SciTech Connect

    Foreman, L.R.; Barbero, R.S.; Carroll, D.W.; Archuleta, T.; Baker, J.; Devlin, D.; Duke, J.; Loemier, D.; Trukla, M.

    1999-07-10

    This is the final report of a two-year, Laboratory Directed Research and Development (LDRD) project at Los Alamos National Laboratory (LANL). The purpose of this project was to develop diamond and diamond-like thin-films as hydrogen isotope permeation barriers. Hydrogen embrittlement limits the life of boost systems which otherwise might be increased to 25 years with a successful non-reactive barrier. Applications in tritium processing such as bottle filling processes, tritium recovery processes, and target filling processes could benefit from an effective barrier. Diamond-like films used for low permeability shells for ICF and HEDP targets were also investigated. Unacceptable high permeabilities for hydrogen were obtained for plasma-CVD diamond-like-carbon films.

  9. Hydrogen plasma and atomic oxygen treatments of diamond: Chemical versus morphological effects

    SciTech Connect

    Shpilman, Z.; Gouzman, I.; Grossman, E.; Akhvlediani, R.; Hoffman, A.

    2008-06-09

    Chemical bonding and morphology of chemical vapor deposited diamond films were studied using high resolution electron energy loss spectroscopy and atomic force microscopy, following hydrogen plasma and atomic oxygen exposures. The hydrogen plasma exposure resulted in preferential etching of nondiamond carbon phases, selective etching of diamond facets, and termination of the diamond surfaces by sp{sup 3}-C-H species. Exposure to atomic oxygen, on the other hand, produced significant chemical changes resulting in oxidized hydrocarbon ill defined top layer, while the morphology of the surface remained almost unchanged.

  10. Competitive graphitization and diamond growth on hot-dip aluminized carbon steel substrate

    NASA Astrophysics Data System (ADS)

    Li, Y. S.; Ma, H. T.; Yang, L. Z.; Zhang, C. Z.; Feng, R. F.; Yang, Q.; Hirose, A.

    2014-09-01

    When carbon steel is directly exposed in 99%H2-1%CH4 gas mixture for plasma enhanced CVD deposition of diamond coatings, an intermediate graphite layer is preferentially formed on the substrate surface, and the substrate is subjected to a severe internal carburization attack. The diamond coatings formed easily delaminate from the steel substrate. Hot dip aluminizing treatment of the carbon steel has markedly promoted diamond nucleation, growth and interfacial adhesion. The formation of graphite intermediate phase on the substrate surface is effectively inhibited and the substrate carburization is also suppressed. The possible mechanism of this transition is discussed based on a series of analytical techniques.

  11. Status review of the science and technology of Ultrananoscrystalline Diamond (UNCD (sup {trademark}) films and application to multifunctional devices.

    SciTech Connect

    Auciello, O.; Sumant, A. V.

    2010-07-01

    This review focuses on a status report on the science and technology of ultrananocrystalline diamond (UNCD) films developed and patented at Argonne National Laboratory. The UNCD material has been developed in thin film form and exhibit multifunctionalities applicable to a broad range of macro to nanoscale multifunctional devices. UNCD thin films are grown by microwave plasma chemical vapor deposition (MPCVD) or hot filament chemical vapor deposition (HFCVD) using new patented Ar-rich/CH4 or H2/CH4 plasma chemistries. UNCD films exhibit a unique nanostructure with 2-5 nm grain size (thus the trade name UNCD) and grain boundaries of 0.4-0.6 nm for plain films, and grain sizes of 7-10 nm and grain boundaries of 2-4 nm when grown with nitrogen introduced in the Ar-rich/CH4 chemistry, to produce UNCD films incorporated with nitrogen, which exhibit electrical conductivity up to semi-metallic level. This review provides a status report on the synthesis of UNCD films via MPCVD and integration with dissimilar materials like oxides for piezoactuated MEMS/NEMS, metal films for contacts, and biological matter for a new generation of biomedical devices and biosensors. A broad range of applications from macro to nanoscale multifunctional devices is reviewed, such as coatings for mechanical pumps seals, field-emission cold cathodes, RF MEMS/NEMS resonators and switches for wireless communications and radar systems, NEMS devices, biomedical devices, biosensors, and UNCD as a platform for developmental biology, involving biological cells growth on the surface. Comparisons with nanocrystalline diamond films and technology are made when appropriate.

  12. Diamond family of nanoparticle superlattices

    NASA Astrophysics Data System (ADS)

    Liu, Wenyan; Tagawa, Miho; Xin, Huolin L.; Wang, Tong; Emamy, Hamed; Li, Huilin; Yager, Kevin G.; Starr, Francis W.; Tkachenko, Alexei V.; Gang, Oleg

    2016-02-01

    Diamond lattices formed by atomic or colloidal elements exhibit remarkable functional properties. However, building such structures via self-assembly has proven to be challenging because of the low packing fraction, sensitivity to bond orientation, and local heterogeneity. We report a strategy for creating a diamond superlattice of nano-objects via self-assembly and demonstrate its experimental realization by assembling two variant diamond lattices, one with and one without atomic analogs. Our approach relies on the association between anisotropic particles with well-defined tetravalent binding topology and isotropic particles. The constrained packing of triangular binding footprints of truncated tetrahedra on a sphere defines a unique three-dimensional lattice. Hence, the diamond self-assembly problem is solved via its mapping onto two-dimensional triangular packing on the surface of isotropic spherical particles.

  13. Method of Dehalogenation using Diamonds

    SciTech Connect

    Farcasiu, Malvina; Kaufman, Phillip B.; Ladner, Edward P.; Anderson, Richard R.

    1999-02-26

    A method for preparing olefins and halogenated olefins is provided comprising contacting halogenated compounds with diamonds for a sufficient time and at a sufficient temperature to convert the halogenated compounds to olefins and halogenated olefins via elimination reactions.

  14. Fabrication of amorphous diamond films

    DOEpatents

    Falabella, S.

    1995-12-12

    Amorphous diamond films having a significant reduction in intrinsic stress are prepared by biasing a substrate to be coated and depositing carbon ions thereon under controlled temperature conditions. 1 fig.

  15. Method of dehalogenation using diamonds

    DOEpatents

    Farcasiu, Malvina (Roslyn Harbor, NY); Kaufman, Phillip B. (Lafayette, LA); Ladner, Edward P. (Pittsburgh, PA); Anderson, Richard R. (Brownsville, PA)

    2000-01-01

    A method for preparing olefins and halogenated olefins is provided comprising contacting halogenated compounds with diamonds for a sufficient time and at a sufficient temperature to convert the halogenated compounds to olefins and halogenated olefins via elimination reactions.

  16. Electron beam activated diamond devices

    SciTech Connect

    Lin, S.H.; Sverdrup, L.H.

    1995-12-31

    Natural type IIa diamond wafers of various thicknesses and active areas were used to construct several electron beam activated diamond devices. The electron bombardment yields a current-voltage characteristic very similar to that of a bipolar transistor. The device on-state resistance is consistent with a simple carrier drift and space charge model. The diamond conduction to bombarding current gain ranges from 1,000 to 3,000 depending upon the target thickness and the bombarding electron energy. Average voltage gradients in diamond targets on the order of a mega-volt per centimeter were obtained. This enabled switch demonstration with delivery of 26kW to a resistive load. Using short duration electron pulses, high-repetition-rate sub-nanosecond switching speed consistent with the circuit time constant is demonstrated.

  17. Improved performance in synthetic diamond neutron detectors: Application to boron neutron capture therapy

    NASA Astrophysics Data System (ADS)

    Almaviva, S.; Marinelli, Marco; Milani, E.; Prestopino, G.; Tucciarone, A.; Verona, C.; Verona-Rinati, G.; Angelone, M.; Pillon, M.

    2010-01-01

    An improved thermal and fast neutrons detector is obtained, modifying a recently proposed multilayered homoepitaxial Chemical Vapor Deposition (CVD) diamond detector (M. Marinelli, et al., Appl. Phys. Lett. 89 (2006) 143509), where a 6LiF layer deposited on the sensing layer was used to convert thermal neutrons into charged particles. By sandwiching this layer between two CVD diamond detectors connected in parallel, a better signal-to-background separation is achieved. This allows to use 10B as converting element, so to realize a detector suitable for Boron Neutron Capture Therapy dosimetry. Also, the doubled detector volume enhances the sensitivity to fast neutrons.

  18. All-Diamond Microelectrodes as Solid State Probes for Localized Electrochemical Sensing.

    PubMed

    Silva, Eduardo L; Gouva, Cristol P; Quevedo, Marcela C; Neto, Miguel A; Archanjo, Braulio S; Fernandes, Antnio J S; Achete, Carlos A; Silva, Rui F; Zheludkevich, Mikhail L; Oliveira, Filipe J

    2015-07-01

    The fabrication of an all-diamond microprobe is demonstrated for the first time. This ME (microelectrode) assembly consists of an inner boron doped diamond (BDD) layer and an outer undoped diamond layer. Both layers were grown on a sharp tungsten tip by chemical vapor deposition (CVD) in a stepwise manner within a single deposition run. BDD is a material with proven potential as an electrochemical sensor. Undoped CVD diamond is an insulating material with superior chemical stability in comparison to conventional insulators. Focused ion beam (FIB) cutting of the apex of the ME was used to expose an electroactive BDD disk. By cyclic voltammetry, the redox reaction of ferrocenemethanol was shown to take place at the BDD microdisk surface. In order to ensure that the outer layer was nonelectrically conductive, a diffusion barrier for boron atoms was established seeking the formation of boron-hydrogen complexes at the interface between the doped and the undoped diamond layers. The applicability of the microelectrodes in localized corrosion was demonstrated by scanning amperometric measurements of oxygen distribution above an Al-Cu-CFRP (Carbon Fiber Reinforced Polymer) galvanic corrosion cell. PMID:26057348

  19. Growth of twin-free heteroepitaxial diamond on Ir/YSZ/Si(111)

    SciTech Connect

    Fischer, M.; Brescia, R.; Gsell, S.; Schreck, M.; Stritzker, B.; Brugger, T.; Greber, T.; Osterwalder, J.

    2008-12-15

    Heteroepitaxial nucleation and growth of twin-free diamond on Ir(111) is reported. The bias enhanced nucleation (BEN) technique was applied in a microwave plasma chemical vapor deposition setup to induce diamond nucleation on the new multilayer stack Ir/YSZ/Si(111). We demonstrate that the gathering of the diamond nuclei in so-called 'domains', a pattern formation process unique for diamond nucleation on iridium, is also present on Ir(111). The 1-2 nm thick carbon layer deposited by BEN does not show any crystalline diamond structures in electron diffraction and high resolution lattice imaging microscopy. In contrast, x-ray photoelectron diffraction (XPD) measurements yield C 1s diffractograms with clear threefold symmetry. The main features are comparable to measurements on diamond (111) single crystal surfaces. The weaker fine structure in the XPD patterns of the BEN layers is attributed to some disorder due to the harsh ion bombardment. However, this ion bombardment did not induce any measurable amount of twinning as deduced from the threefold symmetry. After 3 h diamond growth, the signal due to twins in the x-ray diffraction pole figures is still below the noise level of {approx}1%. Negligible twinning and the low mosaic spread of 0.96 deg. (tilt) and 1.85 deg. (twist) indicate that these films mark a breakthrough toward heteroepitaxial diamond films with (111) orientation. They provide interesting growth substrates, e.g., for phosphorous doped diamond or for the formation of heterojunction devices by deposition of wurtzite-type wide band gap semiconductor materials.

