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Sample records for ultrananocrystalline diamond layers

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

    NASA Astrophysics Data System (ADS)

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

    2014-03-01

    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.

  2. 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.

  3. 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 (2.8×10(-5)Acm(-2) at -1V and 1.9×10(-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 2.5×10(-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.

  4. Electronic properties of ultrananocrystalline diamond surfaces.

    SciTech Connect

    Lud, S. Q.; Niedermeier, M.; Koch, P. S.; Bruno, P.; Gruen, D. M.; Stutzmann, M.; Garriod, J. A.; Materials Science Division; Technische Univ. Munchen

    2010-03-04

    We have characterized ultrananocrystalline diamond films with different surface terminations by x-ray photoelectron spectroscopy (XPS), atomic force microscopy (AFM), scanning tunneling microscopy (STM) and scanning tunneling spectroscopy (STS). The surface terminations were performed by plasma functionalization in atmospheres of hydrogen, fluorine, and oxygen. XPS proves the dense monolayer coverage of the surface functionalization. AFM and STM show low impact of the plasma treatment on the surface morphology. STS has been used to investigate the surface electronic properties, for H-terminated surfaces the electronic structure is dominated by the sp{sup 3} carbon phase of the grain surfaces; for O- and F-terminated surfaces, however, sp{sup 2} carbon from the grain boundaries seems to determine the surface band gap.

  5. Electron field emission for ultrananocrystalline diamond films

    NASA Astrophysics Data System (ADS)

    Krauss, A. R.; Auciello, O.; Ding, M. Q.; Gruen, D. M.; Huang, Y.; Zhirnov, V. V.; Givargizov, E. I.; Breskin, A.; Chechen, R.; Shefer, E.; Konov, V.; Pimenov, S.; Karabutov, A.; Rakhimov, A.; Suetin, N.

    2001-03-01

    Ultrananocrystalline diamond (UNCD) films 0.1-2.4 μm thick were conformally deposited on sharp single Si microtip emitters, using microwave CH4-Ar plasma-enhanced chemical vapor deposition in combination with a dielectrophoretic seeding process. Field-emission studies exhibited stable, extremely high (60-100 μA/tip) emission current, with little variation in threshold fields as a function of film thickness or Si tip radius. The electron emission properties of high aspect ratio Si microtips, coated with diamond using the hot filament chemical vapor deposition (HFCVD) process were found to be very different from those of the UNCD-coated tips. For the HFCVD process, there is a strong dependence of the emission threshold on both the diamond coating thickness and Si tip radius. Quantum photoyield measurements of the UNCD films revealed that these films have an enhanced density of states within the bulk diamond band gap that is correlated with a reduction in the threshold field for electron emission. In addition, scanning tunneling microscopy studies indicate that the emission sites from UNCD films are related to minima or inflection points in the surface topography, and not to surface asperities. These data, in conjunction with tight binding pseudopotential calculations, indicate that grain boundaries play a critical role in the electron emission properties of UNCD films, such that these boundaries: (a) provide a conducting path from the substrate to the diamond-vacuum interface, (b) produce a geometric enhancement in the local electric field via internal structures, rather than surface topography, and (c) produce an enhancement in the local density of states within the bulk diamond band gap.

  6. 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.

  7. Planar Field Emitters and High Efficiency Photocathodes Based on Ultrananocrystalline Diamond

    NASA Technical Reports Server (NTRS)

    Sumant, Anirudha V. (Inventor); Baryshev, Sergey V. (Inventor); Antipov, Sergey P. (Inventor)

    2016-01-01

    A method of forming a field emitter comprises disposing a first layer on a substrate. The first layer is seeded with nanodiamond particles. The substrate with the first layer disposed thereon is maintained at a first temperature and a first pressure in a mixture of gases which includes nitrogen. The first layer is exposed to a microwave plasma to form a nitrogen doped ultrananocrystalline diamond film on the first layer, which has a percentage of nitrogen in the range of about 0.05 atom % to about 0.5 atom %. The field emitter has about 10.sup.12 to about 10.sup.14 emitting sites per cm.sup.2. A photocathode can also be formed similarly by forming a nitrogen doped ultrananocrystalline diamond film on a substrate similar to the field emitter, and then hydrogen terminating the film. The photocathode is responsive to near ultraviolet light as well as to visible light.

  8. Planar field emitters and high efficiency photocathodes based on ultrananocrystalline diamond

    DOEpatents

    Sumant, Anirudha V.; Baryshev, Sergey V.; Antipov, Sergey P.

    2016-08-16

    A method of forming a field emitter comprises disposing a first layer on a substrate. The first layer is seeded with nanodiamond particles. The substrate with the first layer disposed thereon is maintained at a first temperature and a first pressure in a mixture of gases which includes nitrogen. The first layer is exposed to a microwave plasma to form a nitrogen doped ultrananocrystalline diamond film on the first layer, which has a percentage of nitrogen in the range of about 0.05 atom % to about 0.5 atom %. The field emitter has about 10.sup.12 to about 10.sup.14 emitting sites per cm.sup.2. A photocathode can also be formed similarly by forming a nitrogen doped ultrananocrystalline diamond film on a substrate similar to the field emitter, and then hydrogen terminating the film. The photocathode is responsive to near ultraviolet light as well as to visible light.

  9. Ultrananocrystalline diamond contacts for electronic devices

    SciTech Connect

    Sumant, Anirudha V.; Smedley, John; Muller, Erik

    2016-11-01

    A method of forming electrical contacts on a diamond substrate comprises producing a plasma ball using a microwave plasma source in the presence of a mixture of gases. The mixture of gases include a source of a p-type or an n-type dopant. The plasma ball is disposed at a first distance from the diamond substrate. The diamond substrate is maintained at a first temperature. The plasma ball is maintained at the first distance from the diamond substrate for a first time, and a UNCD film, which is doped with at least one of a p-type dopant and an n-type dopant, is disposed on the diamond substrate. The doped UNCD film is patterned to define UNCD electrical contacts on the diamond substrate.

  10. 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.

  11. Low-stress doped ultrananocrystalline diamond

    DOEpatents

    Sumant, Anirudha V.; Buja, Federico; van Spengen, Willem Merlijn

    2016-10-25

    Nanocrystalline diamond coatings exhibit stress in nano/micro-electro mechanical systems (MEMS). Doped nanocrstalline diamond coatings exhibit increased stress. A carbide forming metal coating reduces the in-plane stress. In addition, without any metal coating, simply growing UNCD or NCD with thickness in the range of 3-4 micron also reduces in-plane stress significantly. Such coatings can be used in MEMS applications.

  12. Investigating the role of hydrogen in ultra-nanocrystalline diamond thin film growth

    NASA Astrophysics Data System (ADS)

    Birrell, James; Gerbi, J. E.; Auciello, O. A.; Carlisle, J. A.

    2006-08-01

    Hydrogen has long been known to be critical for the growth of high-quality microcrystalline diamond thin films as well as homoepitaxial single-crystal diamond. A hydrogen-poor growth process that results in ultra-nanocrystalline diamond thin films has also been developed, and it has been theorized that diamond growth with this gas chemistry can occur in the absence of hydrogen. This study investigates the role of hydrogen in the growth of ultra-nanocrystalline diamond thin films in two different regimes. First, we add hydrogen to the gas phase during growth, and observe that there seems to be a competitive growth process occurring between microcrystalline diamond and ultra-nanocrystalline diamond, rather than a simple increase in the grain size of ultra-nanocrystalline diamond. Second, we remove hydrogen from the plasma by changing the hydrocarbon precursor from methane to acetylene and observe that there does seem to be some sort of lower limit to the amount of hydrogen that can sustain ultra-nanocrystalline diamond growth. We speculate that this is due to the amount of hydrogen needed to stabilize the surface of the growing diamond nanocrystals.

  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. Biological evaluation of ultrananocrystalline and nanocrystalline diamond coatings.

    PubMed

    Skoog, Shelby A; Kumar, Girish; Zheng, Jiwen; Sumant, Anirudha V; Goering, Peter L; Narayan, Roger J

    2016-12-01

    Nanostructured biomaterials have been investigated for achieving desirable tissue-material interactions in medical implants. Ultrananocrystalline diamond (UNCD) and nanocrystalline diamond (NCD) coatings are the two most studied classes of synthetic diamond coatings; these materials are grown using chemical vapor deposition and are classified based on their nanostructure, grain size, and sp(3) content. UNCD and NCD are mechanically robust, chemically inert, biocompatible, and wear resistant, making them ideal implant coatings. UNCD and NCD have been recently investigated for ophthalmic, cardiovascular, dental, and orthopaedic device applications. The aim of this study was (a) to evaluate the in vitro biocompatibility of UNCD and NCD coatings and (b) to determine if variations in surface topography and sp(3) content affect cellular response. Diamond coatings with various nanoscale topographies (grain sizes 5-400 nm) were deposited on silicon substrates using microwave plasma chemical vapor deposition. Scanning electron microscopy and atomic force microscopy revealed uniform coatings with different scales of surface topography; Raman spectroscopy confirmed the presence of carbon bonding typical of diamond coatings. Cell viability, proliferation, and morphology responses of human bone marrow-derived mesenchymal stem cells (hBMSCs) to UNCD and NCD surfaces were evaluated. The hBMSCs on UNCD and NCD coatings exhibited similar cell viability, proliferation, and morphology as those on the control material, tissue culture polystyrene. No significant differences in cellular response were observed on UNCD and NCD coatings with different nanoscale topographies. Our data shows that both UNCD and NCD coatings demonstrate in vitro biocompatibility irrespective of surface topography.

  15. 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.

  16. 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.

  17. 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.

  18. 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.

  19. 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)

  20. Structural properties of highly conductive ultra-nanocrystalline diamond films grown by hot-filament CVD

    NASA Astrophysics Data System (ADS)

    Mertens, M.; Lin, I.-N.; Manoharan, D.; Moeinian, A.; Brühne, K.; Fecht, H. J.

    2017-01-01

    In this work we show the correlation of the electrical conductivity of ultra-nanocrystalline (UNCD) diamond films grown by hot filament chemical vapor deposition (HFCVD) with their structural properties. The substrate temperature, the methane to hydrogen ratio and the pressure are the main factor influencing the growth of conductive UNCD films, which extends from electrical resistive diamond films (<10-4 S/cm) to highly conductive diamond films with a specific conductivity of 300 S/cm. High-resolution-transmission-electron-microscopy (HRTEM) and electron-energy-loss-spectroscopy (EELS) have been done on the highly conductive diamond films, to show the origin of the high electrical conductivity. The HRTEM results show random oriented diamond grains and a large amount of nano-graphite between the diamond crystals. EELS investigations are confirming these results. Raman measurements are correlated with the specific conductivity, which shows structural changes of sp2 carbons bonds as function of conductivity. Hall experiments complete the results, which lead to a model of an electron mobility based conductivity, which is influenced by the structural properties of the grain boundary regions in the ultra-nanocrystalline diamond films.

  1. 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)

  2. Microwave plasma assisted chemical vapor deposition of ultra-nanocrystalline diamond films

    NASA Astrophysics Data System (ADS)

    Huang, Wen-Shin

    Microwave plasma assisted ultra-nanocrystalline diamond film deposition was investigated using hydrogen deficient, carbon containing argon plasma chemistries with MSU-developed microwave plasma reactors. Ultra-nanocrystalline diamond film deposition on mechanically scratched silicon wafers was experimentally explored over the following input variables: (1) pressure: 60--240Torr, (2) total gas flow rate: 101--642 sccm, (3) input microwave power 732--1518W, (4) substrate temperature: 500°C--770°C, (5) deposition time: 2--48 hours, and (6) N2 impurities 5--2500 ppm. H2 concentrations were less than 9%, while CH 4 concentration was 0.17--1.85%. It was desired to grow films uniformly over 3″ diameter substrates and to minimize the grain size. Large, uniform, intense, and greenish-white discharges were sustained in contact with three inch silicon substrates over a 60--240 Torr pressure regime. At a given operating pressure, film uniformity was controlled by adjusting substrate holder geometry, substrate position, input microwave power, gas chemistries, and total gas flow rates. Film ultra-nanocrystallinity and smoothness required high purity deposition conditions. Uniform ultra-nanocrystalline films were synthesized in low leak-rate system with crystal sizes ranging from 3--30 nm. Films with 11--50 nm RMS roughness and respective thickness values of 1--23 mum were synthesized over 3″ wafers under a wide range of different deposition conditions. Film RMS roughness 7 nm was synthesized with thickness of 430 nm. Film uniformities of almost 100% were achieved over three inch silicon wafers. UV Raman and XRD characterization results indicated the presence of diamond in the synthesized films. Optical Emission Spectroscopy measurements showed that the discharge gas temperature was in excess of 2000 K. The synthesized films are uniformly smooth and the as grown ultra-nanocrystalline diamond can be used for a high frequency SAW device substrate material. IR measurements

  3. Origin of Ultralow Friction and Wear in Ultrananocrystalline Diamond

    DTIC Science & Technology

    2008-06-11

    flats and Si3N4 spheres [13]. Substrates were ultrasonically pre- treated as in [10] except with functionalized nanodiamond powder (4 nm diameter...5.0%. [24] K. Miyoshi, in Proceedings of the Applied Diamond Conference 1995. Applications of Diamond Films and Related Materials: Third International

  4. 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.

  5. 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.

  6. Wettability of ultrananocrystalline diamond and graphite nanowalls films: a comparison with their single crystal analogs.

    PubMed

    Ostrovskaya, L Y u; Ralchenko, V G; Bolshakov, A P; Saveliev, A V; Dzbanovsky, N N; Shmegera, S V

    2009-06-01

    Dramatic changes in wettability of diamond and graphite are observed when these materials are prepared in nanostructured forms--undoped and nitrogen-doped ultrananocrystalline diamond (UNCD) films, and graphite nanowalls (GNW), respectively. The nanostructured carbon films were deposited on Si by microwave plasma CVD processes. The advancing contact angle theta for water on hydrogenated undoped UNCD films increases to 106 +/- 3 degrees compared to hydrogenated single crystal diamond (theta = 92 degrees). Nitrogen doping (N2 addition to plasma) during UNCD growth makes the film more hydrophilic. The GNW films exhibited superhydrophobic behavior with theta = 144 +/- 3 degrees for water, which is higher than the contact angle of monocrystalline graphite (the basal plane) by a factor of 1.8. No chemical surface treatment is necessary to achieve such high hydrophobicity, it is accomplished solely by a specific (nanoporous, high aspect ratio) surface morphology with very low free surface energy inherent in it. The wetting behaviour of nanostructured films can be described with the Cassie-Baxter equation for heterophase nanoporous surfaces. Oxidation and hydrogenation of UNCD films make it possible to control theta over a much wider range as compared to a single crystal diamond. The influence of diamond grain size on wetting is considered taking into account the surface treatment. The corresponding variation in surface energy has been determined by the modified Young's equation.

  7. Ultrananocrystalline Diamond Membranes for Detection of High-Mass Proteins

    NASA Astrophysics Data System (ADS)

    Kim, H.; Park, J.; Aksamija, Z.; Arbulu, M.; Blick, R. H.

    2016-12-01

    Mechanical resonators realized on the nanoscale by now offer applications in mass sensing of biomolecules with extraordinary sensitivity. The general idea is that perfect mechanical mass sensors should be of extremely small size to achieve zepto- or yoctogram sensitivity in weighing single molecules similar to a classical scale. However, the small effective size and long response time for weighing biomolecules with a cantilever restricts their usefulness as a high-throughput method. Commercial mass spectrometry (MS), on the other hand, such as electrospray ionization and matrix-assisted laser desorption and ionization (MALDI) time of flight (TOF) and their charge-amplifying detectors are the gold standards to which nanomechanical resonators have to live up to. These two methods rely on the ionization and acceleration of biomolecules and the following ion detection after a mass selection step, such as TOF. The principle we describe here for ion detection is based on the conversion of kinetic energy of the biomolecules into thermal excitation of chemical vapor deposition diamond nanomembranes via phonons followed by phonon-mediated detection via field emission of thermally emitted electrons. We fabricate ultrathin diamond membranes with large lateral dimensions for MALDI TOF MS of high-mass proteins. These diamond membranes are realized by straightforward etching methods based on semiconductor processing. With a minimal thickness of 100 nm and cross sections of up to 400 ×400 μ m2 , the membranes offer extreme aspect ratios. Ion detection is demonstrated in MALDI TOF analysis over a broad range from insulin to albumin. The resulting data in detection show much enhanced resolution as compared to existing detectors, which can offer better sensitivity and overall performance in resolving protein masses.

  8. Synthesis of ultra-nano-carbon composite materials with extremely high conductivity by plasma post-treatment process of ultrananocrystalline diamond films

    SciTech Connect

    Yeh, Chien-Jui; Leou, Keh-Chyang; Manoharan, Divinah; Chang, Hsin-Tzer; Lin, I-Nan

    2015-08-24

    Needle-like diamond grains encased in nano-graphitic layers are an ideal granular structure of diamond films to achieve high conductivity and superior electron field emission (EFE) properties. This paper describes the plasma post-treatment (ppt) of ultrananocrystalline diamond (UNCD) films at low substrate temperature to achieve such a unique granular structure. The CH{sub 4}/N{sub 2} plasma ppt-processed films exhibit high conductivity of σ = 1099 S/cm as well as excellent EFE properties with turn-on field of E{sub 0} = 2.48 V/μm (J{sub e} = 1.0 mA/cm{sup 2} at 6.5 V/μm). The ppt of UNCD film is simple and robust process that is especially useful for device applications.

  9. 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.

  10. 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.

  11. 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.

  12. 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.

  13. 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.

  14. 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.

  15. 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 π*C=C and π*C≡C bonds are preferentially formed instead of the σ*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.

  16. 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.

  17. 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

    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.

  18. 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.

  19. Effect of gigaelectron volt Au-ion irradiation on the characteristics of ultrananocrystalline diamond films

    SciTech Connect

    Chen, Huang-Chin; Teng, Kuang-Yau; Tang, Chen-Yau; Lin, I-Nan; Sundaravel, Balakrishnan; Amirthapandian, Sankarakumar

    2010-12-15

    The effect of 2.245 GeV Au-ion irradiation/postannealing processes on the electron field emission (EFE) properties of ultrananocrystalline diamond (UNCD) films was investigated. Au-ion irradiation with a fluence of around 8.4x10{sup 13} ions/cm{sup 2} is required to induce a large improvement in the EFE properties of the UNCD films. Postannealing the Au-ion irradiated films at 1000 deg. C for 1 h slightly degraded the EFE properties of the films but the resulting EFE behavior was still markedly superior to that of pristine UNCD films. Transmission electron microscopy examinations revealed that the EFE properties of the UNCD films are primarily improved by Au-ion irradiation/postannealing processes because of the formation of nanographites along the trajectory of the irradiating ions, which results in an interconnected path for electron transport. In contrast, the induction of grain growth process due to Au-ion irradiation in UNCD films is presumed to insignificantly degrade the EFE properties for the films as the aggregates are scarcely distributed and do not block the electron conducting path.

  20. Enhanced electron field emission properties of conducting ultrananocrystalline diamond films after Cu and Au ion implantation.

    PubMed

    Sankaran, Kamatchi Jothiramalingam; Chen, Huang-Chin; Panda, Kalpataru; Sundaravel, Balakrishnan; Lee, Chi-Young; Tai, Nyan-Hwa; Lin, I-Nan

    2014-04-09

    The effects of Cu and Au ion implantation on the structural and electron field emission (EFE) properties of ultrananocrystalline diamond (UNCD) films were investigated. High electrical conductivity of 186 (Ω•cm)(-1) and enhanced EFE properties with low turn-on field of 4.5 V/μm and high EFE current density of 6.70 mA/cm(2) have been detected for Au-ion implanted UNCD (Au-UNCD) films that are superior to those of Cu-ion implanted UNCD (Cu-UNCD) ones. Transmission electron microscopic investigations revealed that Au-ion implantation induced a larger proportion of nanographitic phases at the grain boundaries for the Au-UNCD films in addition to the formation of uniformly distributed spherically shaped Au nanoparticles. In contrast, for Cu-UNCD films, plate-like Cu nanoparticles arranged in the row-like pattern were formed, and only a smaller proportion of nanographite phases along the grain boundaries was induced. 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 presence of nanosized Au particles and the induction of abundant nanographitic phases in the grain boundaries of Au-UNCD films are believed to be the authentic factors, ensuing in high electrical conductivity and outstanding EFE properties of the films.

  1. Enabling long term monitoring of dopamine using dimensionally stable ultrananocrystalline diamond microelectrodes

    NASA Astrophysics Data System (ADS)

    Dutta, Gaurab; Tan, Chao; Siddiqui, Shabnam; Arumugam, Prabhu U.

    2016-09-01

    Chronic dopamine (DA) monitoring is a critical enabling technology to identify the neural basis of human behavior. Carbon fiber microelectrodes (CFM), the current gold standard electrode for in vivo fast scan cyclic voltammetry (FSCV), rapidly loses sensitivity due to surface fouling during chronic neural testing. Periodic voltage excursions at elevated anodic potentials regenerate fouled CFM surfaces but they also chemically degrade the CFM surfaces. Here, we compare the dimensional stability of 150 μm boron-doped ultrananocrystalline diamond (BDUNCD) microelectrodes in 1X PBS during ‘electrochemical cleaning’ with a similar-sized CFM. Scanning electron microscopy and Raman spectroscopy confirm the exceptional dimensional stability of BDUNCD after 40 h of FSCV cycling (∼8 million cycles). The fitting of electrochemical impedance spectroscopy data to an appropriate circuit model shows a 2x increase in charge transfer resistance and an additional RC element, which suggests oxidation of BDUNCD electrode surface. This could have likely increased the DA oxidation potential by ∼34% to +308 mV. A 2x increase in BDUNCD grain capacitance and a negligible change in grain boundary impedance suggests regeneration of grains and the exposure of new grain boundaries, respectively. Overall, DA voltammogram signals were reduced by only ∼20%. In contrast, the CFM is completely etched with a ∼90% reduction in the DA signal using the same cleaning conditions. Thus, BDUNCD provides a robust electrode surface that is amenable to repeated and aggressive cleaning which could be used for chronic DA sensing.

  2. 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.

  3. Application of nitrogen-doped ultrananocrystalline diamond/hydrogenated amorphous carbon composite films for ultraviolet detection

    NASA Astrophysics Data System (ADS)

    Zkria, Abdelrahman; Gima, Hiroki; Yoshitake, Tsuyoshi

    2017-03-01

    Nitrogen-doped ultrananocrystalline diamond/hydrogenated amorphous carbon (UNCD/a-C:H) films were grown by coaxial arc plasma deposition in the ambient of nitrogen and hydrogen mixed gases. Synthesized films were structurally investigated by X-ray photoemission and near-edge X-ray absorption fine structure spectroscopies. A heterojunction with p-type Si substrate was fabricated to study the ultraviolet photodetection properties of the film. Capacitance-voltage measurements assure the expansion of a depletion region into the film side. Current-voltage curves in the dark showed a good rectifying behaviour in the bias voltages range between ±5 V. Under 254 nm monochromatic light, the heterojunction shows a capability of deep ultraviolet light detection, which can be attribute to the existence of UNCD grains. As the diode was cooled from 300 K down to 150 K, the detectivity has a notable enhancement from 1.94 × 105 cm Hz1/2 W-1 at 300 K to 5.11 × 1010 cm Hz1/2 W-1 at 150 K, which is mainly due to a remarkable reduction in the leakage current at low temperatures. It was experimentally demonstrated that nitrogen-doped UNCD/a-C:H film works as ultraviolet-range photovoltaic material.

  4. 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.

  5. 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.

  6. Strong attachment of circadian pacemaker neurons on modified ultrananocrystalline diamond surfaces.

    PubMed

    Voss, Alexandra; Wei, HongYing; Zhang, Yi; Turner, Stuart; Ceccone, Giacomo; Reithmaier, Johann Peter; Stengl, Monika; Popov, Cyril

    2016-07-01

    Diamond is a promising material for a number of bio-applications, including the fabrication of platforms for attachment and investigation of neurons and of neuroprostheses, such as retinal implants. In the current work ultrananocrystalline diamond (UNCD) films were deposited by microwave plasma chemical vapor deposition, modified by UV/O3 treatment or NH3 plasma, and comprehensively characterized with respect to their bulk and surface properties, such as crystallinity, topography, composition and chemical bonding nature. The interactions of insect circadian pacemaker neurons with UNCD surfaces with H-, O- and NH2-terminations were investigated with respect to cell density and viability. The fast and strong attachment achieved without application of adhesion proteins allowed for advantageous modification of dispersion protocols for the preparation of primary cell cultures. Centrifugation steps, which are employed for pelletizing dispersed cells to separate them from dispersing enzymes, easily damage neurons. Now centrifugation can be avoided since dispersed neurons quickly and strongly attach to the UNCD surfaces. Enzyme solutions can be easily washed off without losing many of the dispersed cells. No adverse effects on the cell viability and physiological responses were observed as revealed by calcium imaging. Furthermore, the enhanced attachment of the neurons, especially on the modified UNCD surfaces, was especially advantageous for the immunocytochemical procedures with the cell cultures. The cell losses during washing steps were significantly reduced by one order of magnitude in comparison to controls. In addition, the integration of a titanium grid structure under the UNCD films allowed for individual assignment of physiologically characterized neurons to immunocytochemically stained cells. Thus, employing UNCD surfaces free of foreign proteins improves cell culture protocols and immunocytochemistry with cultured cells. The fast and strong attachment of

  7. 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).

  8. Biokinetics and tissue response to ultrananocrystalline diamond nanoparticles employed as coating for biomedical devices.

    PubMed

    Tasat, Deborah R; Bruno, Marcos E; Domingo, Mariela; Gurman, Pablo; Auciello, Orlando; Paparella, María L; Evelson, Pablo; Guglielmotti, María B; Olmedo, Daniel G

    2016-09-12

    Although Ultrananocrystalline diamond (UNCD) has been proposed as a coating material for titanium biomedical implants, the biological effects and toxicity of UNCD particles that could eventually detach have not been studied to date. The biokinetics and biological effects of UNCD compared to titanium dioxide (TiO2 ) nanoparticles was evaluated in vivo using Wistar rats (n = 30) i.p. injected with TiO2 , UNCD or saline solution. After 6 months, blood, lung, liver, and kidney samples were histologically analyzed. Oxidative damage by membrane lipidperoxidation (thiobarbituric acid reactive substances-TBARS), generation of reactive oxygen species (superoxide anion- O2-), and antioxidant enzymes (superoxide dismutase-SOD, catalase-CAT) was evaluated in lung and liver. Histologic observation showed agglomerates of TiO2 or UNCD in the parenchyma of the studied organs, though there were fewer UNCD than TiO2 deposits. In addition, TiO2 caused areas compatibles with foci of necrosis in the liver and renal hyaline cylinders. Regarding UNCD, no membrane damage (TBARS) or mobilization of enzymatic antioxidants was observed either in lung or liver samples. No variations in O2- generation were observed in lung (Co: 35.1 ± 4.02 vs. UNCD: 48 ± 9.1, p > 0.05). Conversely, TiO2 exposure caused production of O2- in alveolar macrophages and consumption of catalase (p < 0.05). The studied parameters suggest that UNCD caused neither biochemical nor histological alterations, and therefore may prove useful as a surface coating for biomedical implants. © 2016 Wiley Periodicals, Inc. J Biomed Mater Res Part B: Appl Biomater, 2016.

  9. 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.

  10. Synthesis and characterization of smooth ultrananocrystalline diamond films via low pressure bias-enhanced nucleation and growth

    NASA Astrophysics Data System (ADS)

    Chen, Y. C.; Zhong, X. Y.; Konicek, A. R.; Grierson, D. S.; Tai, N. H.; Lin, I. N.; Kabius, B.; Hiller, J. M.; Sumant, A. V.; Carpick, R. W.; Auciello, O.

    2008-03-01

    This letter describes the fundamental process underlying the synthesis of ultrananocrystalline diamond (UNCD) films, using a new low-pressure, heat-assisted bias-enhanced nucleation (BEN)/bias enhanced growth (BEG) technique, involving H2/CH4 gas chemistry. This growth process yields UNCD films similar to those produced by the Ar-rich/CH4 chemistries, with pure diamond nanograins (3-5nm ), but smoother surfaces (˜6nm rms) and higher growth rate (˜1μm/h). Synchrotron-based x-Ray absorption spectroscopy, atomic force microscopy, and transmission electron microscopy studies on the BEN-BEG UNCD films provided information critical to understanding the nucleation and growth mechanisms, and growth condition-nanostructure-property relationships.

  11. Uncovering the Physical Basis Connecting Environment and Tribological Performance of Ultrananocrystalline Diamond

    DTIC Science & Technology

    2012-10-05

    material known to have extremely high strength and excellent tribological properties, namely low friction, adhesion , and wear, at macroscopic scales...together on an in-situ TEM nanoindentation methodology and obtained preliminary results characterizing the adhesion and wear behavior of computational...modeling , Nanoscale mechanics, Ultrananocrystalline Daimond 16. SECURITY CLASSIFICATION OF: 17. LIMITATION OF ABSTRACT Same as Report (SAR) 18

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

    SciTech Connect

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

    2015-08-28

    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 (Ω cm){sup −1}, and the EFE properties was enhanced reporting a low turn-on field of 2.1 V/μm with high EFE current density of 5.3 mA/cm{sup 2} (at an applied field of 4.9 V/μm) 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.

  13. 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

    2012-01-19

    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 Hα 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] 557°C) using the unique LPLT (30 Torr/460°C) 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).

  14. Synthesis of SiV-diamond particulates via the microwave plasma chemical deposition of ultrananocrystalline diamond on soda-lime glass fibers

    NASA Astrophysics Data System (ADS)

    Kunuku, Srinivasu; Chen, Yen-Chun; Yeh, Chien-Jui; Chang, Wen-Hao; Manoharan, Divinah; Leou, Keh-Chyang; Lin, I.-Nan

    2016-10-01

    We report the synthesis of silicon-vacancy (SiV) incorporated spherical shaped ultrananocrystalline diamond (SiV-UNCD) particulates (size ∼1 μm) with bright luminescence at 738 nm. For this purpose, different granular structured polycrystalline diamond films and particulates were synthesized by using three different kinds of growth plasma conditions on the three types of substrate materials in the microwave plasma enhanced CVD process. The grain size dependent photoluminescence properties of nitrogen vacancy (NV) and SiV color centers have been investigated for different granular structured diamond samples. The luminescence of NV center and the associated phonon sidebands, which are usually observed in microcrystalline diamond and nanocrystalline diamond films, were effectively suppressed in UNCD films and UNCD particulates. Micron sized SiV-UNCD particulates with bright SiV emission has been attained by transfer of SiV-UNCD clusters on soda-lime glass fibers to inverted pyramidal cavities fabricated on Si substrates by the simple crushing of UNCD/soda-lime glass fibers in deionized water and ultrasonication. Such a plasma enhanced CVD process for synthesizing SiV-UNCD particulates with suppressed NV emission is simple and robust to attain the bright SiV-UNCD particulates to employ in practical applications.

  15. 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.

  16. An insight of p-type to n-type conductivity conversion in oxygen ion-implanted ultrananocrystalline diamond films by impedance spectroscopy

    NASA Astrophysics Data System (ADS)

    Xu, Hui; Ye, Haitao; Coathup, David; Mitrovic, Ivona Z.; Weerakkody, Ayendra D.; Hu, Xiaojun

    2017-01-01

    The impedance spectroscopy measurements were used to investigate the separated contributions of diamond grains and grain boundaries (GBs), giving an insight into p-type to n-type conductivity conversion in O+-implanted ultrananocrystalline diamond (UNCD) films. It is found that both diamond grains and GBs promote the conductivity in O+-implanted UNCD films, in which GBs make at least half contribution. The p-type conductivity in O+-implanted samples is a result of H-terminated diamond grains, while n-type conductive samples are closely correlated with O-terminated O+-implanted diamond grains and GBs in the films. The results also suggest that low resistance of GBs is preferable to obtain high mobility n-type conductive UNCD films.

  17. 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.

  18. Hard coating of ultrananocrystalline diamond/nonhydrogenated amorphous carbon composite films on cemented 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

    2016-08-01

    Ultrananocrystalline diamond (UNCD)/nonhydrogenated amorphous carbon (a-C) composite (UNCD/a-C) films were deposited on cemented carbide containing Co by coaxial arc plasma deposition. With decreasing substrate temperature, the hardness was enhanced accompanied by an enhancement in the sp3/(sp2 + sp3). Energy-dispersive X-ray and secondary ion mass spectrometry spectroscopic measurements exhibited that the diffusion of Co atoms from the substrates into the films hardly occurs. The film deposited at room temperature exhibited the maximum hardness of 51.3 GPa and Young's modulus of 520.2 GPa, which evidently indicates that graphitization induced by Co in the WC substrates, and thermal deformation from sp3 to sp2 bonding are suppressed. The hard UNCD/a-C films can be deposited at a thickness of approximately 3 μm, which is an order larger than that of comparably hard a-C films. The internal compressive stress of the 51.3-GPa film is 4.5 GPa, which is evidently smaller than that of comparably hard a-C films. This is a reason for the thick deposition. The presence of a large number of grain boundaries in the film, which is a structural specific to UNCD/a-C films, might play a role in releasing the internal stress of the films.

  19. 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.

  20. 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.

  1. 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.

  2. 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.

  3. 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.

  4. 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.

  5. Hydrogenation effects on carrier transport in boron-doped ultrananocrystalline diamond/amorphous carbon films prepared by coaxial arc plasma deposition

    SciTech Connect

    Katamune, Yūki Takeichi, Satoshi; Ohmagari, Shinya; Yoshitake, Tsuyoshi

    2015-11-15

    Boron-doped ultrananocrystalline diamond/hydrogenated amorphous carbon composite (UNCD/a-C:H) films were deposited by coaxial arc plasma deposition with a boron-blended graphite target at a base pressure of <10{sup −3} Pa and at hydrogen pressures of ≤53.3 Pa. The hydrogenation effects on the electrical properties of the films were investigated in terms of chemical bonding. Hydrogen-scattering spectrometry showed that the maximum hydrogen content was 35 at. % for the film produced at 53.3-Pa hydrogen pressure. The Fourier-transform infrared spectra showed strong absorptions by sp{sup 3} C–H bonds, which were specific to the UNCD/a-C:H, and can be attributed to hydrogen atoms terminating the dangling bonds at ultrananocrystalline diamond grain boundaries. Temperature-dependence of the electrical conductivity showed that the films changed from semimetallic to semiconducting with increasing hydrogen pressure, i.e., with enhanced hydrogenation, probably due to hydrogenation suppressing the formation of graphitic bonds, which are a source of carriers. Carrier transport in semiconducting hydrogenated films can be explained by a variable-range hopping model. The rectifying action of heterojunctions comprising the hydrogenated films and n-type Si substrates implies carrier transport in tunneling.

  6. Uncovering the Physical Basis Connecting Environment and Tribological Performance of Ultrananocrystalline Diamond

    DTIC Science & Technology

    2014-04-17

    plastic behavior induced during the nanoindentation cycle. We also performed experiments using depth- sensing indentation technique. The load-depth...sites for diamond growth during chemical vapor deposition. The effect of a 2 nm thick carbon coating, generated by sputter coating ( Quorum , USA) as

  7. 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 μm, the use of indium bump bonding technology and vertical interconnects facilitates implants with tens of thousands electrodes with a pitch as low as 10 μm, thus ensuring validity of the strategy for future high acuity retinal prostheses, and bionic implants in general.

  8. Chemical bonding structural analysis of nitrogen-doped ultrananocrystalline diamond/hydrogenated amorphous carbon composite films prepared by coaxial arc plasma deposition

    NASA Astrophysics Data System (ADS)

    Gima, Hiroki; Zkria, Abdelrahman; Katamune, Yūki; Ohtani, Ryota; Koizumi, Satoshi; Yoshitake, Tsuyoshi

    2017-01-01

    Nitrogen-doped ultra-nanocrystalline diamond/hydrogenated amorphous carbon composite films prepared in hydrogen and nitrogen mixed-gas atmospheres by coaxial arc plasma deposition with graphite targets were studied electrically and chemical-bonding-structurally. The electrical conductivity was increased by nitrogen doping, accompanied by the production of n-type conduction. From X-ray photoemission, near-edge X-ray absorption fine-structure, hydrogen forward-scattering, and Fourier transform infrared spectral results, it is expected that hydrogen atoms that terminate diamond grain boundaries will be partially replaced by nitrogen atoms and, consequently, π C-N and C=N bonds that easily generate free electrons will be formed at grain boundaries.

  9. 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.

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

    DOEpatents

    Gruen, Dieter M.; Busmann, Hans-Gerd; Meyer, Eva-Maria; Auciello, Orlando; Krauss, Alan R.; Krauss, Julie R.

    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.

  11. Effects of nitrogen doping on the electrical conductivity and optical absorption of ultrananocrystalline diamond/hydrogenated amorphous carbon films prepared by coaxial arc plasma deposition

    NASA Astrophysics Data System (ADS)

    Zkria, Abdelrahman; Katamune, Yūki; Yoshitake, Tsuyoshi

    2016-07-01

    3 at. % nitrogen-doped ultrananocrystalline diamond/hydrogenated amorphous carbon composite (UNCD/a-C:H) films were synthesized by coaxial arc plasma deposition. Optically, the films possess large absorption coefficients of more than 105 cm-1 at photon energies from 3 to 5 eV. The optical band gap was estimated to be 1.28 eV. This value is smaller than that of undoped films, which might be attributable to increased sp2 fractions. The temperature dependence of the electrical conductivity implies that carrier transport follows a hopping conduction model. Heterojunctions with p-type Si substrates exhibited a typical rectifying action. From the capacitance-voltage characteristics that evidently indicated the expansion of a depletion region into the film side, 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 films are applicable as an n-type semiconductor.

  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/μm, attaining a EFE current density as large as 3.19 mA/cm{sup 2} at an applied field of 8.64 V/μm. 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. 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.

  14. 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.

