Sample records for ultrananocrystalline diamond layers

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

    PubMed Central

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

    2014-01-01

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

  2. 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 [Institute of Microelectronics, No.1, University Road, Tainan 701, Taiwan (China); Tu, Chia-Hao [Institute of Nanotechnology and Microsystems Engineering, No.1, University Road, Tainan 701, Taiwan (China); Department of Materials Science and Engineering, National Cheng Kung University, No.1, University Road, Tainan 701, Taiwan (China); Chang Chi [Institute of Nanotechnology and Microsystems Engineering, No.1, University Road, Tainan 701, Taiwan (China); Liu, Chuan-pu; Ting, Jyh-Ming [Department of Materials Science and Engineering, National Cheng Kung University, No.1, University Road, Tainan 701, Taiwan (China); Lee, Hsin-Li [Industrial Technology Research Institute - South, Tainan 701, Taiwan (China); Tzeng, Yonhua [Institute of Microelectronics, No.1, University Road, Tainan 701, Taiwan (China); Advanced Optoelectronics Technology Center, No.1, University Road, Tainan 701, Taiwan (China); Auciello, Orlando [Argonne National Laboratory, Materials Science Division, 9700 S. Cass Avenue, Argonne, Illinois 60439 (United States)

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

    NASA Astrophysics Data System (ADS)

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

    2012-06-01

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

  4. Nanopatterning of ultrananocrystalline diamond nanowires.

    PubMed

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

    2012-02-24

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

  5. Fracture size effect in ultrananocrystalline diamond: Applicability of Weibull theory

    E-print Network

    Espinosa, Horacio D.

    fractographic and transmission electron microscopy microstructural analysis. The Weibull parameters were in the strength of the polysilicon specimens. Weibull analysis predicted a general tendency for strengthFracture size effect in ultrananocrystalline diamond: Applicability of Weibull theory B. Peng, C

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

    NASA Astrophysics Data System (ADS)

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

    2012-02-01

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

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

    PubMed Central

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

    2013-01-01

    We show the technical feasibility of coating and micro patterning boron-doped ultrananocrystalline diamond (UNCD®) on metal microwires and of applying them as microsensors for the detection of dopamine in vivo using fast-scan cyclic voltammetry. UNCD electrode surface consistently generated electrochemical signals with high signal-to-noise ratio of >800 using potassium ferrocyanide-ferricyanide redox couple. Parylene patterned UNCD microelectrodes were effectively applied to detect dopamine reliably in vitro using flow injection analysis with a detection limit of 27?nM and in the striatum of the anesthetized rat during electrical stimulation of dopamine neurons. PMID:23918991

  9. 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.

  10. 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.

  11. Tailoring the Matrix in Ultra-Nanocrystalline Diamond Films

    NASA Astrophysics Data System (ADS)

    Buck, Volker; Woehrl, Nicolas

    2008-10-01

    By depositing films in argon-rich plasmas it is possible to produce ultra-nanocrystalline diamond (UNCD) films with grain sizes of 5-100 nm. By reducing the grain size, these films feature rather distinctive combinations of properties making them potential materials for emerging technological developments such as nano/micro-electro-mechanical systems (N/MEMS), optical coatings, bioelectronics, surface acoustic wave (SAW) filters, and tribological applications. The majority of works dealing with nanocrystalline diamond (NCD) up to now have concentrated on diamond grains (e.g., grain size, texture). In doing so the surrounding crystal matrix has been neglected and its effect on the substrate properties has been dismissed as a grain boundary effect. This view does not accord with its relevance to film properties. Because the matrix consists of amorphous carbon structures, approved methods for the characterization of this appropriate special class of materials were used here such as Raman and Fourier transform infrared spectroscopy (FTIR). The use of an amorphous matrix for nanocrystalline diamond grains has lead to an enormous field of new materials, because a whole class of carbon-based materials (diamondlike carbon, DLC) can be used as a matrix that may contain only carbon (a-C) or carbon and hydrogen (a-C:H) as well as other components such as metals (Me-C:H); additionally, other dopants such as silicon, oxygen, halogens, or nitrogen may be included. As an example, it is shown how the mechanical stress in films can be adjusted by tailoring the matrix.

  12. 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.

  13. 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.

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

    Microsoft Academic Search

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

    2007-01-01

    We present a comprehensive study of surface composition and nanotribology for ultrananocrystalline diamond (UNCD) surfaces, including the influence of film nucleation on these properties. We describe a methodology to characterize the underside of the films as revealed by sacrificial etching of the underlying substrate. This enables the study of the morphology and composition resulting from the nucleation and initial growth

  15. Ultrananocrystalline diamond tip integrated onto a heated atomic force microscope cantilever This article has been downloaded from IOPscience. Please scroll down to see the full text article.

    E-print Network

    King, William P.

    Ultrananocrystalline diamond tip integrated onto a heated atomic force microscope cantilever.1088/0957-4484/23/49/495302 Ultrananocrystalline diamond tip integrated onto a heated atomic force microscope cantilever Hoe Joon Kim1, Nicolaie Urbana-Champaign, Urbana, IL 61801, USA 2 Advanced Diamond Technologies Inc., Romeoville, IL 60446, USA 3

  16. The oxidization behavior and mechanical properties of ultrananocrystalline diamond films at high temperature annealing

    NASA Astrophysics Data System (ADS)

    Huang, Kai; Hu, Xiaojun; Xu, Hui; Shen, Yaogen; Khomich, Alex

    2014-10-01

    Ultrananocrystalline diamond (UNCD) films prepared by hot filament chemical vapor deposition (HFCVD) were annealed at 1000 °C in low degree vacuum under a pressure of 4000 Pa. The correlation between the mechanical and structural properties was investigated to understand the oxidization behavior of UNCD films after high temperature annealing. At the early stage of annealing (?30 min), the amorphous carbon and graphite in grain boundaries are selectively oxidized firstly along the clusters' gaps, with the Young's modulus and hardness decreasing rapidly revealed by nanoindentation results. A special annealing time of ?30-60 min is found to exist as a turning point that the mechanical properties changing trend has a transition, because of the diamond grains starting to be oxidized. With the annealing time increasing to 180 min, the nanoindentation depth increases from ?70 to ?90 nm and the Young's modulus and hardness decrease more slowly with almost keeping constant of ?383 and ?35 GPa, respectively. X-ray photoelectron spectroscopy (XPS) results show that a steady 30-nm-thick oxidized layer has been formed on the top-surface and keeps a balance of the speed between films being oxidized and the carbon oxidation being broken down.