  20. Surface Design and Engineering Toward Wear-Resistant, Self-Lubricating Diamond Films and Coatings

    NASA Technical Reports Server (NTRS)

    Miyoshi, Kazuhisa

    1999-01-01

    The tribological properties of chemical-vapor-deposited (CVD) diamond films vary with the environment, possessing a Jekyll-and-Hyde character. CVD diamond has low coefficient of friction and high wear resistance in air but high coefficient of friction and low wear resistance in vacuum. Improving the tribological functionality of materials (such as achieving low friction and good wear resistance) was an aim of this investigation. Three studies on the surface design, surface engineering, and tribology of CVD diamond have shown that its friction and wear are significantly reduced in ultrahigh vacuum. The main criteria for judging whether diamond films are an effective wear-resistant, self-lubricating material were coefficient of friction and wear rate, which must be less than 0.1 and on the order of 10(exp 6) cu mm/N(dot)m, respectively. In the first study the presence of a thin film (less than 1 micron thick) of amorphous, nondiamond carbon (hydrogenated carbon, also called diamondlike carbon or DLC) on CVD diamond greatly decreased the coefficient of friction and the wear rate. Therefore, a thin DLC film on CVD diamond can be an effective wear-resistant, lubricating coating in ultrahigh vacuum. In the second study the presence of an amorphous, nondiamond carbon surface layer formed on CVD diamond by ion implantation significantly reduced the coefficient of friction and the wear rate in ultrahigh vacuum. Therefore, such surface layers are acceptable for effective self-lubricating, wear-resistant applications of CVD diamond. In the third study CVD diamond in contact with cubic boron nitride exhibited low coefficient of friction in ultra high vacuum. Therefore, this materials combination can provide an effective self-lubricating, wear-resistant couple in ultrahigh vacuum.

  1. Hybrid Group IV Nanophotonic Structures Incorporating Diamond Silicon-Vacancy Color Centers.

    PubMed

    Zhang, Jingyuan Linda; Ishiwata, Hitoshi; Babinec, Thomas M; Radulaski, Marina; Mller, Kai; Lagoudakis, Konstantinos G; Dory, Constantin; Dahl, Jeremy; Edgington, Robert; Soulire, Veronique; Ferro, Gabriel; Fokin, Andrey A; Schreiner, Peter R; Shen, Zhi-Xun; Melosh, Nicholas A; Vu?kovi?, Jelena

    2016-01-13

    We demonstrate a new approach for engineering group IV semiconductor-based quantum photonic structures containing negatively charged silicon-vacancy (SiV(-)) color centers in diamond as quantum emitters. Hybrid diamond-SiC structures are realized by combining the growth of nano- and microdiamonds on silicon carbide (3C or 4H polytype) substrates, with the subsequent use of these diamond crystals as a hard mask for pattern transfer. SiV(-) color centers are incorporated in diamond during its synthesis from molecular diamond seeds (diamondoids), with no need for ion-implantation or annealing. We show that the same growth technique can be used to grow a diamond layer controllably doped with SiV(-) on top of a high purity bulk diamond, in which we subsequently fabricate nanopillar arrays containing high quality SiV(-) centers. Scanning confocal photoluminescence measurements reveal optically active SiV(-) lines both at room temperature and low temperature (5 K) from all fabricated structures, and, in particular, very narrow line widths and small inhomogeneous broadening of SiV(-) lines from all-diamond nanopillar arrays, which is a critical requirement for quantum computation. At low temperatures (5 K) we observe in these structures the signature typical of SiV(-) centers in bulk diamond, consistent with a double lambda. These results indicate that high quality color centers can be incorporated into nanophotonic structures synthetically with properties equivalent to those in bulk diamond, thereby opening opportunities for applications in classical and quantum information processing. PMID:26695059

  2. TOPICAL REVIEW: Direct conversion of graphite into diamond through electronic excited states

    NASA Astrophysics Data System (ADS)

    Nakayama, Hiroyuki; Katayama-Yoshida, Hiroshi

    2003-06-01

    An ab initio total energy calculation has been performed for electronic excited states in diamond and rhombohedral graphite by the full-potential linearized augmented plane wave method within the framework of the local density approximation (LDA). First, calculations for the core-excited state in diamond have been performed to show that the ab initio calculations based on the LDA describe the wavefunctions in the electronic excited states as well as in the ground state quite well. Fairly good coincidence with both experimental data and theoretical prediction has been obtained for the lattice relaxation of the core exciton state. The results of the core exciton state are compared with nitrogen-doped diamond. Next, the structural stability of rhombohedral graphite has been investigated to examine the possibility of the transition into the diamond structure through electronic excited states. While maintaining the rhombohedral symmetry, rhombohedral graphite can be spontaneously transformed to cubic diamond. Total energy in the rhombohedral structure has been calculated as a function of cell volume V, c/a ratio and bond length between layers R. The adiabatic potential energy surfaces for the transition from rhombohedral graphite to diamond in the states after core excitation have been investigated. In core exciton state, the graphite structure is more stable than the diamond. In the valence hole state after the Auger decay process, in contrast, the graphite structure is remarkably unstable compared with the diamond. The conversion into diamond from graphite can be induced spontaneously even at room temperatures due to excited holes. The induced holes decrease the stable interlayer bond length, which can lower the activation energy for buckling displacement of the hexagonal bonds, and the activation energy becomes zero by increasing the concentration of holes up to 0.1/C atom. These results predict that diamond synthesis is possible by a core excitation through the Auger decay process.

  3. A procedure for diamond turning KDP crystals

    SciTech Connect

    Montesanti, R.C.; Thompson, S.L.

    1995-07-07

    A procedure and the equipment necessary for single-point diamond flycutting (loosely referred to as diamond turning) potassium di-hydrogen phosphate (KDP) crystals are described. It is based on current KDP diamond turning activities at the Lawrence Livermore National Laboratory (LLNL), drawing upon knowledge from the Nova crystal finishing development during the 1980`s and incorporating refinements from our efforts during 1995. In addition to describing a step-by-step process for diamond turning KDP, specific discussions are included on the necessary diamond tool geometry and edge sharpness, cutting fluid, and crystal preparation, handling, cleaning, and inspection. The authors presuppose that the reader is already familiar with diamond turning practices.

  4. Biocompatibility of chemical-vapour-deposited diamond.

    PubMed

    Tang, L; Tsai, C; Gerberich, W W; Kruckeberg, L; Kania, D R

    1995-04-01

    The biocompatibility of chemical-vapour-deposited (CVD) diamond surfaces has been assessed. Our results indicate that CVD diamond is as biocompatible as titanium (Ti) and 316 stainless steel (SS). First, the amount of adsorbed and 'denatured' fibrinogen on CVD diamond was very close to that of Ti and SS. Second, both in vitro and in vivo there appears to be less cellular adhesion and activation on the surface of CVD diamond surfaces compared to Ti and SS. This evident biocompatibility, coupled with the corrosion resistance and notable mechanical integrity of CVD diamond, suggests that diamond-coated surfaces may be highly desirable in a number of biomedical applications. PMID:7654876

  5. 3D neutron and X-ray imaging of diamondiferous eclogites, Siberia: Evidence for the secondary origin of diamonds

    NASA Astrophysics Data System (ADS)

    Howarth, G. H.; Pernet-Fisher, J. F.; Sobolev, N. V.; Penumadu, D.; Puplampu, S.; Ketcham, R. A.; Maisano, J. A.; Taylor, D.; Taylor, L. A.

    2013-12-01

    Non-destructive, 3D tomography of diamondiferous eclogites (Siberia) has effectively imaged diamonds and their spatial and textural relationships in situ. A rare suite of 17 diamondiferous eclogites have been analyzed, representing the largest collection outside of Siberia. New innovations in X-ray imaging, in combination with the first effective use of neutron imaging techniques, allow for the identification of secondary metasomatic minerals and the delineation of metasomatic pathways through the eclogites. Combining observations from both imaging techniques provides first-order characterizations and textural descriptions critical for understanding diamond genesis that has heretofore been absent in the literature. Eclogitic diamonds are generally octahedral in morphology, but dodecahedral diamonds are also observed, completely enclosed within the eclogites, implying in situ resorption. Diamonds are never observed in contact with primary minerals - i.e., always surrounded by secondary phases. Primary garnet and clinopyroxene show varying degrees of alteration, discerning the delineation of metasomatic pathways. In general, such pathways are observed as interconnected networks of veinlets, commonly cross-cutting the eclogites. Furthermore, clinopyroxene-rich layers observed show higher degrees of alteration, relative to garnet-rich layers within the same sample, highlighting clinopyroxene as more susceptible to metasomatic alteration than garnet. Diamonds are always observed within such metasomatic pathways. For example, eclogite U-112 contains ~22 macro-diamonds, all of which are contained within an altered clinopyroxene-rich layer. In addition, no spatial relationship is observed between diamonds and sulfide phases. The ubiquitous association of diamonds with metasomatic minerals and pathways provides compelling evidence for the secondary origin of diamonds, in agreement with current interpretations on the origin of diamonds [1,2]. However, diamonds are generally believed to be ancient (1-3 Ga) [3], whereas the metasomatic mineral assemblages observed within eclogites are interpreted to have formed much later, perhaps just prior to incorporation into the rising kimberlite magma [4]. This age dichotomy indicates that either the metasomatic pathways have remained open for billions of years or that diamond growth is significantly younger than previously believed. We suggest that diamond growth may be related to metasomatic fluids circulating just prior to kimberlite emplacement and that diamonds may be significantly younger than previously believed. [1] T. Stachel, J.W. Harris, Ore. Geol. Rev. 34, 5 (2008). [2] Y. Liu et al., Lithos 112S, 1014 (2009). [3] S.B. Shirey, S.H. Richardson, Science 333, 434 (2011). [4] K.C. Misra et al., Contrib. Mineral. Petrol. 146, 696 (2004).

  6. Electron microscopy of gallium nitride growth on polycrystalline diamond

    NASA Astrophysics Data System (ADS)

    Webster, R. F.; Cherns, D.; Kuball, M.; Jiang, Q.; Allsopp, D.

    2015-11-01

    Transmission and scanning electron microscopy were used to examine the growth of gallium nitride (GaN) on polycrystalline diamond substrates grown by metalorganic vapour phase epitaxy with a low-temperature aluminium nitride (AlN) nucleation layer. Growth on unmasked substrates was in the (0001) orientation with threading dislocation densities ?7 109 cm-2. An epitaxial layer overgrowth technique was used to reduce the dislocation densities further, by depositing silicon nitride stripes on the surface and etching the unmasked regions down to the diamond substrate. A re-growth was then performed on the exposed side walls of the original GaN growth, reducing the threading dislocation density in the overgrown regions by two orders of magnitude. The resulting microstructures and the mechanisms of dislocation reduction are discussed.

  7. Diamonds: Exploration, mines and marketing

    NASA Astrophysics Data System (ADS)

    Read, George H.; Janse, A. J. A. (Bram)

    2009-11-01

    The beauty, value and mystique of exceptional quality diamonds such as the 603 carat Lesotho Promise, recovered from the Letseng Mine in 2006, help to drive a multi-billion dollar diamond exploration, mining and marketing industry that operates in some 45 countries across the globe. Five countries, Botswana, Russia, Canada, South Africa and Angola account for 83% by value and 65% by weight of annual diamond production, which is mainly produced by four major companies, De Beers, Alrosa, Rio Tinto and BHP Billiton (BHPB), which together account for 78% by value and 72% by weight of annual diamond production for 2007. During the last twelve years 16 new diamond mines commenced production and 4 re-opened. In addition, 11 projects are in advanced evaluation and may begin operations within the next five years. Exploration for diamondiferous kimberlites was still energetic up to the last quarter of 2008 with most work carried out in Canada, Angola, Democratic Republic of the Congo (DRC) and Botswana. Many kimberlites were discovered but no new economic deposits were outlined as a result of this work, except for the discovery and possible development of the Bunder project by Rio Tinto in India. Exploration methods have benefitted greatly from improved techniques of high resolution geophysical aerial surveying, new research into the geochemistry of indicator minerals and further insights into the formation of diamonds and the relation to tectonic/structural events in the crust and mantle. Recent trends in diamond marketing indicate that prices for rough diamonds and polished goods were still rising up to the last quarter of 2008 and subsequently abruptly sank in line with the worldwide financial crisis. Most analysts predict that prices will rise again in the long term as the gap between supply and demand will widen because no new economic diamond discoveries have been made recently. The disparity between high rough and polished prices and low share prices of publicly traded diamond companies may be due to investors losing patience with the slow pace or absence of new promising discoveries and switching into shares of base metals and fertilizers for agriculture (potash and phosphates).

  8. Evolution of the morphology of diamond particles and mechanism of their growth during the synthesis by chemical vapor deposition

    NASA Astrophysics Data System (ADS)

    Feoktistov, N. A.; Grudinkin, S. A.; Golubev, V. G.; Baranov, M. A.; Bogdanov, K. V.; Kukushkin, S. A.