  15. Nanostructured diamond layers enhance the infrared spectroscopy of biomolecules.

    PubMed

    Kozak, Halyna; Babchenko, Oleg; Artemenko, Anna; Ukraintsev, Egor; Remes, Zdenek; Rezek, Bohuslav; Kromka, Alexander

    2014-03-04

    We report on the fabrication and practical use of high-quality optical elements based on Au mirrors coated with diamond layers with flat, nanocolumnar, and nanoporous morphologies. Diamond layers (100 nm thickness) are grown at low temperatures (about 300 °C) from a methane, carbon dioxide, and hydrogen gas mixture by a pulsed microwave plasma system with linear antennas. Using grazing angle reflectance (GAR) Fourier transform infrared spectroscopy with p-polarized light, we compare the IR spectra of fetal bovine serum proteins adsorbed on diamond layers with oxidized (hydrophilic) surfaces. We show that the nanoporous diamond layers provide IR spectra with a signal gain of about 600% and a significantly improved sensitivity limit. This is attributed to its enhanced internal surface area. The improved sensitivity enabled us to distinguish weak infrared absorption peaks of <10-nm-thick protein layers and thereby to analyze the intimate diamond-molecule interface.

  16. Diamond-based protective layer for optical biosensors

    NASA Astrophysics Data System (ADS)

    Majchrowicz, D.; Ficek, M.; Baran, T.; WÄ sowicz, M.; Struk, P.; Jedrzejewska-Szczerska, M.

    2016-09-01

    Optical biosensors have become a powerful alternative to the conventional ways of measurement owing to their great properties, such as high sensitivity, high dynamic range, cost effectiveness and small size. Choice of an optical biosensor's materials is an important factor and impacts the quality of the obtained spectra. Examined biological objects are placed on a cover layer which may react with samples in a chemical, biological and mechanical way, therefore having a negative impact on the measurement reliability. Diamond, a metastable allotrope of carbon with sp3 hybridization, shows outstanding properties such as: great chemical stability, bio-compatibility, high thermal conductivity, wide bandgap and optical transparency. Additionally it possesses great mechanical durability, which makes it a long-lasting material. The protective diamond thin films were deposited on the substrate using Microwave Plasma Assisted Chemical Vapor Deposition (MW PA CVD) system. The surface morphology and roughness was assessed with atomic force microscopy and profilometry. We have performed a series of measurements to assess the biocompatibility of diamond thin films with whole blood. The results show that thin diamond protective layer does not affect the red blood cells, while retaining the sensors high resolution and dynamic range of measurement. Therefore, we conclude that diamond thin films are a viable protective coating for optical biosensors, which allows to examine many biological elements. We project that it can be particularly useful not only for biological objects but also under extreme conditions like radioactive or chemically aggressive environments and high temperatures.

  17. Lamb waves dispersion curves for diamond based piezoelectric layered structure

    NASA Astrophysics Data System (ADS)

    Sorokin, B. P.; Kvashnin, G. M.; Telichko, A. V.; Novoselov, A. S.; Burkov, S. I.

    2016-03-01

    The presence of spurious peaks in the amplitude-frequency response of diamond based piezoelectric layered structure was shown. Excitation of such peaks results in deterioration of an useful acoustical signal. It was shown that such spurious peaks should be associated with Lamb waves in a layered structure. By means of FEM analysis, the propagation of acoustic waves of different types in the piezoelectric layered structure "Al/AlN/Mo/(100) diamond" has been investigated in detail. By analyzing the elastic displacement patterns at frequencies from 0 up to 250 MHz, a set of all the possible acoustic waves, especially Lamb modes, have been studied, and dispersive curves of phase velocity have been plotted. A revised classification of Lamb modes has been introduced.

  18. 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

  19. 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.

  20. 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.

  1. Single-layer nano-carbon film, diamond film, and diamond/nano-carbon composite film field emission performance comparison

    NASA Astrophysics Data System (ADS)

    Wang, Xiaoping; Wang, Jinye; Wang, Lijun

    2016-05-01

    A series of single-layer nano-carbon (SNC) films, diamond films, and diamond/nano-carbon (D/NC) composite films have been prepared on the highly doped silicon substrate by using microwave plasma chemical vapor deposition techniques. The films were characterised by scanning electron microscopy, Raman spectroscopy, and field emission I-V measurements. The experimental results indicated that the field emission maximum current density of D/NC composite films is 11.8-17.8 times that of diamond films. And the field emission current density of D/NC composite films is 2.9-5 times that of SNC films at an electric field of 3.0 V/μm. At the same time, the D/NC composite film exhibits the advantage of improved reproducibility and long term stability (both of the nano-carbon film within the D/NC composite cathode and the SNC cathode were prepared under the same experimental conditions). And for the D/NC composite sample, a high current density of 10 mA/cm2 at an electric field of 3.0 V/μm was obtained. Diamond layer can effectively improve the field emission characteristics of nano-carbon film. The reason may be due to the diamond film acts as the electron acceleration layer.

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

    DOEpatents

    Chang, R. P. H.; Grannen, Kevin J.

    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.

  3. Effects of Implant Copper Layer on Diamond Film Deposition on Cemented Carbides

    NASA Astrophysics Data System (ADS)

    Ma, Zhi-bin; Wang, Jian-hua; Wu, Qin-chong; Wang, Chuan-xin

    2001-02-01

    The deposition of high-quality diamond films and their adhesion on cemented carbides are strongly influenced by the catalytic effect of cobalt under typical deposition conditions. Decreasing Co content on the surface of the cemented carbide is often used for the diamond film deposition. But the leaching of Co from the WC-Co substrate leading to a mechanical weak surface often causes a poor adhesion. In this paper we adopted an implant copper layer prepared by vaporization to improve the mechanical properties of the Co-leached substrate. The diamond films were grown by microwave plasma chemical vapor deposition from CH4:H2 gas mixture. The cross section and the morphology of the diamond film were characterized by scanning electron microscopy (SEM). The non-diamond content in the film was analyzed by Raman spectroscopy. The effects of pretreatment on the concentrations of Co and Cu near the interfacial region were examined by energy dispersive spectrum (EDS) equipped with SEM. The adhesion of the diamond on the substrate was evaluated with a Rockwell-type hardness tester. The results indicate that the diamond films prepared with implant copper layer have a good adhesion to the cemented carbide substrate due to the recovery of the mechanical properties of the Co-depleted substrate after the copper implantation and the formation of less amorphous carbon between the substrate and the diamond film.

  4. The low coherence Fabry-Pérot interferometer with diamond and ZnO layers

    NASA Astrophysics Data System (ADS)

    Majchrowicz, D.; Den, W.; Hirsch, M.

    2016-09-01

    The authors present a fiber-optic Fabry-Pérot interferometer built with the application of diamond and zinc oxide (ZnO) thin layers. Thin ZnO films were deposited on the tip of a standard telecommunication single-mode optical fiber (SMF- 28) while the diamond layer was grown on the plate of silicon substrate. Investigated ZnO layers were fabricated by atomic layer deposition (ALD) and the diamond films were deposited using Microwave Plasma Enhanced Chemical Vapor Deposition (μPE CVD) system. Different thickness of layers was examined. The measurements were performed for the fiber-optic Fabry-Pérot interferometer working in the reflective mode. Spectra were registered for various thicknesses of ZnO layer and various length of the air cavity. As a light source, two superluminescent diodes (SLD) with central wavelength of 1300 nm and 1550 nm were used in measurement set-up.

  5. Nanoscale solely amorphous layer in silicon wafers induced by a newly developed diamond wheel.

    PubMed

    Zhang, Zhenyu; Guo, Liangchao; Cui, Junfeng; Wang, Bo; Kang, Renke; Guo, Dongming

    2016-10-13

    Nanoscale solely amorphous layer is achieved in silicon (Si) wafers, using a developed diamond wheel with ceria, which is confirmed by high resolution transmission electron microscopy (HRTEM). This is different from previous reports of ultraprecision grinding, nanoindentation and nanoscratch, in which an amorphous layer at the top, followed by a crystalline damaged layer beneath. The thicknesses of amorphous layer are 43 and 48 nm at infeed rates of 8 and 15 μm/min, respectively, which is verified using HRTEM. Diamond-cubic Si-I phase is verified in Si wafers using selected area electron diffraction patterns, indicating the absence of high pressure phases. Ceria plays an important role in the diamond wheel for achieving ultrasmooth and bright surfaces using ultraprecision grinding.

  6. Nanoscale solely amorphous layer in silicon wafers induced by a newly developed diamond wheel

    NASA Astrophysics Data System (ADS)

    Zhang, Zhenyu; Guo, Liangchao; Cui, Junfeng; Wang, Bo; Kang, Renke; Guo, Dongming

    2016-10-01

    Nanoscale solely amorphous layer is achieved in silicon (Si) wafers, using a developed diamond wheel with ceria, which is confirmed by high resolution transmission electron microscopy (HRTEM). This is different from previous reports of ultraprecision grinding, nanoindentation and nanoscratch, in which an amorphous layer at the top, followed by a crystalline damaged layer beneath. The thicknesses of amorphous layer are 43 and 48 nm at infeed rates of 8 and 15 μm/min, respectively, which is verified using HRTEM. Diamond-cubic Si-I phase is verified in Si wafers using selected area electron diffraction patterns, indicating the absence of high pressure phases. Ceria plays an important role in the diamond wheel for achieving ultrasmooth and bright surfaces using ultraprecision grinding.

  7. Nanoscale solely amorphous layer in silicon wafers induced by a newly developed diamond wheel

    PubMed Central

    Zhang, Zhenyu; Guo, Liangchao; Cui, Junfeng; Wang, Bo; Kang, Renke; Guo, Dongming

    2016-01-01

    Nanoscale solely amorphous layer is achieved in silicon (Si) wafers, using a developed diamond wheel with ceria, which is confirmed by high resolution transmission electron microscopy (HRTEM). This is different from previous reports of ultraprecision grinding, nanoindentation and nanoscratch, in which an amorphous layer at the top, followed by a crystalline damaged layer beneath. The thicknesses of amorphous layer are 43 and 48 nm at infeed rates of 8 and 15 μm/min, respectively, which is verified using HRTEM. Diamond-cubic Si-I phase is verified in Si wafers using selected area electron diffraction patterns, indicating the absence of high pressure phases. Ceria plays an important role in the diamond wheel for achieving ultrasmooth and bright surfaces using ultraprecision grinding. PMID:27734934

  8. 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.

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

    NASA Astrophysics Data System (ADS)

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

    2011-12-01

    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 × 4 mm in size is obtained. A discharge with the torch diameter of ˜2 mm and the concentration of the microwave power absorbed in the torch volume of >103 W/cm3 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 μm with high-quality morphology is investigated with an optical microscope as well as using the methods of the Raman scattering and scanning electron microscopy.

  10. DNA-modified nanocrystalline diamond thin-films as stable, biologically active substrates

    NASA Astrophysics Data System (ADS)

    Yang, Wensha; Auciello, Orlando; Butler, James E.; Cai, Wei; Carlisle, John A.; Gerbi, Jennifer E.; Gruen, Dieter M.; Knickerbocker, Tanya; Lasseter, Tami L.; Russell, John N.; Smith, Lloyd M.; Hamers, Robert J.

    2002-12-01

    Diamond, because of its electrical and chemical properties, may be a suitable material for integrated sensing and signal processing. But methods to control chemical or biological modifications on diamond surfaces have not been established. Here, we show that nanocrystalline diamond thin-films covalently modified with DNA oligonucleotides provide an extremely stable, highly selective platform in subsequent surface hybridization processes. We used a photochemical modification scheme to chemically modify clean, H-terminated nanocrystalline diamond surfaces grown on silicon substrates, producing a homogeneous layer of amine groups that serve as sites for DNA attachment. After linking DNA to the amine groups, hybridization reactions with fluorescently tagged complementary and non-complementary oligonucleotides showed no detectable non-specific adsorption, with extremely good selectivity between matched and mismatched sequences. Comparison of DNA-modified ultra-nanocrystalline diamond films with other commonly used surfaces for biological modification, such as gold, silicon, glass and glassy carbon, showed that diamond is unique in its ability to achieve very high stability and sensitivity while also being compatible with microelectronics processing technologies. These results suggest that diamond thin-films may be a nearly ideal substrate for integration of microelectronics with biological modification and sensing.

  11. Patterned hydrophobic and hydrophilic surfaces of ultra-smooth nanocrystalline diamond layers

    NASA Astrophysics Data System (ADS)

    Mertens, M.; Mohr, M.; Brühne, K.; Fecht, H. J.; Łojkowski, M.; Święszkowski, W.; Łojkowski, W.

    2016-12-01

    In this work, we show that ultra nanocrystalline diamond (UNCD) surfaces have been modified to add them hydrophobic and hydrophilic properties. The nanocrystalline diamond films were deposited using the hot filament chemical vapor deposition (HFCVD) technique. This allows growing diamond on different substrates which can be even 3D or structured. Silicon and, for optical applications, transparent quartz glass are the preferred substrates for UNCD layers growth. Fluorine termination leads to strong hydrophobic properties as indicated by a high contact angle for water of more than 100°. Hydrogen termination shows lesser hydrophobic behavior. Hydrophilic characteristics has been realised with oxygen termination. X-ray photoelectron spectroscopy (XPS) and energy dispersive X-ray spectroscopy (EDX) measurements confirm the oxygen and fluorine- termination on the nanocrystalline diamond surface. Further, by micropatterning using photolithography, multi-terminated layers have been created with both hydrophobic and hydrophilic areas. In addition, we have shown that retermination is achieved, and the properties of the surface have been changed from hydrophobic to hydrophilic and vice versa. Micro- roughness and stress in the grown film influences slightly the wetting angle as well. The opportunity to realize local differences in hydrophobicity on nanocrystalline diamond layers, in any size or geometry, offers interesting applications for example in microbiological investigations. Multi-terminated arrays show identical surface roughness and at the same time differences in hydrophobicity. These arrays have been visualized with scanning electron microscopy (SEM) and lateral force microscopy (LFM).

  12. Single crystal diamond boron 'delta doped' nanometric layers for 2D electronic devices (Conference Presentation)

    NASA Astrophysics Data System (ADS)

    Butler, James

    2016-10-01

    Use of diamond as a semiconductor material suffers from the high activation energy of all known impurity dopants (0.37 eV for Boron, 0.6 eV for Phosphorous). To achieve the simultaneous carrier concentration and mobility desired for devices operating at room temperature, growth of a nanometric thick `delta' layer doped to above the metal insulator transition adjacent to high mobility intrinsic material can provide a 2D high mobility conduction layer. Critical to obtaining the enhanced mobility of the carriers in the layer next to the `delta' doped layer is the abruptness of the doping interface. Single and multiple nanometer thick epitaxial layers of heavily boron `delta' doped diamond have been grown on high quality, intrinsic lab grown diamond single crystals. These layers were grown in a custom microwave plasma activated chemical vapor deposition reactor based on a rapid reactant switching technique. Characterization of the `delta' layers by various analytical techniques will be presented. Electrical measurements demonstrating enhanced hole mobility (100 to 800 cm2/V sec) as well as other electrical characterizations will be presented.

  13. 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

  14. Fabrication of Hierarchical Layer-by-Layer Assembled Diamond-based Core-Shell Nanocomposites as Highly Efficient Dye Absorbents for Wastewater Treatment

    PubMed Central

    Zhao, Xinna; Ma, Kai; Jiao, Tifeng; Xing, Ruirui; Ma, Xilong; Hu, Jie; Huang, Hao; Zhang, Lexin; Yan, Xuehai

    2017-01-01

    The effective chemical modification and self-assembly of diamond-based hierarchical composite materials are of key importance for a broad range of diamond applications. Herein, we report the preparation of novel core-shell diamond-based nanocomposites for dye adsorption toward wastewater treatment through a layer-by-layer (LbL) assembled strategy. The synthesis of the reported composites began with the carboxyl functionalization of microdiamond by the chemical modification of diamond@graphene oxide composite through the oxidation of diamond@graphite. The carboxyl-terminated microdiamond was then alternatively immersed in the aqueous solution of amine-containing polyethylenimine and carboxyl-containing poly acrylic acid, which led to the formation of adsorption layer on diamond surface. Alternating (self-limiting) immersions in the solutions of the amine-containing and carboxyl-containing polymers were continued until the desired number of shell layers were formed around the microdiamond. The obtained core-shell nanocomposites were successfully synthesized and characterized by morphological and spectral techniques, demonstrating higher surface areas and mesoporous structures for good dye adsorption capacities than nonporous solid diamond particles. The LbL-assembled core-shell nanocomposites thus obtained demonstrated great adsorption capacity by using two model dyes as pollutants for wastewater treatment. Therefore, the present work on LbL-assembled diamond-based composites provides new alternatives for developing diamond hybrids as well as nanomaterials towards wastewater treatment applications. PMID:28272452

  15. Fabrication of Hierarchical Layer-by-Layer Assembled Diamond-based Core-Shell Nanocomposites as Highly Efficient Dye Absorbents for Wastewater Treatment

    NASA Astrophysics Data System (ADS)

    Zhao, Xinna; Ma, Kai; Jiao, Tifeng; Xing, Ruirui; Ma, Xilong; Hu, Jie; Huang, Hao; Zhang, Lexin; Yan, Xuehai

    2017-03-01

    The effective chemical modification and self-assembly of diamond-based hierarchical composite materials are of key importance for a broad range of diamond applications. Herein, we report the preparation of novel core-shell diamond-based nanocomposites for dye adsorption toward wastewater treatment through a layer-by-layer (LbL) assembled strategy. The synthesis of the reported composites began with the carboxyl functionalization of microdiamond by the chemical modification of diamond@graphene oxide composite through the oxidation of diamond@graphite. The carboxyl-terminated microdiamond was then alternatively immersed in the aqueous solution of amine-containing polyethylenimine and carboxyl-containing poly acrylic acid, which led to the formation of adsorption layer on diamond surface. Alternating (self-limiting) immersions in the solutions of the amine-containing and carboxyl-containing polymers were continued until the desired number of shell layers were formed around the microdiamond. The obtained core-shell nanocomposites were successfully synthesized and characterized by morphological and spectral techniques, demonstrating higher surface areas and mesoporous structures for good dye adsorption capacities than nonporous solid diamond particles. The LbL-assembled core-shell nanocomposites thus obtained demonstrated great adsorption capacity by using two model dyes as pollutants for wastewater treatment. Therefore, the present work on LbL-assembled diamond-based composites provides new alternatives for developing diamond hybrids as well as nanomaterials towards wastewater treatment applications.

  16. The Shock and Release Behavior of Diamond Compressed to 25 Mbar

    NASA Astrophysics Data System (ADS)

    Gregor, M. C.

    2016-10-01

    The behavior of carbon at high pressure is important to the study of ice giants and white dwarfs, and because diamond is used as an ablator for inertial confinement fusion (ICF) targets at the National Ignition Facility (NIF). The adiabat of an ICF implosion is determined by a series of shocks that transit the ablator and fuel layer. To accurately model an implosion and design ignition targets, both the Hugoniot and the release behavior of the ablator material must be known. We report on experiments on the OMEGA laser that shocked diamond samples up to 25 Mbar, which then released into reference materials with known Hugoniots (quartz, 200-mg/cm3 SiO2 foam, liquid deuterium, and polystyrene). The impedance-matching technique with these reference materials provided data that constrains release models for diamond. This technique is applied to two forms of diamond: single-crystal and ultra-nanocrystalline diamond (UNCD); the latter is the NIF ablator material. Models for the release isentropes of both types of diamond will be developed using a Mie-Grüneisen equation of state. This study also provided Hugoniot data for UNCD using the impedance-matching technique with a quartz standard. The accuracy of these data was improved by implementing an unsteady wave correction to determine instantaneous shock velocities in the opaque UNCD samples. This material is based upon work supported by the Department of Energy National Nuclear Security Administration under Award Number DE-NA0001944.

  17. Design of a three-dimensional photonic crystal nanocavity based on a \\langle 110\\rangle -layered diamond structure

    NASA Astrophysics Data System (ADS)

    Tajiri, Takeyoshi; Takahashi, Shun; Tandaechanurat, Aniwat; Iwamoto, Satoshi; Arakawa, Yasuhiko

    2014-01-01

    We design a three-dimensional (3D) photonic crystal (PC) nanocavity based on a \\langle 110\\rangle -layered diamond structure. The designed structure, comprised of self-sustainable layers, is suitable for fabrication by layer stacking techniques. Quality factors (Q-factors) of nanocavities were calculated for the \\langle 110\\rangle -layered diamond and a commonly-used woodpile structures, both of which are generated from the same diamond lattice with a lattice constant adiamond. The Q-factor of the designed nanocavity can reach as high as 230,000 with 35 stacked layers and a square in-plane PC area of the length of one side of 5\\sqrt{2} a^{\\text{diamond}}. This is 1.5 times higher than that of a 3D PC nanocavity based on the woodpile structure with the same in-plane PC size and with the same number of stacked layers. The higher Q-factor in the \\langle 110\\rangle -layered diamond structure originates from its stronger in-plane light confinement over the woodpile structure. The \\langle 110\\rangle -layered diamond structure will be beneficial for improving experimentally attainable Q-factors of 3D PC nanocavities particularly fabricated by a micromanipulation method.

  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. Effect of amorphous carbon layers on the growth of diamond in dual-frequency plasma

    NASA Astrophysics Data System (ADS)

    Reinke, P.; Klemberg-Sapieha, J. E.; Martinu, L.

    1994-11-01

    In the present work we study the growth of diamond in a dual-mode microwave/radio frequency plasma. We investigate the effect of the thickness of predeposited hydrogenated amorphous carbon (a-C:H) films and of ion bombardment of the nucleation process and on the crystal quality. The deposits are characterized by x-ray photoelectron spectroscopy (XPS) and by scanning electron microscopy. The XPS spectra of the C(1s) carbon peak and of the plasmon features confirm the presence of an amorphous, carbonaceous phase and of silicon carbide on the surface. Radio frequency biasing during the initial stage of diamond growth leads to a lower crystal quality, but to a higher nucleation density N(sub D). Without biasing, good quality, predominantly (100) oriented diamond crystals are obtained on a Si(100) surface. The N(sub D) values are found to increase with the thickness of the predeposited a-C:H layer. Evolution of the nucleus size distributions indicates that the a-C:H film contributes to the carbon supply, enhancing the nucleation efficiency and shortening the incubation time of seed crystals. Before a continuous layer is formed, the growth of crystals is determined by the interaction with the gas phase as well as by the amount of carbon available on the surface.

  20. Demonstration of a three-dimensional photonic crystal nanocavity in a 〈110〉-layered diamond structure

    SciTech Connect

    Tajiri, T.; Takahashi, S.; Ota, Y.; Tatebayashi, J.; Iwamoto, S.; Arakawa, Y.

    2015-08-17

    We experimentally demonstrate a three-dimensional photonic crystal (3D PC) nanocavity in a 〈110〉-layered diamond structure with a quality factor (Q-factor) of 12 800 at a wavelength of 1.1 μm. The observed Q is 1.2 times higher than that of a 3D PC nanocavity in a woodpile structure with the same in-plane size and the same number of stacked layers. This result indicates the potential importance of the 〈110〉-layered diamond structure for getting high Q 3D PC nanocavities within a limited in-plane space.

  1. Temperature Dependence of Mechanical Stiffness and Dissipation in Ultrananocrystalline Diamond

    DTIC Science & Technology

    2009-01-01

    In nanocrystalline / nano -scale materials the temperature dependence of the modulus can be much different than for single crystals because of the...presence of a large proportion of grain boundaries. Recent progress has shown that it is possible to correlate changes in Young’s modulus of nano ...thermal properties of nanocrystalline elemental selenium studied by x-ray diffraction," Physical Review B, vol. 56, p. 14330, 1997. [26] C. Seoanez

  2. 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 μm 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 Peñon, 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 cubic—not 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.

  3. 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.

  4. Multilayers Diamond-Like Carbon Film with Germanium Buffer Layers by Pulsed Laser Deposition

    NASA Astrophysics Data System (ADS)

    Cheng, Y.; Lu, Y. M.; Guo, Y. L.; Huang, G. J.; Wang, S. Y.; Tian, F. T.

    Multilayer diamond-like carbon film with germanium buffer layers, which was composed of several thick DLC layers and thin germanium island “layers” and named as Ge-DLC film, was prepared on the germanium substrate by ultraviolet laser. The Ge-DLC film had almost same surface roughness as the pure DLC film. Hardness of the Ge-DLC film was above 48.1GPa, which was almost the same as that of pure DLC film. Meanwhile, compared to the pure DLC film, the critical load of Ge-DLC film on the germanium substrate increased from 81.6mN to 143.8mN. Moreover, Ge-DLC film on germanium substrates had no change after fastness tests. The results showed that Ge-DLC film not only kept high hardness but also had higher critical load than that of pure DLC film. Therefore, it could be used as practical protective films.

  5. Enhancement of plasma illumination characteristics of few-layer graphene-diamond nanorods hybrid

    NASA Astrophysics Data System (ADS)

    Jothiramalingam Sankaran, Kamatchi; Yeh, Chien-Jui; Drijkoningen, Sien; Pobedinskas, Paulius; Van Bael, Marlies K.; Leou, Keh-Chyang; Lin, I.-Nan; Haenen, Ken

    2017-02-01

    Few-layer graphene (FLG) was catalytically formed on vertically aligned diamond nanorods (DNRs) by a high temperature annealing process. The presence of 4-5 layers of FLG on DNRs was confirmed by transmission electron microscopic studies. It enhances the field electron emission (FEE) behavior of the DNRs. The FLG-DNRs show excellent FEE characteristics with a low turn-on field of 4.21 V μm-1 and a large field enhancement factor of 3480. Moreover, using FLG-DNRs as cathode markedly enhances the plasma illumination behavior of a microplasma device, viz not only the plasma current density is increased, but also the robustness of the devices is improved.

  6. Enhancement of plasma illumination characteristics of few-layer graphene-diamond nanorods hybrid.

    PubMed

    Sankaran, Kamatchi Jothiramalingam; Yeh, Chien-Jui; Drijkoningen, Sien; Pobedinskas, Paulius; Van Bael, Marlies K; Leou, Keh-Chyang; Lin, I-Nan; Haenen, Ken

    2017-02-10

    Few-layer graphene (FLG) was catalytically formed on vertically aligned diamond nanorods (DNRs) by a high temperature annealing process. The presence of 4-5 layers of FLG on DNRs was confirmed by transmission electron microscopic studies. It enhances the field electron emission (FEE) behavior of the DNRs. The FLG-DNRs show excellent FEE characteristics with a low turn-on field of 4.21 V μm(-1) and a large field enhancement factor of 3480. Moreover, using FLG-DNRs as cathode markedly enhances the plasma illumination behavior of a microplasma device, viz not only the plasma current density is increased, but also the robustness of the devices is improved.

  7. Fabrication of a nanometer thick nitrogen delta doped layer at the sub-surface region of (100) diamond

    NASA Astrophysics Data System (ADS)

    Chandran, Maneesh; Michaelson, Shaul; Saguy, Cecile; Hoffman, Alon

    2016-11-01

    In this letter, we report on the proof of a concept of an innovative delta doping technique to fabricate an ensemble of nitrogen vacancy centers at shallow depths in (100) diamond. A nitrogen delta doped layer with a concentration of ˜1.8 × 1020 cm-3 and a thickness of a few nanometers was produced using this method. Nitrogen delta doping was realized by producing a stable nitrogen terminated (N-terminated) diamond surface using the RF nitridation process and subsequently depositing a thin layer of diamond on the N-terminated diamond surface. The concentration of nitrogen on the N-terminated diamond surface and its stability upon exposure to chemical vapor deposition conditions are determined by x-ray photoelectron spectroscopy analysis. The SIMS profile exhibits a positive concentration gradient of 1.9 nm/decade and a negative gradient of 4.2 nm/decade. The proposed method offers a finer control on the thickness of the delta doped layer than the currently used ion implantation and delta doping techniques.

  8. Surface characterization and orientation interaction between diamond- like carbon layer structure and dimeric liquid crystals

    NASA Astrophysics Data System (ADS)

    Naradikian, H.; Petrov, M.; Katranchev, B.; Milenov, T.; Tinchev, S.

    2017-01-01

    Diamond-like carbon (DLC) and amorphous carbon films are very promising type of semiconductor materials. Depending on the hybridization sp2/sp3 ratio, the material’s band gap varies between 0.8 and 3 eV. Moreover carbon films possess different interesting for practice properties: comparable to the Silicon, Diamond like structure has 22-time better thermal conductivity etc. Here we present one type of implementation of such type nanostructure. That is one attempt for orientation of dimeric LC by using of pre-deposited DLC layer with different ratio of sp2/sp3 hybridized carbon content. It could be expected a pronounced π1-π2interaction between s and p orbital levels on the surface and the dimeric ring of LC. We present comparison of surface anchoring strengths of both orientation inter-surfaces DLC/dimeric LC and single wall carbon nanotubes (SWCNT)/dimeric LC. The mechanism of interaction of dimeric LC and activated surfaces with DLC or SWCNT will be discussed. In both cases we have π-π interaction, which in combination with hydrogen bonding, typical for the dimeric LCs, influence the LC alignment. The Raman spectroscopy data evidenced the presence of charge transfer between contacting hexagonal rings of DLC and the C = O groups of the LC molecules.

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

    DOEpatents

    Gruen, Dieter M.; Krauss, Alan R.; Auciello, Orlando H.; Carlisle, John A.

    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.

  10. Microplasma device architectures with various diamond nanostructures

    NASA Astrophysics Data System (ADS)

    Kunuku, Srinivasu; Jothiramalingam Sankaran, Kamatchi; Leou, Keh-Chyang; Lin, I.-Nan

    2017-02-01

    Diamond nanostructures (DNSs) were fabricated from three different morphological diamonds, microcrystalline diamond (MCD), nanocrystalline diamond (NCD), and ultrananocrystalline diamond (UNCD) films, using a reactive ion etching method. The plasma illumination (PI) behavior of microplasma devices using the DNSs and the diamond films as cathode were investigated. The Paschen curve approach revealed that the secondary electron emission coefficient (γ value) of diamond materials is similar irrespective of the microstructure (MCD, NCD, and UNCD) and geometry of the materials (DNSs and diamond films). The diamond materials show markedly larger γ-coefficient than conventional metallic cathode materials such as Mo that resulted in markedly better PI behavior for the corresponding microplasma devices. Moreover, the PI behavior, i.e. the voltage dependence of plasma current density (J pl‑V), plasma density (n e‑V), and the robustness of the devices, varied markedly with the microstructure and geometry of the cathode materials that was closely correlated to the electron field emission (EFE) properties of the cathode materials. The UNCD nanopillars, possessing good EFE properties, resulted in superior PI behavior, whereas the MCD diamond films with insufficient EFE properties led to inferior PI behavior. Consequently, enhancement of plasma characteristics is the collective effects of EFE behavior and secondary electron emission characteristics of diamond-based cathode materials.

  11. Topologic connection between 2-D layered structures and 3-D diamond structures for conventional semiconductors

    PubMed Central

    Wang, Jianwei; Zhang, Yong

    2016-01-01

    When coming to identify new 2D materials, our intuition would suggest us to look from layered instead of 3D materials. However, since graphite can be hypothetically derived from diamond by stretching it along its [111] axis, many 3D materials can also potentially be explored as new candidates for 2D materials. Using a density functional theory, we perform a systematic study over the common Group IV, III–V, and II–VI semiconductors along different deformation paths to reveal new structures that are topologically connected to but distinctly different from the 3D parent structure. Specifically, we explore two major phase transition paths, originating respectively from wurtzite and NiAs structure, by applying compressive and tensile strain along the symmetry axis, and calculating the total energy changes to search for potential metastable states, as well as phonon spectra to examine the structural stability. Each path is found to further split into two branches under tensile strain–low buckled and high buckled structures, which respectively lead to a low and high buckled monolayer structure. Most promising new layered or planar structures identified include BeO, GaN, and ZnO on the tensile strain side, Ge, Si, and GaP on the compressive strain side. PMID:27090430

  12. Effects of protein inter-layers on cell-diamond FET characteristics.

    PubMed

    Rezek, Bohuslav; Krátká, Marie; Kromka, Alexander; Kalbacova, Marie

    2010-12-15

    Diamond is recognized as an attractive material for merging solid-state and biological systems. The advantage of diamond field-effect transistors (FET) is that they are chemically resistant, bio-compatible, and can operate without gate oxides. Solution-gated FETs based on H-terminated nanocrystalline diamond films exhibiting surface conductivity are employed here for studying effects of fetal bovine serum (FBS) proteins and osteoblastic SAOS-2 cells on diamond electronic properties. FBS proteins adsorbed on the diamond FETs permanently decrease diamond conductivity as reflected by the -45 mV shift of the FET transfer characteristics. Cell cultivation for 2 days results in a further shift by another -78 mV. We attribute it to a change of diamond material properties rather than purely to the field-effect. Increase in gate leakage currents (by a factor of 4) indicates that the FBS proteins also decrease the diamond-electrolyte electronic barrier induced by C-H surface dipoles. We propose a model where the proteins replace ions in the very vicinity of the H-terminated diamond surface.

  13. 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.

  14. On the development of a dual-layered diamond-coated tool for the effective machining of titanium Ti-6Al-4V alloy

    NASA Astrophysics Data System (ADS)

    Srinivasan, Balaji; Ramachandra Rao, M. S.; Rao, Balkrishna C.

    2017-01-01

    This work is focused on the development of a dual-layered diamond-coated tungsten carbide tool for machining titanium Ti-6Al-4V alloy. A hot-filament chemical vapor deposition technique was used to synthesize diamond films on tungsten carbide tools. A boron-doped diamond interlayer was added to a microcrystalline diamond layer in an attempt to improve the interface adhesion strength. The dual-layered diamond-coated tool was employed in machining at cutting speeds in the range of 70 to 150 m min-1 with a lower feed and a lower depth of cut of 0.5 mm rev-1 and 0.5 mm, respectively, to operate in the transition from adhesion- to diffusion-tool-wear and thereby arrive at suitable conditions for enhancing tool life. The proposed tool was then compared, on the basis of performance under real-time cutting conditions, with commercially available microcrystalline diamond, nanocrystalline diamond, titanium nitride and uncoated tungsten carbide tools. The life and surface finish of the proposed dual-layered tool and uncoated tungsten carbide were also investigated in interrupted cutting such as milling. The results of this study show a significant improvement in tool life and finish of Ti-6Al-4V parts machined with the dual-layered diamond-coated tool when compared with its uncoated counterpart. These results pave the way for the use of a low-cost tool, with respect to, polycrystalline diamond for enhancing both tool life and machining productivity in critical sectors fabricating parts out of titanium Ti-6Al-4V alloy. The application of this coating technology can also be extended to the machining of non-ferrous alloys owing to its better adhesion strength.

  15. Thermally stable diamond brazing

    DOEpatents

    Radtke, Robert P.

    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.

  16. 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.

  17. Diamond heteroepitaxial lateral overgrowth

    NASA Astrophysics Data System (ADS)

    Tang, Yung-Hsiu

    This dissertation describes improvements in the growth of single crystal diamond by microwave plasma-assisted chemical vapor deposition (CVD). Heteroepitaxial (001) diamond was grown on 1 cm. 2 a-plane sapphiresubstrates using an epitaxial (001) Ir thin-film as a buffer layer. Low-energy ion bombardment of the Ir layer, a process known as bias-enhanced nucleation, is a key step in achieving a high density of diamond nuclei. Bias conditions were optimized to form uniformly-high nucleation densities across the substrates, which led to well-coalesced diamond thin films after short growth times. Epitaxial lateral overgrowth (ELO) was used as a means of decreasing diamond internal stress by impeding the propagation of threading dislocations into the growing material. Its use in diamond growth requires adaptation to the aggressive chemical and thermal environment of the hydrogen plasma in a CVD reactor. Three ELO variants were developed. The most successful utilized a gold (Au) mask prepared by vacuum evaporation onto the surface of a thin heteroepitaxial diamond layer. The Au mask pattern, a series of parallel stripes on the micrometer scale, was produced by standard lift-off photolithography. When diamond overgrows the mask, dislocations are largely confined to the substrate. Differing degrees of confinement were studied by varying the stripe geometry and orientation. Significant improvement in diamond quality was found in the overgrown regions, as evidenced by reduction of the Raman scattering linewidth. The Au layer was found to remain intact during diamond overgrowth and did not chemically bond with the diamond surface. Besides impeding the propagation of threading dislocations, it was discovered that the thermally-induced stress in the CVD diamond was significantly reduced as a result of the ductile Au layer. Cracking and delamination of the diamond from the substrate was mostly eliminated. When diamond was grown to thicknesses above 0.1 mm it was found that

  18. Using stepped anvils to make even insulation layers in laser-heated diamond-anvil cell samples

    DOE PAGES

    Du, Zhixue; Gu, Tingting; Dobrosavljevic, Vasilije; ...

    2015-09-01

    Here, we describe a method to make even insulation layers for high-pressure laser-heated diamond-anvil cell samples using stepped anvils. Moreover, the method works for both single-sided and double-sided laser heating using solid or fluid insulation. The stepped anvils are used as matched pairs or paired with a flat culet anvil to make gasket insulation layers and not actually used at high pressures; thus, their longevity is ensured. We also compare the radial temperature gradients and Soret diffusion of iron between self-insulating samples and samples produced with stepped anvils and find that less pronounced Soret diffusion occurs in samples with evenmore » insulation layers produced by stepped anvils.« less

  19. Using stepped anvils to make even insulation layers in laser-heated diamond-anvil cell samples

    SciTech Connect

    Du, Zhixue; Gu, Tingting; Dobrosavljevic, Vasilije; Weir, Samuel T.; Falabella, Steve; Lee, Kanani K. M.

    2015-09-01

    Here, we describe a method to make even insulation layers for high-pressure laser-heated diamond-anvil cell samples using stepped anvils. Moreover, the method works for both single-sided and double-sided laser heating using solid or fluid insulation. The stepped anvils are used as matched pairs or paired with a flat culet anvil to make gasket insulation layers and not actually used at high pressures; thus, their longevity is ensured. We also compare the radial temperature gradients and Soret diffusion of iron between self-insulating samples and samples produced with stepped anvils and find that less pronounced Soret diffusion occurs in samples with even insulation layers produced by stepped anvils.

  20. Diamond heteroepitaxial lateral overgrowth

    SciTech Connect

    Tang, Y. -H.; Bi, B.; Golding, B.

    2015-02-24

    A method of diamond heteroepitaxial lateral overgrowth is demonstrated which utilizes a photolithographic metal mask to pattern a thin (001) epitaxial diamond surface. Significant structural improvement was found, with a threading dislocation density reduced by two orders of magnitude at the top surface of a thick overgrown diamond layer. In the initial stage of overgrowth, a reduction of diamond Raman linewidth in the overgrown area was also realized. Thermally-induced stress and internal stress were determined by Raman spectroscopy of adhering and delaminated diamond films. As a result, the internal stress is found to decrease as sample thickness increases.