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

    NASA Astrophysics Data System (ADS)

    Pauzauskie, Peter

    2013-06-01

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

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

    Microsoft Academic Search

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

    2011-01-01

    The reliability and performance of silicon carbide (SiC) shaft seals on multipurpose mechanical pumps are improved by applying a protective coating of ultrananocrystalline diamond (UNCD). UNCD exhibits extreme hardness (97GPa), low friction (0.1 in air) and outstanding chemical resistance. Consequently, the application of UNCD coatings to multipurpose mechanical pump seals can reduce frictional energy losses and eliminate the downtime and

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

    Microsoft Academic Search

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

    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 -800 C. The films have -4.3% sp² content in the near-surface region as revealed by near edge x-ray absorption fine structure spectroscopy. The films, -1 m thick, exhibit

  20. 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.

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

    SciTech Connect

    Sumant, A. V.; Auciello, O.; Carpick, R. W.; Srinivasan, S.; Butler, J. E. (Center for Nanoscale Materials); ( MSD); ( PSC-USR)

    2010-04-01

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

  2. Electron field emission for ultrananocrystalline diamond films A. R. Krauss

    E-print Network

    , Rehovoth, Israel V. Konov, S. Pimenov, and A. Karabutov General Physics Institute, Russian Academy microelectronic devices and high cur- rent, high frequency tubes. Diamond-coated Si microtip emitters appear

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

    SciTech Connect

    Panda, Kalpataru; Sundaravel, B.; Panigrahi, B. K. [Materials Physics Division, Indira Gandhi Centre for Atomic Research, Kalpakkam 603 102 (India); Chen, Huang-Chin; Lin, I.-Nan [Department of Physics, Tamkang University, New-Taipei 251, Taiwan (China)

    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.

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

    SciTech Connect

    Li, Lin; Zhao, Jing; Hu, Zhaosheng; Quan, Baogang; Li, Junjie, E-mail: jjli@iphy.ac.cn; Gu, Changzhi, E-mail: czgu@iphy.ac.cn [Beijing National Laboratory for Condensed Matter Physics, Institution of Physics Chinese Academy of Sciences, Beijing 100190 (China)

    2014-05-05

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

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

    SciTech Connect

    Sankaran, K. J.; Tai, N. H., E-mail: nhtai@mx.nthu.edu.tw [Department of Materials Science and Engineering, National Tsing-Hua University, Hsinchu 300, Taiwan (China); Lin, I. N., E-mail: inanlin@mail.tku.edu.tw [Department of Physics, Tamkang University, Tamsui 251, Taiwan (China)

    2014-01-20

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

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

    NASA Astrophysics Data System (ADS)

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

    2014-04-01

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

  7. 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.

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

    SciTech Connect

    Kovalchenko, A. M.; Elam, J. W.; Erdemir, A.; Carlisle, J. A.; Auciello, O.; Libera, J. A.; Pellin, M. J.; Gruen, D. M.; Hryn, J. N. (Materials Science Division); (Georgia Inst. of Tech.)

    2011-01-01

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

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

    NASA Astrophysics Data System (ADS)

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

    2014-04-01

    A field emission based flat-panel transmission x-ray source is being developed as an alternative for medical and industrial imaging. A field emitter array (FEA) prototype based on nitrogen incorporated ultrananocrystalline diamond film has been fabricated to be used as the electron source of this flat panel x-ray source. The FEA prototype was developed using conventional microfabrication techniques. The field emission characteristics of the FEA prototype were evaluated. Results indicated that emission current densities of the order of 6 mA/cm2 could be obtained at electric fields as low as 10 V/?m to 20 V/?m. During the prototype microfabrication process, issues such as delamination of the extraction gate and poor etching of the SiO2 insulating layer located between the emitters and the extraction layer were encountered. Consequently, alternative FEA designs were investigated. Experimental and simulation data from the first FEA prototype were compared and the results were used to evaluate the performance of alternative single and double gate designs that would yield better field emission characteristics compared to the first FEA prototype. The best simulation results are obtained for the double gate FEA design, when the diameter of the collimator gate is around 2.6 times the diameter of the extraction gate.

  10. Ultrananocrystalline diamond film as a wear resistant and protective coating for mechanical seal applications.

    SciTech Connect

    Sumant, A. V.; Krauss, A. R.; Gruen, D. M.; Auciello, O.; Erdemir, A.; Williams, M.; Artiles, A. F.; Adams, W.; Western Michigan Univ.; Flowserve Corp.