    2015-11-01

    The evolution of the surface morphology of diamond particles synthesized by chemical vapor deposition (CVD) on silicon substrates has been investigated. It has been found that, when the diamond particles reach a critical size of less than 800 nm, the surface of the diamond faces is transformed. Particles with sizes of no more than 100-300 nm have a well-faceted surface covered by the {100} and {111} faces. An increase in the size of diamond particles leads to a change in the structure of their surface. The surface is covered by the {100} faces surrounded by a disordered phase. With a further increase in the particle size (up to ˜2000 nm), the {100} faces disappear and the diamond particles are covered by high-index faces. A model explaining the evolution of the surface morphology of diamond particles has been proposed. According to this model, during the evolution of diamond particles with an increase in their size, the mechanism of layer-bylayer growth changes to normal growth, which leads to a significant transformation of the entire surface of the diamond particles. The critical size of a two-dimensional nucleus formed on the {100} and {111} faces, at which the change in the growth mechanism begins to occur, has been calculated. A method has been proposed for controlling the morphology of diamond particles during their synthesis.

  9. Study of microwave acoustic attenuation in a multifrequency bulk acoustic wave resonator based on a synthetic diamond single crystal

    NASA Astrophysics Data System (ADS)

    Sorokin, B. P.; Telichko, A. V.; Kvashnin, G. M.; Bormashov, V. S.; Blank, V. D.

    2015-11-01

    Acoustic attenuation in a multifrequency bulk acoustic wave resonator based on the synthetic diamond single crystal is investigated. The acoustic energy loss in a layered piezoelectric Al/AlN/Mo/(001) diamond structure is analyzed. The depth of a damaged surface layer with a thickness of 20-30 nm in diamond after abrasive finishing is estimated using high-energy electron backscattered diffraction and observation of Kikuchi lines. The estimation shows that the acoustic energy loss at a diamond substrate roughness of up to 20 nm, as well as acoustic loss in thin films, is lower than the bulk acoustic attenuation by an order of magnitude and is of no fundamental importance. However, the surface roughness of the piezoelectric AlN film can contribute comparably with the bulk attenuation in the substrate. It is demonstrated that the transition from the Akhiezer to Landau-Rumer regime in diamond occurs at a frequency of ~1 GHz and the phonon-phonon relaxation time is ~1.6 10-10 s. Calculation of acoustic attenuation showed that, although at a frequency of ~1 GHz the acoustic loss in diamond is somewhat higher than in well-known materials with a low attenuation level, the loss in diamond becomes noticeably lower as frequency increases to 8-10 GHz. The obtained maximum experimental value Qf ? 10 1013 Hz (9.5 GHz) makes synthetic diamond promising for microwave acoustoelectronic devices.

  10. Thermionic energy conversion and particle detection using diamond and diamond-like carbon surfaces

    NASA Astrophysics Data System (ADS)

    Smith, Joshua Ryan

    The potential for diamond films were considered for a vacuum thermionic energy conversion device application. First, the effect of field enhancement structures located on the emitter on the output current characteristic was considered. The structures result in Schottky barrier lowering due to enhanced field at the tips and therefore an improved current. Three dimensional simulations were generated and the finite element method was used to calculate the electrostatic potential within the interelectrode space. From these calculations, Schottky barrier lowering enhanced current was determined. The output current was enhanced via two mechanisms: first, the Schottky barrier lowering increased emission at the tips of the structures. Second, an increased surface area contributed to increased emission. These two effects compete with one another to increase the output current, therefore an optimization of the geometric configuration is necessary to maximize output current. A theory was developed to model the electron transport across a vacuum thermionic energy conversion device employing a negative electron affinity material as the emitter electrode. Two specific systems were considered: nitrogen doped diamond with a barrier height of 1.4eV and phosphorus doped diamond with a barrier height of 0.6eV. Results from these calculations were compared against calculations from an ideal model of electron transport where the negative space charge effect is ignored, and a more complete model that included space charge effects. It was shown that, in general, the NEA device outperforms the Langmuir device because the negative electron affinity lowers the boundary condition at the emitter, resulting in electrons emitted with nonzero kinetic energy. It was also shown that for a value of Richardson's constant equal to the theoretical value of 120 Acm-2K-2, the nitrogen doped diamond device outperforms the phosphorus doped diamond device at an interelectrode spacing of 10microm because the phosphorus doped diamond device operates deep in the space charge limited mode. For values of Richardson's constant equal to 10Acm-2K -2 and 1Acm-2K -2, the phosphorus doped diamond device outperforms the phosphorus doped diamond device. It was shown that for certain sets of parameters, it is possible for a TEC to avoid the space charge limited mode and perform equivalent to an ideal device. The Interstellar Boundary Explorer (IBEX) is a satellite which detects energetic neutral atoms in space. The IBEX-Lo detector features a tetrahedral amorphous carbon conversion surface. A procedure was developed to hydrogen terminate the facets making up the conversion surface such that the root mean square roughness did not exceed 0.5nm per 1micro m x 1microm surface area. A remote plasma electron cyclotron resonance chemical vapor deposition technique was used for the hydrogen termination, and ultraviolet photoemission spectroscopy, x-ray photoemission spectroscopy, and atomic force microscopy were used to characterize the surface. After the H-termination, the oxygen peak in the XPS spectrum was not detectable, indicating removal of the adsorbed oxygen layer. Additionally, the vacuum cutoff of the UPS spectrum was lowered, and a large peak appeared near the vacuum cutoff, indicating a negative electron affinity and the presence of hydrogen.

  11. Three-dimensional cathodoluminescence imaging and electron backscatter diffraction: tools for studying the genetic nature of diamond inclusions

    NASA Astrophysics Data System (ADS)

    Wiggers de Vries, D. F.; Drury, M. R.; de Winter, D. A. M.; Bulanova, G. P.; Pearson, D. G.; Davies, G. R.

    2011-04-01

    As a step towards resolving the genesis of inclusions in diamonds, a new technique is presented. This technique combines cathodoluminescence (CL) and electron backscatter diffraction (EBSD) using a focused ion beam-scanning electron microscope (FIB-SEM) instrument with the aim of determining, in detail, the three-dimensional diamond zonation adjacent to a diamond inclusion. EBSD reveals that mineral inclusions in a single diamond have similar crystallographic orientations to the host, within 0.4. The chromite inclusions record a systematic change in Mg# and Cr# from core to the rim of the diamond that corresponds with a ~80C decrease of their formation temperature as established by zinc thermometry. A chromite inclusion, positioned adjacent to a boundary between two major diamond growth zones, is multi-faceted with preferred octahedral and cubic faces. The chromite is surrounded by a volume of non-luminescent diamond (CL halo) that partially obscures any diamond growth structures. The CL halo has apparent crystallographic morphology with symmetrically oriented pointed features. The CL halo is enriched in ~200 ppm Cr and ~80 ppm Fe and is interpreted to have a secondary origin as it overprints a major primary diamond growth structure. The diamond zonation adjacent to the chromite is complex and records both syngenetic and protogenetic features based on current inclusion entrapment models. In this specific case, a syngenetic origin is favoured with the complex form of the inclusion and growth layers indicating changes of growth rates at the diamond-chromite interface. Combined EBSD and 3D-CL imaging appears an extremely useful tool in resolving the ongoing discussion about the timing of inclusion growth and the significance of diamond inclusion studies.

  12. Combined single-crystalline and polycrystalline CVD diamond substrates for diamond electronics

    SciTech Connect

    Vikharev, A. L. Gorbachev, A. M.; Dukhnovsky, M. P.; Muchnikov, A. B.; Ratnikova, A. K.; Fedorov, Yu. Yu.

    2012-02-15

    The fabrication of diamond substrates in which single-crystalline and polycrystalline CVD diamond form a single wafer, and the epitaxial growth of diamond films on such combined substrates containing polycrystalline and (100) single-crystalline CVD diamond regions are studied.

  13. Diamond Blackfan Anemia, Genetics, and You

    MedlinePLUS

    Diamond Blackfan Anemia, Genetics, and You Q0 Is Diamond Blackfan Anemia (DBA) a genetic disorder? A Yes, ... A The body’s failure to make enough red blood cells has been linked to genetic mutations in ...

  14. Carbon carbon detection: Diamond detectors and AMS

    NASA Astrophysics Data System (ADS)

    Wilcken, K. M.; Freeman, S. P. H. T.; Dougans, A.; Xu, S.; Galbiati, A.; Oliver, K.

    2010-04-01

    14C ions (290 keV) have been detected with chemically vapour deposited diamond. Potential benefits of diamond detectors are radiation hardness, high charge collection and very fast response time/high bandwidth.

  15. Self-assembled GaN nanowires on diamond.

    PubMed

    Schuster, Fabian; Furtmayr, Florian; Zamani, Reza; Magn, Cesar; Morante, Joan R; Arbiol, Jordi; Garrido, Jose A; Stutzmann, Martin

    2012-05-01

    We demonstrate the nucleation of self-assembled, epitaxial GaN nanowires (NWs) on (111) single-crystalline diamond without using a catalyst or buffer layer. The NWs show an excellent crystalline quality of the wurtzite crystal structure with m-plane faceting, a low defect density, and axial growth along the c-axis with N-face polarity, as shown by aberration corrected annular bright-field scanning transmission electron microscopy. X-ray diffraction confirms single domain growth with an in-plane epitaxial relationship of (10 ?10)(GaN) [parallel] (01 ?1)(Diamond) as well as some biaxial tensile strain induced by thermal expansion mismatch. In photoluminescence, a strong and sharp excitonic emission reveals excellent optical properties superior to state-of-the-art GaN NWs on silicon substrates. In combination with the high-quality diamond/NW interface, confirmed by high-resolution transmission electron microscopy measurements, these results underline the potential of p-type diamond/n-type nitride heterojunctions for efficient UV optoelectronic devices. PMID:22506554

  16. Diamond radiation detectors I. Detector properties for IIa diamond

    SciTech Connect

    Kania, D.R.

    1997-05-16

    The detector properties and carrier dynamics of type IIa diamonds are reasonably well understood. The trends in the electron and hole mobilities have been characterized as a function of temperature, impurity content, electric field and carrier density. The carrier lifetimes are coupled through the nitrogen impurity. This leaves us with typical samples with collection distances of 20 to 50 micrometers. The detailed dynamics of the carriers can be modeled using a rate equation analysis. Much progress has been made in understanding the detector properties of diamond, but continued progress has been limited by the geologic processes used to make the material, for example sample size and no synthesis control. CVD diamond promises to eliminate these restrictions.

  17. Dynamic consolidation of diamond powder into polycrystalline diamond

    NASA Astrophysics Data System (ADS)

    Potter, David K.; Ahrens, Thomas J.

    1987-08-01

    The formation of a polycrystalline solid compact, by fusing an initially porous aggregate of diamond crystals under dynamic shock pressure (7.5-18 GPa), is shown to depend critically on the size of the initial crystals. Porous aggregates of 100-150 micron diameter crystals upon shock compaction produced compacts. These exhibited pronounced fracturing of the individual crystals and showed no evidence of fusion. Aggregates consisting of ultrafine crystals also exhibited minimal consolidation. However, samples composed of crystals in the range 4-8 microns produced strong fused compacts of polycrystalline diamond. A model calculation indicates that at 10 GPa less than 0.07 mass fraction of the diamond powder can be melted and this molten material is quenched in 0.8 ns for 8-micron-diam crystals.

  18. Electron microscopic evidence for a tribologically induced phase transformation as the origin of wear in diamond

    SciTech Connect

    Zhang, Xinyi; Schneider, Reinhard; Müller, Erich; Gerthsen, Dagmar; Mee, Manuel; Meier, Sven; Gumbsch, Peter

    2014-02-14

    Tribological testing of a coarse-grained diamond layer, deposited by plasma-enhanced chemical vapor deposition, was performed on a ring-on-ring tribometer with a diamond counterpart. The origin of the wear of diamond and of the low friction coefficient of 0.15 was studied by analyzing the microstructure of worn and unworn regions by transmission and scanning electron microscopy. In the worn regions, the formation of an amorphous carbon layer with a thickness below 100 nm is observed. Electron energy loss spectroscopy of the C-K ionization edge reveals the transition from sp{sup 3}-hybridized C-atoms in crystalline diamond to a high fraction of sp{sup 2}-hybridized C-atoms in the tribo-induced amorphous C-layer within a transition region of less than 5 nm thickness. The mechanically induced phase transformation from diamond to the amorphous phase is found to be highly anisotropic which is clearly seen at a grain boundary, where the thickness of the amorphous layer above the two differently oriented grains abruptly changes.