  1. 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.

  2. 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.

  3. Theoretical investigation of superconductivity in ternary silicide NaAlSi with layered diamond-like structure

    NASA Astrophysics Data System (ADS)

    Tütüncü, H. M.; Karaca, Ertuǧrul; Srivastava, G. P.

    2016-04-01

    We have investigated the electronic structure, phonon modes and electron-phonon coupling to understand superconductivity in the ternary silicide NaAlSi with a layered diamond-like structure. Our electronic results, using the density functional theory within a generalized gradient approximation, indicate that the density of states at the Fermi level is mainly governed by Si p states. The largest contributions to the electron-phonon coupling parameter involve Si-related vibrations both in the x-y plane as well as along the z-axis in the x-z plane. Our results indicate that this material is an s-p electron superconductor with a medium level electron-phonon coupling parameter of 0.68. Using the Allen-Dynes modification of the McMillan formula we obtain the superconducting critical temperature of 6.98 K, in excellent agreement with experimentally determined value of 7 K.

  4. 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

    2010-05-07

    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.

  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.

  6. 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.

  7. Biophotonic low-coherence sensors with boron-doped diamond thin layer

    NASA Astrophysics Data System (ADS)

    Milewska, D.; Karpienko, K.; Sobaszek, M.; Jedrzejewska-Szczerska, M.

    2016-03-01

    Low-coherence sensors using Fabry-Perot interferometers are finding new applications in biophotonic sensing, especially due to the rapid technological advances in the development of new materials. In this paper we discuss the possibility of using boron-doped nanodiamond layers to protect mirror in a Fabry-Perot interferometer. A low-coherence sensor using Fabry-Perot interferometer with a boron-doped nanodiamond (B-NCD) thin protective layer has been developed. B-NCD layers with different boron doping level were investigated. The boron level, expressed as the boron to carbon (/[C]) ratio in the gas phase, was: 0, 2000, 5000 or 10000 ppm. B-NCD layers were grown by chemical vapor deposition (CVD). The sensing Fabry-Perot interferometer, working in the reflective mode, was connected to the source and to the optical processor by single-mode fibers. Superluminescent diodes with Gaussian spectral density were used as sources, while an optical spectrum analyzer was used as an optical processor. The design of the sensing interferometer was optimized to attain the maximum interference contrast. The experiment has shown that B-NCD thin layers can be successfully used in biophotonic sensors.

  8. 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.

  9. 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.

  10. 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 Ω·cm2 as the temperature increases to 820°C. However, when the annealing temperature reaches 850°C, 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 550°C, low specific contact resistance was detected for Au contact, which is derived from the enhancement of interdiffusion between Au and diamond films.

  11. 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

  12. 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.

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

    PubMed

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

    2014-06-11

    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.

  14. 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

  15. 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.

  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.

    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.

  18. 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.

  19. 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.

  20. 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.

  1. Plasma enhanced chemical vapor deposition of metalboride interfacial layers as diffusion barriers for nanostructured diamond growth on cobalt containing alloys CoCrMo and WC-Co

    NASA Astrophysics Data System (ADS)

    Johnston, Jamin M.

    This work is a compilation of theory, finite element modeling and experimental research related to the use of microwave plasma enhanced chemical vapor deposition (MPECVD) of diborane to create metal-boride surface coatings on CoCrMo and WC-Co, including the subsequent growth of nanostructured diamond (NSD). Motivation for this research stems from the need for wear resistant coatings on industrial materials, which require improved wear resistance and product lifetime to remain competitive and satisfy growing demand. Nanostructured diamond coatings are a promising solution to material wear but cannot be directly applied to cobalt containing substrates due to graphite nucleation. Unfortunately, conventional pre-treatment methods, such as acid etching, render the substrate too brittle. Thus, the use of boron in a MPECVD process is explored to create robust interlayers which inhibit carbon-cobalt interaction. Furthermore, modeling of the MPECVD process, through the COMSOL MultiphysicsRTM platform, is performed to provide insight into plasma-surface interactions using the simulation of a real-world apparatus. Experimental investigation of MPECVD boriding and NSD deposition was conducted at surface temperatures from 700 to 1100 °C. Several well-adhered metal-boride surface layers were formed: consisting of CoB, CrB, WCoB, CoB and/or W2CoB2. Many of the interlayers were shown to be effective diffusion barriers against elemental cobalt for improving nucleation and adhesion of NSD coatings; diamond on W2CoB2 was well adhered. However, predominantly WCoB and CoB phase interlayers suffered from diamond film delamination. Metal-boride and NSD surfaces were evaluated using glancing-angle x-ray diffraction (XRD), x-ray photoelectron spectroscopy (XPS), cross-sectional scanning electron microscopy (SEM), energy dispersive x-ray spectroscopy (EDS), micro-Raman spectroscopy, nanoindentation, scratch testing and epoxy pull testing. COMSOL MultiphysicsRTM was used to construct a

  2. Use of Diamond as an Optical Material

    DTIC Science & Technology

    1991-09-27

    New polishing methods hpve yielded smooth surfaces in reasonable polishing times. Recent research hclds promise for large optics made from single... forced to the surface , precipitating on the surface as a diamond layer. A halogen-assisted CVD method has recently been discovered for producing...diamond [24]; however, this research is in an early stage and has not yet resulted in good quality diamond films. Optical Properties of CVD Diamond. Many

  3. Formation of silicon carbide and diamond nanoparticles in the surface layer of a silicon target during short-pulse carbon ion implantation

    NASA Astrophysics Data System (ADS)

    Remnev, G. E.; Ivanov, Yu. F.; Naiden, E. P.; Saltymakov, M. S.; Stepanov, A. V.; Shtan'ko, V. F.

    2009-04-01

    Synthesis of silicon carbide and diamond nanoparticles is studied during short-pulse implantation of carbon ions and protons into a silicon target. The experiments are carried out using a TEMP source of pulsed powerful ion beams based on a magnetically insulated diode with radial magnetic field B r . The beam parameters are as follows: the ion energy is 300 keV, the pulse duration is 80 ns, the beam consists of carbon ions and protons, and the ion current density is 30 A/cm2. Single-crystal silicon wafers serve as a target. SiC nanoparticles and nanodiamonds form in the surface layer of silicon subjected to more than 100 pulses. The average coherent domain sizes in the SiC particles and nanodiamonds are 12-16 and 8-9 nm, respectively.

  4. Heteroepitaxial Diamond Growth

    DTIC Science & Technology

    1993-01-12

    of CH3 and C6 H6 adsorbed on nickel. Calculated chemisorption energies of pyramidal CH3 on Ni(l 11) are 38 for the clean surface and 50 , 47, and 17... results from early experiments on the diamond (100) surface . In Figure 3.1 we can easily distinguish features associated with the conversion of the...those 5 reports were for fairly thin (< 2 gm) epitaxial layers. The results reported there for homoepitaxy on the diamond (100) surface were quite

  5. Diamond detector - material science, design and application

    NASA Astrophysics Data System (ADS)

    Gaowei, Mengjia

    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

  6. Electrical stimulation of retinal ganglion cells with diamond and the development of an all diamond retinal prosthesis.

    PubMed

    Hadjinicolaou, Alex E; Leung, Ronald T; Garrett, David J; Ganesan, Kumaravelu; Fox, Kate; Nayagam, David A X; Shivdasani, Mohit N; Meffin, Hamish; Ibbotson, Michael R; Prawer, Steven; O'Brien, Brendan J

    2012-08-01

    Electronic retinal implants for the blind are already a market reality. A world wide effort is underway to find the technology that offers the best combination of performance and safety for potential patients. Our approach is to construct an epi-retinally targeted device entirely encapsulated in diamond to maximise longevity and biocompatibility. The stimulating array of our device comprises a monolith of electrically insulating diamond with thousands of hermetic, microscale nitrogen doped ultra-nanocrystalline diamond (N-UNCD) feedthroughs. Here we seek to establish whether the conducting diamond feedthroughs of the array can be used as stimulating electrodes without further modification with a more traditional neural stimulation material. Efficacious stimulation of retinal ganglion cells was established using single N-UNCD microelectrodes in contact with perfused, explanted, rat retina. Evoked rat retinal ganglion cell action potentials were recorded by patch clamp recording from single ganglion cells, adjacent to the N-UNCD stimulating electrode. Separately, excellent electrochemical stability of N-UNCD was established by prolonged pulsing in phosphate buffered saline at increasing charge density up to the measured charge injection limit for the material.

  7. 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.

  8. 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.

  9. 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.

  10. 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.

  11. 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.

  12. Mo2C coating on diamond: Different effects on thermal conductivity of diamond/Al and diamond/Cu composites

    NASA Astrophysics Data System (ADS)

    Ma, Songdi; Zhao, Naiqin; Shi, Chunsheng; Liu, Enzuo; He, Chunnian; He, Fang; Ma, Liying

    2017-04-01

    Mo2C submicron layer coated diamond particles prepared by a molten salts route with Mo powder as the starting material were used as the filler in Cu- and Al- matrix composites. The microstructure and thermal property of the composites prepared by a vacuum pressure infiltration method were investigated. When introducing a 500 nm thick Mo2C layer, the thermal conductivity of the composites with different matrix presented different performance. A high thermal conductivity (657 W m-1 K-1) was obtained in diamond/Cu composites owing to the improved interfacial bonding and lower interfacial thermal resistance, while the thermal conductivity of diamond/Al composites decreased from 553 W m-1 K-1 to 218 W m-1 K-1 when introducing the Mo2C layer, which can be attributed to the formation of harmful granule-phase (Al12Mo) at the interface of diamond and aluminum. This work provides a promising approach to improve performance of diamond reinforced metal matrix composites by selecting carbide as an interface modifier.

  13. Diamond fiber field emitters

    DOEpatents

    Blanchet-Fincher, Graciela B.; Coates, Don M.; Devlin, David J.; Eaton, David F.; Silzars, Aris K.; Valone, Steven M.

    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.

  14. 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.

  15. '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.

  16. A novel radial anode layer ion source for inner wall pipe coating and materials modification—Hydrogenated 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 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 sp3 bonds in DLC coatings. The results show that commercially interesting coatings can be achieved in short time.

  17. 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.

  18. Synthesis and characterization of layered metal sulfates containing M(μ3-OH/F)2(M = Mg, Co) diamond chains.

    PubMed

    Marri, Subba R; Mahana, Sudipta; Topwal, Dinesh; Behera, J N

    2017-01-24

    Cobalt and magnesium sulfates of the compositions, [C4N2H12]2[Co3F2(SO4)3(H2O)2], (1) and [NH4]2[Mg3(OH)2(SO4)3(H2O)2], (2), respectively, have been synthesized under hydro/solvothermal conditions, and are characterized by IR spectra, elemental analysis, powder X-ray diffraction (PXRD), energy-dispersive X-ray spectroscopy (EDX), thermogravimetric analysis (TGA), and X-ray single-crystal diffraction. 1 and 2 crystallized in the orthorhombic space groups Pnma and Cmc2 respectively. While 1 is templated by the organic piperazinium cation, 2 is obtained in the presence of ammonium ions. The layered structures are formed by the diamond chains comprising of M3(μ3-OH/F)2 units (M = Co: 1, Mg: 2). Magnetic studies of 1 reveal its ferromagnetic nature with a transition at 10.8 K and show it does not exhibit spin-glass freezing. Isothermal magnetization shows a hysteresis loop at 2.5 K with a coercive field of 1200 Oe and remnant magnetization of 0.1μB. A sharp λ-like anomaly is also seen in the heat capacity curve, favoring long range magnetic ordering below Tc.

  19. Amorphous-diamond electron emitter

    DOEpatents

    Falabella, Steven

    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.

  20. High temperature diamond film deposition on a natural diamond anvil

    SciTech Connect

    McCauley, T.S.; Vohra, Y.K.

    1995-12-31

    We report on the growth and characterization of a 100 {mu}m thick by 350 {mu}m diameter diamond layer on the culet of a type Ia brilliant cut natural diamond anvil by microwave plasma-assisted CVD (MPCVD). While our previous work [1] on diamond anvils resulted in homoepitaxial film growth at a rate of approximately 20 {mu}m/hr, the present 100 {mu}m thick diamond layer grew in less than 2 hours. This unprecedented growth rate of {approximately} 50 {mu}m/hr is believed to be the result of the extremely high substrate temperature (1800{degrees}-2100{degrees}C) during deposition. The translucent diamond layer was characterized by micro-Raman, low temperature photoluminescence (PL) and PL excitation spectroscopy, as well as atomic force microscopy (AFM). Raman analysis shows the deposit to be of high quality. The PL spectra show numerous features, including prominent emission bands at 575 nm (2.16 eV), 636 nm (1.95 eV), 735 nm (1.68 eV) and 777 run, (1.60 eV).

  1. 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.

  2. 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.

  3. 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.

    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.

  4. Fabrication of three dimensional diamond ultraviolet photodetector through down-top method

    NASA Astrophysics Data System (ADS)

    Liu, Zhangcheng; Ao, Jin-Ping; Li, Fengnan; Wang, Wei; Wang, Jingjing; Zhang, Jingwen; Wang, Hong-Xing

    2016-10-01

    Three dimensional diamond ultraviolet (UV) photodetector have been fabricated on diamond epitaxial layer through down-top approach, where diamond epitaxial layer was grown between metal electrodes. A thin diamond epitaxial layer was first grown on high-pressure high-temperature single crystal diamond substrate. Then, the diamond epitaxial layer was covered by interdigitated tungsten electrodes. Furthermore, another diamond epitaxial layer was grown on uncovered area. At last, UV-Ozone treatment was used to oxidize the surface. The optoelectronic performance of the photodetector was characterized, exhibiting a large responsivity and a repeatable transient response behavior. Moreover, down-top process is beneficial for the electrode conductivity stability. Also, an ohmic contact could be formed between tungsten and diamond during growth. The results indicate that down-top process is an efficient way for fabrication of three dimensional diamond photodetectors.

  5. 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.

  6. Microstructural Evolution of Nanocrystalline Diamond Films Due to CH4/Ar/H2 Plasma Post-Treatment Process.

    PubMed

    Lin, Sheng-Chang; Yeh, Chien-Jui; Manoharan, Divinah; Leou, Keh-Chyang; Lin, I-Nan

    2015-10-07

    Plasma post-treatment process was observed to markedly enhance the electron field emission (EFE) properties of ultrananocrystalline diamond (UNCD) films. TEM examinations reveal that the prime factor which improves the EFE properties of these films is the coalescence of ultrasmall diamond grains (∼5 nm) forming large diamond grains about hundreds of nanometers accompanied by the formation of nanographitic clusters along the grain boundaries due to the plasma post-treatment process. OES studies reveal the presence of large proportion of atomic hydrogen and C2 (or CH) species, which are the main ingredients that altered the granular structure of the UNCD films. In the post-treatment process, the plasma interacts with the diamond films by a diffusion process. The recrystallization of diamond grains started at the surface region of the material, and the interaction zone increased with the post-treatment period. The entire diamond film can be converted into a nanocrystalline granular structure when post-treated for a sufficient length of time.

  7. Online, efficient and precision laser profiling of bronze-bonded diamond grinding wheels based on a single-layer deep-cutting intermittent feeding method

    NASA Astrophysics Data System (ADS)

    Deng, Hui; Chen, Genyu; He, Jie; Zhou, Cong; Du, Han; Wang, Yanyi

    2016-06-01

    In this study, an online, efficient and precision laser profiling approach that is based on a single-layer deep-cutting intermittent feeding method is described. The effects of the laser cutting depth and the track-overlap ratio of the laser cutting on the efficiency, precision and quality of laser profiling were investigated. Experiments on the online profiling of bronze-bonded diamond grinding wheels were performed using a pulsed fiber laser. The results demonstrate that an increase in the laser cutting depth caused an increase in the material removal efficiency during the laser profiling process. However, the maximum laser profiling efficiency was only achieved when the laser cutting depth was equivalent to the initial surface contour error of the grinding wheel. In addition, the selection of relatively high track-overlap ratios of laser cutting for the profiling of grinding wheels was beneficial with respect to the increase in the precision of laser profiling, whereas the efficiency and quality of the laser profiling were not affected by the change in the track-overlap ratio. After optimized process parameters were employed for online laser profiling, the circular run-out error and the parallelism error of the grinding wheel surface decreased from 83.1 μm and 324.6 μm to 11.3 μm and 3.5 μm, respectively. The surface contour precision of the grinding wheel significantly improved. The highest surface contour precision for grinding wheels of the same type that can be theoretically achieved after laser profiling is completely dependent on the peak power density of the laser. The higher the laser peak power density is, the higher the surface contour precision of the grinding wheel after profiling.

  8. 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.

  9. Organophosphonate biofunctionalization of diamond electrodes.

    PubMed

    Caterino, R; Csiki, R; Wiesinger, M; Sachsenhauser, M; Stutzmann, M; Garrido, J A; Cattani-Scholz, A; Speranza, Giorgio; Janssens, S D; Haenen, K

    2014-08-27

    The modification of the diamond surface with organic molecules is a crucial aspect to be considered for any bioapplication of this material. There is great interest in broadening the range of linker molecules that can be covalently bound to the diamond surface. In the case of protein immobilization, the hydropathicity of the surface has a major influence on the protein conformation and, thus, on the functionality of proteins immobilized at surfaces. For electrochemical applications, particular attention has to be devoted to avoid that the charge transfer between the electrode and the redox center embedded in the protein is hindered by a thick insulating linker layer. This paper reports on the grafting of 6-phosphonohexanoic acid on OH-terminated diamond surfaces, serving as linkers to tether electroactive proteins onto diamond surfaces. X-ray photoelectron spectroscopy (XPS) confirms the formation of a stable layer on the surface. The charge transfer between electroactive molecules and the substrate is studied by electrochemical characterization of the redox activity of aminomethylferrocene and cytochrome c covalently bound to the substrate through this linker. Our work demonstrates that OH-terminated diamond functionalized with 6-phosphonohexanoic acid is a suitable platform to interface redox-proteins, which are fundamental building blocks for many bioelectronics applications.

  10. 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.

  11. 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

  12. 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.

  13. Wear-resistant diamond nanoprobe tips with integrated silicon heater for tip-based nanomanufacturing.

    PubMed

    Fletcher, Patrick C; Felts, Jonathan R; Dai, Zhenting; Jacobs, Tevis D; Zeng, Hongjun; Lee, Woo; Sheehan, Paul E; Carlisle, John A; Carpick, Robert W; King, William P

    2010-06-22

    We report exceptional nanoscale wear and fouling resistance of ultrananocrystalline diamond (UNCD) tips integrated with doped silicon atomic force microscope (AFM) cantilevers. The resistively heated probe can reach temperatures above 600 degrees C. The batch fabrication process produces UNCD tips with radii as small as 15 nm, with average radius 50 nm across the entire wafer. Wear tests were performed on substrates of quartz, silicon carbide, silicon, or UNCD. Tips were scanned for more than 1 m at a scan speed of 25 mum s(-1) at temperatures ranging from 25 to 400 degrees C under loads up to 200 nN. Under these conditions, silicon tips are partially or completely destroyed, while the UNCD tips exhibit little or no wear, no signs of delamination, and exceptional fouling resistance. We demonstrate nanomanufacturing of more than 5000 polymer nanostructures with no deterioration in the tip.

  14. 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.

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

    DOEpatents

    Holcombe, Cressie E.; Seals, Roland D.; Price, R. Eugene

    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.

  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

  17. Status and Applications of Diamond and Diamond-Like Materials: An Emerging Technology

    DTIC Science & Technology

    1990-04-30

    solar -blind detectors. * Modulated structures incorporating layers of BN and diamond, for example, to develop materials that are harder and/or tougher...hundredfold increase in power capability over silicon transistors. e Solar -blind detectors, which take advantage of the large energy gap (greater than...Some success has already been achieved, for example, in applying diamond-like coatings to ZnS and ZnSe windows using a Ge-C intermediate layer . " Anti

  18. Toward deep blue nano hope diamonds: heavily boron-doped diamond nanoparticles.

    PubMed

    Heyer, Steffen; Janssen, Wiebke; Turner, Stuart; Lu, Ying-Gang; Yeap, Weng Siang; Verbeeck, Jo; Haenen, Ken; Krueger, Anke

    2014-06-24

    The production of boron-doped diamond nanoparticles enables the application of this material for a broad range of fields, such as electrochemistry, thermal management, and fundamental superconductivity research. Here we present the production of highly boron-doped diamond nanoparticles using boron-doped CVD diamond films as a starting material. In a multistep milling process followed by purification and surface oxidation we obtained diamond nanoparticles of 10-60 nm with a boron content of approximately 2.3 × 10(21) cm(-3). Aberration-corrected HRTEM reveals the presence of defects within individual diamond grains, as well as a very thin nondiamond carbon layer at the particle surface. The boron K-edge electron energy-loss near-edge fine structure demonstrates that the B atoms are tetrahedrally embedded into the diamond lattice. The boron-doped diamond nanoparticles have been used to nucleate growth of a boron-doped diamond film by CVD that does not contain an insulating seeding layer.

  19. 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.

  20. Physical and tribological characteristics of ion-implanted diamond films

    SciTech Connect

    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.

    1994-11-01

    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.

  1. 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.

  2. 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.

  3. '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.

  4. '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.

  5. '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.

  6. Electrically conductive diamond electrodes

    DOEpatents

    Swain, Greg; Fischer, Anne ,; Bennett, Jason; Lowe, Michael

    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.

  7. 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.

  8. 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.

  9. 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

  10. 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.

  11. 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.

  12. 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.

  13. 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.

  14. Voltammetric and impedance behaviours of surface-treated nano-crystalline diamond film electrodes

    SciTech Connect

    Liu, F. B.; Jing, B.; Cui, Y.; Di, J. J.; Qu, M.

    2015-04-15

    The electrochemical performances of hydrogen- and oxygen-terminated nano-crystalline diamond film electrodes were investigated by cyclic voltammetry and AC impedance spectroscopy. In addition, the surface morphologies, phase structures, and chemical states of the two diamond films were analysed by scanning probe microscopy, Raman spectroscopy, and X-ray photoelectron spectroscopy, respectively. The results indicated that the potential window is narrower for the hydrogen-terminated nano-crystalline diamond film than for the oxygen-terminated one. The diamond film resistance and capacitance of oxygen-terminated diamond film are much larger than those of the hydrogen-terminated diamond film, and the polarization resistances and double-layer capacitance corresponding to oxygen-terminated diamond film are both one order of magnitude larger than those corresponding to the hydrogen-terminated diamond film. The electrochemical behaviours of the two diamond film electrodes are discussed.

  15. 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. _

  16. Ultra thin CVD diamond film deposition by electrostatic self-assembly seeding process with nano-diamond particles.

    PubMed

    Kim, J H; Lee, S K; Kwon, O M; Lim, D S

    2009-07-01

    Ultra thin and smooth nano crystalline diamond films were fabricated with electrostatic self-assembly seeding of explosively synthesized nano-diamond particles. Hard aggregates of nano-diamond particles were crushed by high revolution attrition milling at 1000 RPM to regulate the particle size. Through this process, cationic nano-diamond particles were coated with anionic PSS (poly sodium 4-styrene sulfonate) electrolytes. Anionic Si(100) substrate was coated with cationic PDDA (poly diallyldimethyl ammonium chloride) solution. Si(100)/PDDA/PSS/ND (nano-diamond) layer-by-layer structure was formed as a seeding layer by the simple dipping and rinsing of positively charged substrate into anionic PSS/nano-diamond solution. Throughout the seeding process, neither mechanical damage nor chemical attack was observed on the substrate. Every stage of this preparation was carried out at room temperature and pressure. The effect of attrition milling was determined by changing the milling time from 1 hr to 5 hrs. Through the attritional milling and monolayer formation of the nano-diamond, nucleation density was increased up to 3 x 10(11)/cm2. Typical hot filament chemical vapor deposition system was used to coat the diamond film on the ESA (electrostatic self-assembly) seeded Si(100) substrate. Although typical diamond deposition conditions (90 torr/1% CH4 in H2/800 degrees C) were maintained, ultra thin (< 100 nm) and continuous nano crystalline diamond films were deposited. Regardless of metallic or ceramic substrate, ESND (ESA Seeding of nano-diamond) process is applicable if the substrate has any charge. This simple nano technology based process ensures high thickness uniformity of diamond coating without visible edge effect.

  17. Brazing diamond grits onto a steel substrate using copper alloys as the filler metals

    NASA Astrophysics Data System (ADS)

    Chen, S.-M.; Lin, S.-T.

    1996-12-01

    Surface-set diamond tools were fabricated by an active metal brazing process, using bronze (Cu-8.9Sn) powder and 316L stainless steel powder mixed to various ratios as the braze filler metals. The diamond grits were brazed onto a steel substrate at 1050 °C for 30 min in a dry hydrogen atmosphere. After brazing practice, an intermediate layer rich in chromium formed between the braze filler metal and diamond. A braze filler metal composed of 70 wt % bronze powder and 30 wt % stainless steel powder was found to be optimum in that the diamond grits were strongly impregnated in the filler metal by both mechanical and chemical types of holding. The diamond tools thus fabricated performed better than conventional nickel-plated diamond tools. In service, the braze filler metal wore at almost the same rate as the diamond grits, and no pullout of diamond grits or peeling of the filler metal layer took place.

  18. Catalytic effect of ultrananocrystalline Fe₃O₄ on algal bio-crude production via HTL process.

    PubMed

    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

    2015-11-14

    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.

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

    NASA Astrophysics Data System (ADS)

    Härtl, Andreas; Schmich, Evelyn; Garrido, Jose A.; Hernando, Jorge; Catharino, Silvia C. R.; Walter, Stefan; Feulner, Peter; Kromka, Alexander; Steinmüller, 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.

  20. Low reflection and high transmission by a layered structure containing diamond-like carbon, porous silicon, and left-handed material

    NASA Astrophysics Data System (ADS)

    Ubeid, Muin F.; Shabat, Mohammed M.; Altanany, Sameh M.

    2017-03-01

    In this paper, we propose and theoretically analyze a stratified waveguide structure comprised of diamond-like carbon (DLC), porous silicon (PS), and left-handed material (LHM) subjected to incident light in order to achieve low reflection and high transmission. The proposed waveguide structure is situated between two half free spaces and a TE polarized plane wave incident on it. The main parameters of each material are given and the required equations for the electromagnetic plane wave propagation are presented. Transfer matrix method is implemented to find out the characteristics of the reflected and transmitted powers. In the numerical results, the mentioned powers are computed and illustrated as a function of the incidence angle, the frequency, and the slab thickness to demonstrate the main parameters for low reflection and high transmission. These theoretical parameters could be useful to the researchers and designers working in the area of solar cells and optical sensors.

  1. Nano-inclusions in diamond: Evidence of diamond genesis

    NASA Astrophysics Data System (ADS)

    Wirth, R.

    2015-12-01

    The use of Focused Ion Beam technology (FIB) for TEM sample preparation introduced approximately 15 years ago revolutionized the application of TEM in Geosciences. For the first time, FIB enabled cutting samples for TEM use from exactly the location we are interested in. Applied to diamond investigation, this technique revealed the presence of nanometre-sized inclusions in diamond that have been simply unknown before. Nanoinclusions in diamond from different location and origin such as diamonds from the Lower and Upper Mantle, metamorphic diamonds (Kazakhstan, Erzgebirge, Bohemia), diamonds from ophiolites (Tibet, Mongolia, Xinjiang, Ural Mountains), diamonds from igneous rocks (Hawaii, Kamchatka) and impact diamonds (Popigai Crater, Siberia) have been investigated during the last 15 years. The major conclusion of all these TEM studies is, that the nanoinclusions, their phases and phase composition together with the micro- and nanostructure evidence the origin of diamond and genesis of diamond. We can discriminate Five different mechanisms of diamond genesis in nature are observed: Diamond crystallized from a high-density fluid (Upper mantle and metamorphic diamond). Diamond crystallized from carbonatitic melt (Lower mantle diamond). Diamond precipitates from a metal alloy melt (Diamond from ophiolites). Diamond crystallized by gas phase condensation or chemical vapour condensation (CVD) (Lavas from Kamchatka, xenoliths in Hawaiian lavas). Direct transformation of graphite into diamond.

  2. Diamond tool machining of materials which react with diamond

    DOEpatents

    Lundin, Ralph L.; Stewart, Delbert D.; Evans, Christopher J.

    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.

  3. 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.

  4. Heteroepitaxial Diamond Growth

    DTIC Science & Technology

    1992-11-01

    methyl radicals to a nickel (111) surface . The detailed results are contained in an attached copy of a recently published journal article, "Effects of...nucleation on surfaces which otherwise would not even nucleate diamond. The second area of research is devoted to the development of implant and...in explaining results of hydrogen dosing of diamond surfaces . Experimental results indicated that the dimmer bond on the diamond 2x1 surface was very

  5. 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.

  6. Optimizing growth and post treatment of diamond for high capacitance neural interfaces.

    PubMed

    Tong, Wei; Fox, Kate; Zamani, Akram; Turnley, Ann M; Ganesan, Kumaravelu; Ahnood, Arman; Cicione, Rosemary; Meffin, Hamish; Prawer, Steven; Stacey, Alastair; Garrett, David J

    2016-10-01

    Electrochemical and biological properties are two crucial criteria in the selection of the materials to be used as electrodes for neural interfaces. For neural stimulation, materials are required to exhibit high capacitance and to form intimate contact with neurons for eliciting effective neural responses at acceptably low voltages. Here we report on a new high capacitance material fabricated using nitrogen included ultrananocrystalline diamond (N-UNCD). After exposure to oxygen plasma for 3 h, the activated N-UNCD exhibited extremely high electrochemical capacitance greater than 1 mF/cm(2), which originates from the special hybrid sp(2)/sp(3) structure of N-UNCD. The in vitro biocompatibility of the activated N-UNCD was then assessed using rat cortical neurons and surface roughness was found to be critical for healthy neuron growth, with best results observed on surfaces with a roughness of approximately 20 nm. Therefore, by using oxygen plasma activated N-UNCD with appropriate surface roughness, and considering the chemical and mechanical stability of diamond, the fabricated neural interfaces are expected to exhibit high efficacy, long-term stability and a healthy neuron/electrode interface.

  7. 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.

  8. Effects of pretreatment on the performance of diamond-coated cemented carbide cutting tools

    NASA Astrophysics Data System (ADS)

    Wang, Qiang; Zhang, Qing; Wang, S. G.; Yoon, S. F.; Ahn, J.; Zhao, Biaoqin; Tang, W. Z.; Miao, J. Q.; Lu, F. X.

    2003-11-01

    We studied the cutting performance of diamond-coated cemented carbide cutting tools pretreated using acid etching, Murakami reagent etching, interlayer addition, and boronization techniques. The Rockwell indentation test indicates that the best adhesion is obtained from the diamond-coated cutting tool pretreated using boronization by forming a boronized cobalt compound layer composed of CoW2B2, CoWB, and CoB. The end-milling test shows that this sample exhibits the longest lifetime among diamond-coated cutting tools, 26-times longer than that of the uncoated cutting tool. The wearing mechanism of the cutting tools used is also discussed. During the milling period, the failure of the diamond-coated tool pretreated by boronization was dominated by how the diamond grains were gradually removed from the diamond coating by the workpiece scraps, instead of the peeling off of the diamond coating. This also reveals that the diamond coating exhibits good adhesion and cutting performance.

  9. Preparation of Ti-coated diamond particles by microwave heating

    NASA Astrophysics Data System (ADS)

    Gu, Quanchao; Peng, Jinghui; Xu, Lei; Srinivasakannan, C.; Zhang, Libo; Xia, Yi; Wu, Qingtian; Xia, Hongying

    2016-12-01

    Depositing strong carbide-forming elements on diamond surface can dramatically improve the interfacial bonding strength between diamond grits and metal matrix. In the present work, investigation on the preparation of Ti-coated diamond particles by microwave heating has been conducted. The morphology, microstructure, and the chemical composition of Ti-coated diamond particles were characterized by scanning electron microscopy (SEM), X-ray diffraction (XRD), and energy dispersive x-ray spectrometer (EDX). The thickness of Ti coating was measured and the interfacial binding strength between Ti coating and diamond was analyzed. The results show that the surface of the diamond particles could be successfully coated with Ti, forming a uniform and continuous Ti-coated layer. The TiC was found to form between the surface of diamond particles and Ti-coated layer. The amount of TiC as well as the thickness of coating increased with increasing coating temperature, furthermore, the grain size of the coating also grew gradually. The interfacial bonding strength between coating and diamond was found to be best at the temperature of 760 °C.

  10. 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/.

  11. A wear simulation study of nanostructured CVD diamond-on-diamond articulation involving concave/convex mating surfaces

    PubMed Central

    Baker, Paul A.; Thompson, Raymond G.; Catledge, Shane A.

    2015-01-01

    Using microwave-plasma Chemical Vapor Deposition (CVD), a 3-micron thick nanostructured-diamond (NSD) layer was deposited onto polished, convex and concave components that were machined from Ti-6Al-4V alloy. These components had the same radius of curvature, 25.4mm. Wear testing of the surfaces was performed by rotating articulation of the diamond-deposited surfaces (diamond-on-diamond) with a load of 225N for a total of 5 million cycles in bovine serum resulting in polishing of the diamond surface and formation of very shallow, linear wear grooves of less than 50nm depth. The two diamond surfaces remained adhered to the components and polished each other to an average surface roughness that was reduced by as much as a factor of 80 for the most polished region located at the center of the condyle. Imaging of the surfaces showed that the initial wearing-in phase of diamond was only beginning at the end of the 5 million cycles. Atomic force microscopy, scanning electron microscopy, Raman spectroscopy, and surface profilometry were used to characterize the surfaces and verify that the diamond remained intact and uniform over the surface, thereby protecting the underlying metal. These wear simulation results show that diamond deposition on Ti alloy has potential application for joint replacement devices with improved longevity over existing devices made of cobalt chrome and ultra-high molecular weight polyethylene (UHMWPE). PMID:26989457

  12. Diamond as an Optical Materials

    DTIC Science & Technology

    1992-02-20

    the carbon atoms were expelled and forced to the surface , precipitating on the surface as a diamond layer. A halogen-assisted CVD method has recentiy...Quincy Street Gaitherburg, M 20899ArlingtoV 22217- 50 8a. NAME OF FUNDING, SPONSORING Sb. OFFICE SYMBOL 9. PROCUREMENT INSTRUMENT IDENTIFICATION...TYPE O)F REPORT jI3b. TIME COVERED I14 DATE OF REPORT ( Year . Month. Day) IS. PAGE COUNT Interim FROM TO 1992-Feb-20 I19 16 SUPPLEMENTARY NOTATION 17

  13. 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.

  14. Diamond nucleation using polyethene

    SciTech Connect

    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.

  15. 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.

  16. 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.

  17. Radiation-Induced Nucleation of Diamond from Amorphous Carbon: Effect of Hydrogen.

    PubMed

    Sun, Yanqiu; Kvashnin, Alexander G; Sorokin, Pavel B; Yakobson, Boris I; Billups, W E

    2014-06-05

    Electron irradiation of anthracite functionalized by dodecyl groups leads to recrystallization of the carbon network into diamonds. The diamonds range in size from ∼2 to ∼10 nm and exhibit {111} spacing of 2.1 Å. A bulk process consistent with bias-enhanced nucleation is proposed in which the dodecyl group provides hydrogen during electron irradiation. Recrystallization into diamond occurs in the hydrogenated graphitic subsurface layers. Unfunctionalized anthracite could not be converted into diamond during electron irradiation. The dependence of the phase transition pressure on cluster size was estimated, and it was found that diamond particles with a radius up to 20 nm could be formed.

  18. 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.

  19. Thermally-induced single-crystal-to-single-crystal transformations from a 2D two-fold interpenetrating square lattice layer to a 3D four-fold interpenetrating diamond framework and its application in dye-sensitized solar cells.

    PubMed

    Gao, Song; Fan, Rui Qing; Wang, Xin Ming; Wei, Li Guo; Song, Yang; Du, Xi; Xing, Kai; Wang, Ping; Yang, Yu Lin

    2016-07-28

    In this work, a rare 2D → 3D single-crystal-to-single-crystal transformation (SCSC) is observed in metal-organic coordination complexes, which is triggered by thermal treatment. The 2D two-fold interpenetrating square lattice layer [Cd(IBA)2]n (1) is irreversibly converted into a 3D four-fold interpenetrating diamond framework {[Cd(IBA)2(H2O)]·2.5H2O}n (2) (HIBA = 4-(1H-imidazol-1-yl)benzoic acid). Consideration is given to these two complexes with different interpenetrating structures and dimensionality, and their influence on photovoltaic properties are studied. Encouraged by the UV-visible absorption and HOMO-LUMO energy states matched for sensitizing TiO2, the two complexes are employed in combination with N719 in dye-sensitized solar cells (DSSCs) to compensate absorption in the ultraviolet and blue-violet region, offset competitive visible light absorption of I3(-) and reducing charge the recombination of injected electrons. After co-sensitization with 1 and 2, the device co-sensitized by 1/N719 and 2/N719 to yield overall efficiencies of 7.82% and 8.39%, which are 19.94% and 28.68% higher than that of the device sensitized only by N719 (6.52%). Consequently, high dimensional interpenetrating complexes could serve as excellent co-sensitizers and have application in DSSCs.

  20. 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.

  1. Fabrication of diamond based sensors for use in extreme environments

    DOE PAGES

    Samudrala, Gopi K.; Moore, Samuel L.; Vohra, Yogesh K.

    2015-04-23

    Electrical and magnetic sensors can be lithographically fabricated on top of diamond substrates and encapsulated in a protective layer of chemical vapor deposited single crystalline diamond. This process when carried out on single crystal diamond anvils employed in high pressure research is termed as designer diamond anvil fabrication. These designer diamond anvils allow researchers to study electrical and magnetic properties of materials under extreme conditions without any possibility of damaging the sensing elements. We describe a novel method for the fabrication of designer diamond anvils with the use of maskless lithography and chemical vapor deposition in this paper. This methodmore » can be utilized to produce diamond based sensors which can function in extreme environments of high pressures, high and low temperatures, corrosive and high radiation conditions. Here, we demonstrate applicability of these diamonds under extreme environments by performing electrical resistance measurements during superconducting transition in rare earth doped iron-based compounds under high pressures to 12 GPa and low temperatures to 10 K.« less

  2. Fabrication of diamond based sensors for use in extreme environments

    SciTech Connect

    Samudrala, Gopi K.; Moore, Samuel L.; Vohra, Yogesh K.