    2005-01-01

    Mechanical shaft seals used in pumps are critically important to the safe operation of the paper, pulp, and chemical process industry, as well as petroleum and nuclear power plants. Specifically, these seals prevent the leakage of toxic gases and hazardous chemicals to the environment and final products from the rotating equipment used in manufacturing processes. Diamond coatings have the potential to provide negligible wear, ultralow friction, and high corrosion resistance for the sliding surfaces of mechanical seals, because diamond exhibits outstanding tribological, physical, and chemical properties. However, diamond coatings produced by conventional chemical vapor deposition (CVD) exhibit high surface roughness (R{sub a} {>=} 1 {mu}m), which results in high wear of the seal counterface, leading to premature seal failure. To avoid this problem, we have developed an ultrananocrystalline diamond (UNCD) film formed by a unique CH{sub 4}/Ar microwave plasma CVD method. This method yields extremely smooth diamond coatings with surface roughness R{sub a} = 20-30 nm and an average grain size of 2-5 nm. We report the results of a systematic test program involving uncoated and UNCD-coated SiC shaft seals. Results confirmed that the UNCD-coated seals exhibited neither measurable wear nor any leakage during long-duration tests that took 21 days to complete. In addition, the UNCD coatings reduced the frictional torque for seal rotation by five to six times compared with the uncoated seals. This work promises to lead to rotating shaft seals with much improved service life, reduced maintenance cost, reduced leakage of environmentally hazardous materials, and increased energy savings. This technology may also have many other tribological applications involving rolling or sliding contacts.

  11. 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.

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

    NASA Astrophysics Data System (ADS)

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

    2010-12-01

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

  13. 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.

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

    NASA Astrophysics Data System (ADS)

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

    2015-06-01

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

  15. 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 [Department of Physics, Tamkang University, Tamsui, Taiwan 251 (China); Sundaravel, Balakrishnan [Materials Science Group, Indira Gandhi Centre for Atomic Research, Kalpakkam 603102 (India); Amirthapandian, Sankarakumar [Materials Science Group, Indira Gandhi Centre for Atomic Research, Kalpakkam 603102 (India); Institut fuer Halbleiteroptik und Funktionelle Grenzflaechen, Universitaet Stuttgart, Allmandring 3, 70569 Stuttgart (Germany)

    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.

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

    DOEpatents

    Krauss, Alan R. (Naperville, IL); Gruen, Dieter M. (Downers Grove, IL); Pellin, Michael J. (Naperville, IL); Auciello, Orlando (Bolingbrook, IL)

    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.

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

    DOEpatents

    Krauss, Alan R. (Naperville, IL); Gruen, Dieter M. (Downers Grove, IL); Pellin, Michael J. (Naperville, IL); Auciello, Orlando (Bolingbrook, IL)

    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.

  18. 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.

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

    NASA Astrophysics Data System (ADS)

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

    2013-06-01

    The potential of utilizing the ultra-nanocrystalline (UNCD) films for detecting the Au-ion irradiation was investigated. When the fluence for Au-ion irradiation is lower than the critical value (fc = 5.0 × 1012 ions/cm2) the turn-on field for electron field emission (EFE) process of the UNCD films decreased systematically with the increase in fluence that is correlated with the increase in sp2-bonded phase (?*-band in EELS) due to the Au-ion irradiation. The EFE properties changed irregularly, when the fluence for Au-ion irradiation exceeds this critical value. The transmission electron microscopic microstructural examinations, in conjunction with EELS spectroscopic studies, reveal that the structural change preferentially occurred in the diamond-to-Si interface for the samples experienced over critical fluence of Au-ion irradiation, viz. the crystalline SiC phase was induced in the interfacial region and the thickness of the interface decreased. These observations implied that the UNCD films could be used as irradiation detectors when the fluence for Au-ion irradiation does not exceed such a critical value.

  20. Thermal conductivity of nitrogenated ultrananocrystalline diamond films M. Shamsa,1,a

    E-print Network

    , polycrystalline diamond PCD , diamondlike carbon DLC , carbon nanotubes, and single-layer graphene, have recently-resistive coatings, optical win- dows, surface acoustic-wave devices, heat spreaders, and field-emission flat panel

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

    SciTech Connect

    Panda, Kalpataru, E-mail: panda@afm.eei.eng.osaka-u.ac.jp, E-mail: phy.kalpa@gmail.com; Inami, Eiichi; Sugimoto, Yoshiaki [Graduate School of Engineering, Osaka University, 2-1, Yamada-Oka, Suita, Osaka 565-0871 (Japan); Sankaran, Kamatchi J.; Tai, Nyan Hwa [Department of Materials Science and Engineering, National Tsing Hua University, Hsinchu 30013, Taiwan (China); Lin, I-Nan, E-mail: inanlin@mail.tku.edu.tw [Department of Physics, Tamkang University, Tamsui 251, Taiwan (China)

    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/?m with high EFE current density of 5.08?mA/cm{sup 2} at an applied field of 7.0?V/?m. 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.

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

    NASA Astrophysics Data System (ADS)

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

    2010-01-01

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

  3. Hydrogenation Effects of Ultrananocrystalline Diamond Detected by X-ray Absorption Near Edge Structure and Raman Spectroscopy

    NASA Astrophysics Data System (ADS)

    Ray, Sekhar C.; Erasmus, Rudolph M.; Tsai, H. M.; Pao, C. W.; Lin, I.-N.; Pong, W. F.

    2012-09-01

    Nitrogen-doped ultrananocrystalline diamond (UNCD) thin films functionalized with H2 are significantly affected by the sp2 hybridized carbon defects that are detected and analyzed using X-ray absorption near edge structure (XANES) and Raman spectroscopy using two different excitation wavelengths. The XANES and Raman results provide evidence for the presence of aromatic hydrocarbons and sp2 amorphous matrix in the grain boundaries when UNCD films are functionalized with H2. These hydrocarbons increase on hydrogenation leading to a decrease of the sp2-carbon defects (?* C=C bond) and an increase of sp3-carbon (?* C-C bond). This sp3-carbon (?* C-C bond) is evidently responsible for UNCD crystallites existence in the film structure and hence change the structural integrity, electronic structure, electrical and bonding properties.