  19. Genesis of Diamond-bearing and Diamond-free Podiform Chromitites in the Luobusa Ophiolite, Tibet

    NASA Astrophysics Data System (ADS)

    Yang, J.; Xiong, F.; Xu, X.; Robinson, P. T.; Dilek, Y.; Griffin, W. L.

    2014-12-01

    Micro-diamonds, moissanite and many highly reduced minerals, such as native Fe, Cr, Ni, Si, Al, and metallic alloys, have been reported previously from podiform chromitites and peridotites of the Luobusa ophiolite in the eastern segment of the Yarlung-Zangbo suture of southern Tibet.. Similar mineral associations have now been confirmed in mantle peridotites or chromitites of 11 other ophiolites in 5 orogenic belts, in Tibet, Myanmar, North China and the Polar Urals. However, detailed studies of the Luobusa ophiolite show that not all chromitites contain these UHP and highly reduced minerals. Diamond-bearing chromitites are chiefly massive bodies composed of over 95 modal% magnesiochromite with Cr#s [100Cr/(Cr+Al)] of 77-83 and Mg#s [100Mg/(Mg+Fe)] of 71-82. Most of these bodies have sharp contacts with the host harzburgites and are only rarely enclosed in dunite envelopes. Many magnesiochromite grains in the massive chromitites contain inclusions of forsterite and pyroxene. Forsterite inclusions have Fo numbers of 97-99 and NiO contents of 1.11-1.29 wt%. Mg#s of clinopyroxene inclusions are 96-98 and those of orthopyroxene are 96-97. X-ray studies show that the olivine inclusions have very small unit cells and short cation-oxygen bond distances, suggesting crystallization at high pressure. In contrast, diamond-free chromitites typically occur as layers within thick dunite sequences or as irregular patches surrounded by dunite envelopes. They consist of variable proportions of magnesiochromite (Cr# = 76-78; Mg# = 58-61) and olivine, and have banded, nodular and disseminated textures. The dunite envelopes consist chiefly of granular olivine with a few relatively large, amoeboidal grains of magnesiochromite, and typically grade into the host peridotites with increasing pyroxene. Unlike those in the massive ores, magnesiochromite grains in nodular and disseminated chromitites lack pyroxene inclusions, and their olivine inclusions have relatively low Fo (94-96) and NiO (0.35-0.58 wt%). We propose that the diamond-bearing chromitite ores formed within the deeper parts of the upper mantle and were emplaced at an oceanic spreading ridge, whereas the diamond-free chromitites formed at shallow levels by melt/rock reaction, most likely in a SSZ environment.

  20. A new method for fabrication of diamond-dust blocking filters

    NASA Technical Reports Server (NTRS)

    Collard, H. R.; Hogan, R. C.

    1986-01-01

    Thermal embedding of diamond dust onto a polyethylene-coated Al plate has been used to make a blocking filter for FIR applications. The Al plate is sandwiched between two Mylar 'blankets' and the air between the layers is removed by means of a small vacuum pump. After the polyethylene is heated and softened, the diamond dust is applied to the polyethylene coating using a brush. The optimum diamond dust grain sizes corresponding to polyethylene layer thicknesses of 9-12 microns are given in a table, and the application of the blocking filter to spectrometric measurements in the FIR is described. An exploded view diagram of the layered structure of the blocking filter is provided.

  1. Multivariable study on homoepitaxial growth of diamond on planar and non-planar substrates

    NASA Astrophysics Data System (ADS)

    Samudrala, Gopi Krishna

    In this dissertation research, the roles of three basic parameters in homoepitaxial diamond growth by microwave plasma chemical vapor deposition on planar (type Ib yellow diamond plates) and non-planar (type Ia brilliant cut natural diamonds) substrates have been investigated. Isotopically enriched carbon-13 methane gas has been utilized in the experiments as the source of carbon to clearly distinguish the grown diamond layer from the underlying substrate using Raman spectroscopy. Nitrogen showed a catalytic effect in the growth of diamond on diamond anvil substrates. In the standard H2/O2/N2/ 13CH4 feed gas mixture, when nitrogen was varied between 0 to 3500 parts per million (ppm), an optimum value of 1250 ppm nitrogen resulted in the highest growth rate and smoothest surface morphology. This particular chemistry resulted in 100% success rate during the fabrication of designer diamond anvils. No such optimum value in nitrogen concentration was found for planar substrates indicating a strong dependence of diamond growth rate on the substrate geometry. On planar substrates, the effects of nitrogen concentration, methane concentration and substrate temperatures were studied independently by varying each parameter carefully over a broad range. Dramatic changes in surface morphologies and growth rates were observed by optical and atomic force microscopy. The nitrogen incorporation in carbon-13 diamond layers was monitored through photoluminescence spectroscopy of nitrogen--vacancy complexes. A twentyfold increase in growth rate has been reported as a result of this research. An optimum substrate temperature of 1050 C resulted in the highest growth rate when 2% CH 4/H2 was used in feed gas mixture. Use of high methane concentration in the feed gas mixture resulted in diamond films where twinning on the surface was completely absent. Aggressive incorporation of nitrogen in CVD diamond has been observed at substrate temperatures above 1050 C indicating that species such as HCN, CN and NHX play an active role on the surface at those temperatures. The optimum temperature has been observed to shift to higher values as the C/N ratio in the feed gas mixture increased. The roles of various growth parameters in high growth rate and high quality homoepitaxial diamond growth are discussed in this thesis.

  2. Magnetic properties of carbonado diamonds

    NASA Astrophysics Data System (ADS)

    Fitzgerald, C. B.; Venkatesan, M.; Douvalis, A. P.; Coey, J. M. D.

    2006-05-01

    Carbonados are porous polycrystalline diamonds of uncertain origin, which are found at locations in Bahia (NE Brazil) and in the Central African Republic. Their combination of extreme hardness and toughness is ideal for drilling and cutting tools. A variety of elements including Fe, Ni, Cu and Ag are associated with the diamonds. Following a suggestion that Mn-doped diamond may be intrinsically ferromagnetic, we have analysed six samples from Brazil which show ferromagnetic moments of up to 3 A m 2 kg -1, which is reduced by acid leaching. X-ray diffraction on the crushed powder showed a cubic diamond structure, with no secondary phases visible. Scanning electron microscopy shows an inhomogeneous distribution of heavy metals and Mssbauer spectroscopy indicates that iron is present as native iron. We find no evidence from the carbonados for the existence of transition-metal doped ferromagnetic carbon. The intrinsic diamagnetic susceptibility of carbonados is -4.510 -9 m 3 kg -1, similar to the accepted value for diamond,-510 -9 m 3 kg -1.

  3. Ohmic contacts to semiconducting diamond

    NASA Astrophysics Data System (ADS)

    Zeidler, James R.; Taylor, M. J.; Zeisse, Carl R.; Hewett, C. A.; Delahoussaye, Paul R.

    1990-10-01

    Work was carried out to improve the electron beam evaporation system in order to achieve better deposited films. The basic system is an ion pumped vacuum chamber, with a three-hearth, single-gun e-beam evaporator. Four improvements were made to the system. The system was thoroughly cleaned and new ion pump elements, an e-gun beam adjust unit, and a more accurate crystal monitor were installed. The system now has a base pressure of 3 X 10(exp -9) Torr, and can easily deposit high-melting-temperature metals such as Ta with an accurately controlled thickness. Improved shadow masks were also fabricated for better alignment and control of corner contacts for electrical transport measurements. Appendices include: A Thermally Activated Solid State Reaction Process for Fabricating Ohmic Contacts to Semiconducting Diamond; Tantalum Ohmic Contacts to Diamond by a Solid State Reaction Process; Metallization of Semiconducting Diamond: Mo, Mo/Au, and Mo/Ni/Au; Specific Contact Resistance Measurements of Ohmic Contracts to Diamond; and Electrical Activation of Boron Implanted into Diamond.

  4. Diamond-integrated optomechanical circuits.

    PubMed

    Rath, Patrik; Khasminskaya, Svetlana; Nebel, Christoph; Wild, Christoph; Pernice, Wolfram H P

    2013-01-01

    Diamond offers unique material advantages for the realization of micro- and nanomechanical resonators because of its high Young's modulus, compatibility with harsh environments and superior thermal properties. At the same time, the wide electronic bandgap of 5.45 eV makes diamond a suitable material for integrated optics because of broadband transparency and the absence of free-carrier absorption commonly encountered in silicon photonics. Here we take advantage of both to engineer full-scale optomechanical circuits in diamond thin films. We show that polycrystalline diamond films fabricated by chemical vapour deposition provide a convenient wafer-scale substrate for the realization of high-quality nanophotonic devices. Using free-standing nanomechanical resonators embedded in on-chip Mach-Zehnder interferometers, we demonstrate efficient optomechanical transduction via gradient optical forces. Fabricated diamond resonators reproducibly show high mechanical quality factors up to 11,200. Our low cost, wideband, carrier-free photonic circuits hold promise for all-optical sensing and optomechanical signal processing at ultra-high frequencies. PMID:23575694

  5. Diamond-integrated optomechanical circuits

    NASA Astrophysics Data System (ADS)

    Rath, Patrik; Khasminskaya, Svetlana; Nebel, Christoph; Wild, Christoph; Pernice, Wolfram H. P.

    2013-04-01

    Diamond offers unique material advantages for the realization of micro- and nanomechanical resonators because of its high Young’s modulus, compatibility with harsh environments and superior thermal properties. At the same time, the wide electronic bandgap of 5.45 eV makes diamond a suitable material for integrated optics because of broadband transparency and the absence of free-carrier absorption commonly encountered in silicon photonics. Here we take advantage of both to engineer full-scale optomechanical circuits in diamond thin films. We show that polycrystalline diamond films fabricated by chemical vapour deposition provide a convenient wafer-scale substrate for the realization of high-quality nanophotonic devices. Using free-standing nanomechanical resonators embedded in on-chip Mach-Zehnder interferometers, we demonstrate efficient optomechanical transduction via gradient optical forces. Fabricated diamond resonators reproducibly show high mechanical quality factors up to 11,200. Our low cost, wideband, carrier-free photonic circuits hold promise for all-optical sensing and optomechanical signal processing at ultra-high frequencies.

  6. Ultimate Atomic Bling: Nanotechnology of Diamonds

    SciTech Connect

    Dahl, Jeremy

    2010-05-25

    Diamonds exist in all sizes, from the Hope Diamond to minuscule crystals only a few atoms across. The smallest of these diamonds are created naturally by the same processes that make petroleum. Recently, researchers discovered that these 'diamondoids' are formed in many different structural shapes, and that these shapes can be used like LEGO blocks for nanotechnology. This talk will discuss the discovery of these nano-size diamonds and highlight current SLAC/Stanford research into their applications in electronics and medicine.

  7. Nanocrystalline diamond synthesized from C60

    SciTech Connect

    Dubrovinskaia, N.; Dubrovinsky, L.; Langehorst, F.; Jacobsen, S.; Liebske, C.

    2010-11-30

    A bulk sample of nanocrystalline cubic diamond with crystallite sizes of 5-12 nm was synthesized from fullerene C{sub 60} at 20(1) GPa and 2000 C using a multi-anvil apparatus. The new material is at least as hard as single crystal diamond. It was found that nanocrystalline diamond at high temperature and ambient pressure kinetically is more stable with respect to graphitization than usual diamonds.

  8. Diamond photodiodes for x-ray application

    SciTech Connect

    Distel, James R; Smedley, John; Keister, Jeffrey W; Muller, Erik; Jordan - Sweet, Jean; Bohon, Jen; Dong, Bin

    2009-01-01

    Single crystal high purity CVD diamonds have been metallized and calibrated as photodiodes at the National Synchrotron Light Source (NSLS). Current mode responsivity measurements have been made over a wide range (0.2-28 keV) of photon energies across several beamlines. Linear response has been achieved over ten orders of magnitude of incident flux, along with uniform spatial response. A simple model of responsivity has been used to describe the results, yielding a value of 13.3 {+-} 0.5 eV for the mean pair creation energy. The responsivity vs. photon energy data show a dip for photon energies near the carbon edge (284 eV), indicating incomplete charge collection for carriers created less than one micron from the metallized layer.

  9. Diamond and diamond-like films for transportation applications

    SciTech Connect

    Perez, J.M.