    2015-04-23

    Electrical and magnetic sensors can be lithographically fabricated on top of diamond substrates and encapsulated in a protective layer of chemical vapor deposited single crystalline diamond. This process when carried out on single crystal diamond anvils employed in high pressure research is termed as designer diamond anvil fabrication. These designer diamond anvils allow researchers to study electrical and magnetic properties of materials under extreme conditions without any possibility of damaging the sensing elements. We describe a novel method for the fabrication of designer diamond anvils with the use of maskless lithography and chemical vapor deposition in this paper. This method can be utilized to produce diamond based sensors which can function in extreme environments of high pressures, high and low temperatures, corrosive and high radiation conditions. Here, we demonstrate applicability of these diamonds under extreme environments by performing electrical resistance measurements during superconducting transition in rare earth doped iron-based compounds under high pressures to 12 GPa and low temperatures to 10 K.

  3. Growth of oriented diamond on nickel wafers and thin films

    NASA Astrophysics Data System (ADS)

    Liu, Wei

    2000-10-01

    Growth of highly oriented diamond thin films on nickel was achieved by a multi-step process involving seeding, high temperature carbon dissolution, and growth. This process is very sensitive to the substrate temperature and requires accurate timing of both the nucleation and growth steps. It was observed that the surface morphology changed dramatically during the nucleation process and that in-situ monitoring of the surface morphology could provide valuable feedback for process control. An optical monitoring system developed under this study has significantly improved both the reproducibility and overall quality of the oriented diamond films grown on Ni substrates. However, since a significant fraction of carbon diffused into the bulk, as confirmed by Auger carbon depth profiling, the highest nucleation density on the bulk Ni substrate was 107 cm-2. To prevent carbon diffusion away from the surface and to maintain a supersaturated surface region, epitaxial nickel and iridium thin films were deposited by electron-beam evaporation on MgO which acted as a carbon diffusion barrier. A multi-layer structure with 100 A iridium and 1 mum nickel grown epitaxially on an MgO (100) wafer by electron-beam evaporation was used as a substrate. The 100 A thick Ir interlayer was used to overcome the delamination of Ni from the MgO substrate during processing. Oriented diamond was successfully deposited on these substrates and yielded nucleation densities of 3 x 108 cm-2, that resulted in faster coalescence of diamond particles. Coalesced diamond thin films on Ni/Ir/MgO substrates were grown in about six hours of growth, as compared to about 25 hours for the bulk Ni substrates. However, a much narrower process widow on Ni thin films made reproducible growth of oriented diamond more challenging. Cross-sectional high-resolution transmission electron microscopy (XHRTEM) was used to investigate the interfacial microstructure formed during hot filament chemical vapor deposition (HFCVD

  4. 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/μm, achieving a large s-EFE current density of (Je)MCD = 315 μA/cm2 at an applied field of 8.8 V/μm. These s-EFE properties are markedly better than those for Fe-coated/annealed ultrananocrystalline diamond (UNCD) films with (E0)UNCD = 2.0 V/μm and (Je)UNCD = 120 μA/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.

  5. PROCESS FOR COLORING DIAMONDS

    DOEpatents

    Dugdale, R.A.

    1960-07-19

    A process is given for coloring substantially colorless diamonds in the blue to blue-green range and comprises the steps of irradiating the colorless diamonds with electrons having an energy within the range 0.5 to 2 Mev to obtain an integrated electron flux of between 1 and 2 x 10/sup 18/ thc diamonds may be irradiated 1 hr when they take on a blue color with a slight green tint: After being heated at about 500 deg C for half an hour they become pure blue. Electrons within this energy range contam sufficient energy to displace the diamond atoms from their normal lattice sites into interstitial sites, thereby causing the color changes.

  6. Fabrication of diamond shells

    SciTech Connect

    Hamza, Alex V.; Biener, Juergen; Wild, Christoph; Woerner, Eckhard

    2016-11-01

    A novel method for fabricating diamond shells is introduced. The fabrication of such shells is a multi-step process, which involves diamond chemical vapor deposition on predetermined mandrels followed by polishing, microfabrication of holes, and removal of the mandrel by an etch process. The resultant shells of the present invention can be configured with a surface roughness at the nanometer level (e.g., on the order of down to about 10 nm RMS) on a mm length scale, and exhibit excellent hardness/strength, and good transparency in the both the infra-red and visible. Specifically, a novel process is disclosed herein, which allows coating of spherical substrates with optical-quality diamond films or nanocrystalline diamond films.

  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. Quantum engineering: Diamond envy

    NASA Astrophysics Data System (ADS)

    Nunn, Joshua

    2013-03-01

    Nitrogen atoms trapped tens of nanometres apart in diamond can now be linked by quantum entanglement. This ability to produce and control entanglement in solid systems could enable powerful quantum computers.

  10. RF Diamond Transistors: Current Status and Future Prospects

    NASA Astrophysics Data System (ADS)

    Umezawa, Hitoshi; Hirama, Kazuyuki; Arai, Tatsuya; Hata, Hideo; Takayanagi, Hidenori; Koshiba, Toru; Yohara, Keiichiro; Mejima, Soichi; Satoh, Mitsuya; Song, Kwang-Soup; Kawarada, Hiroshi

    2005-11-01

    RF diamond transistors have been developed on a hydrogen-terminated surface conductive layer. fT and fmax of 23 and 25 GHz, respectively, have been achieved in a diamond MISFET with a 0.2 μm gate length. Utilizing de-embedding and small-signal equivalent circuit analysis, parasitic components are extracted. The intrinsic fT and fmax of the 0.2-μm-gate diamond MISFET are estimated to be 26 and 36 GHz, respectively. In this report, some of the challenging steps in device fabrication processes such as the development of a low-resistivity ohmic layer, a high-quality gate insulator and acceptor density control technology, toward high-power and high-frequency diamond transistors with high reliability, are introduced.

  11. 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.

  12. Hydrogen-terminated diamond vertical-type metal oxide semiconductor field-effect transistors with a trench gate

    NASA Astrophysics Data System (ADS)

    Inaba, Masafumi; Muta, Tsubasa; Kobayashi, Mikinori; Saito, Toshiki; Shibata, Masanobu; Matsumura, Daisuke; Kudo, Takuya; Hiraiwa, Atsushi; Kawarada, Hiroshi

    2016-07-01

    The hydrogen-terminated diamond surface (C-H diamond) has a two-dimensional hole gas (2DHG) layer independent of the crystal orientation. A 2DHG layer is ubiquitously formed on the C-H diamond surface covered by atomic-layer-deposited-Al2O3. Using Al2O3 as a gate oxide, C-H diamond metal oxide semiconductor field-effect transistors (MOSFETs) operate in a trench gate structure where the diamond side-wall acts as a channel. MOSFETs with a side-wall channel exhibit equivalent performance to the lateral C-H diamond MOSFET without a side-wall channel. Here, a vertical-type MOSFET with a drain on the bottom is demonstrated in diamond with channel current modulation by the gate and pinch off.

  13. Control of crystallite size in diamond film chemical vapor deposition

    NASA Astrophysics Data System (ADS)

    Moran, Mark B.; Johnson, Linda F.; Klemm, Karl A.

    1992-12-01

    In depositing an adhering, continuous, polycrystalline diamond film of optical or semiconductor quality on a substrate, as by forming on the substrate a layer of a refractory nitride interlayer and depositing diamond on the interlayer without mechanical treatment or seeding of the substrate or the interlayer, the substrate is heated in a vacuum chamber containing a microwave activated mixture of hydrogen and a gas including carbon, and the size of deposited diamond crystallites and their rate of deposition selectively varied by a bias voltage applied to the substrate.

  14. 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.

  15. Diamond Technology Initiative

    DTIC Science & Technology

    1994-05-01

    thermal stresses of 10 million Watts per meter, 1,000 times better than Zerodur *. This property is also important for many thermal management...products UTD has coated to date include: • Optical windows, lenses, and mirrors . Zinc sulfide infrared windows coated with a 2.5 micron-thick...implants 16, 49 microwave plasma-enhanced CVD 2 mirrors , diamond-coated 49 models of diamond growth 10, 25, 33, 34, 39 moderators 10

  16. 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.

  17. Growth, Characterization and Device Development in Monocrystalline Diamond Films

    DTIC Science & Technology

    1993-10-31

    of these phases must be determined by HRTEM . The research of this grant has included the studies of the process parameters and substrate3 effects on...resolution transmission electron mi- cleation). Fedoseev et al.5- 7 presented theoretical argu- croscopy ( HRTEM ) of diamond nucleation on "diamond ments...diffusivity of the predeposition of carbonaceous layers of diamondlike carbon in the respective carbide. However, attempts in carbon2 -2 ( DLC ) or even oil

  18. Phonon conduction in GaN-diamond composite substrates

    NASA Astrophysics Data System (ADS)

    Cho, Jungwan; Francis, Daniel; Altman, David H.; Asheghi, Mehdi; Goodson, Kenneth E.

    2017-02-01

    The integration of strongly contrasting materials can enable performance benefits for semiconductor devices. One example is composite substrates of gallium nitride (GaN) and diamond, which promise dramatically improved conduction cooling of high-power GaN transistors. Here, we examine phonon conduction in GaN-diamond composite substrates fabricated using a GaN epilayer transfer process through transmission electron microscopy, measurements using time-domain thermoreflectance, and semiclassical transport theory for phonons interacting with interfaces and defects. Thermoreflectance amplitude and ratio signals are analyzed at multiple modulation frequencies to simultaneously extract the thermal conductivity of GaN layers and the thermal boundary resistance across GaN-diamond interfaces at room temperature. Uncertainties in the measurement of these two properties are estimated considering those of parameters, including the thickness of a topmost metal transducer layer, given as an input to a multilayer thermal model, as well as those associated with simultaneously fitting the two properties. The volume resistance of an intermediate, disordered SiN layer between the GaN and diamond, as well as a presence of near-interfacial defects in the GaN and diamond, dominates the measured GaN-diamond thermal boundary resistances as low as 17 m2 K GW-1. The GaN thermal conductivity data are consistent with the semiclassical phonon thermal conductivity integral model that accounts for the size effect as well as phonon scattering on point defects at concentrations near 3 × 1018 cm-3.

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

    SciTech Connect

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

    2016-01-18

    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 μm. 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.

  20. Cryotribology of diamond and graphite

    SciTech Connect

    Iwasa, Yukikazu; Ashaboglu, A.F.; Rabinowicz, E.R.

    1996-12-31

    An experimental study was carried out on the tribological behavior of materials of interest in cryogenic applications, focusing on diamond and graphite. Both natural diamond (referred in the text as diamond) and chemical-vapor-deposition (CVD) diamond (CVD-diamond) were used. The experiment was carried out using a pin-on-disk tribometer capable of operating at cryogenic temperatures, from 4.2 to 293 K. Two basic scenarios of testing were used: (1) frictional coefficient ({mu}) vs velocity (v) characteristics at constant temperatures; (2) {mu} vs temperature (T) behavior at fixed sliding speeds. For diamond/CVD-diamond, graphite/CVD-diamond, stainless steel/CVD-diamond pairs, {mu}`s are virtually velocity independent. For each of diamond/graphite, alumina/graphite, and graphite/graphite pairs, the {partial_derivative}{mu}/{partial_derivative}v characteristic is favorable, i.e., positive. For diamond/CVD-diamond and graphite/CVD-diamond pairs, {mu}`s are nearly temperature independent between in the range 77 - 293 K. Each {mu} vs T plot for pin materials sliding on graphite disks has a peak at a temperature in the range 100 - 200 K.

  1. Hybrid Group IV Nanophotonic Structures Incorporating Diamond Silicon-Vacancy Color Centers

    NASA Astrophysics Data System (ADS)

    Zhang, Jingyuan Linda; Ishiwata, Hitoshi; Babinec, Thomas M.; Radulaski, Marina; Müller, Kai; Lagoudakis, Konstantinos G.; Dory, Constantin; Dahl, Jeremy; Edgington, Robert; Soulière, Veronique; Ferro, Gabriel; Fokin, Andrey A.; Schreiner, Peter R.; Shen, Zhi-Xun; Melosh, Nicholas A.; Vučković, Jelena

    2016-01-01

    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 SiC/diamond structures are realized by combining the growth of nanoand micro-diamonds 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 ionimplantation 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 linewidths and small inhomogeneous broadening of SiV$^-$ lines from all-diamond nano-pillar 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.

  2. 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

  3. The Diamond Makers

    NASA Astrophysics Data System (ADS)

    Hazen, Robert M.

    1999-08-01

    Since time immemorial, we have treasured diamonds for their exquisite beauty and unrivaled hardness. Yet, most of the earth's diamonds lie deep underground and totally unaccessible to us--if only we knew how to fabricate them! In The Diamond Makers Robert Hazen vividly recounts the very human desire to exceed nature and create a synthetic diamond. Spanning centuries of ground-breaking science, instances of bitter rivalry, cases of outright fraud and self-delusion, Hazen blends drama and science to reveal the extraordinary technological advances and devastating failures of the diamond industry. Along the way, readers will be introduced to the brilliant, often eccentric and controversial, pioneers of high-pressure research who have harnessed crushing pressures and scorching temperatures to transform almost any carbon-rich material, from road tar to peanut butter, into the most prized of all gems. Robert M. Hazen is the author of fifteen books, including the bestseller, Science Matters: Achieving Scientific Literacy, which he wrote with James Trefil. Dr. Hazen has won numerous awards for his research and scientific writing.

  4. Heteroepitaxial diamond growth

    NASA Astrophysics Data System (ADS)

    Markunas, R. J.; Rudder, R. A.; Posthill, J. B.; Thomas, R. E.; Hudson, G.

    1994-02-01

    Technical highlights from 1993 include the following: Growth Chemistries: A clear correlation was observed between ionization potential of feedstock gasses and critical power necessary for inductive coupling of the plasma and consequent diamond growth. Substrate preparation and epitaxial film quality: Ion-implantation of C and O has been coupled with either electrochemical etching or acid cleaning for surface preparation prior to homoepitaxial growth. Reactor modifications: Key improvements were made to the RF reactor to allow for long growths to consolidate substrates. Liquid mass flow controllers were added to precisely meter both the water and selected alcohol. Ion-implantation and lift off: Lift off of diamond platelets has been achieved with two processes. Ion-implantation of either C or O followed by annealing and implantation of either C or O followed by water based electrolysis. Diamond characterization: Development of novel detect characterization techniques: (1) Etch delineation of defects by exposure to propane torch flame. (2) Hydrogen plasma exposure to enhance secondary electron emission and provide non-topographical defect contrast. Acetylene will react at room temperature with sites created by partial desorption of oxygen from the (100) diamond surface. Thermal desorption measurements give an apparent activation energy for CO desorption from diamond (100) of 45 kcal/mol. Quantum chemical calculations indicate an activation energy of 38 kcal/mol for CO desorption. Ab initio calculations on (100) surfaces indicates that oxygen adsorbed at one dimer site has an effect on the dimerization of an adjacent site.

  5. Diamond Nanowire for UV Detection

    DTIC Science & Technology

    2010-02-28

    addition to the stated goal of solar - blind , radiation-hard diamond nanowire UV detectors [3]. The use of diamond nanowires in field-effect transistors could...the next phase. As a result, a working diamond nanowire UV detector can be expected within the coming few months. And, a completely new diamond...attractive candidate for use in ultraviolet ( UV ) light detectors and emitters[2]. Of all known materials, it is the hardest, and has the highest

  6. 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.

  7. 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.

  8. 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)

  9. Chemical Vapor Deposited Diamond

    DTIC Science & Technology

    1991-09-27

    surface roughness. 0.9 0.8 p0.7 0.6 0.5 C0.4 0.3 0.2- 0.1- 0-. 0 50 100 150 200 250 300 350 frequency (cm-1) Figure 10. Transmission spectrum of CVD...significantly less than one micrometer. The resultant films show root-mean- squared surface roughnesses -0.02 pm as long as the film thickness is not much... Derjaguin , B.V., Vapor Growth of Diamond on Diamond and Other Surfaces , J. Cryst. Growth 52:219-226 (1981); Spitsyn, B.V., The State of the Art in

  10. Applications Of Diamond In Optics

    NASA Astrophysics Data System (ADS)

    Seal, M.; van Enckevort, W. J. P.

    1989-01-01

    This paper reviews existing and new applications of single crystal diamond, both natural and synthetic, in optical science. The traditional application is as transmissive components, making use of the very wide spectral transmission range, high thermal conductivity, and chemical inertness of diamond. Diamond windows for corrosive environments are well known; diamond surgical endoscope components are under development; and the use of sharpened diamonds as combined surgical cutting instruments and light pipes for internal illumination of the edge is commercial reality. The superb ability of diamond to conduct heat, combined with its very low thermal expansion coefficient makes it suitable for the transmission of high power laser energy, though there is a problem currently being addressed of a high surface reflection coefficient. It is very probable that CVD diamond-like films will form good anti-reflection coatings for diamond. In new applications, the technology of making diamond lenses is being developed. The use of diamond as a detector of ionising radiation is well known, but recent work shows its possibilities in thermoluminescent as well as conduction and pulse counting modes. There are further possibilities of using diamond for the detection and measurement of optical radiation. Examples are low, medium, and high intensity far ultraviolet (< 225 nm) and very high intensity near ultraviolet and visible light from excimer, dye, or argon lasers. Diamond is very radiation resistant! Sensitivities, response times and impurity trap levels have been measured and appropriate diamonds can be synthesised. The use of diamond as fast opto-electronic switches has been reported in the literature and the mechanical and thermal design of diamond "heat sink" substrates for semiconductor laser diodes is advancing rapidly.

  11. 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.

  12. Experimental study of diamond resorption during mantle metasomatism

    NASA Astrophysics Data System (ADS)

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

    2014-05-01

    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.

  13. Fluidized bed deposition of diamond

    DOEpatents

    Laia, Jr., Joseph R.; Carroll, David W.; Trkula, Mitchell; Anderson, Wallace E.; Valone, Steven M.

    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.

  14. Laser patterning of diamond. Part II. Surface nondiamond carbon formation and its removal

    NASA Astrophysics Data System (ADS)

    Smedley, John; Jaye, Cherno; Bohon, Jen; Rao, Triveni; Fischer, Daniel A.

    2009-06-01

    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 ˜60 nm. Ozone cleaning was used to remove the nondiamond carbon layer.

  15. 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.

  16. Growth and tribological properties of diamond films on silicon and tungsten carbide substrates

    NASA Astrophysics Data System (ADS)

    Radhika, R.; Ramachandra Rao, M. S.

    2016-11-01

    Hot filament chemical vapor deposition technique was used to deposit microcrystalline diamond (MCD) and nanocrystalline diamond (NCD) films on silicon (Si) and tungsten carbide (WC-6Co) substrates. Friction coefficient of larger diamond grains deposited on WC-6Co substrate shows less value approximately 0.2 while this differs marginally on films grown on Si substrate. The study claims that for a less friction coefficient, the grain size is not necessarily smaller. However, the less friction coefficient (less than 0.1 saturated value) in MCD and NCD deposited on Si is explained by the formation of graphitized tribolayer. This layer easily forms when diamond phase is thermodynamically unstable.

  17. 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.

  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. California: Diamond Valley

    Atmospheric Science Data Center

    2014-05-15

    ... water storage capacity. In addition to routine water management, Diamond Valley Lake is designed to provide protection against ... 20, 2001 (Terra orbit 7564), is a false-color view combining data from the instrument's 26-degree forward view (displayed as blue) with data ...

  20. 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.

  1. Diamond growth in mantle fluids

    NASA Astrophysics Data System (ADS)

    Bureau, Hélène; Frost, Daniel J.; Bolfan-Casanova, Nathalie; Leroy, Clémence; Esteve, Imène; Cordier, Patrick

    2016-11-01

    In the upper mantle, diamonds can potentially grow from various forms of media (solid, gas, fluid) with a range of compositions (e.g. graphite, C-O-H fluids, silicate or carbonate melts). Inclusions trapped in diamonds are one of the few diagnostic tools that can constrain diamond growth conditions in the Earth's mantle. In this study, inclusion-bearing diamonds have been synthesized to understand the growth conditions of natural diamonds in the upper mantle. Diamonds containing syngenetic inclusions were synthesized in multi-anvil presses employing starting mixtures of carbonates, and silicate compositions in the presence of pure water and saline fluids (H2O-NaCl). Experiments were performed at conditions compatible with the Earth's geotherm (7 GPa, 1300-1400 °C). Results show that within the timescale of the experiments (6 to 30 h) diamond growth occurs if water and carbonates are present in the fluid phase. Water promotes faster diamond growth (up to 14 mm/year at 1400 °C, 7 GPa, 10 g/l NaCl), which is favorable to the inclusion trapping process. At 7 GPa, temperature and fluid composition are the main factors controlling diamond growth. In these experiments, diamonds grew in the presence of two fluids: an aqueous fluid and a hydrous silicate melt. The carbon source for diamond growth must be carbonate (CO32) dissolved in the melt or carbon dioxide species in the aqueous fluid (CO2aq). The presence of NaCl affects the growth kinetics but is not a prerequisite for inclusion-bearing diamond formation. The presence of small discrete or isolated volumes of water-rich fluids is necessary to grow inclusion-bearing peridotitic, eclogitic, fibrous, cloudy and coated diamonds, and may also be involved in the growth of ultradeep, ultrahigh-pressure metamorphic diamonds.

  2. Chemical vapor deposition of diamond thin films on titanium silicon carbide

    NASA Astrophysics Data System (ADS)

    Yang, Songlan

    2008-10-01

    Chemical vapor deposition (CVD) has been the main method for synthesizing diamond thin films on hetero substrate materials since 1980s. It has been well acknowledged that both nucleation and growth of diamond on non-diamond surfaces without pre-treatment are very difficult and slow. Furthermore, the weak adhesion between the diamond thin films and substrates has been a major problem for widespread application of diamond thin films. Up to now, Si has been the most frequently used substrate for the study of diamond thin films and various methods, including bias and diamond powder scratching, have been applied to enhance diamond nucleation density. In the present study, nucleation and growth of diamond thin films on Ti3SiC2, a newly developed ceramic-metallic material, using Microwave Plasma Enhanced (MPE) and Hot- Filament (HF) CVD reactors were carried out. In addition, synchrotron-based Near Edge Extended X-Ray Absorption Fine Structure Spectroscopy (NEXAFS) was used to identify the electronic and chemical structures of various NCD films. The results from MPECVD showed that a much higher diamond nucleation density and a much higher film growth rate can be obtained on Ti3SiC2 compared with on Si. Consequently, nanocrystalline diamond (NCD) thin films were feasibly synthesized on Ti3SiC2 under the typical conditions for microcrystalline diamond film synthesis. Furthermore, the diamond films on Ti3SiC 2 exhibited better adhesion than on Si. The early stage growth of diamond thin films on Ti3SiC2 by HFCVD indicated that a nanowhisker-like diamond-graphite composite layer, different from diamond nucleation on Si, initially formed on the surface of Ti3SiC2, which resulted in high diamond nucleation density. These results indicate that Ti3SiC 2 has great potentials to be used both as substrates and interlayers on metals for diamond thin film deposition and application. This research may greatly expand the tribological application of both Ti3SiC 2 and diamond thin films

  3. Lower pressure synthesis of diamond material

    DOEpatents

    Lueking, Angela; Gutierrez, Humberto; Narayanan, Deepa; Burgess Clifford, Caroline E.; Jain, Puja

    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.

  4. Improvements in the Formation of Boron-Doped Diamond Coatings on Platinum Wires Using the Novel Nucleation Process (NNP)

    PubMed Central

    Fhaner, Mathew; Zhao, Hong; Bian, Xiaochun; Galligan, James J.; Swain, Greg M.

    2010-01-01

    In order to increase the initial nucleation density for the growth of boron-doped diamond on platinum wires, we employed the novel nucleation process (NNP) originally developed by Rotter et al. and discussed by others [1–3]. This pretreatment method involves (i) the initial formation of a thin carbon layer over the substrate followed by (ii) ultrasonic seeding of this “soft” carbon layer with nanoscale particles of diamond. This two-step pretreatment is followed by the deposition of boron-doped diamond by microwave plasma-assisted CVD. Both the diamond seed particles and sites on the carbon layer itself function as the initial nucleation zones for diamond growth from an H2-rich source gas mixture. We report herein on the characterization of the pre-growth carbon layer formed on Pt as well as boron-doped films grown for 2, 4 and 6 h post NNP pretreatment. Results from scanning electron microscopy, Raman spectroscopy and electrochemical studies are reported. The NNP method increases the initial nucleation density on Pt and leads to the formation of a continuous diamond film in a shorter deposition time than is typical for wires pretreated by conventional ultrasonic seeding. The results indicate that the pregrowth layer itself consists of nanoscopic domains of diamond and functions well to enhance the initial nucleation of diamond without any diamond powder seeding. PMID:21617759

  5. 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,...

  6. 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,...

  7. 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,...

  8. 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,...

  9. 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...

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

    DOEpatents

    Shurter,; Roger Philips, Devlin [Los Alamos, NM; David James, Moody [Santa Fe, NM; Nathan Andrew, Taccetti [Los Alamos, NM; Jose Martin, Russell [Santa Fe, NM; John, Steven [Los Alamos, NM

    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.

  11. 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.

  12. 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

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

    NASA Astrophysics Data System (ADS)

    Poulon-Quintin, A.; Faure, C.; Teulé-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.

  14. 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.

  15. 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 σD ∼ 5.2 × 10-4 S cm-1, ΔE ∼ 143 meV and σPh ∼ 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.

  16. Carbon onions as nanoscopic pressure cells for diamond formation

    NASA Astrophysics Data System (ADS)

    Banhart, F.; Ajayan, P. M.

    1996-08-01

    SPHERICAL particles of carbon consisting of concentric graphite-like shells ('carbon onions') can be formed by electron irradiation of graphitic carbon materials1,2. Here we report that, when such particles are heated to ~700 °C and irradiated with electrons, their cores can be transformed to diamond. Under these conditions the spacing between layers in the carbon onions decreases from 0.31 in the outer shells (slightly less than the 0.34-nm layer spacing of graphite) to about 0.22 nm in the core, indicating considerable compression towards the particle centres. We find that this compression allows diamond to nucleate-in effect the carbon onions act as nanoscopic pressure cells for diamond formation.

  17. Mechanics in alumina ceramics modified by ultradispersed diamonds

    NASA Astrophysics Data System (ADS)

    Kireitseu, Maksim V.; Yerakhavets, Sergey G.; Basenuk, Vladimir L.; Jornik, Victor

    2003-10-01

    Alumina coating modified by ultra-dispersed diamonds (UDD) have been produced by combination of thermal flame spraying and micro arc oxidizing technologies on sprayed aluminum substrate was. Structures of alumina-based ultra dispersed diamond particles composite coatings were investigated in detail by transmission electron microscopy and SEM imaging. The particles were deposited with alumina layer on aluminum substrates under various conditions and have different levels of strength, hardness and internal stresses. It was revealed that by UDD strengthening the coating is to have high microhardness of 22 - 26 GPa, fine structure and smooth surface. Diamonds was found to be conglomerated in clusters along the interface obtained with high current density, but it disappeared when deposited with lower current regimes of alternating pulse current. On the other hand, the failure of crystal diamonds became smaller with decreasing current density concentrations. From the correspondence between the structures and the hardness of the composite, it was suggested that the effect of ultra dispersed diamonds resulted in the complicated trend of hardness, strength and fine structure with respect to current density and diamonds concentration in the electrolyte. In view of technological setup pulse current regime at high current frequency improve microhardness and roughness of the coatings. Potential application of the coating is sliding bearings, insulators, aerospace units.

  18. Progress on Diamond-Based Cylindrical Dielectric Accelerating Structures

    NASA Astrophysics Data System (ADS)

    Kanareykin, A.; Schoessow, P.; Conde, M.; Gai, W.

    2006-11-01

    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.

  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. 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.

  1. 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.

  2. Genetics Home Reference: Diamond-Blackfan anemia

    MedlinePlus

    ... Understand Genetics Home Health Conditions Diamond-Blackfan anemia Diamond-Blackfan anemia Enable Javascript to view the expand/ ... boxes. Download PDF Open All Close All Description Diamond-Blackfan anemia is a disorder of the bone ...

  3. Genetics Home Reference: Shwachman-Diamond syndrome

    MedlinePlus

    ... Genetics Home Health Conditions Shwachman-Diamond syndrome Shwachman-Diamond syndrome Enable Javascript to view the expand/collapse ... Download PDF Open All Close All Description Shwachman-Diamond syndrome is an inherited condition that affects many ...

  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.

    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. Conversion of fullerenes to diamond

    DOEpatents

    Gruen, Dieter M.

    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.

  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 Technology Study.

    DTIC Science & Technology

    1979-06-11

    has been conducted into the use of diamond as a TWT helix support material to increase the average output power capability of broadband high frequency...unifilar helix is the one TWT circuit capable of broadband operation with good efficiency, methods to increase jT its power dissipation capability are of...BIBLIOGRAPHY IRa D> AE .,L,-,# ACot .,i n iv 4 I IPT-5413 LIST OF ILLUSTRATIONS Figure No. Title 1 Temperature Differences in a PPM Focused Helix TWT

  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. 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.

  11. Characteristics of Impact Diamonds

    NASA Astrophysics Data System (ADS)

    Skala, R.; Bouska, V. J.

    1992-07-01

    Having studied two Czech diamonds in UV light (lambda=366 nm) they appeared to be an extraordinary dirty orange color [1], the same as in the case of Popigai and ureilites impact diamonds (ID) [2]. SEM images show evidence of a thatch-like surface that is very similar to that of the Abee chondrite [3]. Commonly, the ID contain microscopic black plates which are formed by graphite or a carbon matter with indefinite structure, and they are always associated with hexagonal moissanite [2,4]. One unexplained fact is connected with a fabric of the ID aggregates, i.e. both Czech diamonds are single crystals, otherwise other ID form polycrystalline strongly textured aggregates. [1] Bouska V.J. and Skala R.M. (1992) Abstracts for International Conference on Large Meteorite Impacts and Planetary Evolution, in press. [2] Masaitis V.L., Shafranovskii G.I., Ezerskii V.A., and Reshetnyak N.B. (1990) Meteoritica 49, 180-196. [3] Russell S.S. and Pillinger C.T. (1991) Abstracts 54th Ann. Meet. Meteor. Soc. 200. [4] Bauer J., Fiala J., and Hrichova R. (1963) Amer. Mineral. 48, 620-634.

  12. Conversion of fullerenes to diamonds

    DOEpatents

    Gruen, Dieter M.

    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.

  13. 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

  14. 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

  15. Effects of hydrogen atoms on surface conductivity of diamond film

    SciTech Connect

    Liu, Fengbin Cui, Yan; Qu, Min; Di, Jiejian

    2015-04-15

    To investigate the effects of surface chemisorbed hydrogen atoms and hydrogen atoms in the subsurface region of diamond on surface conductivity, models of hydrogen atoms chemisorbed on diamond with (100) orientation and various concentrations of hydrogen atoms in the subsurface layer of the diamond were built. By using the first-principles method based on density functional theory, the equilibrium geometries and densities of states of the models were studied. The results showed that the surface chemisorbed hydrogen alone could not induce high surface conductivity. In addition, isolated hydrogen atoms in the subsurface layer of the diamond prefer to exist at the bond centre site of the C-C bond. However, such a structure would induce deep localized states, which could not improve the surface conductivity. When the hydrogen concentration increases, the C-H-C-H structure and C-3H{sub bc}-C structure in the subsurface region are more stable than other configurations. The former is not beneficial to the increase of the surface conductivity. However, the latter would induce strong surface states near the Fermi level, which would give rise to high surface conductivity. Thus, a high concentration of subsurface hydrogen atoms in diamond would make significant contributions to surface conductivity.

  16. Diamond Pixel Detectors and 3D Diamond Devices

    NASA Astrophysics Data System (ADS)

    Venturi, N.

    2016-12-01

    Results from detectors of poly-crystalline chemical vapour deposited (pCVD) diamond are presented. These include the first analysis of data of the ATLAS Diamond Beam Monitor (DBM). The DBM module consists of pCVD diamond sensors instrumented with pixellated FE-I4 front-end electronics. Six diamond telescopes, each with three modules, are placed symmetrically around the ATLAS interaction point. The DBM tracking capabilities allow it to discriminate between particles coming from the interaction point and background particles passing through the ATLAS detector. Also, analysis of test beam data of pCVD DBM modules are presented. A new low threshold tuning algorithm based on noise occupancy was developed which increases the DBM module signal to noise ratio significantly. Finally first results from prototypes of a novel detector using pCVD diamond and resistive electrodes in the bulk, forming a 3D diamond device, are discussed. 3D devices based on pCVD diamond were successfully tested with test beams at CERN. The measured charge is compared to that of a strip detector mounted on the same pCVD diamond showing that the 3D device collects significantly more charge than the planar device.

  17. Advanced laser diagnostics for diamond deposition research

    SciTech Connect

    Kruger, C.H.; Owano, T.G.; Wahl, E.H.

    1995-12-31

    Chemical Vapor Deposition (CVD) using thermal plasmas is attractive for diamond synthesis applications due to the inherently high reactant densities and throughput, but the associated high gas-phase collision rates in the boundary layer above the substrate produce steep thermal and species gradients which can drive the complex plasma chemistry away from optimal conditions. To understand and control these environments, accurate measurements of temperature and species concentrations within the reacting boundary layer are needed. This is challenging in atmospheric pressure reactors due to the highly luminous environment, steep thermal and species gradients, and small spatial scales. The applicability of degenerate four-wave mixing (DFWM) as a spectroscopic probe of atmospheric pressure reacting plasmas has been investigated. This powerful, nonlinear technique has been applied to the measurement of temperature and radical species concentrations in the boundary layer of a diamond growth substrate immersed in a flowing atmospheric pressure plasma. In-situ measurements of CH and C{sub 2} radicals have been performed to determine spatially resolved profiles of vibrational temperature, rotational temperature, and species concentration. Results of these measurements are compared with the predictions of a detailed numerical simulation.

  18. 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.

  19. Topomineralogy of the Siberian diamonds

    NASA Astrophysics Data System (ADS)

    Afanasyev, Valentin; Lobanov, Sergey; Vasiliy, Koptil; Bogdan, Pomazanskiy; Alexander, Gerasimchuk; Nikolay, Pokhilenko

    2010-05-01

    Diamond placers are widespread in the modern alluvial deposits and ancient sedimentary collectors of the Siberian craton and can be divided into two major types: 1) related with the rich and famous kimberlites such as Mir and International pipe and 2) with unidentified root source. The lattert are wide spread, industrially significant and in use in the north-east of the Siberian craton. Yet, kimberlites known in the north-east of the Siberian craton have poor diamond concentrations or non-diamondiferous at all. A contradiction occur between high alluvial and extremely-low host diamond content of this region. Detailed studies of this problem led to the fact that diamonds from the alluvial deposits of the Siberian craton, as well as other diamondiferous regions, show broader spectrum of typomorphic features than diamonds from the known kimberlites. Moreover, some diamond groups are not typical for the phanerozoic kimberlites of Siberia, or do not occur in significant amounts. The foregoing suggests that diamonds from the unknown host rock type occur in the diamond placers of the Siberian craton along with typical kimberlite diamonds. Based on the detailed studies of the typomorphic features of the alluvial diamonds from Siberian craton 5 parasteresis groups, probably related to different host rock types, were distinguished. Parasteresis is a regular spatial mineral association which are united by single geological process, such as kimberlite indicator minerals and diamonds from kimberlites which differ in genesis but united by the whole kimberlitic process. Parasteresis 1 (kimberlite-type) involves diamonds which are common for the phanerozoic kimberlites. Parasteresis 2 (supposed to be lamproitic) includes roundish (cryptolaminar) diamonds of dodecahedron habit, the so called "brazilian" or "ural" types. In Siberian phanerozoic industrial kimberlites the part of such diamonds does not exceed 15%. That is the diamonds which dominate in the placers of the Urals and

  20. Twin Quintuplets in CVD Diamond

    DTIC Science & Technology

    1992-08-26

    microscopy (HRTEM). We conclude that the twin quintuplets have two main morphologies. The first consists of four Sigma = 3 twin boundaries and one...slightly more than the 70.53 deg tilt of a Sigma = 3 boundary. These grain boundaries and the conventional diamond lattice twin boundaries are the only types of boundaries that we have observed in CVD diamond.

  1. Theoretical Study of Diamond-Like Carbons and Nucleation of Diamond

    NASA Astrophysics Data System (ADS)

    Lee, Choon-Heung

    Different forms of amorphous carbon and hydrocarbons with varying elastic and optical properties, hardness, density and hydrogen content exist depending on the preparation technique. The structure can vary from graphitic to diamond -like, i.e., from mainly threefold coordinated to mainly four-fold coordinated. In order to study the properties of such materials, microscopic models must be developed. These studies include the modelling of crosslinked defective graphite, diamond nucleation along the graphite edges, and diamond-like carbons. Tamor's proposed structure for diamondlike carbon consists of crosslinked graphitic regions. We studied a concrete realization of this model in which the cross -links are produced by shortening the interplanar bond lengths. The model study was accomplished with a pure rhombohedral graphite cell. For this study we used a semi-empirical potential based on Tersoff's environment-dependent potential which contains angular terms. It is enhanced by a long-range potential which describes the interplanar interactions. We found a configuration corresponding to a local minimum. More general features such as the randomness of the distribution of cross-links are needed for a realistic model. A model study of diamond/graphite interfaces was motivated by recent observations by Li and Angus. They observed a significant enhancement of diamond nucleation on the graphite edge planes with the preferential orientation relationship: {0001} _{g} | {111 }_{d}, < 1120 >_{g} | < 101>_{d}. Two possible interface structures were studied using the Tersoff potential. We found that the models have comparable low interface energies even if they contain some dangling bonds. Moreover, lower interface energies were found when the dangling bonds of the non-bonded diamond layer were satisfied with hydrogen. We have proposed a growth mechanism based on this study. Finally, we constructed realistic models of dense amorphous carbon. The WWW (introduced earlier for a

  2. 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.

  3. Gardner-Diamond syndrome.

    PubMed

    Park, Joyce H; Yagerman, Sarah; Feng, Hao; Kim, Randie H; Meehan, Shane A; Lewin, Jesse

    2016-12-15

    Gardner-Diamond syndrome, which also is knownas autoerythrocyte sensitization disorder, is a raresyndrome of inflammatory, edematous papulesthat evolve into painful ecchymoses on the trunkand lower legs after a period of stress with no priorhistory of trauma. This syndrome usually occurs inwomen with a history of psychiatric disorders, themost common one being depression. Although theexact mechanism of injury is not well understood,it is hypothesized that these patients haveautoantibodies to phosphatidylserine, which is aphospholipid membrane component in erythrocytes.Treatment for this disorder includes symptomatictherapies and psychotropic medications to treat theunderlying psychiatric disorder.