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

    PubMed

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

    2015-04-15

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

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

    NASA Astrophysics Data System (ADS)

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

    2015-04-01

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

  6. 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: nhtai@mx.nthu.edu.tw, E-mail: inanlin@mail.tku.edu.tw [Department of Materials Science and Engineering, National Tsing-Hua University, Hsinchu 300, Taiwan (China); Panda, K.; Sundaravel, B. [Materials Science Group, Indira Gandhi Centre for Atomic Research, Kalpakkam 603 102 (India); Lin, I. N., E-mail: nhtai@mx.nthu.edu.tw, E-mail: inanlin@mail.tku.edu.tw [Department of Physics, Tamkang University, Tamsui 251, Taiwan (China)

    2014-02-14

    Copper ion implantation and subsequent annealing at 600?°C achieved high electrical conductivity of 95.0 (?cm){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/?m and high EFE current density of 3.60?mA/cm{sup 2} at an applied field of 8.0?V/?m.

  7. 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. [Graduate Institute of Electro-Optical Engineering and Department of Electronic Engineering, National Taiwan University of Science and Technology, Taipei 106, Taiwan (China); Sankaran, K. J.; Tai, N. H. [Department of Materials Science and Engineering, National TsingHua University, Hsinchu 300, Taiwan (China); Dong, C. L. [Scientific Research Division, National Synchrotron Radiation Research Center, Hsinchu 300, Taiwan (China); Lin, I. N., E-mail: inanlin@mail.tku.edu.tw [Department of Physics, Tamkang University, Tamsui 251, Taiwan (China)

    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.

  8. High density plasma etching of ultrananocrystalline diamond films in O2/CF4 and O2/SF6 inductively coupled plasmas

    NASA Astrophysics Data System (ADS)

    Park, Jong Cheon; Kim, Seong Hak; Kim, Tae Gyu; Kim, Jin Kon; Cho, Hyun; Lee, Byeong Woo

    2015-03-01

    Inductively coupled plasma etching of ultrananocrystalline diamond (UNCD) films was performed in O2/CF4 and O2/SF6 discharges. Higher etch rates were produced for the O2/SF6 discharges and the films etched in the 10O2/5CF4 discharges retained smooth surface morphology similar to the unetched control sample. Al mask showed a good etch selectivity to the UNCD for both plasma chemistries and highly anisotropic pattern transfer with a vertical sidewall profile was achieved.

  9. Origin of Ultralow Friction and Wear in Ultrananocrystalline Diamond A. R. Konicek,1

    E-print Network

    Sawyer, Wallace

    carbon [6]. The significant energy barrier to convert diamond to graphite or amorphous carbon (1:0 eV=atom) [7] may be lowered by shear, frictional heating, and oxygen and water vapor. However, passivation many of the properties of diamond [11,12]. UNCD films 1 m thick were deposited onto silicon flats

  10. 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.

  11. Heteroepitaxial Ir layers on diamond

    NASA Astrophysics Data System (ADS)

    Martovitsky, V. P.; Evlashin, S. A.; Suetin, N. V.; Khmelnitsky, R. A.

    2011-06-01

    Ir layers were deposited on single-crystal diamond using magnetron sputtering at substrate temperatures ranging from 830 to 1150 °C. The grown films have high adhesion to diamond and a low surface roughness Rq = 4-6 nm according to the AFM measurements. Crystalline perfection of Ir layers was investigated using x-ray diffraction and heteroepitaxial growth of Ir on diamond was confirmed. Because the lattice parameters of Ir and diamond are significantly different (7.65%) and because the deposition temperature of Ir is low in comparison with its melting point (2443 °C), diffraction reflections of the films are similar to analogous reflections of diamond, but wider. The films consist of elongated crystallites of length 10-100 nm. By broadening the reciprocal lattice points, we conclude that the level of microstresses in the Ir films increases as the substrate temperature during deposition of Ir films on the (0 0 1) diamond substrate increases, and that the level of microstresses decreases for the films on the (0 1 1) substrate. Simultaneously, the misorientation of Ir crystallites on the (0 1 1) substrate also decreases with increasing temperature.

  12. Ultrananocrystalline Diamond Film as a Wear-Resistant and Protective Coating for Mechanical Seal Applications

    Microsoft Academic Search

    A. V. Sumant; A. R. Krauss; D. M. Gruen; O. Auciello; A. Erdemir; M. Williams; A. F. Artiles; W. Adams; Flowserve Corp

    2005-01-01

    Mechanical shaft seals used in pumps are critically important to the safe operation of the paper, pulp, and chemical process industry, as well as petroleum and nuclear power plants. Specifically, these seals prevent the leakage of toxic gases and hazardous chemicals to the environment and final products from the rotating equipment used in manufacturing processes. Diamond coatings have the potential

  13. Surface functionalization of ultrananocrystalline diamond using atom transfer radical polymerization (ATRP) initiated by

    E-print Network

    Paris-Sud XI, Université de

    to perform SI-ATRP from undoped diamond films produced by microwave plasma assisted chemical vapour such as polymer coatings, molecular junctions in electronic circuits, and the detection of molecules of biomedical- chemically reduced on glassy carbon (GC) and iron [8]. The resulting ­C6H4­CH(CH3)­Br group (1) grafted onto

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

    NASA Astrophysics Data System (ADS)

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

    2010-08-01

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

  15. 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: inanlin@mail.tku.edu.tw, E-mail: nhtai@mse.nthu.edu.tw [Department of Materials Science and Engineering, National Tsing Hua University, Hsinchu 300, Taiwan (China); Huang, B. R.; Saravanan, A. [Graduate Institute of Electro-Optical Engineering and Department of Electronic Engineering, National Taiwan University of Science and Technology, Taipei 106, Taiwan (China); Lin, I. N., E-mail: inanlin@mail.tku.edu.tw, E-mail: nhtai@mse.nthu.edu.tw [Department of Physics, Tamkang University, Tamsui 251, Taiwan (China)

    2014-10-28

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

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

    SciTech Connect

    Auciello, O.; Sumant, A. V.; Hiller, J.; Kabius, B.; Ma, Z.; Srinivasan, S. (Center for Nanoscale Materials); ( MSD); (Univ. of Wisconsin at Madison); (INTEL)

    2008-12-01

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

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

    NASA Astrophysics Data System (ADS)

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

    2014-11-01

    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.