    1993-01-01

    This section is a compilation of transparency templates which describe the goals of the Office of Transportation Materials (OTM) Tribology Program. The positions of personnel on the OTM are listed. The role and mission of the OTM is reviewed. The purpose of the Tribology Program is stated to be `to obtain industry input on program(s) in tribology/advanced lubricants areas of interest`. The objective addressed here is to identify opportunities for cost effective application of diamond and diamond-like carbon in transportation systems.

  10. 46 CFR 45.33 - Diamond.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... 46 Shipping 2 2010-10-01 2010-10-01 false Diamond. 45.33 Section 45.33 Shipping COAST GUARD, DEPARTMENT OF HOMELAND SECURITY (CONTINUED) LOAD LINES GREAT LAKES LOAD LINES Load Line Marks § 45.33 Diamond. (a) Each vessel must be marked with the diamond mark described in figure 2 of § 45.35 amidships...

  11. 46 CFR 45.33 - Diamond.

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ... 46 Shipping 2 2014-10-01 2014-10-01 false Diamond. 45.33 Section 45.33 Shipping COAST GUARD, DEPARTMENT OF HOMELAND SECURITY (CONTINUED) LOAD LINES GREAT LAKES LOAD LINES Load Line Marks § 45.33 Diamond. (a) Each vessel must be marked with the diamond mark described in figure 2 of § 45.35 amidships...

  12. 46 CFR 45.33 - Diamond.

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ... 46 Shipping 2 2012-10-01 2012-10-01 false Diamond. 45.33 Section 45.33 Shipping COAST GUARD, DEPARTMENT OF HOMELAND SECURITY (CONTINUED) LOAD LINES GREAT LAKES LOAD LINES Load Line Marks § 45.33 Diamond. (a) Each vessel must be marked with the diamond mark described in figure 2 of § 45.35 amidships...

  13. 46 CFR 45.33 - Diamond.

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ... 46 Shipping 2 2013-10-01 2013-10-01 false Diamond. 45.33 Section 45.33 Shipping COAST GUARD, DEPARTMENT OF HOMELAND SECURITY (CONTINUED) LOAD LINES GREAT LAKES LOAD LINES Load Line Marks § 45.33 Diamond. (a) Each vessel must be marked with the diamond mark described in figure 2 of § 45.35 amidships...

  14. 46 CFR 45.33 - Diamond.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... 46 Shipping 2 2011-10-01 2011-10-01 false Diamond. 45.33 Section 45.33 Shipping COAST GUARD, DEPARTMENT OF HOMELAND SECURITY (CONTINUED) LOAD LINES GREAT LAKES LOAD LINES Load Line Marks § 45.33 Diamond. (a) Each vessel must be marked with the diamond mark described in figure 2 of § 45.35 amidships...

  15. Diamond Drilling Specification Manual and Course Outline.

    ERIC Educational Resources Information Center

    British Columbia Dept. of Education, Victoria.

    This publication presents the standards required of a person practicing diamond drilling in western Canada and provides an outline for teaching the skills and knowledge. It is divided into two parts. The Diamond Drilling Specification Manual establishes the levels of skill and knowledge required in the four certified levels of diamond drilling.…

  16. Ultratough single crystal boron-doped diamond

    DOEpatents

    Hemley, Russell J [Carnegie Inst. for Science, Washington, DC ; Mao, Ho-Kwang [Carnegie Inst. for Science, Washington, DC ; Yan, Chih-Shiue [Carnegie Inst. for Science, Washington, DC ; Liang, Qi [Carnegie Inst. for Science, Washington, DC

    2015-05-05

    The invention relates to a single crystal boron doped CVD diamond that has a toughness of at least about 22 MPa m.sup.1/2. The invention further relates to a method of manufacturing single crystal boron doped CVD diamond. The growth rate of the diamond can be from about 20-100 .mu.m/h.

  17. Chemical Erosion of Diamond-Coated Graphite under Low-Energy Hydrogen Atom Irradiation

    NASA Astrophysics Data System (ADS)

    Takeguchi, Yuji; Kyo, Masaaki; Uesugi, Yoshihiko; Tanaka, Yasunori; Masuzaki, Suguru

    We experimentally investigate chemical erosion of polycrystalline graphite targets coated with boron-doped diamond (BDD) using an induction plasma containing low-energy, high-atomic-hydrogen flux. Chemical erosion is drastically suppressed by diamond coating the graphite target. The chemical sputtering yield for the BDD layer is about two orders of magnitude lower than that for the graphite target. After exposure in low-temperature hydrogen plasmas, however, the surface morphology of the BDD target is significantly modified. The polycrystalline diamond is eroded near the grain boundary, and many pits with diamond-like shapes are observed on the crystal surface. X-ray photoelectron spectroscopy and Raman spectroscopy reveal that the hydrogen atoms penetrate into the BDD target to a depth of at least 20 nm.

  18. Diamond Composite Films for Protective Coatings on Metals and Method of Formation

    NASA Technical Reports Server (NTRS)

    Ong, Tiong P. (Inventor); Shing, Yuh-Han (Inventor)

    1997-01-01

    Composite films consisting of diamond crystallites and hard amorphous films such as diamond-like carbon, titanium nitride, and titanium oxide are provided as protective coatings for metal substrates against extremely harsh environments. A composite layer having diamond crystallites and a hard amorphous film is affixed to a metal substrate via an interlayer including a bottom metal silicide film and a top silicon carbide film. The interlayer is formed either by depositing metal silicide and silicon carbide directly onto the metal substrate, or by first depositing an amorphous silicon film, then allowing top and bottom portions of the amorphous silicon to react during deposition of the diamond crystallites, to yield the desired interlayer structure.

  19. YBa2Cu3O7 thin films on nanocrystalline diamond films for HTSC bolometer

    NASA Technical Reports Server (NTRS)

    Cui, G.; Beetz, C. P., Jr.; Boerstler, R.; Steinbeck, J.

    1993-01-01

    Superconducting YBa2Cu3O(7-x) films on nanocrystalline diamond thin films have been fabricated. A composite buffer layer system consisting of diamond/Si3N4/YSZ/YBCO was explored for this purpose. The as-deposited YBCO films were superconducting with Tc of about 84 K and a relatively narrow transition width of about 8 K. SEM cross sections of the films showed very sharp interfaces between diamond/Si3N4 and between Si3N4/YSZ. The deposited YBCO film had a surface roughness of about 1000 A, which is suitable for high-temperature superconductive (HTSC) bolometer fabrication. It was also found that preannealing of the nanocrystalline diamond thin films at high temperature was very important for obtaining high-quality YBCO films.

  20. Diamond nanowires for highly sensitive matrix-free mass spectrometry analysis of small molecules

    NASA Astrophysics Data System (ADS)

    Coffinier, Yannick; Szunerits, Sabine; Drobecq, Herv; Melnyk, Oleg; Boukherroub, Rabah

    2011-12-01

    This paper reports on the use of boron-doped diamond nanowires (BDD NWs) as an inorganic substrate for matrix-free laser desorption/ionization mass spectrometry (LDI-MS) analysis of small molecules. The diamond nanowires are prepared by reactive ion etching (RIE) with oxygen plasma of highly boron-doped (the boron level is 1019 B cm-3) or undoped nanocrystalline diamond substrates. The resulting diamond nanowires are coated with a thin silicon oxide layer that confers a superhydrophilic character to the surface. To minimize droplet spreading, the nanowires were chemically functionalized with octadecyltrichlorosilane (OTS) and then UV/ozone treated to reach a final water contact angle of 120. The sub-bandgap absorption under UV laser irradiation and the heat confinement inside the nanowires allowed desorption/ionization, most likely via a thermal mechanism, and mass spectrometry analysis of small molecules. A detection limit of 200 zeptomole for verapamil was demonstrated.

  1. Diamond nanowires for highly sensitive matrix-free mass spectrometry analysis of small molecules.

    PubMed

    Coffinier, Yannick; Szunerits, Sabine; Drobecq, Herv; Melnyk, Oleg; Boukherroub, Rabah

    2012-01-01

    This paper reports on the use of boron-doped diamond nanowires (BDD NWs) as an inorganic substrate for matrix-free laser desorption/ionization mass spectrometry (LDI-MS) analysis of small molecules. The diamond nanowires are prepared by reactive ion etching (RIE) with oxygen plasma of highly boron-doped (the boron level is 10(19) B cm(-3)) or undoped nanocrystalline diamond substrates. The resulting diamond nanowires are coated with a thin silicon oxide layer that confers a superhydrophilic character to the surface. To minimize droplet spreading, the nanowires were chemically functionalized with octadecyltrichlorosilane (OTS) and then UV/ozone treated to reach a final water contact angle of 120. The sub-bandgap absorption under UV laser irradiation and the heat confinement inside the nanowires allowed desorption/ionization, most likely via a thermal mechanism, and mass spectrometry analysis of small molecules. A detection limit of 200 zeptomole for verapamil was demonstrated. PMID:22080363

  2. Impact of nucleation density on thermal resistance near diamond-substrate boundaries

    SciTech Connect

    Touzelbaev, M.N.; Goodson, K.E.

    1996-12-31

    Existing theory cannot account for the experimentally-observed thermal boundary resistance between deposited layers and substrates at room temperature. This is due to microstructural disorder in the deposited film within tens of nanometers of the interface. This work develops a model for the resulting thermal resistance near diamond-substrate interfaces, where the best deposition processes continue to yield high concentrations of amorphous inclusions and nanocrystalline material. The model relies on phonon transport theory and a novel subdivision of the near-interfacial region, which shows that the resistance is governed by the number of diamond nucleation sites per unit substrate area, i.e. The nucleation density. The predictions are consistent with experimental data for diamond-silicon interfaces and indicate that the resistance reaches a minimum for a nucleation density near 10{sup 10} cm{sup {minus}2}. This work facilitates the development microstructures that benefit more strongly from the excellent thermal-conduction properties of diamond.

  3. Theory of impurities in diamond

    NASA Astrophysics Data System (ADS)

    Briddon, P. R.; Jones, R.

    1993-04-01

    Recent theoretical investigations into the structure and properties of two major impurities in diamond are reviewed. Particular attention is placed on nitrogen (N), the dominant impurity in natural type I diamond. It is shown how calculations of the structure, electronic and vibrational properties of nitrogen-containing defects have shed light on a variety of experimental information gathered in the last 50 years. Problems considered include nitrogen as an isolated impurity, in the A and B centres (complexes believed to contain two and four nitrogen atoms, respectively) and in the platelet defects which may contain thousands of N atoms. Finally, the present understanding of hydrogen, a major impurity in type II diamond, is reviewed.

  4. The diamond nano-balance.

    PubMed

    Williams, Oliver A; Mortet, Vincent; Daenen, Michael; Haenen, Ken

    2009-06-01

    Detecting nano-gram quantities of analyte in the liquid or gas phase is crucial for pathogen detection, antigen/DNA detection, water monitoring, electrochemical analysis, and many other bio-electrochemical applications. The quartz crystal microbalance (QCM) has become a significant sensor for both liquid and gas phase graviometry due to its high sensitivity, robustness, ease of use and simultaneous electrochemistry capabilities. One key factor plaguing the QCM in most sensor applications is the stability of the surface functionalisation. Diamond offers the most stable surface for functionalisation, the widest electrochemical window and the lowest noise floor. Unfortunately the growth of diamond on QCMs is problematic due to the low curie point of quartz, resulting in the loss of the piezoelectric properties of the QCM. In this work the replacement of the quartz with a high temperature stable piezoelectric material is proposed, and a nanocrystalline diamond coated sensor demonstrated. PMID:19504872

  5. Diamond-silicon carbide composite

    DOEpatents

    Qian, Jiang; Zhao, Yusheng

    2006-06-13

    Fully dense, diamond-silicon carbide composites are prepared from ball-milled microcrystalline diamond/amorphous silicon powder mixture. The ball-milled powder is sintered (P=5–8 GPa, T=1400K–2300K) to form composites having high fracture toughness. A composite made at 5 GPa/1673K had a measured fracture toughness of 12 MPa.dot.m1/2. By contrast, liquid infiltration of silicon into diamond powder at 5 GPa/1673K produces a composite with higher hardness but lower fracture toughness. X-ray diffraction patterns and Raman spectra indicate that amorphous silicon is partially transformed into nanocrystalline silicon at 5 GPa/873K, and nanocrystalline silicon carbide forms at higher temperatures.