  4. Diamond Anvil Cell Techniques

    NASA Astrophysics Data System (ADS)

    Piermarini, Gasper J.

    It has often been said that scientific advances are made either in a dramatic and revolutionary way, or, as in the case of the diamond anvil cell (DAC), in a slow and evolutionary manner over a period of several years. For more than 2 decades, commencing in 1958, the DAC developed stepwise from a rather crude qualitative instrument to the sophisticated quantitative research tool it is today, capable of routinely producing sustained static pressures in the multi-megabar range and readily adaptable to numerous scientific measurement techniques because of its optical accessibility, miniature size, and portability.

  5. 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

  6. 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.

  7. Large gem diamonds from metallic liquid in Earth's deep mantle.

    PubMed

    Smith, Evan M; Shirey, Steven B; Nestola, Fabrizio; Bullock, Emma S; Wang, Jianhua; Richardson, Stephen H; Wang, Wuyi

    2016-12-16

    The redox state of Earth's convecting mantle, masked by the lithospheric plates and basaltic magmatism of plate tectonics, is a key unknown in the evolutionary history of our planet. Here we report that large, exceptional gem diamonds like the Cullinan, Constellation, and Koh-i-Noor carry direct evidence of crystallization from a redox-sensitive metallic liquid phase in the deep mantle. These sublithospheric diamonds contain inclusions of solidified iron-nickel-carbon-sulfur melt, accompanied by a thin fluid layer of methane ± hydrogen, and sometimes majoritic garnet or former calcium silicate perovskite. The metal-dominated mineral assemblages and reduced volatiles in large gem diamonds indicate formation under metal-saturated conditions. We verify previous predictions that Earth has highly reducing deep mantle regions capable of precipitating a metallic iron phase that contains dissolved carbon and hydrogen.

  8. Onion-like carbon from ultra-disperse diamond

    NASA Astrophysics Data System (ADS)

    Kuznetsov, Vladimir L.; Chuvilin, Andrey L.; Butenko, Yuri V.; Mal'kov, Igor Yu.; Titov, Vladimir M.

    1994-05-01

    A new material containing macroscopic quantities of onion-like carbon (OLC) particles is produced by heat treatment of ultra-disperse diamond (UDD) powder (2-6 nm). Annealing products (characterized by high-resolution electron microscopy) are presented by; (a) quasi-spherical particles with closed concentric graphite shells, (b) polyhedron particles with closed shells, (c) elongated particles with linked external graphite-like layers and closed quasi-spherical internal shells. The intermediates of UDD transformation have been registered. The structural transformation of UDD begins from the surface of the diamond particles towards a crystal bulk. The transformation rate of (111) diamond planes to graphite-like sheets is higher than that of other planes.

  9. 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

  10. Structure, properties, and possible mechanisms of formation of diamond-like phases

    NASA Astrophysics Data System (ADS)

    Belenkov, E. A.; Greshnyakov, V. A.

    2016-10-01

    An analysis was performed for relations between the structural parameters and the properties of 36 carbon diamond-like phases consisting of atoms occupying crystallographically equivalent positions. It was found that the crystal lattices of these phases were in stressed states with respect to the cubic diamond lattice. The density of diamond-like phases, their sublimation energies, bulk moduli, hardnesses, and band gaps depend on the deformation parameters Def and Str. The most stable phases must be phases with minimal parameters Def and Str and also with ring parameter Rng that is most close to the corresponding parameter of cubic diamond. The structures and energy characteristics of fullerites, nanotube bundles, and graphene layers of which diamond-like phases can be obtained as a result of polymerization at high pressures have been calculated.

  11. 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

  12. 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

    2015-09-24

    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.

  13. 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.

  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. Micron-scale coupled carbon isotope and nitrogen abundance variations in diamonds: Evidence for episodic diamond formation beneath the Siberian Craton

    NASA Astrophysics Data System (ADS)

    Wiggers de Vries, D. F.; Bulanova, G. P.; De Corte, K.; Pearson, D. G.; Craven, J. A.; Davies, G. R.

    2013-01-01

    The internal structure and growth history of six macro-diamonds from kimberlite pipes in Yakutia (Russia) were investigated with cathodoluminescence imaging and coupled carbon isotope and nitrogen abundance analyses along detailed core to rim traverses. The diamonds are characterised by octahedral zonation with layer-by-layer growth. High spatial resolution SIMS profiles establish that there is no exchange of the carbon isotope composition across growth boundaries at the μm scale and that isotopic variations observed between (sub)zones within the diamonds are primary. The macro-diamonds have δ13C values that vary within 2‰ of -5.3‰ and their nitrogen contents range between 0-1334 at. ppm. There are markedly different nitrogen aggregation states between major growth zones within individual diamonds that demonstrate Yakutian diamonds grew in multiple growth events. Growth intervals were punctuated by stages of dissolution now associated with <10 μm wide zones of nitrogen absent type II diamond. Across these resorption interfaces carbon isotope ratios and nitrogen contents record shifts between 0.5-2.3‰ and up to 407 at. ppm, respectively. Co-variation in δ13C value-nitrogen content suggests that parts of individual diamonds precipitated in a Rayleigh process from either oxidised or reduced fluids/melts, with two single diamonds showing evidence of both fluid types. Modelling the co-variation establishes that nitrogen is a compatible element in diamond relative to its growth medium and that the nitrogen partition coefficient is different between oxidised (3-4.1) and reduced (3) sources. The reduced sources have δ13C values between -7.3‰ and -4.6‰, while the oxidised sources have higher δ13C values between -5.8‰ and -1.8‰ (if grown from carbonatitic media) or between -3.8‰ and +0.2‰ (if grown from CO2-rich media). It is therefore concluded that individual Yakutian diamonds originate from distinct fluids/melts of variable compositions. The

  16. Diamond and Carbon Nanotube Composites for Supercapacitor Devices

    NASA Astrophysics Data System (ADS)

    Moreira, João Vitor Silva; May, Paul William; Corat, Evaldo José; Peterlevitz, Alfredo Carlos; Pinheiro, Romário Araújo; Zanin, Hudson

    2017-02-01

    We report on the synthesis and electrochemical properties of diamond grown onto vertically aligned carbon nanotubes with high surface areas as a template, resulting in a composite material exhibiting high double-layer capacitance as well as low electrochemical impedance electrodes suitable for applications as supercapacitor devices. We contrast results from devices fabricated with samples which differ in both their initial substrates (Si and Ti) and their final diamond coatings, such as boron-doped diamond and diamond-like carbon (DLC). We present for first time a conducting model for non-doped DLC thin-films. All samples were characterized by scanning and transmission electron microscopy and Fourier transform infrared and Raman spectroscopy. Our results show specific capacitance as high as 8.25 F g-1 (˜1 F cm-2) and gravimetric specific energy and power as high as 0.7 W h kg-1 and 176.4 W kg-1, respectively, which suggest that these diamond/carbon nanotube composite electrodes are excellent candidates for supercapacitor fabrication.

  17. 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.

  18. 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.

  19. A study of diamond synthesis by hot filament chemical vapor deposition on Nc coatings

    NASA Astrophysics Data System (ADS)

    Polini, R.; Kumashiro, S.; Jackson, M. J.; Amar, M.; Ahmed, W.; Sein, H.

    2006-04-01

    Deposition of diamond films onto various substrates can result in significant technological advantages in terms of functionality and improved life and performance of components. Diamond is hard, wear resistant, chemically inert, and biocompatible. It is considered to be the ideal material for surfaces of cutting tools and biomedical components. However, it is well known that diamond deposition onto technologically important substrates, such as co-cemented carbides and steels, is problematic due to carbon interaction with the substrate, low nucleation densities, and poor adhesion. Several papers previously published in the relevant literature have reported the application of interlayer materials such as metal nitrides and carbides to provide bonding between diamond and hostile substrates. In this study, the chemical vapor deposition (CVD) of polycrystalline diamond on TiN/SiN x nc (nc) interlayers deposited at relatively low temperatures has been investigated for the first time. The nc layers were deposited at 70 or 400 °C on Si substrates using a dual ion beam deposition system. The results showed that a preliminary seeding pretreatment with diamond suspension was necessary to achieve large diamond nucleation densities and that diamond nucleation was larger on nc films than on bare sc-Si subjected to the same pretreatment and CVD process parameters. TiN/SiN x layers synthesized at 70 or 400 °C underwent different nanostructure modifications during diamond CVD. The data also showed that TiN/SiN x films obtained at 400 °C are preferable in so far as their use as interlayers between hostile substrates and CVD diamond is concerned.

  20. Tailoring nanocrystalline diamond film properties

    DOEpatents

    Gruen, Dieter M.; McCauley, Thomas G.; Zhou, Dan; Krauss, Alan R.

    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.

  1. Conversion of fullerenes to diamond

    DOEpatents

    Gruen, Dieter M.

    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.

  2. 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.

  3. CVD diamond metallization and characterization

    NASA Astrophysics Data System (ADS)

    Fraimovitch, D.; Adelberd, A.; Marunko, S.; Lefeuvre, G.; Ruzin, A.

    2017-02-01

    In this study we compared three diamond substrate grades: polycrystalline, optical grade single crystal, and electronic grade single crystal for detector application. Beside the bulk type, the choice of contact material, pre-treatment, and sputtering process details have shown to alter significantly the diamond detector performance. Characterization of diamond substrate permittivity and losses indicate grade and crystallinity related, characteristic differences for frequencies in 1 kHz-1 MHz range. Substantial grade related variations were also observed in surface electrostatic characterization performed by contact potential difference (CPD) mode of an atomic force microscope. Study of conductivity variations with temperature reveal that bulk trap energy levels are also dependent on the crystal grade.

  4. Diamonds from the Machado River alluvial deposit, Rondônia, Brazil, derived from both lithospheric and sublithospheric mantle

    NASA Astrophysics Data System (ADS)

    Burnham, A. D.; Bulanova, G. P.; Smith, C. B.; Whitehead, S. C.; Kohn, S. C.; Gobbo, L.; Walter, M. J.

    2016-11-01

    Diamonds from the Machado River alluvial deposit have been characterised on the basis of external morphology, internal textures, carbon isotopic composition, nitrogen concentration and aggregation state and mineral inclusion chemistry. Variations in morphology and features of abrasion suggest some diamonds have been derived directly from local kimberlites, whereas others have been through extensive sedimentary recycling. On the basis of mineral inclusion compositions, both lithospheric and sublithospheric diamonds are present at the deposit. The lithospheric diamonds have clear layer-by-layer octahedral and/or cuboid internal growth zonation, contain measurable nitrogen and indicate a heterogeneous lithospheric mantle beneath the region. The sublithospheric diamonds show a lack of regular sharp zonation, do not contain detectable nitrogen, are isotopically heavy (δ13CPDB predominantly - 0.7 to - 5.5) and contain inclusions of ferropericlase, former bridgmanite, majoritic garnet and former CaSiO3-perovskite. This suggests source lithologies that are Mg- and Ca-rich, probably including carbonates and serpentinites, subducted to lower mantle depths. The studied suite of sublithospheric diamonds has many similarities to the alluvial diamonds from Kankan, Guinea, but has more extreme variations in mineral inclusion chemistry. Of all superdeep diamond suites yet discovered, Machado River represents an end-member in terms of either the compositional range of materials being subducted to Transition Zone and lower mantle or the process by which materials are transferred from the subducted slab to the diamond-forming region.

  5. Theoretical investigation of the electronic structure and quantum transport in the graphene-C(111) diamond surface system.

    PubMed

    Selli, Daniele; Baburin, Igor; Leoni, Stefano; Zhu, Zhen; Tománek, David; Seifert, Gotthard

    2013-10-30

    We investigate the interaction of a graphene monolayer with the C(111) diamond surface using ab initio density functional theory. To accommodate the lattice mismatch between graphene and diamond, the overlayer deforms into a wavy structure that binds strongly to the diamond substrate. The detached ridges of the wavy graphene overlayer behave electronically as free-standing polyacetylene chains with delocalized π electrons, separated by regions containing only sp(3) carbon atoms covalently bonded to the (111) diamond surface. We performed quantum transport calculations for different geometries of the system to study how the buckling of the graphene layer and the associated bonding to the diamond substrate affect the transport properties. The system displays high carrier mobility along the ridges and a wide transport gap in the direction normal to the ridges. These intriguing, strongly anisotropic transport properties qualify the hybrid graphene-diamond system as a viable candidate for electronic nanodevices.

  6. 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

  7. Inversion channel diamond metal-oxide-semiconductor field-effect transistor with normally off characteristics

    NASA Astrophysics Data System (ADS)

    Matsumoto, Tsubasa; Kato, Hiromitsu; Oyama, Kazuhiro; Makino, Toshiharu; Ogura, Masahiko; Takeuchi, Daisuke; Inokuma, Takao; Tokuda, Norio; Yamasaki, Satoshi

    2016-08-01

    We fabricated inversion channel diamond metal-oxide-semiconductor field-effect transistors (MOSFETs) with normally off characteristics. At present, Si MOSFETs and insulated gate bipolar transistors (IGBTs) with inversion channels are widely used because of their high controllability of electric power and high tolerance. Although a diamond semiconductor is considered to be a material with a strong potential for application in next-generation power devices, diamond MOSFETs with an inversion channel have not yet been reported. We precisely controlled the MOS interface for diamond by wet annealing and fabricated p-channel and planar-type MOSFETs with phosphorus-doped n-type body on diamond (111) substrate. The gate oxide of Al2O3 was deposited onto the n-type diamond body by atomic layer deposition at 300 °C. The drain current was controlled by the negative gate voltage, indicating that an inversion channel with a p-type character was formed at a high-quality n-type diamond body/Al2O3 interface. The maximum drain current density and the field-effect mobility of a diamond MOSFET with a gate electrode length of 5 μm were 1.6 mA/mm and 8.0 cm2/Vs, respectively, at room temperature.

  8. Inversion channel diamond metal-oxide-semiconductor field-effect transistor with normally off characteristics.

    PubMed

    Matsumoto, Tsubasa; Kato, Hiromitsu; Oyama, Kazuhiro; Makino, Toshiharu; Ogura, Masahiko; Takeuchi, Daisuke; Inokuma, Takao; Tokuda, Norio; Yamasaki, Satoshi

    2016-08-22

    We fabricated inversion channel diamond metal-oxide-semiconductor field-effect transistors (MOSFETs) with normally off characteristics. At present, Si MOSFETs and insulated gate bipolar transistors (IGBTs) with inversion channels are widely used because of their high controllability of electric power and high tolerance. Although a diamond semiconductor is considered to be a material with a strong potential for application in next-generation power devices, diamond MOSFETs with an inversion channel have not yet been reported. We precisely controlled the MOS interface for diamond by wet annealing and fabricated p-channel and planar-type MOSFETs with phosphorus-doped n-type body on diamond (111) substrate. The gate oxide of Al2O3 was deposited onto the n-type diamond body by atomic layer deposition at 300 °C. The drain current was controlled by the negative gate voltage, indicating that an inversion channel with a p-type character was formed at a high-quality n-type diamond body/Al2O3 interface. The maximum drain current density and the field-effect mobility of a diamond MOSFET with a gate electrode length of 5 μm were 1.6 mA/mm and 8.0 cm(2)/Vs, respectively, at room temperature.

  9. Inversion channel diamond metal-oxide-semiconductor field-effect transistor with normally off characteristics

    PubMed Central

    Matsumoto, Tsubasa; Kato, Hiromitsu; Oyama, Kazuhiro; Makino, Toshiharu; Ogura, Masahiko; Takeuchi, Daisuke; Inokuma, Takao; Tokuda, Norio; Yamasaki, Satoshi

    2016-01-01

    We fabricated inversion channel diamond metal-oxide-semiconductor field-effect transistors (MOSFETs) with normally off characteristics. At present, Si MOSFETs and insulated gate bipolar transistors (IGBTs) with inversion channels are widely used because of their high controllability of electric power and high tolerance. Although a diamond semiconductor is considered to be a material with a strong potential for application in next-generation power devices, diamond MOSFETs with an inversion channel have not yet been reported. We precisely controlled the MOS interface for diamond by wet annealing and fabricated p-channel and planar-type MOSFETs with phosphorus-doped n-type body on diamond (111) substrate. The gate oxide of Al2O3 was deposited onto the n-type diamond body by atomic layer deposition at 300 °C. The drain current was controlled by the negative gate voltage, indicating that an inversion channel with a p-type character was formed at a high-quality n-type diamond body/Al2O3 interface. The maximum drain current density and the field-effect mobility of a diamond MOSFET with a gate electrode length of 5 μm were 1.6 mA/mm and 8.0 cm2/Vs, respectively, at room temperature. PMID:27545201

  10. Enhanced hardness of CVD diamond after high pressure and high-temperature treatments

    NASA Astrophysics Data System (ADS)

    Wang, Yongkun; Yin, Shuai; Lei, Li; Wang, Qiming; Wang, Wendan; Chen, Hongyang; Zhang, Yu; Liu, Fangming; Hu, Yi; Liu, Jin; Gao, Shangpan; Peng, Fang; He, Xuejing; He, Duanwei

    2015-10-01

    The diamond thick layers prepared using chemical vapor deposition (CVD) methods have been treated at high pressures and high temperatures (HP-HT). It was found that the Vickers hardness of the HP-HT treated bulks was nearly two times as high as that of the starting CVD diamond samples. The hardness of the samples treated at 8 GPa and 1800°C is ∼80 GPa at a loading force of 49 N, close to that of the single-crystal diamond (∼100 GPa). In addition, the oxidation resistance of CVD diamond samples was also enhanced greatly after HP-HT treatments, and the diamondization of sp2 bonded carbon in the CVD diamond samples could occur at 7-8 GPa and 1600-1800°C. The HP-HT conditions of diamondization in our works are much lower than the case of the graphite-to-diamond direct transformation without the presence of catalyst (>15 GPa and 2000°C).

  11. Fabrication of thin diamond membranes by using hot implantation and ion-cut methods

    NASA Astrophysics Data System (ADS)

    Suk, Jaekwon; Kim, Hyeongkwon; Lim, Weon Cheol; Yune, Jiwon; Moon, Sung; Eliades, John A.; Kim, Joonkon; Lee, Jaeyong; Song, Jonghan

    2017-03-01

    A thin (2 μm) and relatively large area (3 × 3 mm2) diamond membrane was fabricated by cleaving a surface from a single crystal chemical vapor deposition (CVD) diamond wafer (3 × 3 mm2× 300 μm) using a hot implantation and ion-cut method. First, while maintaining the CVD diamond at 400 °C, a damage zone was created at a depth of 2.3 μm underneath the surface by implanting 4 MeV carbon ions into the diamond in order to promote membrane cleavage (hot implantation). According to TEM data, hot implantation reduces the thickness of the implantation damage zone by about a factor of 10 when compared to implanting carbon ions with the CVD diamond at room temperature (RT). In order to recover crystallinity, the implanted sample was then annealed at 850 °C. Next, 380 keV hydrogen ions were implanted into the sample to a depth of 2.3 μm below the surface with the CVD diamond at RT. After annealing at 850 °C, the CVD diamond surface layer was cleaved at the damage-zone due to internal pressure from H2 gas arising from the implanted hydrogen (ion-cut). A thin layer of graphite (˜300 nm) on the cleavage surface, arising from the implanted carbon, was removed by O2 annealing. This technique can potentially be used to produce much larger area membranes of variable thickness.

  12. 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.

  13. Method of dehalogenation using diamonds

    DOEpatents

    Farcasiu, Malvina; Kaufman, Phillip B.; Ladner, Edward P.; Anderson, Richard R.

    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.

  14. 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.

  15. A diffraction grating created in diamond substrate by boron ion implantation

    NASA Astrophysics Data System (ADS)

    Stepanov, A. L.; Nuzhdin, V. I.; Galyautdinov, M. F.; Kurbatova, N. V.; Valeev, V. F.; Vorobev, V. V.; Osin, Yu. N.

    2017-01-01

    This work is devoted to new method of manufacturing of diffractive optical elements (gratings). A grating was formed in a diamond substrate by implantation with boron ions through a mask. Ion implantation led to the graphitization of diamond in unmasked regions and resulted in swelling of the irradiated layer. The formation of periodic graphitized surface microstructures on the diamond substrate was confirmed by optical, electron, and atomic force microscopy. The efficiency of operation of the obtained diffractive optical element was demonstrated by probing with He-Ne laser radiation.

  16. Novel Manufacturing Technologies for GHZ/THz Integrated Circuits on Synthetic Diamond Substrates

    DTIC Science & Technology

    2010-11-15

    indicate possibility of realization of ICs on diamond substrates. In the course of our studies it was found that the Ti- Pd -Au metallization system...Ti– Pd –Au metallization layers at temperatures up to 400 ºС. This indicates its rather high thermal stability and possibility of application in...24 Figure 22. Auger concentration depth profiles in the Ti Pd Au metallization system on synthetic diamond after vacuum

  17. 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.

  18. 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

  19. Diamond crystallization in a CO2-rich alkaline carbonate melt with a nitrogen additive

    NASA Astrophysics Data System (ADS)

    Khokhryakov, Alexander F.; Palyanov, Yuri N.; Kupriyanov, Igor N.; Nechaev, Denis V.

    2016-09-01

    Diamond crystallization was experimentally studied in a CO2-bearing alkaline carbonate melt with an increased content of nitrogen at pressure of 6.3 GPa and temperature of 1500 °C. The growth rate, morphology, internal structure of overgrown layers, and defect-impurity composition of newly formed diamond were investigated. The type of growth patterns on faces, internal structure, and nitrogen content were found to be controlled by both the crystallographic orientation of the growth surfaces and the structure of the original faces of diamond seed crystals. An overgrown layer has a uniform structure on the {100} plane faces of synthetic diamond and a fibrillar (fibrous) structure on the faceted surfaces of a natural diamond cube. The {111} faces have a polycentric vicinal relief with numerous twin intergrowths and micro twin lamellae. The stable form of diamond growth under experimental conditions is a curved-face hexoctahedron with small cube faces. The nitrogen impurity concentration in overgrown layers varies depending on the growth direction and surface type, from 100 to 1100 ppm.

  20. Charge transport across high surface area metal/diamond nanostructured composites.

    PubMed

    Plana, D; Humphrey, J J L; Bradley, K A; Celorrio, V; Fermín, D J

    2013-04-24

    electrochemical formation of charge carriers in the diamond particles, percolation theory, and charge screening at the double layer.

  1. 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.

  2. The electrical and optical properties of thin film diamond implanted with silicon

    NASA Astrophysics Data System (ADS)

    Roe, K. J.; Kolodzey, J.; Swann, C. P.; Tsao, M. W.; Rabolt, J. F.; Chen, J.; Brandes, G. R.

    2001-05-01

    The superb mechanical and electrical properties of diamond make it an attractive material for use in extreme conditions. Diamond devices have been fabricated, but the combination of diamond with other materials to form alloys is not yet well-understood. We have investigated the electrical and optical properties of diamond implanted with Si, which is in principle isoelectronic in diamond. The diamond layers were 23 μm thick p-type layers grown on Si(1 0 0) substrates. Silicon was implanted at room temperature, at energy of 300 keV with doses of up to 8.0×10 16 cm -3. A two-stage post-implant anneal process was then performed at 500°C for 30 min, then 800°C for 30 min. Rutherford backscattering spectrometry (RBS) measurements indicated Si concentrations up to 2 at.%, in agreement with simulations of implant profiles. X-ray measurements indicated that about 60-70% of the Si was incorporated substitutionally, corresponding to up to 1.5 at.% from linear interpolation of lattice constants. Raman spectroscopy measurements confirmed that the diamond structure was reconstructed with the post-implant anneal treatment. NEXAFS measurements confirmed the reconstruction of the sp 3 diamond bonds from sp 2 graphite after annealing. Electrical measurements indicated an increase in diode current density with increased Si dose and a decrease in contact resistance with contact anneals. These novel diamond alloys may be useful for electronic and optical devices. We report on the preparation and properties of these alloys.

  3. All-Diamond Microelectrodes as Solid State Probes for Localized Electrochemical Sensing.

    PubMed

    Silva, Eduardo L; Gouvêa, Cristol P; Quevedo, Marcela C; Neto, Miguel A; Archanjo, Braulio S; Fernandes, António J S; Achete, Carlos A; Silva, Rui F; Zheludkevich, Mikhail L; Oliveira, Filipe J

    2015-07-07

    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.

  4. A Preliminary Evaluation of Diamond-Like Carbon Coated Polycarbonate

    DTIC Science & Technology

    1991-09-01

    moisture sensitive coatings provide good protection against laser induced damage. Proper adhesion between each coating layers needs to be estab- lished... coating that is being pursued is to increase the wear, abra- sion, and chemical resistance of the current ballistic/laser protective spectacles (BLPS...unique ion beam system. These diamond-like carbon coatings have considera’le potential as wear-resistant protective hardcoatings for transparent

  5. Tiny radio is based on diamond effects

    NASA Astrophysics Data System (ADS)

    2017-02-01

    You could soon be tuning into “Diamond FM”, thanks to a new radio receiver based on atomic-scale defects in diamond, unveiled by physicists at Harvard University in the US and Element Six in the UK.

  6. 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.

  7. 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 ~80°C 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.

  8. 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.

  9. 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.

  10. 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.

  11. Chemical gases sensing properties of diamond nanocone arrays formed by plasma etching

    NASA Astrophysics Data System (ADS)

    Wang, Q.; Qu, S. L.; Fu, S. Y.; Liu, W. J.; Li, J. J.; Gu, C. Z.

    2007-11-01

    A uniform diamond nanocone array was formed by plasma etching of diamond film in a hot filament chemical vapor deposition (HFCVD) system. A surface amorphous carbon coating layer, which is formed during CH4/H2 plasma-etching process, was removed by Ar plasma in a reactive ion etching system. The hydrogenation of diamond nanocones was performed in H2 ambience by using the same HFCVD system. The air-diluted NH3 and NO2 gases sensing properties of the diamond cone arrays had been studied by using electric current versus measurement time characteristics at room temperature. The repeatable chemical sensing properties of the hydrogenated diamond cone array sensor are enhanced, in comparison with as-formed diamond film. Surface two-dimensional hole gas structure and greatly increased surface-to-volume ratio both play a key role for the excellent detection performance. As-formed diamond nanocone arrays show a promising prospect for applications as chemical sensor for both reducing (NH3) and oxidizing (NO2) gases.

  12. Chemical gases sensing properties of diamond nanocone arrays formed by plasma etching

    SciTech Connect

    Wang, Q.; Qu, S. L.; Fu, S. Y.; Liu, W. J.; Li, J. J.; Gu, C. Z.

    2007-11-15

    A uniform diamond nanocone array was formed by plasma etching of diamond film in a hot filament chemical vapor deposition (HFCVD) system. A surface amorphous carbon coating layer, which is formed during CH{sub 4}/H{sub 2} plasma-etching process, was removed by Ar plasma in a reactive ion etching system. The hydrogenation of diamond nanocones was performed in H{sub 2} ambience by using the same HFCVD system. The air-diluted NH{sub 3} and NO{sub 2} gases sensing properties of the diamond cone arrays had been studied by using electric current versus measurement time characteristics at room temperature. The repeatable chemical sensing properties of the hydrogenated diamond cone array sensor are enhanced, in comparison with as-formed diamond film. Surface two-dimensional hole gas structure and greatly increased surface-to-volume ratio both play a key role for the excellent detection performance. As-formed diamond nanocone arrays show a promising prospect for applications as chemical sensor for both reducing (NH{sub 3}) and oxidizing (NO{sub 2}) gases.

  13. 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 Ni

  14. Thermal neutron dosimeter by synthetic single crystal diamond devices.

    PubMed

    Almaviva, S; Marinelli, Marco; Milani, E; Prestopino, G; Tucciarone, A; Verona, C; Verona-Rinati, G; Angelone, M; Pillon, M

    2009-07-01

    We report on a new solid state dosimeter based on chemical vapor deposition (CVD) single crystal diamond fabricated at Roma "Tor Vergata" University laboratories. The dosimeter has been specifically designed for direct neutron dose measurements in boron neutron capture therapy (BNCT). The response to thermal neutrons of the proposed diamond dosimeter is directly due to (10)B and, therefore, the dosimeter response is directly proportional to the boron absorbed doses in BNCT. Two single crystal diamond detectors are fabricated in a p-type/intrinsic/metal configuration and are sandwiched together with a boron containing layer in between the metallic contacts (see Fig.1). Neutron irradiations were performed at the Frascati Neutron Generator (FNG) using the 2.5 MeV neutrons produced through the D(d,n)(3)He fusion reaction. Thermal neutrons were then produced by slowing down the 2.5 MeV neutrons using a cylindrical polymethylmethacrylate (PMMA) moderator. The diamond dosimeter was placed in the center of the moderator. The products of (10)B(n,alpha)Li nuclear reaction were collected simultaneously giving rise to a single peak. Stable performance, high reproducibility, high efficiency and good linearity were observed.

  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. 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...

  17. 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...

  18. 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...

  19. 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.

  20. 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...

  1. 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...

  2. Underground at Black Diamond Mines

    SciTech Connect

    Higgins, C.T.

    1989-10-01

    Although California is noted for its mining history and annually leads the nation in total monetary value of minerals produced, there a few opportunities for the public to tour underground mines. One reason is that nearly all mining in the state today is done above ground in open pits. Another reason is that active underground mines are not commonly favorable to public tours. There is one place, Black Diamond Mines Regional Preserve, where the public can safely tour a formerly active underground mine. Black Diamond Mines Regional Preserve is a 3,600-acre parkland about 5 miles southwest of Antioch in Contra Costa County. The Preserve was established in the early 1970s and is administered by the East Bay Regional Park District. Black Diamond Mines Preserve is noteworthy for its mining history as well as its natural history, both of which are briefly described here.

  3. Diamond drumhead crystals (Conference Presentation)

    NASA Astrophysics Data System (ADS)

    Kolodziej, Tomasz; Vodnala, Preeti; Terentyev, Sergey A.; Blank, Vladimir D.; Shvyd'ko, Yuri V.

    2016-09-01

    Ultra-thin (< 100 um) diamond single crystals are essential for the realization of numerous next generation x-ray optical devices. Fabrication and handling of such ultra-thin crystal components without introducing damage and strain is a challenge. Drumhead crystals, monolithic crystal structures comprised of a thin membrane furnished with a surrounding solid collar would be a solution for the proper handling ensuring mechanically stable and strain-free mount of the membranes with efficient thermal transport. However, diamond being one of the hardest and chemically inert materials poses insurmountable difficulties in the fabrication. Here we report on a successful manufacturing of the diamond drumhead crystals using picosecond laser milling. Subsequent temperature treatment appears to be crucial for the membranes to become defect-free and unstrained, as revealed by x-ray double-crystal topography on an example of drumhead crystals with 1-mm in diameter and 28 um to 47 um-thick membranes in the (100) orientation.

  4. 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.

  5. 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.

  6. Diamonds on Diamond: structural studies at extreme conditions on the Diamond Light Source.

    PubMed

    McMahon, M I

    2015-03-06

    Extreme conditions (EC) research investigates how the structures and physical and chemical properties of materials change when subjected to extremes of pressure and temperature. Pressures in excess of one million times atmospheric pressure can be achieved using a diamond anvil cell, and, in combination with high-energy, micro-focused radiation from a third-generation synchrotron such as Diamond, detailed structural information can be obtained using either powder or single-crystal diffraction techniques. Here, I summarize some of the research drivers behind international EC research, and then briefly describe the techniques by which high-quality diffraction data are obtained. I then highlight the breadth of EC research possible on Diamond by summarizing four examples from work conducted on the I15 and I19 beamlines, including a study which resulted in the first research paper from Diamond. Finally, I look to the future, and speculate as to the type of EC research might be conducted at Diamond over the next 10 years.

  7. Prospects of bipolar diamond devices

    NASA Astrophysics Data System (ADS)

    Aleksov, A.; Denisenko, A.; Kohn, E.

    2000-02-01

    The prospects of diamond bipolar devices are analysed theoretically and experimentally in respect to the problem of deep doping, especially the deep donor in diamond. For this purpose a set of p- n- p bipolar junction transistors (BJTs) is fabricated on p-type diamond substrates by epitaxial growth using boron ( EA=0.4 eV) and nitrogen ( ED=1.7 eV) as the p- and n-type dopants respectively. It is shown that at the boron/nitrogen junction a p- n junction is formed. The built-in potential of the junction is determined by the ionised boron/nitrogen impurities. The specific features of the fabricated devices are the high resistivity of the nitrogen doped base (10 GΩ·cm at 20°C) and a significant leakage current of the reverse biased p- n junctions. These factors limit the transistor action to d.c.-operation in the nA-current range and to temperatures below 200°C where leakage starts to dominate. The values of the static current gain IC/ IB are measured in the common base mode 200 and in the common emitter mode 1.1. The theoretical section of the paper deals with the calculation of the static current gain of diamond pnp transistor structures in dependence of the donor energy level, temperature and frequency. Both the theoretical and the experimental results indicate that diamond bipolar transistors with a nitrogen doped n-type base can exhibit a current gain β of up to 30,000 in the d.c.-regime provided the leakage of the p- n junctions is sufficiently low. High-gain diamond transistors operating in GHz-frequency can be expected as soon as n-doping by shallow donor like phosphorous ( ED<0.5 eV) becomes available.

  8. 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.

  9. Metal-induced rapid transformation of diamond into single and multilayer graphene on wafer scale

    SciTech Connect

    Berman, Diana; Deshmukh, Sanket; Narayanan, Badri; Sankaranarayanan, Subramanian K.R.S.; Yan, Zhong; Balandin, Alexander A.; Zinovev, Alexander; Rosenmann, Daniel; Sumant, Anirudha V.

    2016-07-04

    The degradation of intrinsic properties of graphene during the transfer process constitutes a major challenge in graphene device fabrication, stimulating the need for direct growth of graphene on dielectric substrates. Previous attempts of metal-induced transformation of diamond and silicon carbide into graphene suffers from metal contamination and inability to scale graphene growth over large area. Here in this article, we introduce a direct approach to transform polycrystalline diamond into high-quality graphene layers on wafer scale (4 inch in diameter) using a rapid thermal annealing process facilitated by a nickel, Ni thin film catalyst on top. We show that the process can be tuned to grow single or multilayer graphene with good electronic properties. Molecular dynamics simulations elucidate the mechanism of graphene growth on polycrystalline diamond. Additionally, we demonstrate the lateral growth of free-standing graphene over micron-sized pre-fabricated holes, opening exciting opportunities for future graphene/diamond-based electronics.

  10. 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.

  11. Metal-induced rapid transformation of diamond into single and multilayer graphene on wafer scale

    PubMed Central

    Berman, Diana; Deshmukh, Sanket A.; Narayanan, Badri; Sankaranarayanan, Subramanian K. R. S.; Yan, Zhong; Balandin, Alexander A.; Zinovev, Alexander; Rosenmann, Daniel; Sumant, Anirudha V.

    2016-01-01

    The degradation of intrinsic properties of graphene during the transfer process constitutes a major challenge in graphene device fabrication, stimulating the need for direct growth of graphene on dielectric substrates. Previous attempts of metal-induced transformation of diamond and silicon carbide into graphene suffers from metal contamination and inability to scale graphene growth over large area. Here, we introduce a direct approach to transform polycrystalline diamond into high-quality graphene layers on wafer scale (4 inch in diameter) using a rapid thermal annealing process facilitated by a nickel, Ni thin film catalyst on top. We show that the process can be tuned to grow single or multilayer graphene with good electronic properties. Molecular dynamics simulations elucidate the mechanism of graphene growth on polycrystalline diamond. In addition, we demonstrate the lateral growth of free-standing graphene over micron-sized pre-fabricated holes, opening exciting opportunities for future graphene/diamond-based electronics. PMID:27373740

  12. 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.

  13. Crystallographic orientations of olivine inclusions in diamonds

    NASA Astrophysics Data System (ADS)

    Milani, S.; Nestola, F.; Angel, R. J.; Nimis, P.; Harris, J. W.

    2016-11-01

    In this work we report for the first time the crystallographic orientations of olivine inclusions trapped in diamonds from the Kaapvaal craton (South Africa) determined by single-crystal X-ray diffraction, and analyze them together with all available data in the literature. The overall data set indicates no preferred orientation of the olivine inclusions with respect to their diamond hosts. However, diamonds containing multiple olivine inclusions sometimes show clusters of olivines with the same orientation in the same diamond host. We conclude that such clusters can only be interpreted as the remnants of single olivine crystals pre-dating the growth of the host diamonds.

  14. Diamond Ablators for Inertial Confinement Fusion

    SciTech Connect

    Biener, J; Mirkarimi, P B; Tringe, J W; Baker, S L; Wang, Y M; Kucheyev, S O; Teslich, N E; Wu, K J; Hamza, A V; Wild, C; Woerner, E; Koidl, P; Bruehne, K; Fecht, H

    2005-06-21

    Diamond has a unique combination of physical properties for the inertial confinement fusion ablator application, such as appropriate optical properties, high atomic density, high yield strength, and high thermal conductivity. Here, we present a feasible concept to fabricate diamond ablator shells. The fabrication of diamond capsules is a multi-step process, which involves diamond chemical vapor deposition on silicon mandrels followed by polishing, microfabrication of holes, and removing of the silicon mandrel by an etch process. We also discuss the pros and cons of coarse-grained optical quality and nanocrystalline chemical vapor deposition diamond films for the ablator application.

  15. 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.

  16. 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.

  17. 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.

  18. 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.