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

    EPA Science Inventory

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

  19. Field emission characteristics of 2D hole accumulation layer on H-terminated CVD diamond

    Microsoft Academic Search

    T. Yamada; C. E. Nebel; S. Shikata

    2009-01-01

    Field emission properties from 2D-hole accumulation layers on H-terminated undoped intrinsic CVD diamonds were measured. We also measured field emission properties of pand n-type semiconducting diamonds with H-terminations. Plateau in field emission properties of undoped intrinsic diamond were observed, while no pand n-type diamonds showed continuous increase of emission currents. It was considered that the discrete energy levels of hole

  20. Diamond Deposition on WC/Co Alloy with a Molybdenum Intermediate Layer

    NASA Astrophysics Data System (ADS)

    Liu, Sha; Yu, Zhi-Ming; Yi, Dan-Qing

    It is known that in the condition of chemical vapor deposition (CVD) diamond process, molybdenum is capable of forming carbide known as the "glue" which promotes growth of the CVD diamond, and aids its adhesion by (partial) relief of stresses at the interface. Furthermore, the WC grains are reaction bonded to the Mo2C phase. Therefore, molybdenum is a good candidate material for the intermediate layer between WC-Co substrates and diamond coatings. A molybdenum intermediate layer of 1-3 ?m thickness was magnetron sputter-deposited on WC/Co alloy prior to the deposition of diamond coatings. Diamond films were deposited by hot filament chemical vapor deposition (HFCVD). The chemical quality, morphology, and crystal structure of the molybdenum intermediate layer and the diamond coatings were characterized by means of SEM, EDX, XRD and Raman spectroscopy. It was found that the continuous Mo intermediate layer emerged in spherical shapes and had grain sizes of 0.5-1.5 ?m after 30 min sputter deposition. The diamond grain growth rate was slightly slower as compared with that of uncoated Mo layer on the WC-Co substrate. The morphologies of the diamond films on the WC-Co substrate varied with the amount of Mo and Co on the substrate. The Mo intermediate layer was effective to act as a buffer layer for both Co diffusion and diamond growth.

  1. Diamonds

    NSDL National Science Digital Library

    Brieske, Joel A.

    2002-01-01

    The first site related to diamonds comes from the American Museum of Natural History entitled The Nature of Diamonds (1). A comprehensive site, visitors can learn about what a diamond is, its related history, mining, industry and technology use, and more. The next site, offered by De Beers Industrial Diamonds (2), offers a history of industrial diamond use as well as a look at their various applications such as saw and wheel grits. The third site, Industrial Diamonds Statistics and Information (3), is maintained by the US Geological Survey. Various publications related to diamonds can be found here, including yearly mineral commodity summaries and mineral yearbooks. Next, a companion Web site to the PBS broadcast "The Diamond Deception" (4) chronicles the efforts to create synthetic diamonds. The site contains the science behind the sparkle, diamonds on other planets, an interactive look inside diamonds, and more. The fifth site comes from HowThingsWork.com that is called How Diamonds Work (5). Descriptions of the origin of diamonds, their properties, famous diamonds, etc., are offered here. Next is The Science of Diamonds (6) site, offered by DiamondCutters.com. Uniquely offered is a description of the diamond cutting process along with other diamond science and history information. From a University of Wisconsin Geology Course Web site comes a photographic gallery called Diamonds (7). Dozens of photographs of diamonds, colored diamonds, and synthetic and diamond simulants can be found here. Lastly, a lesson plan entitled The Hope Diamond Legend (8) is offered by Indiana Academy. Among other things, students can learn that carbon atoms can bond to one another in chains, rings, and branching networks to form a variety of structures, including synthetic polymers, oils, and the large molecules essential to life.

  2. Alumina atomic layer deposition nanocoatings on primary diamond particles using a fluidized bed reactor

    E-print Network

    George, Steven M.

    Alumina atomic layer deposition nanocoatings on primary diamond particles using a fluidized bed]. Atomic layer deposition (ALD) is a nanocoating process that is an ideal method for such an application

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

    DOEpatents

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

    2002-01-01

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

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

    NASA Astrophysics Data System (ADS)

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

    2014-09-01

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

  5. Multimode photoacoustic method for the evaluation of mechanical properties of heteroepitaxial diamond layers

    NASA Astrophysics Data System (ADS)

    Shen, Zhonghua H.; Lomonosov, Alexey M.; Hess, Peter; Fischer, Martin; Gsell, Stefan; Schreck, Matthias

    2010-10-01

    A multimode photoacoustic method was developed for evaluating acoustically thick anisotropic layers, using surface acoustic waves. Such layers support multiple acoustic modes. This complicates the reverse problem, but on the other hand, makes it possible to extract more materials properties. Several mechanical properties of a layer-substrate system, consisting of a 110 ?m thick heteroepitaxial chemical vapor deposited diamond layer on Ir/YSZ (yttria-stabilized zirconia)/Si(001), were evaluated, based on two surface acoustic modes. A dispersive and a nondispersive mode measured in two different crystallographic directions were employed to evaluate the three elastic stiffness coefficients C11, C12, C44, and the mass density of the diamond layer. It is demonstrated that accurate elastic moduli can be determined without special sample preparation, employing the layered system as obtained from the heteroepitaxial diamond growth process.