  6. Diamond-silicon carbide composite

    DOEpatents

    Qian, Jiang; Zhao, Yusheng

    2006-06-13

    Fully dense, diamond-silicon carbide composites are prepared from ball-milled microcrystalline diamond/amorphous silicon powder mixture. The ball-milled powder is sintered (P=58 GPa, T=1400K2300K) to form composites having high fracture toughness. A composite made at 5 GPa/1673K had a measured fracture toughness of 12 MPa.dot.m1/2. By contrast, liquid infiltration of silicon into diamond powder at 5 GPa/1673K produces a composite with higher hardness but lower fracture toughness. X-ray diffraction patterns and Raman spectra indicate that amorphous silicon is partially transformed into nanocrystalline silicon at 5 GPa/873K, and nanocrystalline silicon carbide forms at higher temperatures.

  7. Diamond-structured photonic crystals.

    PubMed

    Maldovan, Martin; Thomas, Edwin L

    2004-09-01

    Certain periodic dielectric structures can prohibit the propagation of light for all directions within a frequency range. These 'photonic crystals' allow researchers to modify the interaction between electromagnetic fields and dielectric media from radio to optical wavelengths. Their technological potential, such as the inhibition of spontaneous emission, enhancement of semiconductor lasers, and integration and miniaturization of optical components, makes the search for an easy-to-craft photonic crystal with a large bandgap a major field of study. This progress article surveys a collection of robust complete three-dimensional dielectric photonic-bandgap structures for the visible and near-infrared regimes based on the diamond morphology together with their specific fabrication techniques. The basic origin of the complete photonic bandgap for the 'champion' diamond morphology is described in terms of dielectric modulations along principal directions. Progress in three-dimensional interference lithography for fabrication of near-champion diamond-based structures is also discussed. PMID:15343291

  8. Design and fabrication of nano-scale single crystal diamond cutting tool by focused ion beam (FIB) milling

    NASA Astrophysics Data System (ADS)

    Baek, Seung-Yub

    2015-07-01

    Micro/nanoscale diamond cutting tools used in ultra-precision machining can be fabricated by precision grinding, but it is hard to fabricate a tool with a nanometric cutting edge and complex configurations. High-precision geometry accuracy and special shapes for microcutting tools with sharp edges can be achieved by FIB milling. Because the FIB milling method induces much smaller machining stress compared with conventional precision grinding methods. In this study, the FIB milling characteristics of single-crystal diamond were investigated, along with methods for decreasing the FIB-induced damage on diamond tools. Lift-off process method and Pt(Platinum) coating process method with FIB milling were investigated to reduce the damage layer on diamond substrate and quadrilateral-shaped single-crystal diamond cutting tool with cutting edge width under 500 nm were obtained.

  9. Development of Designer Diamond Technology for High Pressure High Temperature Experiments in Support of Stockpile Stewardship Program

    SciTech Connect

    Vohra, Yogesh, K.

    2009-10-28

    The role of nitrogen in the fabrication of designer diamond was systematically investigated by adding controlled amount of nitrogen in hydrogen/methane/oxygen plasma. This has led to a successful recipe for reproducible fabrication of designer diamond anvils for high-pressure high-temperature research in support of stockpile stewardship program. In the three-year support period, several designer diamonds fabricated with this new growth chemistry were utilized in high-pressure experiments at UAB and Lawrence Livermore National Laboratory. The designer diamond anvils were utilized in high-pressure studies on heavy rare earth metals, high pressure melting studies on metals, and electrical resistance measurements on iron-based layered superconductors under high pressures. The growth chemistry developed under NNSA support can be adapted for commercial production of designer diamonds.

  10. Diamond, Carbide and Carbonate Planets

    NASA Astrophysics Data System (ADS)

    Unterborn, C. T.; Panero, W. R.; Kabbes, J. E.

    2011-12-01

    More than five hundred planets have been discovered outside of our solar system to date, yet very little is known of their internal compositions and subsequent mineralogy. The principal factors in determining planetary mineralogy are nebula composition, pressure, temperature and oxygen fugacity. While work has been done on determining the stable minerals with respect to pressure and temperature in these planets, very little has been done in determining the oxygen fugacity and the resulting geology. Planetary formation models propose a new kind of planet: carbon super-Earths. The planets have very high C/Fe ratios and are unlike any in our solar system. The interplay between carbon, oxygen and iron in these planets provide an end-member test of the effects of oxygen fugacity on carbon mineralogy as well as the potential for carbon entering Earth's core as iron-carbide. We combine experimental diamond anvil cell x-ray diffraction and Raman spectroscopy with thermochemical modeling to determine the oxidation state and relative oxidation potential of the siderite-diamond-wstite (SDW) buffer relative to the iron-wstite (IW) buffer over a range of pressures spanning those of Earth's lower mantle to that of a carbon super-Earth. We find that over all pressures along a mantle adiabat, the SDW buffer is above the IW buffer, suggesting that both the Earth and carbon super-Earth mantles contain reduced species of carbon. Experiments to 65 GPa and 2400 K on siderite, iron, and wstite mixtures show reduction of carbon to diamond via x-ray diffraction, Raman spectroscopy, and STEM-EDX. The reduced carbon present in these planets will therefore be present as iron carbide with excess diamond. In a carbon super-Earth, differentiation processes will sequester iron carbide into a core, leaving a significant inventory of diamond in the mantle. We present mass-radius relationships for such planets and implications for the dynamical evolution of diamond-rich mantles.

  11. Fabrication of GaP disk resonator arrays coupled to nitrogen-vacancy centers in diamond

    NASA Astrophysics Data System (ADS)

    Thomas, Nicole K.; Barbour, Russell; Song, Yuncheng; Lee, Minjoo L.; Fu, Kai-Mei C.

    2014-02-01

    Nitrogen-vacancy (NV) centers coupled to scalable optical networks have the potential to realize solid-state quantum information processing platforms. Toward this goal, we demonstrate coupling of near-surface NV- centers to an array of GaP optical resonators. The use of GaP as the optical waveguiding materials is appealing due to the possibility of realizing integrated photonic switches based on the linear electro-optic effect. We explore large-area integration of GaP on diamond through two routes: molecular beam deposition directly onto diamond substrates and layer transfer of single-crystalline sheets. While the direct deposition benefits from simpler, monolithic processing, the layer transfer route benefits from higher material quality. In the latter approach, we demonstrate the transfer of submicrometer thick, mm2-sized GaP sheets from a GaP/AlGaP/GaP substrate to a diamond sample prepared with near-surface NV- centers. We fabricate large arrays of GaP disk resonators with varying diameters (1 to 20 μm) on the diamond substrate via electron beam lithography and dry etching, and show coupling of the NV- center emission to the cavity structures. Quality factors above 10,000 were observed in 5 μm diameter disks on the non-etched diamond substrate. Similar quality factors in smaller sized devices are expected with diamond substrate etching to further confine the optical mode. This approach opens a path towards the integration of coupled optical components in the hybrid GaP/diamond system, an essential step towards large-scale photonic networks utilizing NV- centers in diamond.

  12. Nanodiamonds in the Younger Dryas boundary sediment layer.

    PubMed

    Kennett, D J; Kennett, J P; West, A; Mercer, C; Hee, S S Que; Bement, L; Bunch, T E; Sellers, M; Wolbach, W S

    2009-01-01

    We report abundant nanodiamonds in sediments dating to 12.9 +/- 0.1 thousand calendar years before the present at multiple locations across North America. Selected area electron diffraction patterns reveal two diamond allotropes in this boundary layer but not above or below that interval. Cubic diamonds form under high temperature-pressure regimes, and n-diamonds also require extraordinary conditions, well outside the range of Earth's typical surficial processes but common to cosmic impacts. N-diamond concentrations range from approximately 10 to 3700 parts per billion by weight, comparable to amounts found in known impact layers. These diamonds provide strong evidence for Earth's collision with a rare swarm of carbonaceous chondrites or comets at the onset of the Younger Dryas cool interval, producing multiple airbursts and possible surface impacts, with severe repercussions for plants, animals, and humans in North America. PMID:19119227

  13. Confocal luminescence study of nitrogen-vacancy distribution within nitrogen-rich single crystal CVD diamond

    NASA Astrophysics Data System (ADS)

    Shershulin, V. A.; Samoylenko, S. R.; Kudryavtsev, O. S.; Bolshakov, A. P.; Ashkinazi, E. E.; Yurov, V. Yu; Ralchenko, V. G.; Konov, V. I.; Vlasov, I. I.

    2016-01-01

    Confocal photoluminescence (PL) microscopy was used to study a distribution of negatively charged nitrogen-vacancy (NV‑) defects within a surface and in a cross section of a homoepitaxial chemical vapor deposition (CVD) diamond layer intentionally grown with a nitrogen concentration close to the solubility limit. A variation in the PL intensity within the whole sample was found to exceed no more than 30% of the intensity maximum. The diamond layers with densely packed NV‑ arrays are a promising material platform for the design of highly sensitive magnetic field and temperature sensors, as well as for using this material in quantum optics and informatics technologies based on NV‑ spins.

  14. Spectroscopic ellipsometry of homoepitaxial diamond multilayers and delta-doped structures

    SciTech Connect

    Bousquet, J.; Chicot, G.; Eon, D.; Bustarret, E.

    2014-01-13

    The optimization of diamond-based unipolar electronic devices such as pseudo-vertical Schottky diodes or delta-doped field effect transistors relies in part on the sequential growth of nominally undoped (p{sup –}) and heavily boron doped (p{sup ++}) layers with well-controlled thicknesses and steep interfaces. Optical ellipsometry offers a swift and contactless method to characterize the thickness, roughness, and electronic properties of semiconducting and metallic diamond layers. We report ellipsometric studies carried out on delta-doped structures and other epitaxial multilayers with various boron concentrations and thicknesses (down to the nanometer range). The results are compared with Secondary Ion Mass Spectroscopy and transport measurements.

  15. Diamond/graphite content and biocompatibility of DLC films fabricated by PLD

    NASA Astrophysics Data System (ADS)

    Jelnek, Miroslav; Kocourek, Tom; Remsa, Jan; Mikovsk, Jan; Zemek, Josef; Smetana, Karel; Dvo?nkov, Barbora; Luxbacher, Thomas

    2010-12-01

    Biocompatibility and physicochemical properties of diamond-like carbon (DLC) thin layers prepared by pulsed laser deposition method were studied. The films of high and low diamond/graphite content were prepared by changing the laser energy density on the graphite target from 4 to 11 J cm-2. The bonds and surface properties as roughness, atomic force microscopy topology, contact angle parameters, and zeta potential were measured. The cell adhesion/proliferation on DLC layers was tested using normal human fibroblasts and keratinocytes.

  16. Diamond cutting element in a rotating bit

    SciTech Connect

    Grappendorf, R. H.

    1985-01-01

    An improved tooth for use in rotating diamond bits incorporating a generally triangular prismatic polycrystalline diamond element is devised by integrally forming an oval shaped base about the tooth or element extending from the face of the rotating bit, thereby providing a lateral reinforcing collar. The diamond element is also reinforced by a tapered trailing support having a leading surface contiguous and substantially congruous with the trailing surface of the diamond element. In one embodiment, a prepad provides reinforcement or support for the leading surface of the diamond element.

  17. Thermal Conductivity Of Natural Type IIa Diamond

    NASA Technical Reports Server (NTRS)

    Vandersande, Jan; Vining, Cronin; Zoltan, Andrew

    1992-01-01

    Report describes application of flash diffusivity method to measure thermal conductivity of 8.04 x 8.84 x 2.35-mm specimen of natural, white, type-IIa diamond at temperatures between 500 and 1,250 K. Provides baseline for comparison to isotopically pure (12C) diamond. Results used as reference against which diamond films produced by chemical-vapor deposition at low pressures can be compared. High thermal conductivity of diamond exploited for wide variety of applications, and present results also used to estimate heat-conduction performances of diamond films in high-temperature applications.

  18. Electron Microscopy of Natural and Epitaxial Diamond

    NASA Technical Reports Server (NTRS)

    Posthill, J. B.; George, T.; Malta, D. P.; Humphreys, T. P.; Rudder, R. A.; Hudson, G. C.; Thomas, R. E.; Markunas, R. J.

    1993-01-01

    Semiconducting diamond films have the potential for use as a material in which to build active electronic devices capable of operating at high temperatures or in high radiation environments. Ultimately, it is preferable to use low-defect-density single crystal diamond for device fabrication. We have previously investigated polycrystalline diamond films with transmission electron microscopy (TEM) and scanning electron microscopy (SEM), and homoepitaxial films with SEM-based techniques. This contribution describes some of our most recent observations of the microstructure of natural diamond single crystals and homoepitaxial diamond thin films using TEM.