  19. Alkene/diamond liquid/solid interface characterization using internal photoemission spectroscopy.

    PubMed

    Nebel, C E; Shin, D; Takeuchi, D; Yamamoto, T; Watanabe, H; Nakamura, T

    2006-06-20

    The photochemical attachment of 10-amino-dec-1-ene molecules protected with a trifluoroacetic acid group (TFAAD) on hydrogen-terminated single-crystalline chemical vapor deposited (CVD) diamond is characterized by total photoyield spectroscopy (TPYS), conductivity, Hall-effect, spectrally resolved photoconductivity (SPC), optical transmission experiments, and, for the first time, by in situ internal photoemission (IPE) spectroscopy applied in the spectral regime from 4 to 6 eV on the alkene/diamond (liquid/solid) heterostructures. These experiments are performed on undoped, (100) oriented, single-crystalline CVD diamond films, which contain no grain boundaries and have negligible bulk and surface defect densities. X-ray photoelectron spectroscopy (XPS) is used to investigate the chemical bonding of alkene molecules to diamond. The spectroscopic set of data shows that the photochemical reaction window of H-terminated diamond is shifted below the optical gap of diamond because of the negative electron affinity. In situ IPE experiments reveal electron emission between 4.5 and 5.2 eV. A model is introduced and discussed in which valence-band electrons are optically excited into empty hydrogen-induced surface states of diamond from where they tunnel into empty pi states of alkene molecules. We theoretically discuss the fastest attachment time to achieve a saturated TFAAD layer of about 2 x 10(14) cm(-)(2) on diamond, which is experimentally detected to be 7 h. In the case of direct optical electron excitations from diamond, the bonding efficiency will be one TFAAD molecule attachment arising from about 1600 emitted electrons.

  20. Superkimberlites: A geodynamic diamond window to the Earth's core

    NASA Astrophysics Data System (ADS)

    Haggerty, Stephen E.

    1994-03-01

    Carbon is the fourth most abundant element in the solar system. In the Earth carbon is in atmospheric CO2, limestone, other organic products, graphite and trace diamond; interstellar diamond, however, is ubiquitous. Diamond is well known for some unique physical and chemical properties, but it is perhaps less well known that the mineral is geologically ancient (3.3 Ga), that its origins are deep in the mantle (greater than 180 km), and that diamonds are among the deepest solid objects to reach the surface of the Earth; rare diamonds are from the transition zone (400-670 km), and other diamonds possibly nucleated in the lower mantle (greater than 670 km). Transport to the surface is in volatile (C-O-H-N-S)-charged highly explosive kimberlite and lamproite volcanoes. These volcanoes are sited exclusively in the oldest (greater than 1.7 Ga), tectonically most stable, and thickest (approximately 200 km) regions of crust and upper mantle lithosphere. The energetics required for volcanism are so exceptional and the sources so deep that possible connections between and among the core, geomagnetism, plumes and diamonds are explored. Some correlations are established and others are implied. The results are sufficiently enticing to propose that kimberlites and geographically and temporally associated carbonatites are continental recorders of plumes dating back to at least 2.8 Ga, and that some diamonds may have recorded core events dating back to 3.3 Ga, or possibly earlier. Peaks in kimberlite magmatic activity correlate , on average, with normal and reverse superchron and subchron behavior of the geomagnetic field. The time lag between magnetohydrodynamic activity in the core and kimberlite eruptive cycles at the Earth's surface is of the order of 25-50 Ma, consistent with the travel times modeled for the passage of plumes from the D'' layer to the subcontinental lithosphere. Although the existence of plumes and the nature of D'' are debated, the correlations established

  1. The effects of Ti carbonization on the nucleation and oriented growth of diamond films on cemented carbide.

    PubMed

    Yu, Xiang; Zhao, Xi-an; Liu, Ya-yun; Hua, Meng; Jiang, Xin

    2014-04-09

    To better understand the influence of carbonization of the Ti interlayer on diamond nucleation and growth, a series of Ti/diamond composite films were deposited on cemented carbide (WC:Co) substrates using a two-step deposition technique. The microstructural properties of the composite films were then characterized by scanning electron microscopy, X-ray diffractometry, and Raman spectroscopy, and their tribological properties were evaluated using a ball-on-disc tester and a metalloscope. The results showed that differences in carbonization for five Ti interlayers of different thicknesses led to variations in the preferred orientations of the TiC layers and in the subsequent nucleation and oriented growth of diamond. This suggests that Ti carbonization significantly influences the nucleation and growth of diamond and subsequently causes variations in the tribological properties of the produced diamond films.

  2. 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.

  3. 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.

  4. Fabrication and characterization of boron-doped nanocrystalline diamond-coated MEMS probes

    NASA Astrophysics Data System (ADS)

    Bogdanowicz, Robert; Sobaszek, Michał; Ficek, Mateusz; Kopiec, Daniel; Moczała, Magdalena; Orłowska, Karolina; Sawczak, Mirosław; Gotszalk, Teodor

    2016-04-01

    Fabrication processes of thin boron-doped nanocrystalline diamond (B-NCD) films on silicon-based micro- and nano-electromechanical structures have been investigated. B-NCD films were deposited using microwave plasma assisted chemical vapour deposition method. The variation in B-NCD morphology, structure and optical parameters was particularly investigated. The use of truncated cone-shaped substrate holder enabled to grow thin fully encapsulated nanocrystalline diamond film with a thickness of approx. 60 nm and RMS roughness of 17 nm. Raman spectra present the typical boron-doped nanocrystalline diamond line recorded at 1148 cm-1. Moreover, the change in mechanical parameters of silicon cantilevers over-coated with boron-doped diamond films was investigated with laser vibrometer. The increase of resonance to frequency of over-coated cantilever is attributed to the change in spring constant caused by B-NCD coating. Topography and electrical parameters of boron-doped diamond films were investigated by tapping mode AFM and electrical mode of AFM-Kelvin probe force microscopy (KPFM). The crystallite-grain size was recorded at 153 and 238 nm for boron-doped film and undoped, respectively. Based on the contact potential difference data from the KPFM measurements, the work function of diamond layers was estimated. For the undoped diamond films, average CPD of 650 mV and for boron-doped layer 155 mV were achieved. Based on CPD values, the values of work functions were calculated as 4.65 and 5.15 eV for doped and undoped diamond film, respectively. Boron doping increases the carrier density and the conductivity of the material and, consequently, the Fermi level.

  5. Superhard material comparable in hardness to diamond

    SciTech Connect

    Badzian, A.R.

    1988-12-19

    Superhard boron suboxides, with hardness close to that of diamond, were synthesized from boron/boron oxide mixtures. Such hardness is expected when a material's molar volume approaches the value characteristic for diamond. These materials consist of boron-rich phases belonging to the boron-oxygen system. The phase which contains 4 at. % oxygen and a crystal structure related to ..beta..rhombohedral boron can scratch diamond faces. During scratching of diamond the suboxide is worn also, and the wear debris is amorphized. Wear on the lt. slash/100/ diamond faces results from a cleavage mechanism which leaves a rough surface covered with cleaved lt. slash/111/ microfaces. The lt. slash/100/ faces are more easily abraded than the lt. slash/111/ diamond faces. Wear on lt. slash/111/ faces consumes much more energy and leaves grooves of plastically deformed diamond.

  6. 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.

  7. 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.

  8. Shock loading of graphite between water layers: Numerical experiments

    NASA Astrophysics Data System (ADS)

    Shurshalov, L. V.; Charakhch'yan, A. A.; Khishchenko, K. V.

    2016-11-01

    A series of numerical experiments on shock loading of graphite between water layers is realized. A simple model of the phase transition of graphite to diamond is formulated. The general scheme of the computational experiment is based on mechanical and thermal interactions of different substances (graphite, diamond, water) subjected to impact by a massive steel flyer in a cylindrical channel. The process of graphite-to-diamond transformation is traced out. The important problem of retaining the formed diamond sample and some favorable conditions to solve this question are discussed.

  9. Fabrication of ultra-thin diamond films using hydrogen implantation and Lift-off technique

    NASA Astrophysics Data System (ADS)

    Popov, V. P.; Antonov, V. A.; Safronov, L. N.; Kupriyanov, I. N.; Pal'yanov, Yu. N.; Rubanov, S.

    2012-11-01

    The Lift-off technique based on high fluence (>3×1016cm-2) implantation of hydrogen (H-) ions has been developed to increase the structural quality and electro-optical properties of the diamond thin membranes. According to the XTEM study the Vacuum Pressure - High Temperature (VPHT) treatment of the H2+ implanted (111) diamond plates at 1200-1600°C and 10-3Pa forms buried glassy like graphite layers in the implanted areas. High Pressure - High Temperature (HPHT) annealing at the same temperatures but under the pressure 4-8 GPa leads to the epitaxial growth of graphite in the buried implanted layers, which could not be etched chemically, but could be easily removed by etching in the anodic cell. Visible light Raman spectroscopy has shown that the H-Lift-off technique is suitable for formation of ultra-thin (down to 30 nm) high quality single crystal diamond membranes and heterostructures. High concentration of nitrogen-vacancy NV- centres (˜1020cm-3) was observed under graphite contacts in thin layer (≤100 nm). Thin, 30 nm single crystal diamond films are the thinnest and largest area single crystal diamond structure produced to date by the Lift-off technique.

  10. 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

  11. 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

  12. The ATLAS Diamond Beam Monitor: Luminosity detector at the LHC

    NASA Astrophysics Data System (ADS)

    Schaefer, D. M.

    2016-07-01

    After the first three years of the LHC running, the ATLAS experiment extracted its pixel detector system to refurbish and re-position the optical readout drivers and install a new barrel layer of pixels. The experiment has also taken advantage of this access to install a set of beam monitoring telescopes with pixel sensors, four each in the forward and backward regions. These telescopes are based on chemical vapor deposited (CVD) diamond sensors to survive in this high radiation environment without needing extensive cooling. This paper describes the lessons learned in construction and commissioning of the ATLAS Diamond Beam Monitor (DBM). We show results from the construction quality assurance tests and commissioning performance, including results from cosmic ray running in early 2015.

  13. 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.

  14. Heteroepitaxial growth of highly oriented diamond on cubic silicon carbide

    SciTech Connect

    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 {beta}-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{degree} have been determined, which is the smallest value ever reported in heteroepitaxial diamond films and appears to be smaller than those of the {beta}-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. {copyright} {ital 1997 American Institute of Physics.}

  15. Characterization of synthesized and treated gem diamonds

    NASA Astrophysics Data System (ADS)

    Song, Ohsung

    2007-10-01

    Synthesized diamonds have been widely employed as polishing media for precise machining and noble substrates for microelectronics. The recent development of the split sphere press has led to the commercial HPHT (high pressure high temperature) synthesis of bulk gem diamonds from graphite and to the enhancement of low quality natural diamonds. Synthesized and treated diamonds are sometimes traded deceptively as high quality natural diamonds because it is hard to distinguish among these diamonds with conventional gemological characterization methods. Therefore, we need to develop a new identification method that is non-destructive, fast, and inexpensive. We proposed using new methods of UV fluorescence and X-ray Lang topography for checking the local HPHT stress field as well as using a vibrating sample magnetometer for checking ferromagnetic residue in synthesized diamonds to distinguish these diamonds from natural ones. We observe unique differences in the local stress field images in synthesized and treated diamonds using Lang topography and UV fluorescence characterization. Our result implies that our proposed methods may be appropriate for identification of the synthesized and treated diamonds.

  16. Synthesizing Diamond from Liquid Feedstock

    NASA Technical Reports Server (NTRS)

    Tzeng, Yonhua

    2005-01-01

    A relatively economical method of chemical vapor deposition (CVD) has been developed for synthesizing diamond crystals and films. Unlike prior CVD methods for synthesizing diamond, this method does not require precisely proportioned flows of compressed gas feedstocks or the use of electrical discharges to decompose the feedstocks to obtain free radicals needed for deposition chemical reactions. Instead, the feedstocks used in this method are mixtures of common organic liquids that can be prepared in advance, and decomposition of feedstock vapors is effected simply by heating. The feedstock used in this method is a solution comprising between 90 and 99 weight percent of methanol and the balance of one or more other oxyhydrocarbons that could include ethanol, isopropanol, and/or acetone. This mixture of compounds is chosen so that dissociation of molecules results in the desired proportions of carbon-containing radicals (principally, CH3) and of OH, H, and O radicals. Undesirably, the CVD temperature and pressure conditions thermodynamically favor the growth of graphite over the growth of diamond. The H radicals are desirable because they help to stabilize the growing surface of diamond by shifting the thermodynamic balance toward favoring the growth of diamond. The OH and O radicals are desirable because they preferentially etch graphite and other non-diamond carbon, thereby helping to ensure the net deposition of pure diamond. The non-methanol compounds are included in the solution because (1) methanol contains equal numbers of C and O atoms; (2) an excess of C over O is needed to obtain net deposition of diamond; and (3) the non-methanol molecules contain multiple carbon atoms for each oxygen atom and thus supply the needed excess carbon A typical apparatus used in this method includes a reservoir containing the feedstock liquid and a partially evacuated stainless-steel reaction chamber. The reservoir is connected to the chamber via tubing and a needle valve or

  17. INTERACTION OF LASER RADIATION WITH MATTER: Effect of the pulse duration on graphitisation of diamond during laser ablation

    NASA Astrophysics Data System (ADS)

    Kononenko, Vitalii V.; Kononenko, Taras V.; Pimenov, S. M.; Sinyavskii, M. N.; Konov, Vitalii I.; Dausinger, F.

    2005-03-01

    Processes of graphitisation of laser-irradiated polycrystalline diamond surface exposed to multipulse irradiation are studied experimentally. The thickness of the laser-modified layer as a function of the laser-pulse duration ranging from 100 fs to 1.5 μs and the effect of the radiation wavelength on this thickness are studied. It is shown that the diamond graphitisation during multipulse laser ablation is a thermally stimulated process. The dependences of the diamond-ablation rates on the radiation energy density under the action of laser pulses of various durations are presented.

  18. 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...

  19. 33 CFR 110.6 - Portland Harbor, Portland, Maine (between Little Diamond Island and Great Diamond Island).

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... (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...

  1. 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...

  2. 33 CFR 110.6 - Portland Harbor, Portland, Maine (between Little Diamond Island and Great Diamond Island).

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... (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...

  3. Realization of direct bonding of single crystal diamond and Si substrates

    NASA Astrophysics Data System (ADS)

    Liang, Jianbo; Masuya, Satoshi; Kasu, Makoto; Shigekawa, Naoteru

    2017-03-01

    Diamond/Si junctions have been achieved by surface activated bonding method without any chemical and heating treatments. Bonded interfaces were obtained that were free from voids and mechanical cracks. Observations by using transmission electron microscopy indicated that an amorphous layer with a thickness of ˜20 nm across the bonded interface was formed, and no structural defects were observed at the interface. The amorphous layer of the diamond side was confirmed to be the mixture of sp2 and sp3 carbons by electron energy loss spectroscopy analyzation. The sp3/(sp2 + sp3) ratio estimated from the X-ray photoemission spectra decreased from 53.8% to 27.5%, while the relative intensity of sp2 increased from 26.8% to 72.5% after the irradiation with Ar fast beam which should be predominantly attributable to the diamond-graphite conversion.

  4. Boron δ-doped (111) diamond solution gate field effect transistors.

    PubMed

    Edgington, Robert; Ruslinda, A Rahim; Sato, Syunsuke; Ishiyama, Yuichiro; Tsuge, Kyosuke; Ono, Tasuku; Kawarada, Hiroshi; Jackman, Richard B

    2012-03-15

    A solution gate field effect transistor (SGFET) using an oxidised boron δ-doped channel on (111) diamond is presented for the first time. Employing an optimised plasma chemical vapour deposition (PECVD) recipe to deposit δ-layers, SGFETs show improved current-voltage (I-V) characteristics in comparison to previous similar devices fabricated on (100) and polycrystalline diamond, where the device is shown to operate in the enhancement mode of operation, achieving channel pinch-off and drain-source current saturation within the electrochemical window of diamond. A maximum gain and transconductance of 3 and 200μS/mm are extracted, showing comparable figures of merit to hydrogen-based SGFET. The oxidised device shows a site-binding model pH sensitivity of 36 mV/pH, displaying fast temporal responses. Considering the biocompatibility of diamond towards cells, the device's highly mutable transistor characteristics, pH sensitivity and stability against anodic oxidation common to hydrogen terminated diamond SGFET, oxidised boron δ-doped diamond SGFETs show promise for the recording of action potentials from electrogenic cells.

  5. Measurements and Studies of Secondary Electron Emission of Diamond Amplified Photocathode

    SciTech Connect

    Wu,Q.

    2008-10-01

    The Diamond Amplified Photocathode (DAP) is a novel approach to generating electrons. By following the primary electron beam, which is generated by traditional electron sources, with an amplifier, the electron beam available to the eventual application is increased by 1 to 2 orders of magnitude in current. Diamond has a very wide band gap of 5.47eV which allows for a good negative electron affinity with simple hydrogenation, diamond can hold more than 2000MV/m field before breakdown. Diamond also provides the best rigidity among all materials. These two characters offer the capability of applying high voltage across very thin diamond film to achieve high SEY and desired emission phase. The diamond amplifier also is capable of handling a large heat load by conduction and sub-nanosecond pulse input. The preparation of the diamond amplifier includes thinning and polishing, cleaning with acid etching, metallization, and hydrogenation. The best mechanical polishing available can provide high purity single crystal diamond films with no less than 100 {micro}m thickness and <15 nm Ra surface roughness. The ideal thickness for 700MHz beam is {approx}30 {micro}m, which requires further thinning with RIE or laser ablation. RIE can achieve atomic layer removal precision and roughness eventually, but the time consumption for this procedure is very significant. Laser ablation proved that with <266nm ps laser beam, the ablation process on the diamond can easily achieve removing a few microns per hour from the surface and <100nm roughness. For amplifier application, laser ablation is an adequate and efficient process to make ultra thin diamond wafers following mechanical polishing. Hydrogenation will terminate the diamond surface with monolayer of hydrogen, and form NEA so that secondary electrons in the conduction band can escape into the vacuum. The method is using hydrogen cracker to strike hydrogen atoms onto the bare diamond surface to form H-C bonds. Two independent

  6. Copper-micrometer-sized diamond nanostructured composites

    NASA Astrophysics Data System (ADS)

    Nunes, D.; Livramento, V.; Shohoji, N.; Fernandes, H.; Silva, C.; Correia, J. B.; Carvalho, P. A.

    2011-12-01

    Reinforcement of a copper matrix with diamond enables tailoring the properties demanded for thermal management applications at high temperature, such as the ones required for heat sink materials in low activated nuclear fusion reactors. For an optimum compromise between thermal conductivity and mechanical properties, a novel approach based on multiscale diamond dispersions is proposed: a Cu-nanodiamond composite produced by milling is used as a nanostructured matrix for further dispersion of micrometer-sized diamondDiamond). A series of Cu-nanodiamond mixtures have been milled to establish a suitable nanodiamond fraction. A refined matrix with homogeneously dispersed nanoparticles was obtained with 4 at.% μDiamond for posterior mixture with microdiamond and subsequent consolidation. Preliminary consolidation by hot extrusion of a mixture of pure copper and μDiamond has been carried out to define optimal processing parameters. The materials produced were characterized by x-ray diffraction, scanning and transmission electron microscopy and microhardness measurements.

  7. Diamond thermoluminescence properties of different chondrites

    NASA Technical Reports Server (NTRS)

    Fisenko, A. V.; Kashkarov, L. L.; Semjonova, L. F.; Pillinger, C. T.

    1993-01-01

    It was found that thermoluminescence (TL) glows of diamonds depend on the origin of diamonds and the chondrite metamorphism degree. The investigation of TL of diamonds was continued and the results for diamonds from Murchison CM2, Krymka LL3.0, Kainsaz CO3, and Abee E4 were considered. The diamonds synthesized by CVD-process (samples 133, 159) and by detonation from soot (DDS-B14-89) were also analyzed for comparison. Before the TL measuring samples were annealed at approximately 350 C for a few seconds and then irradiated by gamma-rays of Cs-137 up to dose approximately 200 krad. TL-measurements were performed in the air atmosphere on the standard equipment. TL data for samples are shown. TL glow for some diamonds are also presented.

  8. Chemical vapor deposited diamond-on-diamond powder composites (LDRD final report)

    SciTech Connect

    Panitz, J.K.; Hsu, W.L.; Tallant, D.R.; McMaster, M.; Fox, C.; Staley, D.

    1995-12-01

    Densifying non-mined diamond powder precursors with diamond produced by chemical vapor infiltration (CVI) is an attractive approach for forming thick diamond deposits that avoids many potential manufacturability problems associated with predominantly chemical vapor deposition (CVD) processes. The authors developed techniques for forming diamond powder precursors and densified these precursors in a hot filament-assisted reactor and a microwave plasma-assisted reactor. Densification conditions were varied following a fractional factorial statistical design. A number of conclusions can be drawn as a result of this study. High density diamond powder green bodies that contain a mixture of particle sizes solidify more readily than more porous diamond powder green bodies with narrow distributions of particle sizes. No composite was completely densified although all of the deposits were densified to some degree. The hot filament-assisted reactor deposited more material below the exterior surface, in the interior of the powder deposits; in contrast, the microwave-assisted reactor tended to deposit a CVD diamond skin over the top of the powder precursors which inhibited vapor phase diamond growth in the interior of the powder deposits. There were subtle variations in diamond quality as a function of the CVI process parameters. Diamond and glassy carbon tended to form at the exterior surface of the composites directly exposed to either the hot filament or the microwave plasma. However, in the interior, e.g. the powder/substrate interface, diamond plus diamond-like-carbon formed. All of the diamond composites produced were grey and relatively opaque because they contained flawed diamond, diamond-like-carbon and glassy carbon. A large amount of flawed and non-diamond material could be removed by post-CVI oxygen heat treatments. Heat treatments in oxygen changed the color of the composites to white.

  9. The Toucan's Diamond

    NASA Astrophysics Data System (ADS)

    2006-06-01

    The Southern constellation Tucana (the Toucan) is probably best known as the home of the Small Magellanic Cloud, one of the satellite galaxies of the Milky Way. But Tucana also hosts another famous object that shines thousands of lights, like a magnificent, oversized diamond in the sky: the globular cluster 47 Tucanae. More popularly known as 47 Tuc, it is surpassed in size and brightness by only one other globular cluster, Omega Centauri. Globular clusters are gigantic families of stars, comprising several tens of thousands of stars, all thought to be born at the same time from the same cloud of gas [1]. As such, they constitute unique laboratories for the study of how stars evolve and interact. This is even more so because they are located at the same distance, so the brightness of different types of stars, at different stages in their evolution can be directly compared. The stars in globular clusters are held together by their mutual gravity which gives them their spherical shape, hence their name. Globular clusters are thought to be among the oldest objects in our Milky Way galaxy, and contain therefore mostly old, low-mass stars. ESO PR Photo 20/06 ESO PR Photo 20/06 Globular Cluster 47 Tuc 47 Tucanae is an impressive globular cluster that is visible with the unaided eye from the southern hemisphere. It was discovered in 1751 by the French astronomer Nicholas Louis de Lacaille who cataloged it in his list of southern nebulous objects. Located about 16 000 light years away, it has a total mass of about 1 million times the mass of the Sun and is 120 light years across, making it appear on the sky as big as the full moon. The colour image of 47 Tucanae presented here was taken with FORS1 on ESO's Very Large Telescope in 2001. The image covers only the densest, very central part of the cluster. The globular cluster extends in reality four times further away! As can be seen however, the density of stars rapidly drops off when moving away from the centre. The red

  10. Diamond grinding wheels production study with the use of the finite element method.

    PubMed

    Kundrák, J; Fedorovich, V; Markopoulos, A P; Pyzhov, I; Kryukova, N

    2016-11-01

    Research results on 3D modeling of the diamond grain and its bearing layer when sintering diamond grinding wheels are provided in this paper. The influence of the main characteristics of the wheel materials and the wheel production process, namely the quantity of metallic phase within diamond grain, coefficient of thermal expansion of the metallic phase, the modulus of elasticity of bond material and sintering temperature, on the internal stresses arising in grains is investigated. The results indicate that the stresses in the grains are higher in the areas around the metallic phase. Additionally, sintering temperature has the greatest impact on the stresses of the grain-metallic phase-bond system regardless of the type of the bond. Furthermore, by employing factorial design for the carried out finite element model, a mathematical model that reflects the impact of these factors on the deflected mode of the diamond grain-metallic phase-bond material system is obtained. The results of the analysis allow for the identification of optimal conditions for the efficient production of improved diamond grinding wheels. More specifically, the smallest stresses are observed when using the metal bond with modulus of elasticity 204 GPa, the quantity of metallic phase in diamond grain of not higher than 7% and coefficient of thermal expansion of 1.32 × 10(-5) 1/K or lower. The results obtained from the proposed 3D model can lead to the increase in the diamond grains utilization and improve the overall efficiency of diamond grinding.

  11. Adhesive bonding and brazing of nanocrystalline diamond foil onto different substrate materials

    NASA Astrophysics Data System (ADS)

    Lodes, Matthias A.; Sailer, Stefan; Rosiwal, Stefan M.; Singer, Robert F.

    2013-10-01

    Diamond coatings are used in heavily stressed industrial applications to reduce friction and wear. Hot-filament chemical vapour deposition (HFCVD) is the favourable coating method, as it allows a coating of large surface areas with high homogeneity. Due to the high temperatures occurring in this CVD-process, the selection of substrate materials is limited. With the desire to coat light materials, steels and polymers a new approach has been developed. First, by using temperature-stable templates in the HFCVD and stripping off the diamond layer afterwards, a flexible, up to 150 μm thick and free standing nanocrystalline diamond foil (NCDF) can be produced. Afterwards, these NCDF can be applied on technical components through bonding and brazing, allowing any material as substrate. This two-step process offers the possibility to join a diamond layer on any desired surface. With a modified scratch test and Rockwell indentation testing the adhesion strength of NCDF on aluminium and steel is analysed. The results show that sufficient adhesion strength is reached both on steel and aluminium. The thermal stress in the substrates is very low and if failure occurs, cracks grow undercritically. Adhesion strength is even higher for the brazed samples, but here crack growth is critical, delaminating the diamond layer to some extent. In comparison to a sample directly coated with diamond, using a high-temperature CVD interlayer, the brazed as well as the adhesively bonded samples show very good performance, proving their competitiveness. A high support of the bonding layer could be identified as crucial, though in some cases a lower stiffness of the latter might be acceptable considering the possibility to completely avoid thermal stresses which occur during joining at higher temperatures.

  12. Polishing of polycrystalline diamond films

    NASA Astrophysics Data System (ADS)

    Harker, Alan B.; Flintoff, John F.; DeNatale, Jeffrey F.

    1990-12-01

    Optically smooth surfaces can be produced on initially rough polycrystalline diamond film through the combined use of reactive ion etching and high temperature lapping on Fe metai Protective thin film barriers are first applied to the diamond surface to restrict the reactiv oxygen or hydrogen ion etching process to regions of greatest roughness. When the overaJ surface roughness has been reduced sufficiently by etching mechanical lapping of the surfac on an Fe plate at temperatures of 730C-900C in the presence of hydrogen can be used t produce surface roughnesses of less than 10 nm as measured by profilimetry. The tw techniques are complementary for flat surfaces while the reactive etching process alone can b used with shaped substrates to produce a surface finish suitable for LWIR optical applications. 1.

  13. Diamond turning machine controller implementation

    SciTech Connect

    Garrard, K.P.; Taylor, L.W.; Knight, B.F.; Fornaro, R.J.

    1988-12-01

    The standard controller for a Pnuemo ASG 2500 Diamond Turning Machine, an Allen Bradley 8200, has been replaced with a custom high-performance design. This controller consists of four major components. Axis position feedback information is provided by a Zygo Axiom 2/20 laser interferometer with 0.1 micro-inch resolution. Hardware interface logic couples the computers digital and analog I/O channels to the diamond turning machine`s analog motor controllers, the laser interferometer, and other machine status and control information. It also provides front panel switches for operator override of the computer controller and implement the emergency stop sequence. The remaining two components, the control computer hardware and software, are discussed in detail below.

  14. Diamonds and the african lithosphere.

    PubMed

    Boyd, F R; Gurney, J J

    1986-04-25

    Data and inferences drawn from studies of diamond inclusions, xenocrysts, and xenoliths in the kimberlites of southern Africa are combined to characterize the structure of that portion of the Kaapvaal craton that lies within the mantle. The craton has a root composed in large part of peridotites that are strongly depleted in basaltic components. The asthenosphere boundary shelves from depths of 170 to 190 kilometers beneath the craton to approximately 140 kilometers beneath the mobile belts bordering the craton on the south and west. The root formed earlier than 3 billion years ago, and at that time ambient temperatures in it were 900 degrees to 1200 degrees C; these temperatures are near those estimated from data for xenoliths erupted in the Late Cretaceous or from present-day heat-flow measurements. Many of the diamonds in southern Africa are believed to have crystallized in this root in Archean time and were xenocrysts in the kimberlites that brought them to the surface.

  15. Diamond detector for alpha-particle spectrometry.

    PubMed

    Dueñas, J A; de la Torre Pérez, J; Martín Sánchez, A; Martel, I

    2014-08-01

    An artificially grown high purity diamond was used as a detector for alpha-particle spectrometry. Diamond detectors can match the performance of silicon detectors employed in standard continuous air monitoring systems. Its radiation hardness and electronic properties make them ideal to work under extreme condition such as high temperature and ambient lights. A 50 μm thickness single-crystal diamond detector has been compared with a 300 μm passivated implanted planar silicon detector, under ambient conditions.

  16. Controlled Nucleation and Growth of Semiconducting Diamond

    DTIC Science & Technology

    1992-12-18

    analytical measurements of film growth have been coupled with novel precursor chemistry to study the effect of precursor chemical structure on the...efficiency of diamond film nucleation and growth. The goal is to optimize source gases and substrate surface preparation methods for both doped and...undoped diamond film nucleation and growth, enabling the use of diamond in field emission, semiconductor, and optoelectronic applications. "Surface

  17. Dental Diamond Rotary Instruments. Test and Evaluation

    DTIC Science & Technology

    1983-09-01

    Service, USAF School of Aerospace Med- icine. 17. DISTRIBUTION STATEMENT (of the ebetract entered In Block 20, it different from Report) 13...SUPPLEMENTARY NOTES 19. KEY WORDS (Continue on reverse ide iI neceseay and identify by block number) Dental diamond rotary instruments Diamond instrument cutting...performance Diamond instrument quality ABS.TLRACT fConi on, revere aide It neceeary aid Identify by block number) -’In this test and evaluation of the

  18. Diamond-silicon carbide composite and method

    DOEpatents

    Zhao, Yusheng

    2011-06-14

    Uniformly dense, diamond-silicon carbide composites having high hardness, high fracture toughness, and high thermal stability are prepared by consolidating a powder mixture of diamond and amorphous silicon. A composite made at 5 GPa/1673K had a measured fracture toughness of 12 MPam.sup.1/2. By contrast, liquid infiltration of silicon into diamond powder at 5 GPa/1673K produces a composite with higher hardness but lower fracture toughness.

  19. Mineral resource of the month: diamond

    USGS Publications Warehouse

    Olson, Donald W.

    2009-01-01

    The article presents information on diamond, which is regarded as the world's most popular gemstone. It states that there is strength in the covalent bonding between its carbon atoms, resulting to the strength of its physical properties. The presence of colors in diamonds may be attributed to the impurities that settle in the crystal lattice. Diamonds have been used as decorative items since the ancient era.

  20. Surface Structure of Aerobically Oxidized Diamond Nanocrystals

    DTIC Science & Technology

    2014-10-27

    distribution is unlimited. Surface Structure of Aerobically Oxidized Diamond Nanocrystals The views, opinions and/or findings contained in this report...2211 diamond nanocrystals, REPORT DOCUMENTATION PAGE 11. SPONSOR/MONITOR’S REPORT NUMBER(S) 10. SPONSOR/MONITOR’S ACRONYM(S) ARO 8. PERFORMING...Room 254, Mail Code 8725 New York, NY 10027 -7922 ABSTRACT Surface Structure of Aerobically Oxidized Diamond Nanocrystals Report Title We investigate

  1. Nanotwinned diamond with unprecedented hardness and stability.

    PubMed

    Huang, Quan; Yu, Dongli; Xu, Bo; Hu, Wentao; Ma, Yanming; Wang, Yanbin; Zhao, Zhisheng; Wen, Bin; He, Julong; Liu, Zhongyuan; Tian, Yongjun

    2014-06-12

    Although diamond is the hardest material for cutting tools, poor thermal stability has limited its applications, especially at high temperatures. Simultaneous improvement of the hardness and thermal stability of diamond has long been desirable. According to the Hall-Petch effect, the hardness of diamond can be enhanced by nanostructuring (by means of nanograined and nanotwinned microstructures), as shown in previous studies. However, for well-sintered nanograined diamonds, the grain sizes are technically limited to 10-30 nm (ref. 3), with degraded thermal stability compared with that of natural diamond. Recent success in synthesizing nanotwinned cubic boron nitride (nt-cBN) with a twin thickness down to ∼3.8 nm makes it feasible to simultaneously achieve smaller nanosize, ultrahardness and superior thermal stability. At present, nanotwinned diamond (nt-diamond) has not been fabricated successfully through direct conversions of various carbon precursors (such as graphite, amorphous carbon, glassy carbon and C60). Here we report the direct synthesis of nt-diamond with an average twin thickness of ∼5 nm, using a precursor of onion carbon nanoparticles at high pressure and high temperature, and the observation of a new monoclinic crystalline form of diamond coexisting with nt-diamond. The pure synthetic bulk nt-diamond material shows unprecedented hardness and thermal stability, with Vickers hardness up to ∼200 GPa and an in-air oxidization temperature more than 200 °C higher than that of natural diamond. The creation of nanotwinned microstructures offers a general pathway for manufacturing new advanced carbon-based materials with exceptional thermal stability and mechanical properties.

  2. Rapid Sintering of Nano-Diamond Compacts

    SciTech Connect

    Osipov, A.; Nauyoks, S; Zerda, T; Zaporozhets, O

    2009-01-01

    Diamond compacts were sintered from nano-size diamond crystals at high pressure, 8 GPa, and temperature above 1500 degrees C for very short times ranging from 5 to 11 s. Structure and mechanical properties of the compacts have been characterized. Although we have not completely avoided graphitization of diamonds, the amount of graphite produced was low, less than 2%, and despite relatively high porosity, the compacts were characterized by high hardness, bulk and Young moduli.

  3. Diamond turning of thermoplastic polymers

    SciTech Connect

    Smith, E.; Scattergood, R.O.

    1988-12-01

    Single point diamond turning studies were made using a series of thermoplastic polymers with different glass transition temperatures. Variations in surface morphology and surface roughness were observed as a function of cutting speed. Lower glass transition temperatures facilitate smoother surface cuts and better surface finish. This can be attributed to the frictional heating that occurs during machining. Because of the very low glass transition temperatures in polymeric compared to inorganic glasses, the precision machining response can be very speed sensitive.

  4. 76 FR 37684 - Airworthiness Directives; Diamond Aircraft Industries GmbH Model (Diamond) DA 40 Airplanes...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2011-06-28

    ... Federal Aviation Administration 14 CFR Part 39 RIN 2120-AA64 Airworthiness Directives; Diamond Aircraft Industries GmbH Model (Diamond) DA 40 Airplanes Equipped With Certain Cabin Air Conditioning Systems AGENCY... inspections of the Diamond Model DA 40 airplanes equipped with a VCS installed per Premier Aircraft...

  5. (Chemically vapor deposited diamond films)

    SciTech Connect

    Clausing, R.E.; Heatherly, L. Jr.

    1990-09-22

    The NATO-ASI on Diamond and Diamond-Like Films and Coatings'' was an opportunity for us to learn the latest research results from ongoing programs in the leading laboratories of the world and relate them to our work. Specific examples are given in the comprehensive report which follows. The meeting format provided an ideal environment to meet and interact with our international counterparts. It is clear that our studies are well regarded, and that we have established an excellent reputation in a short time. New opportunities for collaboration were identified. A panel discussion at the end of the meeting addressed the needs and opportunities in the synthesis of CVD diamond. The key scientific needs are those related to modeling the nucleation and growth processes and to elucidation of the critical roles of atomic hydrogen and the mechanisms of carbon addition to the growing surfaces. The development and more extensive use of in situ diagnostics for both surface and gas phases are important to solving these issues. The more immediate practical questions concern the identification of the growth-rate-limiting steps, the relation of growth parameters to the resulting film structure, and the dependence of properties on structure.

  6. CVD diamond growth by dc plasma torch

    NASA Astrophysics Data System (ADS)

    Klocek, Paul; Hoggins, James T.; Taborek, Peter; McKenna, Tom A.

    1990-12-01

    A dc arc discharge plasma torch has been developed for chemical vapor deposition (CVD) diamond growth. The apparatus and process parameters are described. Free-standing polycrystalline diamond samples of 50 mm by 50 mm by a few mm have been grown at high rates. The Raman spectra of the samples show little nondiamond structure. Transmission electron microscopy indicates that the diamond is highly twinned and has a high defect concentration. The infrared spectra indicate the presence of hydrogen contamination in the diamond via absorption bands associated with carbon-hydrogen motion. 2.

  7. A diamond trilogy: superplumes, supercontinents, and supernovae

    PubMed

    Haggerty

    1999-08-06

    Diamond is a remarkable mineral and has been long recognized for its unusual physical and chemical properties: robust and widespread in industry, yet regally adorned. This diversity is even greater than formally appreciated because diamond is recognized as an extraordinary recorder of astrophysical and geodynamic events that extend from the far reaches of space to Earth's deep interior. Many diamonds are natural antiques that formed in presolar supernovae by carbon vapor deposition, in asteroidal impacts and meteorite craters by shock metamorphism, and in Earth's mantle 1 to 2 billion years after planetary accretion from fluids and melts. The carbon in diamond is primordial, but there are unexplained isotopic fractionations and uncertainties in heterogeneity.

  8. Wave-front correctors by diamond turning

    NASA Technical Reports Server (NTRS)

    Meinel, A. B.; Meinel, M. P.; Stacy, J. E.; Saito, T. T.; Patterson, S. R.

    1986-01-01

    The production of wave-front correctors by single-point diamond turning is reported. Interferograms are shown which demonstrate excellent agreement between the diamond-turned surface and the desired surface. It is concluded from this experiment that it is now feasible by means of single-point diamond turning to make generalized wave-front control surfaces or to produce any unusual surface desired by the optical designer. The maximum departure from the nearest regular surface is set by the dynamic range and maximum diamond point acceleration permitted by the machine.

  9. Laser processing in 3D diamond detectors

    NASA Astrophysics Data System (ADS)

    Murphy, S. A.; Booth, M.; Li, L.; Oh, A.; Salter, P.; Sun, B.; Whitehead, D.; Zadoroshnyj, A.