  6. 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 ?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.

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

    SciTech Connect

    Buijnsters, J. G. [Department of Metallurgy and Materials Engineering, Katholieke Universiteit Leuven, Kasteelpark Arenberg 44, B-3001 Leuven (Belgium); Institute for Molecules and Materials, Radboud University Nijmegen, Heijendaalseweg 135, 6525 AJ Nijmegen (Netherlands); Vazquez, L. [Instituto de Ciencia de Materiales de Madrid (ICMM-CSIC), Cantoblanco, C/Sor Juana Ines de la Cruz 3, 28049 Madrid (Spain); Dreumel, G. W. G. van; Meulen, J. J. ter; Enckevort, W. J. P. van [Institute for Molecules and Materials, Radboud University Nijmegen, Heijendaalseweg 135, 6525 AJ Nijmegen (Netherlands); Celis, J. P. [Department of Metallurgy and Materials Engineering, Katholieke Universiteit Leuven, Kasteelpark Arenberg 44, B-3001 Leuven (Belgium)

    2010-11-15

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

  8. Analysis of coating fracture and substrate plasticity induced by spherical indentors: diamond and diamond-like carbon layers on steel substrates

    Microsoft Academic Search

    J. Michler; E Blank

    2001-01-01

    Hard coatings as diamond or diamond-like carbon (DLC) layers are widely used as protective coatings on metal substrates, such as steel or hard metal. Failure mechanisms of the substrate\\/coating composite are studied in this paper through a parametric elastic-plastic finite element analysis, for the common load case of the indentation of spherical bodies into a layered surface considering a wide

  9. A route to diamond wafers by epitaxial deposition on silicon via iridium/yttria-stabilized zirconia buffer layers

    NASA Astrophysics Data System (ADS)

    Gsell, S.; Bauer, T.; Goldfuß, J.; Schreck, M.; Stritzker, B.

    2004-05-01

    A multilayer structure is presented which allows the deposition of high-quality heteroepitaxial diamond films on silicon. After pulsed-laser deposition of a thin yttria-stabilized zirconia (YSZ) layer on silicon, iridium was deposited by e-beam evaporation. Subsequently, diamond nucleation and growth was performed in a chemical vapor deposition setup. The epitaxial orientation relationship measured by x-ray diffraction is diamond(001)[110]?Ir(001)[110]?YSZ(001) [110]?Si(001)[110]. The mosaicity of the diamond films is about an order of magnitude lower than for deposition directly on silicon without buffer layers and nearly reaches the values reported for single-crystal diamond on Ir/SrTiO3. In the effort towards single-crystal diamond wafers, the present solution offers advantages over alternative growth substrates like large-area oxide single crystals due to the low thermal expansion mismatch.

  10. Effective extraction of photoluminescence from a diamond layer with a photonic crystal.

    PubMed

    Ondic, Lukás; Dohnalová, Katerina; Ledinský, Martin; Kromka, Alexander; Babchenko, Oleg; Rezek, Bohuslav

    2011-01-25

    Diamond-based materials possess many unique properties, one of them being a broad-band visible photoluminescence due to a variety of color centers. However, a high material refractive index makes the extraction of photoluminescence (PL) from a diamond layer inefficient. In this paper, we show that by periodical nanopatterning of the film's surface into a form of two-dimensional photonic crystal, the extraction of PL can be strongly enhanced within the whole visible spectrum compared to the extraction of PL in a pristine or randomly nanopatterned film. On the basis of theoretical calculations, enhancement is shown to be due to the photonic crystal effect, including efficient coupling of an excitation laser into the diamond. PMID:21189027

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

    NASA Astrophysics Data System (ADS)

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

    2015-06-01

    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.

  12. Diamond nucleation on iridium buffer layers and subsequent textured growth: A route for the realization of single-crystal diamond films

    NASA Astrophysics Data System (ADS)

    Schreck, M.; Hörmann, F.; Roll, H.; Lindner, J. K. N.; Stritzker, B.

    2001-01-01

    It is shown that diamond nucleation on iridium buffer layers followed by an appropriate textured-growth step offers a viable way to realize single-crystal diamond films. Bias-enhanced nucleation on iridium layers results in heteroepitaxial diamond films with highly improved alignment. By a subsequent textured-growth step, the mosaicity can be further reduced for tilt as well as for twist in sharp contrast to former experiments using silicon substrates. Minimum values of 0.17° and 0.38° have been measured for tilt and twist, respectively. Plan view transmission electron microscopy of these films shows that, for low thicknesses (0.6 ?m and 8 ?m), the films are polycrystalline, consisting of a closed network of grain boundaries. In contrast, at the highest thickness (34 ?m) most of the remaining structural defects are concentrated in bands of limited extension. The absence of an interconnected network of grain boundaries shows that the latter films are no longer polycrystalline.

  13. Effect of a buffer layer on the properties of UV photodetectors based on a ZnO/diamond film structure

    NASA Astrophysics Data System (ADS)

    Huang, Jian; Wang, Linjun; Xu, Run; Shi, Weimin; Xia, Yiben

    2008-12-01

    In this paper, ZnO films were grown on the nucleation sides of freestanding diamond substrates with and without a ZnO homobuffer layer by the radio-frequency (RF) magnetron sputtering method. The effects of buffer layers on the properties of the ZnO film and UV photodetectors based on a ZnO/freestanding diamond film structure were studied. The experimental results suggested that the buffer layer was helpful in improving the crystalline quality of ZnO/diamond heteroepitaxial films and the electrical property of the ZnO photodetectors was relative to the crystalline quality of ZnO films. For the photodetector based on the ZnO film with a buffer layer, a higher value of photo-responsivity under a 10 V bias voltage and a better time-dependent photocurrent characteristic were obtained.