  19. Method for machining steel with diamond tools

    DOEpatents

    Casstevens, J.M.

    1984-01-01

    The present invention is directed to a method for machine optical quality finishes and contour accuracies of workpieces of carbon-containing metals such as steel with diamond tooling. The wear rate of the diamond tooling is significantly reduced by saturating the atmosphere at the interface of the workpiece and the diamond tool with a gaseous hydrocarbon during the machining operation. The presence of the gaseous hydrocarbon effectively eliminates the deterioration of the diamond tool by inhibiting or preventing the conversion of the diamond carbon to graphite carbon at the point of contact between the cutting tool and the workpiece.

  20. Method for machining steel with diamond tools

    DOEpatents

    Casstevens, John M.

    1986-01-01

    The present invention is directed to a method for machining optical quality inishes and contour accuracies of workpieces of carbon-containing metals such as steel with diamond tooling. The wear rate of the diamond tooling is significantly reduced by saturating the atmosphere at the interface of the workpiece and the diamond tool with a gaseous hydrocarbon during the machining operation. The presence of the gaseous hydrocarbon effectively eliminates the deterioration of the diamond tool by inhibiting or preventing the conversion of the diamond carbon to graphite carbon at the point of contact between the cutting tool and the workpiece.

  1. Microstructure and tribological performance of self-lubricating diamond/tetrahedral amorphous carbon composite film

    NASA Astrophysics Data System (ADS)

    Chen, Xinchun; Peng, Zhijian; Yu, Xiang; Fu, Zhiqiang; Yue, Wen; Wang, Chengbiao

    2011-02-01

    In order to smooth the rough surface and further improve the wear-resistance of coarse chemical vapor deposition diamond films, diamond/tetrahedral amorphous carbon composite films were synthesized by a two-step preparation technique including hot-filament chemical vapor deposition for polycrystalline diamond (PCD) and subsequent filtered cathodic vacuum arc growth for tetrahedral amorphous carbon (ta-C). The microstructure and tribological performance of the composite films were investigated by means of various characterization techniques. The results indicated that the composite films consisted of a thick well-grained diamond base layer with a thickness up to 150 ?m and a thin covering ta-C layer with a thickness of about 0.3 ?m, and sp3-C fraction up to 73.93%. Deposition of a smooth ta-C film on coarse polycrystalline diamond films was proved to be an effective tool to lower the surface roughness of the polycrystalline diamond film. The wear-resistance of the diamond film was also enhanced by the self-lubricating effect of the covering ta-C film due to graphitic phase transformation. Under dry pin-on-disk wear test against Si3N4 ball, the friction coefficients of the composite films were much lower than that of the single PCD film. An extremely low friction coefficient (?0.05) was achieved for the PCD/ta-C composite film. Moreover, the addition of Ti interlayer between the ta-C and the PCD layers can further reduce the surface roughness of the composite film. The main wear mechanism of the composite films was abrasive wear.

  2. Friction and wear performance of boron doped, undoped microcrystalline and fine grained composite diamond films

    NASA Astrophysics Data System (ADS)

    Wang, Xinchang; Wang, Liang; Shen, Bin; Sun, Fanghong

    2015-01-01

    Chemical vapor deposition (CVD) diamond films have attracted more attentions due to their excellent mechanical properties. Whereas as-fabricated traditional diamond films in the previous studies don't have enough adhesion or surface smoothness, which seriously impact their friction and wear performance, and thus limit their applications under extremely harsh conditions. A boron doped, undoped microcrystalline and fine grained composite diamond (BD-UM-FGCD) film is fabricated by a three-step method adopting hot filament CVD (HFCVD) method in the present study, presenting outstanding comprehensive performance, including the good adhesion between the substrate and the underlying boron doped diamond (BDD) layer, the extremely high hardness of the middle undoped microcrystalline diamond (UMCD) layer, as well as the low surface roughness and favorable polished convenience of the surface fine grained diamond (FGD) layer. The friction and wear behavior of this composite film sliding against low-carbon steel and silicon nitride balls are studied on a ball-on-plate rotational friction tester. Besides, its wear rate is further evaluated under a severer condition using an inner-hole polishing apparatus, with low-carbon steel wire as the counterpart. The test results show that the BD-UM-FGCD film performs very small friction coefficient and great friction behavior owing to its high surface smoothness, and meanwhile it also has excellent wear resistance because of the relatively high hardness of the surface FGD film and the extremely high hardness of the middle UMCD film. Moreover, under the industrial conditions for producing low-carbon steel wires, this composite film can sufficiently prolong the working lifetime of the drawing dies and improve their application effects. This research develops a novel composite diamond films owning great comprehensive properties, which have great potentials as protecting coatings on working surfaces of the wear-resistant and anti-frictional components.

  3. The boron doping of single crystal diamond for high power diode applications

    NASA Astrophysics Data System (ADS)

    Nicley, Shannon Singer

    Diamond has the potential to revolutionize the field of high power and high frequency electronic devices as a superlative electronic material. The realization of diamond electronics depends on the control of the growth process of both lightly and heavily boron doped diamond. This dissertation work is focused on furthering the state of the art of boron doped diamond (BDD) growth toward the realization of high power diamond Schottky barrier diodes (SBDs). The achievements of this work include the fabrication of a new dedicated reactor for lightly boron doped diamond deposition, the optimization of growth processes for both heavily and lightly boron doped single crystal diamond (SCD), and the proposal and realization of the corner architecture SBD. Boron doped SCD is grown in microwave plasma-assisted chemical vapor deposition (MPACVD) plasma disc bell-jar reactors, with feedgas mixtures including hydrogen, methane, carbon dioxide, and diborane. Characterization methods for the analysis of BDD are described, including Fourier-transformed infrared spectroscopy (FTIR), Secondary Ion Mass Spectroscopy (SIMS) and temperature-dependent four point probe conductivity for activation energy. The effect of adding carbon dioxide to the plasma feedgas for lightly boron doped diamond is investigated. The effect of diborane levels and other growth parameters on the incorporated boron levels are reported, and the doping efficiency is calculated over a range of boron concentrations. The presence of defects is shown to affect the doping uniformity. The substrate growth temperature dependence of the plasma gas-phase to solid-phase doping efficiency in heavily boron doped SCD deposition is investigated. The substrate temperature during growth is shown to have a significant effect on the grown sample defect morphology, and a temperature dependence of the doping efficiency is also shown. The effect of the growth rate on the doping efficiency is discussed, and the ratio of the boron concentration in the gas phase to the flux of carbon incorporated into the solid diamond phase is shown to be a more predictive measure of the resulting boron concentration than the gas phase boron to carbon ratio that is more commonly reported. The corner architecture SBD structure is proposed as an alternative vertical architecture for the realization of high power, high temperature single crystal diamond diodes. The lightly doped layer of the diode is grown in a direction perpendicular to the previous epitaxial growth of the heavily doped layer, to reduce the threading type dislocations in the active region of the fabricated diodes. The first ever corner architecture SBD is fabricated and evaluated for diode performance, using the regimes identified for high quality boron doped diamond deposition at light and heavy doping levels.

  4. Valleytronics: Electrons dance in diamond

    NASA Astrophysics Data System (ADS)

    Nebel, Christoph E.

    2013-08-01

    In addition to manipulating the charge or spin of electrons, another way to control electric current is by using the 'valley' degree-of-freedom of electrons. The first demonstration of the generation, transport and detection of valley-polarized electrons in bulk diamond now opens up new opportunities for quantum control in electronic devices.

  5. Designing shallow donors in diamond

    NASA Astrophysics Data System (ADS)

    Moussa, Jonathan

    2015-03-01

    The production of n-type semiconducting diamond has been a long-standing experimental challenge. The first-principles simulation of shallow dopants in semiconductors has been a long-standing theoretical challenge. A desirable theoretical goal is to identify impurities that will act as shallow donors in diamond and assess their experimental viability. I will discuss this identification process for the LiN4 donor complex. It builds a scientific argument from several models and computational results in the absence of computational tools that are both trustworthy and computationally tractable for this task. I will compare the theoretical assessment of viability with recent experimental efforts to co-dope diamond with lithium and nitrogen. Finally, I discuss the computational tools needed to facilitate future work on this problem and some preliminary simulations of donors near diamond surfaces. Sandia National Laboratories is a multi-program lab managed and operated by Sandia Corp., a wholly owned subsidiary of Lockheed Martin Corp., for the U.S. Department of Energy's National Nuclear Security Administration under Contract DE-AC04-94AL85000.

  6. A diamond (1 0 0) surface with perfect phase purity

    NASA Astrophysics Data System (ADS)

    Dyachenko, Oleksiy; Diek, Nadine; Shapiro, Yevgeniy; Tamang, Rajesh; Harneit, Wolfgang; Reichling, Michael; Borodin, Andriy

    2015-11-01

    Diamond surfaces with (1 0 0) orientation and perfect phase purity regarding the coexistence of sp3 and sp2 bonding as well as near surface nitrogen implanted layers are repeatedly produced from one sample by a cycle of nitrogen implantation, etching in oxygen and wet chemical etching. Comprehensive surface studies carried out by X-ray photoelectron spectroscopy (XPS) involving a deconvolution of the C 1s peak into contributions of C sp3, C sp2 and C sp3(N) reveal the surface and near-surface phase and stoichiometry. It is demonstrated that efficient etching of nitrogen implanted diamond occurs by high temperature annealing in oxygen and a wet chemical treatment.

  7. Zr/oxidized diamond interface for high power Schottky diodes

    SciTech Connect

    Traoré, A. Muret, P.; Fiori, A.; Eon, D.; Gheeraert, E.; Pernot, J.

    2014-02-03

    High forward current density of 10{sup 3} A/cm{sup 2} (at 6 V) and a breakdown field larger than 7.7 MV/cm for diamond diodes with a pseudo-vertical architecture, are demonstrated. The power figure of merit is above 244 MW/cm{sup 2} and the relative standard deviation of the reverse current density over 83 diodes is 10% with a mean value of 10{sup −9} A/cm{sup 2}. These results are obtained with zirconium as Schottky contacts on the oxygenated (100) oriented surface of a stack comprising an optimized lightly boron doped diamond layer on a heavily boron doped one, epitaxially grown on a Ib substrate. The origin of such performances are discussed.

  8. Heteroepitaxial growth of highly oriented diamond on cubic silicon carbide

    NASA Astrophysics Data System (ADS)

    Kawarada, H.; Wild, C.; Herres, N.; Locher, R.; Koidl, P.; Nagasawa, H.

    1997-04-01

    We have deposited epitaxial diamond films with very low angular spread on epitaxial ?-phase silicon carbide layers on silicon (001) substrates. From x-ray rocking curve measurements, half-widths of the angular spread of the crystal orientation as low as 0.6 have been determined, which is the smallest value ever reported in heteroepitaxial diamond films and appears to be smaller than those of the ?-phase silicon carbide underlayers. The film surface exhibits a roughness of about 100 nm with very few discernible boundaries due to misorientation. The optimization of the bias-enhanced nucleation process and the control of selective growth are the main factors for the improvement of the crystallinity.

  9. Thermal conductivity of ultrathin nano-crystalline diamond films determined by Raman thermography assisted by silicon nanowires

    NASA Astrophysics Data System (ADS)

    Anaya, Julian; Rossi, Stefano; Alomari, Mohammed; Kohn, Erhard; Tth, Lajos; Pcz, Bla; Kuball, Martin

    2015-06-01

    The thermal transport in polycrystalline diamond films near its nucleation region is still not well understood. Here, a steady-state technique to determine the thermal transport within the nano-crystalline diamond present at their nucleation site has been demonstrated. Taking advantage of silicon nanowires as surface temperature nano-sensors, and using Raman Thermography, the in-plane and cross-plane components of the thermal conductivity of ultra-thin diamond layers and their thermal barrier to the Si substrate were determined. Both components of the thermal conductivity of the nano-crystalline diamond were found to be well below the values of polycrystalline bulk diamond, with a cross-plane thermal conductivity larger than the in-plane thermal conductivity. Also a depth dependence of the lateral thermal conductivity through the diamond layer was determined. The results impact the design and integration of diamond for thermal management of AlGaN/GaN high power transistors and also show the usefulness of the nanowires as accurate nano-thermometers.