    2017-02-01

    A technique for electrode production within diamond using a femtosecond laser system is described. Diagnosis tests to quantify the stress, the diamond to graphite ratio, and the resistivity of these electrodes are discussed. A 3D electronic grade single crystal diamond detector produced using this technique is shown, and the electrodes have a resistivity of O(1 Ω cm). An improvement to the technique through the use of an adaptive wavefront shows a reduction of the diamond to graphite ratio, and smaller, higher quality electrodes were manufactured.

  10. Direct Coating of Nanocrystalline Diamond on Steel

    NASA Astrophysics Data System (ADS)

    Tsugawa, Kazuo; Kawaki, Shyunsuke; Ishihara, Masatou; Hasegawa, Masataka

    2012-09-01

    Nanocrystalline diamond films have been successfully deposited on stainless steel substrates without any substrate pretreatments to promote diamond nucleation, including the formation of interlayers. A low-temperature growth technique, 400 °C or lower, in microwave plasma chemical vapor deposition using a surface-wave plasma has cleared up problems in diamond growth on ferrous materials, such as the surface graphitization, long incubation time, substrate softening, and poor adhesion. The deposited nanocrystalline diamond films on stainless steel exhibit good adhesion and tribological properties, such as a high wear resistance, a low friction coefficient, and a low aggression strength, at room temperature in air without lubrication.

  11. Negative Electron Affinity Mechanism for Diamond Surfaces

    NASA Technical Reports Server (NTRS)

    Krainsky, I. L.; Asnin, V. M.

    1998-01-01

    The energy distribution of the secondary electrons for chemical vacuum deposited diamond films with Negative Electron Affinity (NEA) was investigated. It was found that while for completely hydrogenated diamond surfaces the negative electron affinity peak in the energy spectrum of the secondary electrons is present for any energy of the primary electrons, for partially hydrogenated diamond surfaces there is a critical energy above which the peak is present in the spectrum. This critical energy increases sharply when hydrogen coverage of the diamond surface diminishes. This effect was explained by the change of the NEA from the true type for the completely hydrogenated surface to the effective type for the partially hydrogenated surfaces.

  12. Diamond film deposition on WC-Co and steel substrates with a CrN interlayer for tribological applications

    NASA Astrophysics Data System (ADS)

    Chandran, Maneesh; Hoffman, Alon

    2016-06-01

    The most renowned property of diamond is its exceptional hardness. By depositing diamond films on tungsten carbide (WC-Co) and steel substrates, the hardness of diamond can be combined with the toughness of these materials, resulting in an excellent wear resistance material for tribological applications. However, poor adhesion of diamond coating on these substrates leads to a lesser lifetime for the diamond coated tools than expected. The prime reasons for the lack of proper adhesion are the preferential formation of graphitic layer at the interface due to the catalytic activities of cobalt/iron and the interfacial residual stresses due to the mismatch in thermal expansion coefficients of diamond (1.5  ×  10-6 K-1) and WC-Co (5.2  ×  10-6 K-1) or steel (12  ×  10-6 K-1). In this review, we discuss the possibility of using a Cr-N interlayer as a diffusion barrier to prevent the catalytic activities of cobalt/iron and also to relax the interfacial residual stresses to some extent to enhance the adhesion of diamond coatings on these substrates. An overview of the most pertinent results of the last two decades, including the recent progress is introduced. We describe in detail how the Cr-N interlayer with the desired properties is fabricated. We give a concise overview of diamond deposition process, including the methods to vary the grain size from microcrystalline to nanocrystalline, which are suitable for some tribological applications. We describe in detail on surface and interface analysis, residual stress measurements, assessment adhesion strength and tribological performance of diamond coated WC-Co and steel substrates using various characterization techniques. We conclude by highlighting the current progress and future perspectives of diamond coatings on these substrates for tribological applications.

  13. An important source of 4He (and 3He) in diamonds

    NASA Astrophysics Data System (ADS)

    Lal, D.

    1989-12-01

    A large data base has recently accumulated on the concentrations of helium isotopes in diamonds mined from various regions. It was noted earlier (Ozima et al. (1985) [1]; Lal et al. (1989) [2]) that the frequency distribution of the 4He concentrations is a fairly narrow one, whereas that of 3He concentrations is a broad one with no pronounced peaks. The ratios 3He/ 4He , on the other hand show a broad maximum around 2 R a ( R a equals atmospheric 3He/ 4He ratio, = 1.40 × 10 -6) with a slow decrease over two orders of magnitude on either side. Does this imply that the diamonds sample a wide variety of helium reservoirs having a range of 3He/ 4He ratios but somehow attain similar 4He concentrations? We propose that in a majority of the diamonds studied, 4He is primarily due to implantation of radiogenic alpha particles from the host material after emplacement in the crust, usually kimberlite, and that the concentrations of 4He in diamonds often get appreciably altered by this process. Thus the 4He trapped in the diamond at the time of its crystallization is usually overwhelmed by the implanted helium and the measured 3He/ 4He ratios do not generally correspond to any "sources" in the mantle. However, the implanted 4He resides in the outer 16 μm of the diamond, and the intrinsic 4He and 3He/ 4He ratios in the diamond can be studied if its outer layers are removed. The wider implications of diamond being the "target" material for nuclear reaction products from the host material are discussed. Radiogenic 3He produced in the host material is also implanted in the diamond, but this contribution is small on a gross basis. However, since the depth of implantation of 3He is greater than that of 4He, some of the very high 3He/ 4He ratios observed in diamonds could be due to the "implantation" of radiogenic 3He. The radiogenic reactions in the host material can also contribute to appreciable 21Ne in diamonds.

  14. Diamond anvil cell for spectroscopic investigation of materials at high temperature, high pressure and shear

    DOEpatents

    Westerfield, C.L.; Morris, J.S.; Agnew, S.F.

    1997-01-14

    Diamond anvil cell is described for spectroscopic investigation of materials at high temperature, high pressure and shear. A cell is described which, in combination with Fourier transform IR spectroscopy, permits the spectroscopic investigation of boundary layers under conditions of high temperature, high pressure and shear. 4 figs.

  15. Argonne News Brief: Self-Healing Diamond-Like Carbon Coating Could Revolutionize Lubrication

    SciTech Connect

    2016-08-01

    Argonne scientists discovered a technique to create a layer of diamond-like carbon on the surfaces between moving parts. This could change the future of lubrication—potentially making engines more efficient, more reliable, and even greener (by reducing heavy metal additives needed in engine oils.)

  16. Diamond anvil cell for spectroscopic investigation of materials at high temperature, high pressure and shear

    DOEpatents

    Westerfield, Curtis L.; Morris, John S.; Agnew, Stephen F.

    1997-01-01

    Diamond anvil cell for spectroscopic investigation of materials at high temperature, high pressure and shear. A cell is described which, in combination with Fourier transform IR spectroscopy, permits the spectroscopic investigation of boundary layers under conditions of high temperature, high pressure and shear.

  17. 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

  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

    2015-08-24

    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.

  19. Properties of chemical vapor infiltration diamond deposited in a diamond powder matrix

    SciTech Connect

    Panitz, J.K.G.; Tallant, D.R.; Hills, C.R.; Staley, D.J.

    1993-12-31

    Densifying non-mined diamond powder precursors with diamond produced by chemical vapor infiltration (CVI) is an attractive approach for forming thick diamond deposits that avoids many potential manufacturability problems associated with predominantly chemical vapor deposition (CVD) processes. The authors have developed two techniques: electrophoretic deposition and screen printing, to form nonmined diamond powder precursors on substrates. They then densify these precursors in a hot filament assisted reactor. Analysis indicated that a hot filament assisted chemical vapor infiltration process forms intergranular diamond deposits with properties that are to some degree different from predominantly hot-filament-assisted CVD material.

  20. The mechanical and strength properties of diamond.

    PubMed

    Field, J E

    2012-12-01

    Diamond is an exciting material with many outstanding properties; see, for example Field J E (ed) 1979 The Properties of Diamond (London: Academic) and Field J E (ed) 1992 The Properties of Natural and Synthetic Diamond (London: Academic). It is pre-eminent as a gemstone, an industrial tool and as a material for solid state research. Since natural diamonds grew deep below the Earth's surface before their ejection to mineable levels, they also contain valuable information for geologists. The key to many of diamond's properties is the rigidity of its structure which explains, for example, its exceptional hardness and its high thermal conductivity. Since 1953, it has been possible to grow synthetic diamond. Before then, it was effectively only possible to have natural diamond, with a small number of these found in the vicinity of meteorite impacts. Techniques are now available to grow gem quality synthetic diamonds greater than 1 carat (0.2 g) using high temperatures and pressures (HTHP) similar to those found in nature. However, the costs are high, and the largest commercially available industrial diamonds are about 0.01 carat in weight or about 1 mm in linear dimension. The bulk of synthetic diamonds used industrially are 600 µm or less. Over 75% of diamond used for industrial purposes today is synthetic material. In recent years, there have been two significant developments. The first is the production of composites based on diamond; these materials have a significantly greater toughness than diamond while still maintaining very high hardness and reasonable thermal conductivity. The second is the production at low pressures by metastable growth using chemical vapour deposition techniques. Deposition onto non-diamond substrates was first demonstrated by Spitsyn et al 1981 J. Cryst. Growth 52 219-26 and confirmed by Matsumoto et al 1982 Japan J. Appl. Phys. 21 L183-5. These developments have added further to the versatility of diamond. Two other groups of

  1. Formation of diamond in the Earth's mantle

    NASA Astrophysics Data System (ADS)

    Stachel, Thomas; Harris, Jeff W.

    2009-09-01

    The principal sources of natural diamonds are peridotitic (about 2/3 of diamonds) and eclogitic (1/3) domains located at 140-200 km depth in the subcratonic lithospheric mantle. There, diamonds probably form during redox reactions in the presence of melt (likely for eclogitic and lherzolitic diamonds) or under subsolidus conditions in the presence of CHO fluids (likely for harzburgitic diamonds). Co-variations of δ13C and the nitrogen content of diamonds suggest that two modes of formation may have been operational in peridotitic sources: (1) reduction of carbonates, that during closed system fractionation drives diamond compositions to higher δ13C values and lower nitrogen concentrations and (2) oxidation of methane, that in a closed system leads to a trend of decreasing δ13C with decreasing nitrogen. The present day redox state of subcratonic lithospheric mantle is generally too reduced to allow for methane oxidation to be a widespread process. Therefore, reduction of carbonate dissolved in melts and fluids is likely the dominant mode of diamond formation for the Phanerozoic (545 Ma-present) and Proterozoic (2.5 Ga-545 Ma). Model calculations indicate, however, that for predominantly Paleoarchean (3.6-3.2 Ga) to Mesoarchean (3.2-2.8 Ga) harzburgitic diamonds, methane reduction is the principal mode of precipitation. This suggests that the reduced present day character (oxygen fugacity below carbonate stability) of peridotitic diamond sources may be a secondary feature, possibly acquired during reducing Archean (>2.5 Ga) metasomatism. Recycling of biogenic carbonates back into the mantle through subduction only became an important process in the Paleoproterozoic (2.5-1.6 Ga) and diamonds forming during carbonate reduction, therefore, may predominantly be post-Archean in age. For eclogitic diamonds, open system fractionation processes involving separation of a CO2 fluid appear to dominate, but in principal the same two modes of formation (methane oxidation

  2. The mechanical and strength properties of diamond

    NASA Astrophysics Data System (ADS)

    Field, J. E.

    2012-12-01

    Diamond is an exciting material with many outstanding properties; see, for example Field J E (ed) 1979 The Properties of Diamond (London: Academic) and Field J E (ed) 1992 The Properties of Natural and Synthetic Diamond (London: Academic). It is pre-eminent as a gemstone, an industrial tool and as a material for solid state research. Since natural diamonds grew deep below the Earth's surface before their ejection to mineable levels, they also contain valuable information for geologists. The key to many of diamond's properties is the rigidity of its structure which explains, for example, its exceptional hardness and its high thermal conductivity. Since 1953, it has been possible to grow synthetic diamond. Before then, it was effectively only possible to have natural diamond, with a small number of these found in the vicinity of meteorite impacts. Techniques are now available to grow gem quality synthetic diamonds greater than 1 carat (0.2 g) using high temperatures and pressures (HTHP) similar to those found in nature. However, the costs are high, and the largest commercially available industrial diamonds are about 0.01 carat in weight or about 1 mm in linear dimension. The bulk of synthetic diamonds used industrially are 600 µm or less. Over 75% of diamond used for industrial purposes today is synthetic material. In recent years, there have been two significant developments. The first is the production of composites based on diamond; these materials have a significantly greater toughness than diamond while still maintaining very high hardness and reasonable thermal conductivity. The second is the production at low pressures by metastable growth using chemical vapour deposition techniques. Deposition onto non-diamond substrates was first demonstrated by Spitsyn et al 1981 J. Cryst. Growth 52 219-26 and confirmed by Matsumoto et al 1982 Japan J. Appl. Phys. 21 L183-5. These developments have added further to the versatility of diamond. Two other groups of materials

  3. The provenance of Borneo's enigmatic alluvial diamonds

    NASA Astrophysics Data System (ADS)

    White, Lloyd; Graham, Ian; Tanner, Dominique; Hall, Robert; Armstrong, Richard; Yaxley, Greg; Barron, Larry; Spencer, Lee; van Leeuwen, Theo

    2016-04-01

    Gem-quality diamonds occur in several alluvial deposits across central and southern Borneo. Borneo has been a known source of diamonds for centuries, but the location of their primary igneous source remains enigmatic. Numerous geological models have been proposed to explain the distribution of Borneo's diamonds. To assess these models, we used a variety of techniques to examine heavy minerals from Kalimantan's Cempaka paleoalluvial diamond deposit. This involved collecting U-Pb isotopic data, fission track and trace element geochemistry of zircon as well as major element geochemical data of spinels and morphological descriptions of zircon and diamond. Our results indicate that the Cempaka diamonds were likely derived from at least two sources, one which was relatively local and/or involved little reworking, and the other more distal recording several periods of reworking. The distal diamond source is interpreted to be diamond-bearing pipes that intruded the basement of a block that: (1) rifted from northwest Australia (East Java or SW Borneo) and the diamonds were recycled into its sedimentary cover, or: (2) were emplaced elsewhere (e.g. NW Australia) and transported to a block (e.g. East Java or SW Borneo). Both of these scenarios require the diamonds to be transported with the block when it rifted from NW Australia in the Late Jurassic. The 'local' diamonds could be associated with ophiolitic rocks that are exposed in the nearby Meratus Mountains, or could be diamondiferous diatremes associated with eroded Miocene high-K alkaline intrusions north of the Barito Basin. If this were the case, these intrusions would indicate that the lithosphere beneath SW Borneo is thick (~150 km or greater).

  4. Influence on Diamonds During the Spraying of Diamond-Bronze Abrasive Coatings

    NASA Astrophysics Data System (ADS)

    Tillmann, W.; Vogli, E.; Nebel, J.; Buck, V.; Reuter, S.

    2010-01-01

    Detonation spraying provides the opportunity to produce diamond grinding tools for the machining of stone, cement, and concrete. Especially the atmospheric conditions of the spraying process yield in a high production flexibility. However, during detonation spraying, the oxygenic atmosphere as well as the thermal and kinetic energy have an impact on the processed diamond. Despite its importance for the tools’ performance, the influence of the spraying process on the superabrasive diamond is predominantly unknown. The potential decrease of the diamond durability and strength due to degradation effects during the production of sprayed diamond-CuSn 85/15 composites has not yet been determined. X-ray diffraction and Raman spectroscopy were used to verify thermally initiated surface reactions of the sprayed diamonds after exposure to the spraying process. Additionally, reference measurements on the degradation of diamonds in oxidizing and inert conditions were carried out to compare the spraying results. Differential thermal and thermogravimetric analyses were employed. To validate the mechanical properties of the diamond superabrasives, friability tests and fracture force tests were performed. It was found that under optimized detonation spraying conditions the thermal and mechanical impact remains low enough to ensure a good reliability of the processed diamonds. The diamond crystal structure endured the spraying process without detectable graphitization or oxidation. Deterioration indicators were not observed in SEM micrographs, x-ray diffraction patterns or Raman spectra. Furthermore, a high durability and strength of the sprayed diamonds were confirmed by mechanical testing.

  5. Method and apparatus for making diamond-like carbon films

    DOEpatents

    Pern, Fu-Jann; Touryan, Kenell J.; Panosyan, Zhozef Retevos; Gippius, Aleksey Alekseyevich

    2008-12-02

    Ion-assisted plasma enhanced deposition of diamond-like carbon (DLC) films on the surface of photovoltaic solar cells is accomplished with a method and apparatus for controlling ion energy. The quality of DLC layers is fine-tuned by a properly biased system of special electrodes and by exact control of the feed gas mixture compositions. Uniform (with degree of non-uniformity of optical parameters less than 5%) large area (more than 110 cm.sup.2) DLC films with optical parameters varied within the given range and with stability against harmful effects of the environment are achieved.

  6. Very High Efficiency, Miniaturized, Long-Lived Alpha Particle Power Source Using Diamond Devices for Extreme Space Environments

    NASA Technical Reports Server (NTRS)

    Kolawa, Elizabeth A. (Inventor); Patel, Jagdishbhai U. (Inventor); Fleurial, Jean-Pierre (Inventor)

    2004-01-01

    A power source that converts a-particle energy into electricity by coulomb collision in doped diamond films is described. Alpha particle decay from curium-244 creates electron-hole pairs by free- ing electrons and holes inside the crystal lattice in N- and P-doped diamond films. Ohmic contacts provide electrical connection to an electronic device. Due to the built-in electric field at the rectifying junction across the hT- and P-doped diamond films, the free electrons are constrained to traveling in generally one direction. This one direction then supplies electrons in a manner similar to that of a battery. The radioactive curium layer may be disposed on diamond films for even distribution of a-particle radiation. The resulting power source may be mounted on a diamond substrate that serves to insulate structures below the diamond substrate from a-particle emission. Additional insulation or isolation may be provided in order to prevent damage from a-particle collision. N-doped silicon may be used instead of N-doped diamond.

  7. Anisotropic mechanical amorphization drives wear in diamond.

    PubMed

    Pastewka, Lars; Moser, Stefan; Gumbsch, Peter; Moseler, Michael

    2011-01-01

    Diamond is the hardest material on Earth. Nevertheless, polishing diamond is possible with a process that has remained unaltered for centuries and is still used for jewellery and coatings: the diamond is pressed against a rotating disc with embedded diamond grit. When polishing polycrystalline diamond, surface topographies become non-uniform because wear rates depend on crystal orientations. This anisotropy is not fully understood and impedes diamond's widespread use in applications that require planar polycrystalline films, ranging from cutting tools to confinement fusion. Here, we use molecular dynamics to show that polished diamond undergoes an sp(3)-sp(2) order-disorder transition resulting in an amorphous adlayer with a growth rate that strongly depends on surface orientation and sliding direction, in excellent correlation with experimental wear rates. This anisotropy originates in mechanically steered dissociation of individual crystal bonds. Similarly to other planarization processes, the diamond surface is chemically activated by mechanical means. Final removal of the amorphous interlayer proceeds either mechanically or through etching by ambient oxygen.

  8. Diamond film growth from fullerene precursors

    DOEpatents

    Gruen, Dieter M.; Liu, Shengzhong; Krauss, Alan R.; Pan, Xianzheng

    1997-01-01

    A method and system for manufacturing diamond film. The method involves forming a fullerene vapor, providing a noble gas stream and combining the gas with the fullerene vapor, passing the combined fullerene vapor and noble gas carrier stream into a chamber, forming a plasma in the chamber causing fragmentation of the fullerene and deposition of a diamond film on a substrate.

  9. The World According to Jared Diamond.

    ERIC Educational Resources Information Center

    McNeil, J. R.

    2001-01-01

    Reviews the book, "Guns, Germs, and Steel: The Fates of Human Societies" (Jared Diamond). Examines the strengths of the book, focusing on its distinctive aspects, while also offering criticism. States that the final chapter is the most problematic part of Diamond's work. (CMK)

  10. Diamond film growth argon-carbon plasmas

    DOEpatents

    Gruen, Dieter M.; Krauss, Alan R.; Liu, Shengzhong; Pan, Xianzheng; Zuiker, Christopher D.

    1998-01-01

    A method and system for manufacturing diamond film. The method involves forming a carbonaceous vapor, providing a gas stream of argon, hydrogen and hydrocarbon and combining the gas with the carbonaceous vapor, passing the combined carbonaceous vapor and gas carrier stream into a chamber, forming a plasma in the chamber causing fragmentation of the carbonaceous and deposition of a diamond film on a substrate.

  11. Fluorinated diamond bonded in fluorocarbon resin

    DOEpatents

    Taylor, Gene W.

    1982-01-01

    By fluorinating diamond grit, the grit may be readily bonded into a fluorocarbon resin matrix. The matrix is formed by simple hot pressing techniques. Diamond grinding wheels may advantageously be manufactured using such a matrix. Teflon fluorocarbon resins are particularly well suited for using in forming the matrix.

  12. Double bevel construction of a diamond anvil

    DOEpatents

    Moss, W.C.

    1988-10-11

    A double or multiple bevel culet geometry is used on a diamond anvil in a high pressure cell apparatus to provide increased sample pressure and stability for a given force applied to the diamond tables. Double or multiple bevel culet geometries can also be used for sapphire or other hard crystal anvils. Pressures up to and above 5 Megabars can be reached. 8 figs.

  13. Double bevel construction of a diamond anvil

    DOEpatents

    Moss, William C.

    1988-01-01

    A double or multiple bevel culet geometry is used on a diamond anvil in a high pressure cell apparatus to provide increased sample pressure and stability for a given force applied to the diamond tables. Double or multiple bevel culet geometries can also be used for sapphire or other hard crystal anvils. Pressures up to and above 5 Megabars can be reached.

  14. Robust diamond meshes with unique wettability properties.

    PubMed

    Yang, Yizhou; Li, Hongdong; Cheng, Shaoheng; Zou, Guangtian; Wang, Chuanxi; Lin, Quan

    2014-03-18

    Robust diamond meshes with excellent superhydrophobic and superoleophilic properties have been fabricated. Superhydrophobicity is observed for water with varying pH from 1 to 14 with good recyclability. Reversible superhydrophobicity and hydrophilicity can be easily controlled. The diamond meshes show highly efficient water-oil separation and water pH droplet transference.

  15. Diamond photonic crystal slab: leaky modes and modified photoluminescence emission of surface-deposited quantum dots.

    PubMed

    Ondič, Lukáš; Babchenko, Oleg; Varga, Marián; Kromka, Alexander; Ctyroký, Jiří; Pelant, Ivan

    2012-01-01

    Detailed analysis of a band diagram of a photonic crystal (PhC) slab prepared on a nano-diamond layer is presented. Even though the PhC is structurally imperfect, the existence of leaky modes, determined both theoretically and experimentally in the broad spectral region, implies that an efficient light interaction with a material periodicity occurs in the sample. It is shown that the luminescence emission spectrum of a light source placed directly on the PhC surface can be modified by employing the optical modes of the studied structure. We stress also the impact of intrinsic optical losses of the nano-diamond on this modification.

  16. Nature and genesis of Kalimantan diamonds

    NASA Astrophysics Data System (ADS)

    Smith, Chris B.; Bulanova, Galina P.; Kohn, Simon C.; Milledge, H. Judith; Hall, Anne E.; Griffin, Brendan J.; Pearson, D. Graham

    2009-11-01

    The origin of alluvial diamonds from the four main diamond mining districts in Kalimantan was studied through characterisation of their properties, and determination of PT and age of formation of representative collections of diamonds from four localities of the island. The diamonds are mostly colourless, yellow or pale brown, shiny surfaced, dodecahedroids, octahedron/dodecahedroids, and more rarely cube combination forms. They are intensively resorbed. They have surface radiation damage and show abrasion features indicative of fluvial transportation and crustal recycling. The diamonds were polished down to expose internal structures and mineral inclusions. The majority of the diamonds are internally homogeneous or have simple octahedral zonation and show plastic deformation. Analysis by Fourier transform infra red spectroscopy of their N content and aggregation characteristics shows that many diamonds are well-aggregated type IaB implying a long-term, mantle residence time and/or high temperatures of formation. Identified inclusion parageneses are 68% peridotitic and 32% eclogitic. The peridotitic inclusions are represented by olivine, chromite, garnet, orthopyroxene and pentlandite. Olivines (Fo 92-93) belong to the dunite-harzburgite paragenesis, with one at Fo 90 identified as lherzolitic. Chromite inclusions with 65-66 wt.% Cr 2O 3 and < 1 wt.% TiO 2 are typical of chromite diamond inclusions world-wide. Two garnet inclusions identified are a subcalcic high chrome harzburgite "G10" and a mildly subcalcic type transitional between "G9" and "G10". The eclogitic inclusions are represented by omphacite, rutile, kyanite and coesite. Re/Os dating of a high Ni sulphide inclusion from one peridotitic diamond gave an Archean model age of 3.1 Ga ± 0.2 (2 sigma). In terms of their external and internal morphology, N aggregation characteristics and paragenesis the Kalimantan diamonds resemble those transported to surface by kimberlite or lamproite from sources in the

  17. Development of Photodeposited Diamond Films

    DTIC Science & Technology

    1989-03-31

    DEPOSITED DIAMOND FILMS SBIR PHASE I FINAL REPORT CONTRACT # F49620-88-C-0099 SPONSORED BY UNITED STATES AIR FORCE OFFICE OF SCIENTIFIC RESEARCH BOLLING AIR... FORCE BASE WASHINGTON, D.C. C REPORT DATE: 3-31-89 Dr. Anthony O’Keefe Deacon Research 900 Welch Rd., Suite 203 Palo Alto, CA 94304 (415)326-1520 The...policies or endorsements, either ex- pressed or implied, of the Air Force Office of Scientific Research or the U.S. Government. 2 EXECUTIVE SUMMARY s

  18. Infrared spectral and carbon isotopic characteristics of micro- and macro-diamonds from the Panda kimberlite (Central Slave Craton, Canada)

    NASA Astrophysics Data System (ADS)

    Melton, G. L.; Stachel, T.; Stern, R. A.; Carlson, J.; Harris, J. W.

    2013-09-01

    One hundred and twenty-one micro-diamonds (< 1 mm) and 90 macro-diamonds (2.5 mm to 3.4 mm) from the Panda kimberlite (Ekati mine, Central Slave Craton, Canada) were analyzed for nitrogen content, nitrogen aggregation state (%B) and platelet and hydrogen peak areas (cm- 2). Micro-diamond nitrogen concentrations range from < 10 at. ppm to 1696 at. ppm (median = 805 at. ppm) and the median aggregation state is 23%B. Macro-diamonds range from < 10 at. ppm to 1260 at. ppm (median = 187 at. ppm) nitrogen and have a median nitrogen aggregation of 26%B. Platelet and hydrogen peaks were observed in 37% and 79% of the micro-diamonds and 79% and 56% of the macro-diamonds, respectively. Nitrogen based time averaged residence temperatures indicate that micro- and macro-diamonds experienced similar thermal mantle residence histories, both populations displaying bimodal residence temperature distributions with a gap between 1130 °C and 1160 °C (at 3.5 Ga residence). In addition, SIMS carbon isotopic analyses for the micro-diamonds were obtained: δ13C compositions range from - 6.9‰ to + 1.8‰ (median = - 4.3‰). CL imaging reveals distinct growth layers that in some samples differ by > 2‰, but mostly vary by < 0.5‰. Comparison of only the “gem-quality” samples (n = 49 micro- and 90 macro-diamonds) between the two diamond sets, indicates a statistically significant shift of + 1.3‰ in average δ13C from macro- to micro-diamonds and this shift documents distinct diamond forming fluids, fractionation process or growth histories. A broad transition to heavier isotopic values is also observed in connection to decreasing mantle residence temperatures. The bimodal mantle residence temperature distribution may coincide with the transition from highly depleted shallow to more fertile deep lithospheric mantle observed beneath the Central Slave Craton. The increase in δ13C with decreasing residence temperature (proxy for decreasing depth) is interpreted to reflect diamond

  19. Toroidal plasma enhanced CVD of diamond films

    SciTech Connect

    Zvanya, John Cullen, Christopher Morris, Thomas Krchnavek, Robert R.; Holber, William Basnett, Andrew Basnett, Robert; Hettinger, Jeffrey

    2014-09-01

    An inductively coupled toroidal plasma source is used as an alternative to microwave plasmas for chemical vapor deposition of diamond films. The source, operating at a frequency of 400 kHz, synthesizes diamond films from a mixture of argon, methane, and hydrogen. The toroidal design has been adapted to create a highly efficient environment for diamond film deposition: high gas temperature and a short distance from the sample to the plasma core. Using a toroidal plasma geometry operating in the medium frequency band allows for efficient (≈90%) coupling of AC line power to the plasma and a scalable path to high-power and large-area operation. In test runs, the source generates a high flux of atomic hydrogen over a large area, which is favorable for diamond film growth. Using a deposition temperature of 900–1050 °C and a source to sample distance of 0.1–2.0 cm, diamond films are deposited onto silicon substrates. The results showed that the deposition rate of the diamond films could be controlled using the sample temperature and source to sample spacing. The results also show the films exhibit good-quality polycrystalline diamond as verified by Raman spectroscopy, x-ray diffraction, and scanning electron microscopy. The scanning electron microscopy and x-ray diffraction results show that the samples exhibit diamond (111) and diamond (022) crystallites. The Raman results show that the sp{sup 3} peak has a narrow spectral width (FWHM 12 ± 0.5 cm{sup −1}) and that negligible amounts of the sp{sup 2} band are present, indicating good-quality diamond films.

  20. Opalescent Diamonds Enriched in Hydrocarbon Fluids

    NASA Astrophysics Data System (ADS)

    Leung, I.; Tsao, C.

    2006-05-01

    We studied a large number of diamonds from Liaoning, China. These diamonds are not gem-quality, do not have sharp corners and sharp edges, they are not suitable for making cutting tools. Such industrial diamonds are usually crushed to form abrasives, thus, they might escape the scrutiny of researchers. In China, diamonds were routinely soaked in HF overnight to remove mud and other substances, and no oil and grease were used in the processing. It is not uncommon to see iridescence in pink, pale yellow and grey diamonds. The most common opalescent colors are alternating sharp bands of intense pink and indigo blue, and, less frequently, bands of yellow and blue-green, all may appear in the same diamond. As the bands have uniform thickness, their colors might not be due simply to optical effects, but rather, might be chemically related. We had chosen 10 diamonds to study their FT-IR spectra. Six of the crystals exhibited a group of hydrocarbons (HCs) peaks located just below 3000 cm-1, while all but one had a C-H stretch peak at 3107 cm-1. Two other diamonds had weak HCs peaks, but a very strong peak at 3107 cm-1. Two more diamonds had very weak HCs and C-H stretch peaks. To sum up, when a spectrum has strong HCs peaks, the C-H stretch peak is weak, and vice versa. There seems to be a chemical relationship between the substances represented by these peaks. Our observations indicate that hydrocarbon fluids might have been trapped during crystallization, but subsequently unmixed into well- organized thin bands. If fluids observed in the opalescent diamonds were soaked up in the mantle, then the amount of hydrocarbons existing in Earth's mantle might be quite appreciable in some environment.

  1. Graphene diamond-like carbon films heterostructure

    SciTech Connect

    Zhao, Fang; Afandi, Abdulkareem; Jackman, Richard B.

    2015-03-09

    A limitation to the potential use of graphene as an electronic material is the lack of control over the 2D materials properties once it is deposited on a supporting substrate. Here, the use of Diamond-like Carbon (DLC) interlayers between the substrate and the graphene is shown to offer the prospect of overcoming this problem. The DLC films used here, more properly known as a-C:H with ∼25% hydrogen content, have been terminated with N or F moieties prior to graphene deposition. It is found that nitrogen terminations lead to an optical band gap shrinkage in the DLC, whilst fluorine groups reduce the DLC's surface energy. CVD monolayer graphene subsequently transferred to DLC, N terminated DLC, and F terminated DLC has then been studied with AFM, Raman and XPS analysis, and correlated with Hall effect measurements that give an insight into the heterostructures electrical properties. The results show that different terminations strongly affect the electronic properties of the graphene heterostructures. G-F-DLC samples were p-type and displayed considerably higher mobility than the other heterostructures, whilst G-N-DLC samples supported higher carrier densities, being almost metallic in character. Since it would be possible to locally pattern the distribution of these differing surface terminations, this work offers the prospect for 2D lateral control of the electronic properties of graphene layers for device applications.

  2. The Science of Diamonds and Their Inclusions: Can such Data be Used to Establish Diamond Provenance?

    NASA Astrophysics Data System (ADS)

    Taylor, L. A.; Sobolev, N. V.; Ghazi, M.; Anand, M.; Bodner, R. J.

    2002-05-01

    The physics and chemistry of diamonds and their mineral inclusions can be used to determine the geographic source of rough diamonds. The science of diamonds includes their morphology and external features, N aggregation states and zonations, δ 13C, δ 15N, trace-element chemistry, and the nature of their rims and coatings. The science of the diamond inclusions (DIs) includes their mineralogy and chemical/isotopic compositions, the variation of mineral chemistry between diamonds and as multiple DIs within a single diamond, and the relations of DIs to geologic locales. For example, the exotic DIs in Brazilian diamonds appear to be unique and world famous; but are they really? The δ 34S values of the sulfide DIs are yet another type of data that may prove useful for paragenetic identification, but the requisite data are not presently available. A recently attempted method for discerning the locale of a diamond's origin involves the combined use of laser-ablation, high-resolution, inductively-coupled-plasma, mass spectrometry (LA-HR-ICPMS) and Raman spectroscopy. These sophisticated instruments are combined in a study of the outermost rims of coated diamonds. The premise to this endeavor is that these coatings contain the signatures of the very latest stages of diamond formation, within the kimberlite, as the diamonds are carried to the Earth's surface. Based upon xenolith and DI studies, the mantle of the Earth at a depth of 150 km, although heterogeneous on a small scale, is actually quite similar worldwide. Diamonds grown in the mantle may also have similar characteristics worldwide. However, the chemistry of kimberlite magmas, as they traverse the upper mantle and lower crust, on their way to the surface, can pick up late-stage characteristics that differ from place to place. Some of these definitive signatures may be preserved in the outermost coated regions of the diamonds. The bottom line to the question of provenance for rough diamonds, as addressed at the

  3. Microstructure and thermal properties of copper–diamond composites with tungsten carbide coating on diamond particles

    SciTech Connect

    Kang, Qiping; He, Xinbo Ren, Shubin; Liu, Tingting; Liu, Qian; Wu, Mao; Qu, Xuanhui

    2015-07-15

    An effective method for preparing tungsten carbide coating on diamond surfaces was proposed to improve the interface bonding between diamond and copper. The WC coating was formed on the diamond surfaces with a reaction medium of WO{sub 3} in mixed molten NaCl–KCl salts and the copper–diamond composites were obtained by vacuum pressure infiltration of WC-coated diamond particles with pure copper. The microstructure of interface bonding between diamond and copper was discussed. Thermal conductivity and thermal expansion behavior of the obtained copper–diamond composites were investigated. Results indicated that the thermal conductivity of as-fabricated composite reached 658 W m{sup −} {sup 1} K{sup −} {sup 1}. Significant reduction in coefficient of thermal expansion of the composite compared with that of pure copper was obtained. - Highlights: • WC coating was successfully synthesized on diamond particles in molten salts. • WC coating obviously promoted the wettability of diamond and copper matrix. • WC coating greatly enhanced the thermal conductivity of Cu–diamond composite. • The composites are suitable candidates for heat sink applications.

  4. 16 CFR 23.13 - Disclosure of treatments to diamonds

    Code of Federal Regulations, 2011 CFR

    2011-01-01

    ... 16 Commercial Practices 1 2011-01-01 2011-01-01 false Disclosure of treatments to diamonds 23.13... JEWELRY, PRECIOUS METALS, AND PEWTER INDUSTRIES § 23.13 Disclosure of treatments to diamonds A diamond is a gemstone product. Treatments to diamonds should be disclosed in the manner prescribed in §...

  5. 16 CFR 23.13 - Disclosure of treatments to diamonds

    Code of Federal Regulations, 2010 CFR

    2010-01-01

    ... 16 Commercial Practices 1 2010-01-01 2010-01-01 false Disclosure of treatments to diamonds 23.13... JEWELRY, PRECIOUS METALS, AND PEWTER INDUSTRIES § 23.13 Disclosure of treatments to diamonds A diamond is a gemstone product. Treatments to diamonds should be disclosed in the manner prescribed in §...

  6. 16 CFR 23.13 - Disclosure of treatments to diamonds.

    Code of Federal Regulations, 2014 CFR

    2014-01-01

    ... 16 Commercial Practices 1 2014-01-01 2014-01-01 false Disclosure of treatments to diamonds. 23.13... JEWELRY, PRECIOUS METALS, AND PEWTER INDUSTRIES § 23.13 Disclosure of treatments to diamonds. A diamond is a gemstone product. Treatments to diamonds should be disclosed in the manner prescribed in §...

  7. 16 CFR 23.13 - Disclosure of treatments to diamonds.

    Code of Federal Regulations, 2013 CFR

    2013-01-01

    ... 16 Commercial Practices 1 2013-01-01 2013-01-01 false Disclosure of treatments to diamonds. 23.13... JEWELRY, PRECIOUS METALS, AND PEWTER INDUSTRIES § 23.13 Disclosure of treatments to diamonds. A diamond is a gemstone product. Treatments to diamonds should be disclosed in the manner prescribed in §...

  8. 16 CFR 23.13 - Disclosure of treatments to diamonds.

    Code of Federal Regulations, 2012 CFR

    2012-01-01

    ... 16 Commercial Practices 1 2012-01-01 2012-01-01 false Disclosure of treatments to diamonds. 23.13... JEWELRY, PRECIOUS METALS, AND PEWTER INDUSTRIES § 23.13 Disclosure of treatments to diamonds. A diamond is a gemstone product. Treatments to diamonds should be disclosed in the manner prescribed in §...

  9. Impact of keV-energy argon clusters on diamond and graphite

    NASA Astrophysics Data System (ADS)

    Popok, V. N.; Samela, J.; Nordlund, K.; Popov, V. P.

    2012-07-01

    Impact of keV-energy size-selected Arn (n = 16, 27, 41) cluster ions on diamond and graphite is studied both experimentally and by molecular dynamics simulations. For the case of diamond, relatively high cluster kinetic energies (above certain threshold) are required to produce severe radiation damage and originate crater formation on the surface. This is related to very strong chemical bonds and both the melting (or sublimation) point and thermal conductivity of diamond being the highest among the solids. For the case of graphite, which is layered material with weak van der Waals bonds between the graphene planes, significant radiation damage is already introduced by impact of clusters with low kinetic energies (a few tens of eV/atom). However, collisions of the argon clusters cause very elastic response of the graphene planes that leads to efficient closure of the craters which could be formed at the initial stage of impact.