  14. Preparation of Diamond-Like Carbon on Ti Film with Tetramethylsilane Buffer Layer

    NASA Astrophysics Data System (ADS)

    Kaneko, Satoru; Horiuchi, Takahiro; Ito, Takeshi; Takagi, Shin-ichi; Yasui, Manabu; Saitoh, Mitsuhiro; Matsunaga, Takashi; Ikenaga, Kaoru; Yasuhara, Shigeo; Mihirogi, Katsuhiro; Kobayashi, Masazumi; Kumagai, Masao; Shimodaira, Eiji; Sudo, Rieko

    2013-11-01

    Diamond-like carbon (DLC) has been applied as a coating material to improve the basic properties of strength, chemical stability, and biocompatibility. In this study, a DLC film was prepared on a titanium (Ti) coating film with tetramethylsilane (TMS) buffer for application in vivo. Although the surface roughness of the Ti film increased with increasing Ti thickness, both TMS and DLC coatings deposited on Ti films resulted in the formation of a flat surface. Observation of the initial growth of the TMS layer indicated that a TMS buffer of more than 50 nm thickness was required for DLC coating even on the flat surface of the Ti thin film.

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

    SciTech Connect

    Bhattacharyya, Somnath, E-mail: Somnath.Bhattacharyya@wits.ac.za [Nano-Scale Transport Physics Laboratory, School of Physics, University of the Witwatersrand, Private Bag 3, WITS 2050, Johannesburg (South Africa); DST/NRF Centre of Excellence in Strong Materials, University of the Witwatersrand, Private Bag 3, WITS 2050, Johannesburg, South Africa and Department of Physics and Astronomy, University of Leeds, Leeds LS2 9JT (United Kingdom); Churochkin, Dmitry [Nano-Scale Transport Physics Laboratory, School of Physics, University of the Witwatersrand, Private Bag 3, WITS 2050, Johannesburg (South Africa)

    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.

  16. Conductive layers in diamond formed by hydrogen ion implantation and annealing

    NASA Astrophysics Data System (ADS)

    Popov, V. P.; Safronov, L. N.; Naumova, O. V.; Nikolaev, D. V.; Kupriyanov, I. N.; Palyanov, Yu. N.

    2012-07-01

    High conductivity is extremely difficult to obtain in diamond due to its wide band gap and low solubility of dopands. The goal of the investigation was to form a conductor inside HPHT synthetic diamond plates with initial high sheet resistivity ?s (˜1012 ?/sq) for 400 ?m thickness. We used metastable character of diamond structures relative to the graphitization of defective layers formed by 50 keV hydrogen molecular ions at high fluence ? = (1-13) × 1016 cm-2 ion implantation. High temperature (HT) (500-1600 °C) and vacuum or high pressure (VP/HP) (3 × 10-3/4 × 109 Pa) thermal annealing were chosen to provide the annealing regimes where the graphitic carbon is the most stable phase. Sheet resistance, dropped down up to nine orders of magnitude (?s ˜ 103 ?/sq), as well as Raman spectroscopy, and AFM measurements were used to determine electrical, optical and geometrical properties of multilayered heterostructures formed in the set of experiments. Temperature dependences of the conductivity show, that after highest fluencies and annealing temperatures the conductivity is quasimetallic and electronic system is above metal-insulator transition (MIT). At lower fluences and/or annealing temperatures the system is under MIT with the transport of charge carriers being well described by variable range hopping (VRH) mechanism with variable decay length of wave function for localized states. Two or three order of magnitude differences in the conductivity in VP and HP annealed samples are attributed with the higher dimensions of graphite nanocrystals in the case of vacuum annealing. This suggestion coincides with Raman spectra and optimum hopping length for carrier jumps in VRH model for conductivity in the buried layers.

  17. Effects of metal buffer layer on characteristics of surface acoustic waves in ZnO/metal/diamond structures

    NASA Astrophysics Data System (ADS)

    Chiang, Yuan-Feng; Sung, Chia-Chi; Ro, Ruyen

    2010-04-01

    The interdigital transducer (IDT)/ZnO/metal/diamond structure is investigated for use in the design surface acoustic wave (SAW) devices in the super-high-frequency (SHF) band. Simulation results indicate that adding a metal buffer layer with a finite thickness significantly increases the coupling coefficient. In the Sezawa mode, the coupling coefficient is 4.71% when an Al interlayer is applied. This coupling coefficient is 75% and 77% larger than those in the IDT/ZnO/diamond and IDT/ZnO/shorted surface/diamond structures, respectively. The results in this study are useful in designing SAW devices using diamond-based structures with a large coupling coefficient in the SHF band.

  18. Hydrogen-free diamond-like carbon deposited by a layer-by-layer technique using PECVD

    SciTech Connect

    Jang, J.; Chung, S.J.

    2000-01-30

    The authors developed a hydrogen-free diamond like carbon (DLC) film by a novel deposition technique of a layer-by-layer technique using plasma enhanced chemical vapor deposition (PECVD) in which a repeated deposition of a thin DLC layer and subsequently CF{sub 4} plasma treatment on its surface have been carried out. The electrical, optical and structural properties of the DLC films deposited depend on the CF{sub 4} plasma exposure time. The hydrogen content is less than 1 at % when the CF{sub 4} plasma exposure time is 140s. Its emission current is much higher and stability is much improved compared with conventional DLC.N-type, hydrogen-free DLC could be obtained by N ion doping or by N{sub 2} gas-phase doping in the CH{sub 4} plasma. The optimum [N{sub 2}]/[CH{sub 4}] flow rate ratio was found to be 9% for the efficient electron emission, at which the onset-field was 7.2 V/{micro}m. The nitrogen gas-phase doped hydrogen-free DLC coating on Mo tip field emitter arrays (FEAs) increased the electron emission current from 160{micro}A to 1.52 mA and improved the stability in electron emission current.