  10. Diamond/diamond-like carbon coated nanotube structures for efficient electron field emission

    NASA Technical Reports Server (NTRS)

    Dimitrijevic, Steven (Inventor); Withers, James C. (Inventor); Loutfy, Raouf O. (Inventor)

    2005-01-01

    The present invention is directed to a nanotube coated with diamond or diamond-like carbon, a field emitter cathode comprising same, and a field emitter comprising the cathode. It is also directed to a method of preventing the evaporation of carbon from a field emitter comprising a cathode comprised of nanotubes by coating the nanotube with diamond or diamond-like carbon. In another aspect, the present invention is directed to a method of preventing the evaporation of carbon from an electron field emitter comprising a cathode comprised of nanotubes, which method comprises coating the nanotubes with diamond or diamond-like carbon.

  11. Surface smoothing of CVD-diamond membrane for X-ray lithography by Gas Cluster Ion Beam

    SciTech Connect

    Nishiyama, A.; Adachi, M.; Toyoda, N.; Hagiwara, N.; Matsuo, J.; Yamada, I.

    1999-06-10

    Results of the surface smoothing of a CVD-diamond membrane by gas cluster ion beams are presented. An as-deposited diamond membrane with a surface roughness of 400 Aa Ra was irradiated by Ar cluster ions with a energy of 20 keV. A very smooth surface of 30 Aa Ra was obtained at a dose of 3x10{sup 17} ions/cm{sup 2}. This result can be clarified by computer simulation which shows that the surface smoothing of the diamond membrane was improved by a lateral sputtering of the cluster ions. However, a thin graphite layer was formed on the surface by contamination of monomer ions in the cluster beam, which decreased the transparency of the diamond membrane. A subsequent irradiation with O{sub 2} cluster ions removed these graphite layers.

  12. Multiple Diamond Anvil (MDA) apparatus using nano-polycrystalline diamond

    NASA Astrophysics Data System (ADS)

    Irifune, T.; Kunimoto, T.; Tange, Y.; Shinmei, T.; Isobe, F.; Kurio, A.; Funakoshi, K.

    2011-12-01

    Thanks to the great efforts by Dave Mao, Bill Bassett, Taro Takahashi, and their colleagues at the University of Rochester through 1960s-70s, diamond anvil cell (DAC) became a major tool to investigate the deep Earth after its invention by scientists at NBS in 1958. DAC can now cover almost the entire pressure and temperature regimes of the Earth's interior, which seems to have solved the longstanding debate on the crystal structure of iron under the P-T conditions of the Earth's inner core. In contrast, various types of static large-volume presses (LVP) have been invented, where tungsten carbide has conventionally been used as anvils. Kawai-type multianvil apparatus (MA), which utilize 6 first-stage harden steel and 8 tungsten carbide anvils, is the most successful LVP, and has been used for accurate measurements of phase transitions, physical properties, element partitioning, etc. at high pressure and temperature. However, pressures using tungsten carbide as the second-stage anvils have been limited to about 30 GPa due to significant plastic deformation of the anvils. Efforts have been made to expand this pressure limit by replacing tungsten carbide anvils with harder sintered diamond (SD) anvils over the last two decades, but the pressures available in KMA with SD anvils have still been limited to below 100 GPa. We succeeded to produce nano-polycrystalline diamond (NPD or HIME-Diamond) in 2003, which is known to have ultrahigh hardness, very high toughness and elastic stiffness, high transmittance of light, relatively low thermal conductivity. These properties are feasible for its use as anvils, and some preliminary experiments of application of NPD anvils to laser heated DAC have successfully made in the last few years. We are now able to synthesize NPD rods with about 1cm in both diameter and length using a newly constructed 6000-ton KMA at Geodynamics Research Center, Ehime University, and have just started to apply this new polycrystalline diamond as anvils for multianvil apparatus. Various versions of the Multiple Diamond Anvil (MDA) apparatus with NPD anvils (Fig.1), amalgamated forms of MA and DAC, are currently being tested for experiments under Mbar regimes without sacrificing the advantages of MA over DAC.

  13. Correlations between the density distributions of C{sub 2}, CH and OH and the growth of diamond in an oxyacetylene flame measured by LIF

    SciTech Connect

    Klein-Douwel, R.J.H.; Spaanjaars, J.J.L.; Meulen, J.J. ter

    1995-12-31

    Two-dimensional Laser Induced Fluorescence (2D-LIF) measurements are applied to the chemical vapour deposition (CVD) of diamond by an oxyacetylene flame. The fluorescence distributions of C{sub 2}, CH and OH are measured for various deposition conditions. The influence of the temperature of the molybdenum substrate and the distance between the substrate and the flame front on the two-dimensional distributions and on the quality and morphology of the deposited diamond is investigated. A clear relation is observed between the C{sub 2} distribution in the flame and the local growth rate and quality of the diamond layer, therefore C{sub 2} is thought to be an important species for diamond growth. Due to lower signal to noise ratios the role of CH as a growth species is less clear. The OH radical is not observed in the boundary layer, so OH seems to be of minor importance. All measurements are performed during diamond deposition.

  14. Self-Lubricating, Wear-Resistant Diamond Films Developed for Use in Vacuum Environment

    NASA Technical Reports Server (NTRS)

    1996-01-01

    Diamond's outstanding properties--extreme hardness, chemical and thermal inertness, and high strength and rigidity--make it an ideal material for many tribological applications, such as the bearings, valves, and engine parts in the harsh environment found in internal-combustion engines, jet engines, and space propulsion systems. It has been demonstrated that chemical-vapor-deposited diamond films have low coefficients of friction (on the order of 0.01) and low wear rates (less than 10(sup -7) mm (sup 3/N-m)) both in humid air and dry nitrogen but that they have both high coefficients of friction (greater than 0.4) and high wear rates (on the order of 1(sup -4) mm sup 3/N-m)) in vacuum. It is clear that surface modifications that provide acceptable levels of friction and wear properties will be necessary before diamond films can be used for tribological applications in a space-like, vacuum environment. Previously, it was found that coatings of amorphous, non-diamond carbon can provide low friction in vacuum. Therefore, to reduce the friction and wear of diamond film in vacuum, carbon ions were implanted in an attempt to form a surface layer of amorphous carbon phases on the diamond films.

  15. Micro-IBICC and micro-IL analyses of CVD diamond microdosimeters

    NASA Astrophysics Data System (ADS)

    Vittone, E.; Ricciardi, C.; Lo Giudice, A.; Fizzotti, F.; Manfredotti, C.; Egeni, G.; Rudello, V.

    2001-07-01

    Diamond is an ideal material to fabricate dosimeters because it is tissue equivalent, chemically stable, non-toxic, mechanical and radiation hard. Chemical vapour deposition technique (CVD) allows for the fabrication of small diamond detectors, which can be considered for in vivo dose measurements. We have fabricated microdosimeters by depositing thin diamond films (<20 ?m thick) on tungsten wires (diameter below 300 ?m). Such devices work as solid state ionisation chambers where the electrodes are the W substrate and a thin gold layer evaporated on the diamond surface. The ion beam-induced charge collection (IBICC) and ionoluminescence (IL) techniques turn out to be very suitable to characterise such small and irregularly shaped microdosimeters. The uniformity of the electronic quality of diamond has been evaluated by mapping the charge collection efficiency as obtained by IBICC measurements, whereas IL was used to map radiative recombination centres as well as to study radiation damage effects. Finally, a synergetic combination of PIXE and IL maps allowed us to evaluate the shape of the diamond film covering the W substrate.

  16. Medical applications of diamond particles and surfaces.

    SciTech Connect

    Narayan, R. J.; Boehm, R. D.; Sumant, A. V.

    2011-04-01

    Diamond has been considered for use in several medical applications due to its unique mechanical, chemical, optical, and biological properties. In this paper, methods for preparing synthetic diamond surfaces and particles are described. In addition, recent developments involving the use of diamond in prostheses, sensing, imaging, and drug delivery applications are reviewed. These developments suggest that diamond-containing structures will provide significant improvements in the diagnosis and treatment of medical conditions over the coming years. Diamond is an allotrope of carbon that is being considered for use in several medical applications. Ramachandran determined that the crystal structure of diamond consists of two close packed interpenetrating face centered cubic lattices; one lattice is shifted with respect to the other along the elemental cube space diagonal by one-quarter of its length. If one approximates carbon atoms as equal diameter rigid spheres, the filling of this construction is 34%. Due to the carbon-carbon distance (1.54 {angstrom}), diamond crystal exhibits the highest atomic density (1.76 x 10{sup 23} cm{sup -3}) of any solid. The very high bond energy between two carbon atoms (83 kcal/mol) and the directionality of tetrahedral bonds are the main reasons for the high strength of diamond. Diamond demonstrates the highest Vickers hardness value of any material (10,000 kg/mm{sup 2}). The tribological properties of diamond are also impressive; the coefficient of friction of polished diamond is 0.07 in argon and 0.05 in humid air. Diamond is resistant to corrosion except in an oxygen atmosphere at temperatures over 800 C. In addition, type IIa diamond exhibits the highest thermal conductivity of all materials (20 W cm{sup -1} K{sup -1} at room temperature).

  17. Surface electronic properties of H-terminated diamond in contact with adsorbates and electrolytes

    NASA Astrophysics Data System (ADS)

    Nebel, C. E.; Rezek, B.; Shin, D.; Watanabe, H.

    2006-10-01

    A comprehensive summary of surface electronic properties of undoped hydrogen terminated diamond covered with adsorbates or in electrolyte solutions is given. The formation of a conductive layer at the surface is characterized using Hall effect, conductivity, contact potential difference (CPM), scanning electron microscopy (SEM), and cyclic voltammetry experiments. Data are from measurements on homoepitaxially grown CVD diamond films with atomically smooth hydrogen terminated surfaces. The data show that due to electron transfer from the valence band into empty states in of the electrolyte, a highly conductive surface layer is generated. Holes propagate in the layer with mobilities up to 350 cm2/Vs. The sheet hole density in this layer is in the range 1011 to 5 × 1012 cm-2, and dependents on pH of the electrolyte or adsorbate. This has been utilized to manufacture ion sensitive field effect transistors (ISFET) from diamond. The drain source conductivity of single crystalline CVD diamond is pH dependent, with about 66 mV/pH, which is in reasonable agreement with the Nernst law. Due to strong coulomb repulsion between positive ions in the electrolyte and the H+-surface termination of diamond, an enlarged tunneling gap is established which prevents electronic interactions between the electrolyte and diamond. This is a virtual gate insulator of diamond ISFETs. Application of potentials larger than the oxidation threshold of +0.7 V (pH 13) to +1.6 V (pH 1) gives rise to strong leakage currents and to partial surface oxidation. In addition, the electronic interaction of diamond with redox couples is characterized using cyclic voltammetry experiments. The results are well described by the transfer doping model which accounts for the specific properties of undoped diamond immersed in electrolyte solutions are covered simply by adsorbates. In addition, numerical solutions of the Schrödinger and Poisson equations are used to show that the density of state distribution of unoccupied valence band states in case of a perfect interface would be governed by two-dimensional properties (2D).

  18. 33 CFR 110.6 - Portland Harbor, Portland, Maine (between Little Diamond Island and Great Diamond Island).

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... (between Little Diamond Island and Great Diamond Island). 110.6 Section 110.6 Navigation and Navigable... Areas § 110.6 Portland Harbor, Portland, Maine (between Little Diamond Island and Great Diamond Island). Beginning at the southeasterly corner of the wharf, at the most southerly point of Great Diamond Island...

  19. 33 CFR 110.6 - Portland Harbor, Portland, Maine (between Little Diamond Island and Great Diamond Island).

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... (between Little Diamond Island and Great Diamond Island). 110.6 Section 110.6 Navigation and Navigable... Areas § 110.6 Portland Harbor, Portland, Maine (between Little Diamond Island and Great Diamond Island). Beginning at the southeasterly corner of the wharf, at the most southerly point of Great Diamond Island...

  20. 33 CFR 110.6 - Portland Harbor, Portland, Maine (between Little Diamond Island and Great Diamond Island).

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... (between Little Diamond Island and Great Diamond Island). 110.6 Section 110.6 Navigation and Navigable... Areas § 110.6 Portland Harbor, Portland, Maine (between Little Diamond Island and Great Diamond Island). Beginning at the southeasterly corner of the wharf, at the most southerly point of Great Diamond Island...