  10. Large gem diamonds from metallic liquid in Earth’s deep mantle

    NASA Astrophysics Data System (ADS)

    Smith, Evan M.; Shirey, Steven B.; Nestola, Fabrizio; Bullock, Emma S.; Wang, Jianhua; Richardson, Stephen H.; Wang, Wuyi

    2016-12-01

    The redox state of Earth’s convecting mantle, masked by the lithospheric plates and basaltic magmatism of plate tectonics, is a key unknown in the evolutionary history of our planet. Here we report that large, exceptional gem diamonds like the Cullinan, Constellation, and Koh-i-Noor carry direct evidence of crystallization from a redox-sensitive metallic liquid phase in the deep mantle. These sublithospheric diamonds contain inclusions of solidified iron-nickel-carbon-sulfur melt, accompanied by a thin fluid layer of methane ± hydrogen, and sometimes majoritic garnet or former calcium silicate perovskite. The metal-dominated mineral assemblages and reduced volatiles in large gem diamonds indicate formation under metal-saturated conditions. We verify previous predictions that Earth has highly reducing deep mantle regions capable of precipitating a metallic iron phase that contains dissolved carbon and hydrogen.

  11. Time Dependent DD Neutrons Measurement Using a Single Crystal Chemical Vapor Deposition Diamond Detector on EAST

    NASA Astrophysics Data System (ADS)

    Du, Tengfei; Peng, Xingyu; Chen, Zhongjing; Hu, Zhimeng; Ge, Lijian; Hu, Liqun; Zhong, Guoqiang; Pu, Neng; Chen, Jinxiang; Fan, Tieshuan

    2016-09-01

    A single crystal chemical vapor deposition (scCVD) diamond detector has been successfully employed for neutron measurements in the EAST (Experimental Advanced Superconducting Tokamak) plasmas. The scCVD diamond detector coated with a 5 μm 6LiF (95% 6Li enriched) layer was placed inside a polyethylene moderator to enhance the detection efficiency. The time-dependent neutron emission from deuteron plasmas during neutral beam injection (NBI) heating was obtained. The measured results are compared with that of fission chamber detectors, which always act as standard neutron flux monitors. The scCVD diamond detector exhibits good reliability, stability and the capability to withstand harsh radiation environments despite its low detection efficiency due to the small active volume. supported by the National Magnetic Confinement Fusion Science Program of China (Nos. 2013GB106004 and 2012GB101003) and National Natural Science Foundation of China (No. 91226102)

  12. Transparent nanocrystalline diamond ceramics fabricated from C{sub 60} fullerene by shock compression

    SciTech Connect

    Hirai, H.; Kondo, K.; Kim, M.; Koinuma, H.; Kurashima, K.; Bando, Y.

    1997-11-01

    Transparent nanocrystalline diamond ceramics, consisting of a few nanometer-sized diamond crystallites that are unstable in themselves because of higher surface energy, were fabricated successfully from C{sub 60} fullerene using a shock compression and rapid quenching technique. The platelets were transparent and very hard, nearly comparable to type IIa diamond. Transmission electron microscopy and electron energy loss spectroscopy revealed that individual crystallites had combined directly or through a very thin and modified sp{sup 3} carbon layer, which possibly stabilized the nanometer-sized crystallites. The size order and sp{sup 3} configuration of the nanotexture caused the transparency and hardness of the present material. {copyright} {ital 1997 American Institute of Physics.}

  13. Comparison theorems for causal diamonds

    NASA Astrophysics Data System (ADS)

    Berthiere, Clément; Gibbons, Gary; Solodukhin, Sergey N.

    2015-09-01

    We formulate certain inequalities for the geometric quantities characterizing causal diamonds in curved and Minkowski spacetimes. These inequalities involve the redshift factor which, as we show explicitly in the spherically symmetric case, is monotonic in the radial direction, and it takes its maximal value at the center. As a by-product of our discussion we rederive Bishop's inequality without assuming the positivity of the spatial Ricci tensor. We then generalize our considerations to arbitrary, static and not necessarily spherically symmetric, asymptotically flat spacetimes. In the case of spacetimes with a horizon our generalization involves the so-called domain of dependence. The respective volume, expressed in terms of the duration measured by a distant observer compared with the volume of the domain in Minkowski spacetime, exhibits behaviors which differ if d =4 or d >4 . This peculiarity of four dimensions is due to the logarithmic subleading term in the asymptotic expansion of the metric near infinity. In terms of the invariant duration measured by a comoving observer associated with the diamond we establish an inequality which is universal for all d . We suggest some possible applications of our results including comparison theorems for entanglement entropy, causal set theory, and fundamental limits on computation.

  14. Localized vibrational modes in diamond

    NASA Astrophysics Data System (ADS)

    Murzaev, R. T.; Bachurin, D. V.; Korznikova, E. A.; Dmitriev, S. V.

    2017-03-01

    Discrete breather (DB) or, synonymously, intrinsic localized mode (ILM) is a spatially localized and time-periodic vibrational mode in a defect-free nonlinear lattice, e.g., in a crystal lattice. Standing DB and DB clusters (double and triple) are studied in diamond using molecular dynamics method with the AIREBO interatomic potentials. Single DB can be easily excited by applying initial shifts, A0, to a pair of nearest atoms along the valence bond in the opposite directions. Admissible excitation amplitudes are 0.09 ≤A0 /a0 ≤ 0.12, where a0 is the equilibrium interatomic distance. The core of a DB is a pair of nearest carbon atoms oscillating out-of-phase, while the neighboring atoms oscillate with one order of magnitude lower amplitudes. DB frequency is above the top of the phonon spectrum and increases with the oscillation amplitude. DB lives for more than 100 oscillation periods which approximately corresponds to 2 ps. The range of initial amplitudes and other conditions necessary for the excitation of double and triple DB clusters as well as their lifetime are investigated in detail. Two different mechanisms of energy exchange between DBs in the DB clusters are revealed, which is the main result of the present study. Our results contribute to a deeper understanding of the nonlinear lattice dynamics of diamond.

  15. Absolute age Determinations on Diamond by Radioisotopic Methods: NOT the way to Accurately Identify Diamond Provenance

    NASA Astrophysics Data System (ADS)

    Shirey, S. B.

    2002-05-01

    Gem-quality diamond contains such low abundances of parent-daughter radionuclides that dating the diamond lattice directly by isotopic measurements has been and will be impossible. Absolute ages on diamonds typically are obtained through measurements of their syngenetic mineral inclusions: Rb-Sr in garnet; Sm-Nd in garnet and pyroxene; Re-Os and U-Th-Pb in sulfide; K-Ar in pyroxene; and U-Pb in zircon. The application of the first two isotope schemes in the list requires putting together many inclusions from many diamonds whereas the latter isotope schemes permit ages on single diamonds. The key limitations on the application of these decay pairs are the availability and size of the inclusions, the abundance levels of the radionuclides, and instrumental sensitivity. Practical complications of radioisotope dating of inclusions are fatal to the application of the technique for diamond provenance. In all mines, the ratio of gem-quality diamonds to stones with datable inclusions is very high. Thus there is no way to date the valuable, marketable stones that are part of the conflict diamond problem, just their rare, flawed cousins. Each analysis destroys the diamond host plus the inclusion and can only be carried out in research labs by highly trained scientists. Thus, these methods can not be automated or applied to the bulk of diamond production. The geological problems with age dating are equally fatal to its application to diamond provenance. From the geological perspective, for age determination to work as a tool for diamond provenance studies, diamond ages would have to be specific to particular kimberlites or kimberlite fields and different between fields. The southern African Kaapvaal-Zimbabwe Craton and Limpopo Mobile Belt is the only cratonic region where age determinations have been applied on a large enough scale to a number of kimberlites to illustrate the geological problems in age measurements for diamond provenance. However, this southern African example

  16. Diamonds in an Archean greenstone belt: Diamond suites in unconventional rocks of Wawa, Northern Ontario (Canada)

    NASA Astrophysics Data System (ADS)

    Kopylova, Maya; Bruce, Loryn; Ryder, John

    2010-05-01

    Diamonds typically are found on Archean cratons entrained by younger Phanerozoic kimberlites. In contrast, Wawa diamonds are hosted in "unconventional", non-kimberlitic rocks that formed contemporaneously with the mafic and sedimentary rocks of the Archean Michipicoten Greenstone Belt (MGB). We studied two diamond suites that occur within the 2.9-2.7 Ga greenschist facies rocks of MGB located in the southwest portion of the Superior Craton (E. Canada). The first diamond suite henceforth referred to as the Wawa breccia diamonds (384 stones), are hosted in the 2618-2744 Ma calc-alkaline lamprophyres and volcaniclastic breccias, contemporaneous with pillow basalts and felsic volcanics of MGB. The second suite, the Wawa conglomerate diamonds (80 crystals), are hosted in the 2697-2700 Ma poorly sorted sedimentary polymictic conglomerate which is interpreted as a proximal alluvial fan debris flow in a fan-delta environment. The majority of the diamonds was found within the matrix of the conglomerate. The diamondiferous breccia occurs 20 km north of the town of Wawa, whereas the conglomerate is found 12 km northeast of Wawa. Diamonds from the 2 occurrences were characterized and described for provenance studies. Both the breccia and conglomerate diamonds show similar crystal habits, with the predominance of octahedral single crystals and ~ 10% of cubes. The conglomerate diamonds are significantly less resorbed (no resorbtion in 43% of the stones) than the breccia diamonds (8% non-resorbed stones). In both suites, only 21-24% show high degrees of resorption. The majority of crystals in both suites are colourless, with some yellow, brown and grey stones. Conglomerate diamonds had a wider variety of colours that were not seen in the breccia diamonds, including green and pink. The breccia diamonds contain 0-740 ppm N and show two modes of N aggregation at 0-30 and 60-95%. Among the breccia diamonds, Type IaA stones comprise 17%, whereas IaAB stones make up 49% of the

  17. Alpha-Voltaic Sources Using Diamond as Conversion Medium

    NASA Technical Reports Server (NTRS)

    Patel, Jagadish U.; Fleurial, Jean-Pierre; Kolawa, Elizabeth

    2006-01-01

    A family of proposed miniature sources of power would exploit the direct conversion of the kinetic energy of a particles into electricity in diamond semiconductor diodes. These power sources would function over a wide range of temperatures encountered in terrestrial and outer-space environments. These sources are expected to have operational lifetimes of 10 to 20 years and energy conversion efficiencies >35 percent. A power source according to the proposal would include a pair of devices like that shown in the figure. Each device would contain Schottky and p/n diode devices made from high-band-gap, radiation-hard diamond substrates. The n and p layers in the diode portion would be doped sparsely (<1014 cm-3) in order to maximize the volume of the depletion region and thereby maximize efficiency. The diode layers would be supported by an undoped diamond substrate. The source of a particles would be a thin film of 244Cm (half-life 18 years) sandwiched between the two paired devices. The sandwich arrangement would force almost every a particle to go through the active volume of at least one of the devices. Typical a particle track lengths in the devices would range from 20 to 30 microns. The a particles would be made to stop only in the undoped substrates to prevent damage to the crystalline structures of the diode portions. The overall dimensions of a typical source are expected to be about 2 by 2 by 1 mm. Assuming an initial 244Cm mass of 20 mg, the estimated initial output of the source is 20 mW (a current of 20 mA at a potential of 1 V).

  18. An insight into what superconducts in polycrystalline boron-doped diamonds based on investigations of microstructure

    PubMed Central

    Dubrovinskaia, N.; Wirth, R.; Wosnitza, J.; Papageorgiou, T.; Braun, H. F.; Miyajima, N.; Dubrovinsky, L.

    2008-01-01

    The discovery of superconductivity in polycrystalline boron-doped diamond (BDD) synthesized under high pressure and high temperatures [Ekimov, et al. (2004) Nature 428:542–545] has raised a number of questions on the origin of the superconducting state. It was suggested that the heavy boron doping of diamond eventually leads to superconductivity. To justify such statements more detailed information on the microstructure of the composite materials and on the exact boron content in the diamond grains is needed. For that we used high-resolution transmission electron microscopy and electron energy loss spectroscopy. For the studied superconducting BDD samples synthesized at high pressures and high temperatures the diamond grain sizes are ≈1–2 μm with a boron content between 0.2 (2) and 0.5 (1) at %. The grains are separated by 10- to 20-nm-thick layers and triangular-shaped pockets of predominantly (at least 95 at %) amorphous boron. These results render superconductivity caused by the heavy boron doping in diamond highly unlikely. PMID:18697937

  19. Optical determination and modification of Schottky barrier heights of metals on diamond surfaces

    NASA Astrophysics Data System (ADS)

    Beetz, Charles P., Jr.; Tan, S. H.

    1992-11-01

    We have investigated the formation of Schottky barriers on diamond employing metal systems coupled with a shallow Si implant that would form low resistivity, high temperature stable metal silicide contact layer. We find that the barrier height of metals such as Pt, Ti and Mo were reduced when deposited on shallow Si implants and given a heat treatment at 500 degree(s)C. The barrier height of Pt on diamond was reduced from 1.89 eV to 0.97 eV by annealing of a sputtered Pt contact on a Si implanted dose of 1015 cm-2 that peaks at approximately 120 angstroms into the diamond surface. Using the same approach, the barrier height of Ti on diamond was reduced from 2.00 eV to 1.29 eV, while the barrier height of Mo remained essentially unchanged. Although we have no direct evidence for silicide formation at this time, the reduction of the barrier height scaled inversely to the temperature of formation of the metal silicide. This is an extremely interesting observation and points to the possibility of achieving very low resistance contacts. We also re-examine the interpretation of barrier height measurements using internal photoemission and attempt to explain the appearance of two barriers and resolve the wide range of reported barrier heights of metals on diamond.

  20. Microcrystalline diamond cylindrical resonators with quality-factor up to 0.5 million

    SciTech Connect

    Saito, Daisuke; Yang, Chen; Lin, Liwei; Heidari, Amir; Najar, Hadi; Horsley, David A.

    2016-02-01

    We demonstrate high quality-factor 1.5 mm diameter batch-fabricated microcrystalline diamond cylindrical resonators (CR) with quality-factors limited by thermoelastic damping (TED) and surface loss. Resonators were fabricated 2.6 and 5.3 μm thick in-situ boron-doped microcrystalline diamond films deposited using hot filament chemical vapor deposition. The quality-factor (Q) of as-fabricated CR's was found to increase with the resonator diameter and diamond thickness. Annealing the CRs at 700 °C in a nitrogen atmosphere led to a three-fold increase in Q, a result we attribute to thinning of the diamond layer via reaction with residual O{sub 2} in the annealing furnace. Post-anneal Q exceeding 0.5 million (528 000) was measured at the 19 kHz elliptical wineglass modes, producing a ring-down time of 8.9 s. A model for Q versus diamond thickness and resonance frequency is developed including the effects of TED and surface loss. Measured quality factors are shown to agree with the predictions of this model.

  1. Morphology, functionality and molecular conformation study of CVD diamond surfaces functionalised with organic linkers and DNA

    NASA Astrophysics Data System (ADS)

    Wenmackers, Sylvia

    This PhD thesis fits within a joint-venture of physicists and biomedical researchers, aimed at the development of diamond-based DNA sensors. CVD diamond was chosen as the substrate material, because a strong covalent carbon-carbon bond can be created in this case, creating a highly stable platform for reusable biosensors or even for continuous monitoring. Moreover, diamond has favourable properties for sensing based on optical (transparency for a large spectral range) as well as electrical signals (semiconductor, stable in aqueous solutions with a wide potential window). The first specific goal for this thesis within the project was to establish the initial functionalisation of CVD diamond surfaces that would allow for the covalent linking of biomolecules, in casu DNA. This was obtained by UV attachement of omega-unsaturated fatty acid molecules (10-undecenoic acid) followed by the use of the zero-length crosslinker EDC to attach amino-modified DNA. The second goal was to characterise the diamond surfaces extensively with physical and (bio-)chemical methods to check the effectiveness of various surface treatments, and to elucidate the molecular organisation of the obtained linker layers and DNA brushes. Point mutation-sensitivity was achieved with end-point fluorescence as well as a real-time label-free electrical sensor prototype. The conformation of the end-tethered DNA molecules was investigated with spectroscopic ellipsometry.

  2. The Geopolitical Setting of Conflict Diamonds.

    NASA Astrophysics Data System (ADS)

    Haggerty, S. E.

    2002-05-01

    September 11, 2001 will live in infamy. Ideological differences have also led to senseless atrocities in Angola, Congo Republic, Sierra Leone, and Liberia. Hundreds of thousands have died, scores mutilated, and millions displaced. These have gone virtually unnoticed for decades. Unnoticed that is until it became evident that these barbaric acts were fueled by the sale or bartering of diamonds for arms, or by more ingenious ways that are less traceable. There is no end in sight. Industry has long recognized that about 20% of diamonds reaching the open market are smuggled from operating mines, and more recently that an additional 4% originates from conflict diamond sources. Diamond identification by laser inscription, ion implantation, or certification protocols are subject to fraudulent tampering. And these applied methods are thwarted if cutting and polishing centers are infiltrated, or if terrorist facilities are independently established. Mark ups are substantial (40-60%) from raw material to finished product. Tracking the paths of rough stones from mines to faceted gems is impractical because some 30-50 million cts of top quality material, or about 100 million stones, would require branding each year. Moreover, the long standing tradition of site-holdings and the bourse system of mixing or matching diamonds, inadvertently ensures regional anonymity. Conflict diamonds are mined in primary kimberlites and from widely dispersed alluvial fields in tropical jungle. Landscapes, eroded by 1-5 vertical km over 100 Ma, have transformed low grade primary deposits into unconsolidated sedimentary bonanzas. The current value of stones retrieved, by motivated diggers and skillful jiggers, in rebel held territories, is impossible to determine, but in 1993 amounted to tens of millions USD. Diamonds over 100 cts continue to surface at premier prices. Borders are porous, diamonds flow easily, and armed networks are permeable and mobile. Diamonds form at great depths (over 200 km

  3. Cathodoluminescence of natural, plastically deformed pink diamonds.

    PubMed

    Gaillou, E; Post, J E; Rose, T; Butler, J E

    2012-12-01

    The 49 type I natural pink diamonds examined exhibit color restricted to lamellae or bands oriented along {111} that are created by plastic deformation. Pink diamonds fall into two groups: (1) diamonds from Argyle in Australia and Santa Elena in Venezuela are heavily strained throughout and exhibit pink bands alternating with colorless areas, and (2) diamonds from other localities have strain localized near the discrete pink lamellae. Growth zones are highlighted by a blue cathodoluminescence (CL) and crosscut by the pink lamellae that emit yellowish-green CL that originates from the H3 center. This center probably forms by the recombination of nitrogen-related centers (A-aggregates) and vacancies mobilized by natural annealing in the Earth's mantle. Twinning is the most likely mechanism through which plastic deformation is accommodated for the two groups of diamonds. The plastic deformation creates new centers visible through spectroscopic methods, including the one responsible for the pink color, which remains unidentified. The differences in the plastic deformation features, and resulting CL properties, for the two groups might correlate to the particular geologic conditions under which the diamonds formed; those from Argyle and Santa Elena are deposits located within Proterozoic cratons, whereas most diamonds originate from Archean cratons.

  4. Anisotropic mechanical amorphization drives wear in diamond

    NASA Astrophysics Data System (ADS)

    Pastewka, Lars; Moser, Stefan; Gumbsch, Peter; Moseler, Michael

    2011-01-01

    Diamond is the hardest material on Earth. Nevertheless, polishing diamond is possible with a process that has remained unaltered for centuries and is still used for jewellery and coatings: the diamond is pressed against a rotating disc with embedded diamond grit. When polishing polycrystalline diamond, surface topographies become non-uniform because wear rates depend on crystal orientations. This anisotropy is not fully understood and impedes diamond’s widespread use in applications that require planar polycrystalline films, ranging from cutting tools to confinement fusion. Here, we use molecular dynamics to show that polished diamond undergoes an sp3-sp2 order-disorder transition resulting in an amorphous adlayer with a growth rate that strongly depends on surface orientation and sliding direction, in excellent correlation with experimental wear rates. This anisotropy originates in mechanically steered dissociation of individual crystal bonds. Similarly to other planarization processes, the diamond surface is chemically activated by mechanical means. Final removal of the amorphous interlayer proceeds either mechanically or through etching by ambient oxygen.

  5. Progress on diamond amplified photo-cathode

    SciTech Connect

    Wang, E.; Ben-Zvi, I.; Burrill, A.; Kewisch, J.; Chang, X.; Rao, T.; Smedley, J.; Wu, Q.; Muller, E.; Xin, T.

    2011-03-28

    Two years ago, we obtained an emission gain of 40 from the Diamond Amplifier Cathode (DAC) in our test system. In our current systematic study of hydrogenation, the highest gain we registered in emission scanning was 178. We proved that our treatments for improving the diamond amplifiers are reproducible. Upcoming tests planned include testing DAC in a RF cavity. Already, we have designed a system for these tests using our 112 MHz superconducting cavity, wherein we will measure DAC parameters, such as the limit, if any, on emission current density, the bunch charge, and the bunch length. The diamond-amplified photocathode, that promises to support a high average current, low emittance, and a highly stable electron beam with a long lifetime, is under development for an electron source. The diamond, functioning as a secondary emitter amplifies the primary current, with a few KeV energy, that comes from the traditional cathode. Earlier, our group recorded a maximum gain of 40 in the secondary electron emission from a diamond amplifier. In this article, we detail our optimization of the hydrogenation process for a diamond amplifier that resulted in a stable emission gain of 140. We proved that these characteristics are reproducible. We now are designing a system to test the diamond amplifier cathode using an 112MHz SRF gun to measure the limits of the emission current's density, and on the bunch charge and bunch length.

  6. Self-composite comprised of nanocrystalline diamond and a non-diamond component useful for thermoelectric applications

    DOEpatents

    Gruen, Dieter M.

    2012-09-04

    One provides nanocrystalline diamond material that comprises a plurality of substantially ordered diamond crystallites that are sized no larger than about 10 nanometers. One then disposes a non-diamond component within the nanocrystalline diamond material. By one approach this non-diamond component comprises an electrical conductor that is formed at the grain boundaries that separate the diamond crystallites from one another. The resultant nanowire is then able to exhibit a desired increase with respect to its ability to conduct electricity while also preserving the thermal conductivity behavior of the nanocrystalline diamond material.

  7. Self-composite comprised of nanocrystalline diamond and a non-diamond component useful for thermoelectric applications

    DOEpatents

    Gruen, Dieter M.

    2009-08-11

    One provides nanocrystalline diamond material that comprises a plurality of substantially ordered diamond crystallites that are sized no larger than about 10 nanometers. One then disposes a non-diamond component within the nanocrystalline diamond material. By one approach this non-diamond component comprises an electrical conductor that is formed at the grain boundaries that separate the diamond crystallites from one another. The resultant nanowire is then able to exhibit a desired increase with respect to its ability to conduct electricity while also preserving the thermal conductivity behavior of the nanocrystalline diamond material.

  8. Triple ion beam cutting of diamond/Al composites for interface characterization

    SciTech Connect

    Ji, Gang; Tan, Zhanqiu; Shabadi, Rajashekhara; Li, Zhiqiang; Grünewald, Wolfgang; Addad, Ahmed; Schryvers, Dominique; Zhang, Di

    2014-03-01

    A novel triple ion beam cutting technique was employed to prepare high-quality surfaces of diamond/Al composites for interfacial characterization, which has been unachievable so far. Near-perfect and artifact-free surfaces were obtained without mechanical pre-polishing. Hence, the as-prepared surfaces are readily available for further study and also, ready to be employed in a focus ion beam system for preferential selection of transmission electron microscopy samples. Dramatically different diamond/Al interface configurations — sub-micrometer Al{sub 2}O{sub 3} particles and clean interfaces were unambiguously revealed. - Highlights: • A new triple ion beam technique was employed to prepare diamond/Al composites. • Near-perfect and artifact-free surfaces were obtained for interface characterization. • Sub-micrometer Al{sub 2}O{sub 3} particles and clean interfaces were unambiguously revealed.

  9. Surface effects on nitrogen vacancy centers neutralization in diamond

    NASA Astrophysics Data System (ADS)

    Newell, Arthur N.; Dowdell, Dontray A.; Santamore, D. H.

    2016-11-01

    The performance of nitrogen vacancy (NV-) based magnetic sensors strongly depends on the stability of nitrogen vacancy centers near the diamond surface. The sensitivity of magnetic field detection is diminished as the NV- turns into the neutralized charge state NV0. We investigate the neutralization of NV- and calculate the ratio of NV0 to total NV (NV-+NV0) caused by a hydrogen terminated diamond with a surface water layer. We find that NV- neutralization exhibits two distinct regions: near the surface, where the NV- is completely neutralized, and in the bulk, where the neutralization ratio is inversely proportional to depth following the electrostatic force law. In addition, small changes in concentration can lead to large differences in neutralization behavior. This phenomenon allows one to carefully control the concentration to decrease the NV- neutralization. The presence of nitrogen dopant greatly reduces NV- neutralization as the nitrogen ionizes in preference to NV- neutralization at the same depth. The water layer pH also affects neutralization. If the pH is very low due to cleaning agent residue, then we see a change in the band bending and the reduction of the two-dimensional hole gas region. Finally, we find that dissolved carbon dioxide resulting from direct contact with the atmosphere at room temperature hardly affects the NV- neutralization.

  10. Residual radioactivity of treated green diamonds.

    PubMed

    Cassette, Philippe; Notari, Franck; Lépy, Marie-Christine; Caplan, Candice; Pierre, Sylvie; Hainschwang, Thomas; Fritsch, Emmanuel

    2017-01-29

    Treated green diamonds can show residual radioactivity, generally due to immersion in radium salts. We report various activity measurements on two radioactive diamonds. The activity was characterized by alpha and gamma ray spectrometry, and the radon emanation was measured by alpha counting of a frozen source. Even when no residual radium contamination can be identified, measurable alpha and high-energy beta emissions could be detected. The potential health impact of radioactive diamonds and their status with regard to the regulatory policy for radioactive products are discussed.

  11. Selected Bibliography II-Diamond Surface Chemistry

    DTIC Science & Technology

    1993-09-30

    34 JNL: Surface Science REF: 1 (1964) 3-21 AUTHOR: Evans T. and James P.F. TITLE: "A Study of the Transformation of Diamond to Graphite" JNL: Proc. R... Less -ordered Carbons by X-Ray Photo-electron Spectroscopy" JNL: Trans. Faraday Soc. REF: 67 (1971) 1875 3 AUTHOR: Runciman W.A. and Carter T. TITLE...on the Diamond (111) Surface" JNL: New Diamond Sci. Technol., Proc. Int. Conf., 2nd REF: (1991) 51 69 AUTHOR: Blatter A., Boegli U., Builov L.L

  12. Synchrotron Bragg diffraction imaging characterization of synthetic diamond crystals for optical and electronic power device applications1 1

    PubMed Central

    Tran Thi, Thu Nhi; Morse, J.; Caliste, D.; Fernandez, B.; Eon, D.; Härtwig, J.; Mer-Calfati, C.; Tranchant, N.; Arnault, J. C.; Lafford, T. A.; Baruchel, J.

    2017-01-01

    Bragg diffraction imaging enables the quality of synthetic single-crystal diamond substrates and their overgrown, mostly doped, diamond layers to be characterized. This is very important for improving diamond-based devices produced for X-ray optics and power electronics applications. The usual first step for this characterization is white-beam X-ray diffraction topography, which is a simple and fast method to identify the extended defects (dislocations, growth sectors, boundaries, stacking faults, overall curvature etc.) within the crystal. This allows easy and quick comparison of the crystal quality of diamond plates available from various commercial suppliers. When needed, rocking curve imaging (RCI) is also employed, which is the quantitative counterpart of monochromatic Bragg diffraction imaging. RCI enables the local determination of both the effective misorientation, which results from lattice parameter variation and the local lattice tilt, and the local Bragg position. Maps derived from these parameters are used to measure the magnitude of the distortions associated with polishing damage and the depth of this damage within the volume of the crystal. For overgrown layers, these maps also reveal the distortion induced by the incorporation of impurities such as boron, or the lattice parameter variations associated with the presence of growth-incorporated nitrogen. These techniques are described, and their capabilities for studying the quality of diamond substrates and overgrown layers, and the surface damage caused by mechanical polishing, are illustrated by examples. PMID:28381981

  13. A MEMS diamond hemispherical resonator

    NASA Astrophysics Data System (ADS)

    Bernstein, J. J.; Bancu, M. G.; Cook, E. H.; Chaparala, M. V.; Teynor, W. A.; Weinberg, M. S.

    2013-12-01

    In this paper we report the fabrication of hemispherical polycrystalline diamond resonators fabricated on a novel high-temperature glass substrate. The hemispherical resonator gyroscope is one of the most accurate and rugged of the mechanical gyroscopes, and can be operated in either rate or whole-angle mode due to its high degree of symmetry. A fabrication sequence for creating extremely symmetric 3D MEMS hemispheres is presented. Mode shapes and frequencies obtained with a laser vibrometer are shown, as well as curves of Q versus pressure, and the dependence of frequency on anchor size. Fundamental mode frequency matching to <0.1% in as-fabricated devices has been achieved, which is essential to gyroscope operation in whole-angle mode.

  14. Normally-off HfO2-gated diamond field effect transistors

    NASA Astrophysics Data System (ADS)

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

    2013-08-01

    A normally-off hydrogenated-diamond (H-diamond) field effect transistor (FET) using a HfO2 gate oxide is demonstrated. The HfO2 gate oxide has a bilayer structure which is fabricated by a sputter-deposition (SD) technique on a thin buffer layer prepared by an atomic layer deposition (ALD) technique. The role of the ALD-HfO2 is found to prevent deterioration of the H-diamond surface by the SD process. The leakage current density of the SD-HfO2/ALD-HfO2/H-diamond structure is smaller than 1.1 × 10-4 A cm-2 at gate voltages from -9.0 to 2.0 V. The capacitance-voltage characteristic shows that fixed and trapped charge densities are low enough to operate the FET. The HfO2-gated FET has p-type channel and complete normally-off characteristics. The drain-source current maximum, threshold voltage, extrinsic transconductance maximum, and effective mobility of the FET with gate length of 4 μm are -37.6 mA mm-1, -1.3 ± 0.1 V, 11.2 ± 0.1 mS mm-1, and 38.7 ± 0.5 cm2 V-1 s-1, respectively.

  15. Large improvement of phosphorus incorporation efficiency in n-type chemical vapor deposition of diamond

    NASA Astrophysics Data System (ADS)

    Ohtani, Ryota; Yamamoto, Takashi; Janssens, Stoffel D.; Yamasaki, Satoshi; Koizumi, Satoshi

    2014-12-01

    Microwave plasma enhanced chemical vapor deposition is a promising way to generate n-type, e.g., phosphorus-doped, diamond layers for the fabrication of electronic components, which can operate at extreme conditions. However, a deeper understanding of the doping process is lacking and low phosphorus incorporation efficiencies are generally observed. In this work, it is shown that systematically changing the internal design of a non-commercial chemical vapor deposition chamber, used to grow diamond layers, leads to a large increase of the phosphorus doping efficiency in diamond, produced in this device, without compromising its electronic properties. Compared to the initial reactor design, the doping efficiency is about 100 times higher, reaching 10%, and for a very broad doping range, the doping efficiency remains highly constant. It is hypothesized that redesigning the deposition chamber generates a higher flow of active phosphorus species towards the substrate, thereby increasing phosphorus incorporation in diamond and reducing deposition of phosphorus species at reactor walls, which additionally reduces undesirable memory effects.

  16. Epithelial cell morphology and adhesion on diamond films deposited and chemically modified by plasma processes.

    PubMed

    Rezek, Bohuslav; Ukraintsev, Egor; Krátká, Marie; Taylor, Andrew; Fendrych, Frantisek; Mandys, Vaclav

    2014-09-01

    The authors show that nanocrystalline diamond (NCD) thin films prepared by microwave plasma enhanced chemical vapor deposition apparatus with a linear antenna delivery system are well compatible with epithelial cells (5637 human bladder carcinoma) and significantly improve the cell adhesion compared to reference glass substrates. This is attributed to better adhesion of adsorbed layers to diamond as observed by atomic force microscopy (AFM) beneath the cells. Moreover, the cell morphology can be adjusted by appropriate surface treatment of diamond by using hydrogen and oxygen plasma. Cell bodies, cytoplasmic rims, and filopodia were characterized by Peakforce AFM. Oxidized NCD films perform better than other substrates under all conditions (96% of cells adhered well). A thin adsorbed layer formed from culture medium and supplemented with fetal bovine serum (FBS) covered the diamond surface and played an important role in the cell adhesion. Nevertheless, 50-100 nm large aggregates formed from the RPMI medium without FBS facilitated cell adhesion also on hydrophobic hydrogenated NCD (increase from 23% to 61%). The authors discuss applicability for biomedical uses.

  17. Large improvement of phosphorus incorporation efficiency in n-type chemical vapor deposition of diamond

    SciTech Connect

    Ohtani, Ryota; Yamamoto, Takashi; Janssens, Stoffel D.; Yamasaki, Satoshi

    2014-12-08

    Microwave plasma enhanced chemical vapor deposition is a promising way to generate n-type, e.g., phosphorus-doped, diamond layers for the fabrication of electronic components, which can operate at extreme conditions. However, a deeper understanding of the doping process is lacking and low phosphorus incorporation efficiencies are generally observed. In this work, it is shown that systematically changing the internal design of a non-commercial chemical vapor deposition chamber, used to grow diamond layers, leads to a large increase of the phosphorus doping efficiency in diamond, produced in this device, without compromising its electronic properties. Compared to the initial reactor design, the doping efficiency is about 100 times higher, reaching 10%, and for a very broad doping range, the doping efficiency remains highly constant. It is hypothesized that redesigning the deposition chamber generates a higher flow of active phosphorus species towards the substrate, thereby increasing phosphorus incorporation in diamond and reducing deposition of phosphorus species at reactor walls, which additionally reduces undesirable memory effects.

  18. Development of boron-doped diamond thin-films as voltammetric and amperometric detectors

    NASA Astrophysics Data System (ADS)

    Xu, Jishou

    2000-10-01

    The utilization of boron-doped diamond thin-films for applications in electroanalysis was investigated. Voltammetric analysis in static solution, and amperometric detection coupled with flow injection analysis and HPLC were performed. The results were compared to those for glassy carbon. The electroactivity, the merit of detection figures, the adsorption of polar organic molecules, and the resistance to fouling were studied. Surface characterization was performed to elucidate the surface property-electroacticvity relationship. The results showed that diamond thin-films, compared with glassy carbon, had comparable electroactivity to simple electron transfer processes (e.g., Ru(NH3)6+2/+3, Fe(CN)6 -3/-4, IrCl6-2/-3, azide, chlorpromazine), but had lower electroactivity for the electron transfer processes involving surface-confined intermediate (e.g., hydrogen evolution, oxygen evolution, 4-methyl catechol, hydrazine). The diamond thin-films had a wide working potential up to 4.0 V in aqueous media. They also had small double layer capacitance, voltammetric background current, and amperometric residual current. These properties had leaded to higher signal-to-background ratios and signal-to-noise ratios. The diamond thin-films had lower limits of detection in voltammetric measurements of several analytes, and had lower limits of detection in amperometric measurements of all compounds studied. The diamond thin-films had negligible adsorption of polar organic molecules (e.g., anthraquinone 2,6-disulfonate, chlorpromazine), compared to glassy carbon. This is due to the fact that the diamond surfaces are primarily composed of sp3 carbon and hydrogen terminated. This leaded to less decay of the electroactivity by storage and operation, and higher resistance to fouling. The surface property-electroactivity relationship depends on the specific mechanism for electron transfer. The extent of non-diamond impurities (e.g., oxygen evolution), diamond crystalline size, surface

  19. Astronomers debate diamonds in space

    NASA Astrophysics Data System (ADS)

    1999-04-01

    This is not the first time the intriguing carbonaceous compound has been detected in space. A peculiar elite of twelve stars are known to produce it. The star now added by ISO to this elite is one of the best representatives of this exclusive family, since it emits a very strong signal of the compound. Additionally ISO found a second new member of the group with weaker emission, and also observed with a spectral resolution never achieved before other already known stars in this class. Astronomers think these ISO results will help solve the mystery of the true nature of the compound. Their publication by two different groups, from Spain and Canada, has triggered a debate on the topic, both in astronomy institutes and in chemistry laboratories. At present, mixed teams of astrophysicists and chemists are investigating in the lab compounds whose chemical signature or "fingerprint" matches that detected by ISO. Neither diamonds nor fullerenes have ever been detected in space, but their presence has been predicted. Tiny diamonds of pre-solar origin --older than the Solar System-- have been found in meteorites, which supports the as yet unconfirmed theory of their presence in interstellar space. The fullerene molecule, made of 60 carbon atoms linked to form a sphere (hence the name "buckyball"), has also been extensively searched for in space but never found. If the carbonaceous compound detected by ISO is a fullerene or a diamond, there will be new data on the production of these industrially interesting materials. Fullerenes are being investigated as "capsules" to deliver new pharmaceuticals to the body. Diamonds are commonly used in the electronics industry and for the development of new materials; if they are formed in the dust surrounding some stars, at relatively low temperatures and conditions of low pressure, companies could learn more about the ideal physical conditions to produce them. A textbook case The latest star in which the compound has been found is

  20. Ion-beam-assisted etching of diamond

    NASA Technical Reports Server (NTRS)

    Efremow, N. N.; Geis, M. W.; Flanders, D. C.; Lincoln, G. A.; Economou, N. P.

    1985-01-01

    The high thermal conductivity, low RF loss, and inertness of diamond make it useful in traveling wave tubes operating in excess of 500 GHz. Such use requires the controlled etching of type IIA diamond to produce grating like structures tens of micrometers deep. Previous work on reactive ion etching with O2 gave etching rates on the order of 20 nm/min and poor etch selectivity between the masking material (Ni or Cr) and the diamond. An alternative approach which uses a Xe(+) beam and a reactive gas flux of NO2 in an ion-beam-assisted etching system is reported. An etching rate of 200 nm/min was obtained with an etching rate ratio of 20 between the diamond and an aluminum mask.