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

    PubMed

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

    2003-07-15

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

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

    DOEpatents

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

    2004-09-21

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

  1. Three-dimensional kinetic Monte Carlo simulations of diamond chemical vapor deposition

    NASA Astrophysics Data System (ADS)

    Rodgers, W. J.; May, P. W.; Allan, N. L.; Harvey, J. N.

    2015-06-01

    A three-dimensional kinetic Monte Carlo model has been developed to simulate the chemical vapor deposition of a diamond (100) surface under conditions used to grow single-crystal diamond (SCD), microcrystalline diamond (MCD), nanocrystalline diamond (NCD), and ultrananocrystalline diamond (UNCD) films. The model includes adsorption of CHx (x = 0, 3) species, insertion of CHy (y = 0-2) into surface dimer bonds, etching/desorption of both transient adsorbed species and lattice sidewalls, lattice incorporation, and surface migration but not defect formation or renucleation processes. A value of ˜200 kJ mol-1 for the activation Gibbs energy, ?G‡etch, for etching an adsorbed CHx species reproduces the experimental growth rate accurately. SCD and MCD growths are dominated by migration and step-edge growth, whereas in NCD and UNCD growths, migration is less and species nucleate where they land. Etching of species from the lattice sidewalls has been modelled as a function of geometry and the number of bonded neighbors of each species. Choice of appropriate parameters for the relative decrease in etch rate as a function of number of neighbors allows flat-bottomed etch pits and/or sharp-pointed etch pits to be simulated, which resemble those seen when etching diamond in H2 or O2 atmospheres. Simulation of surface defects using unetchable, immobile species reproduces other observed growth phenomena, such as needles and hillocks. The critical nucleus for new layer growth is 2 adjacent surface carbons, irrespective of the growth regime. We conclude that twinning and formation of multiple grains rather than pristine single-crystals may be a result of misoriented growth islands merging, with each island forming a grain, rather than renucleation caused by an adsorbing defect species.

  2. Three-dimensional kinetic Monte Carlo simulations of diamond chemical vapor deposition.

    PubMed

    Rodgers, W J; May, P W; Allan, N L; Harvey, J N

    2015-06-01

    A three-dimensional kinetic Monte Carlo model has been developed to simulate the chemical vapor deposition of a diamond (100) surface under conditions used to grow single-crystal diamond (SCD), microcrystalline diamond (MCD), nanocrystalline diamond (NCD), and ultrananocrystalline diamond (UNCD) films. The model includes adsorption of CHx (x = 0, 3) species, insertion of CHy (y = 0-2) into surface dimer bonds, etching/desorption of both transient adsorbed species and lattice sidewalls, lattice incorporation, and surface migration but not defect formation or renucleation processes. A value of ?200 kJ mol(-1) for the activation Gibbs energy, ?G(‡) etch, for etching an adsorbed CHx species reproduces the experimental growth rate accurately. SCD and MCD growths are dominated by migration and step-edge growth, whereas in NCD and UNCD growths, migration is less and species nucleate where they land. Etching of species from the lattice sidewalls has been modelled as a function of geometry and the number of bonded neighbors of each species. Choice of appropriate parameters for the relative decrease in etch rate as a function of number of neighbors allows flat-bottomed etch pits and/or sharp-pointed etch pits to be simulated, which resemble those seen when etching diamond in H2 or O2 atmospheres. Simulation of surface defects using unetchable, immobile species reproduces other observed growth phenomena, such as needles and hillocks. The critical nucleus for new layer growth is 2 adjacent surface carbons, irrespective of the growth regime. We conclude that twinning and formation of multiple grains rather than pristine single-crystals may be a result of misoriented growth islands merging, with each island forming a grain, rather than renucleation caused by an adsorbing defect species. PMID:26049516

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

    SciTech Connect

    Liu, J.; Grierson, D. S.; Notbohm, J.; Li, S.; O'Connor, S. D.; Turner, K. T.; Sumant, A. V.; Neelakantan, N.; Moldovan, N.; Carlisle, J. A.; Jaroenapibal, P.; Carpick, R. W. (Center for Nanoscale Materials); ( PSC-USR); (Univ. of Wisconsin at Madison); (Advanced Diamond Tech.); (Univ. of Pennsylvania)

    2010-01-01

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

  4. RAPID COMMUNICATION: Low reflectance of diamond-like carbon\\/porous silicon double layer antireflection coating for silicon solar cells

    Microsoft Academic Search

    V. M. Aroutiounian; Kh Martirosyan; P. Soukiassian

    2004-01-01

    Reflectance calculations for diamond-like carbon (DLC) antireflection thin-film coatings on porous silicon (PS) have been carried out using the optical matrix approach method. Comparison with the reflectance spectrum obtained for other antireflection coatings shows a much lower reflectance with a larger energy range including the ultraviolet, visible and infrared regions of the solar spectrum for the DLC\\/PS double layer. This

  5. Mosaicity reduction during growth of heteroepitaxial diamond films on iridium buffer layers: Experimental results and numerical simulations

    NASA Astrophysics Data System (ADS)

    Schreck, M.; Schury, A.; Hörmann, F.; Roll, H.; Stritzker, B.

    2002-01-01

    Heteroepitaxial diamond films can be grown by bias enhanced nucleation on iridium buffer layers followed by an appropriate textured-growth step. Unlike epitaxial diamond films on silicon, the mosaicity reduction during textured growth includes tilt as well as twist. We conclude that different mechanisms causing the grain coarsening are working in the two cases. It is shown that the principle of evolutionary selection can be excluded as a decisive mechanism in the present films. Merging of neighboring grains by disclination formation yields an alternative explanation, that can convincingly substantiate the differences between the textured growth on iridium and silicon. From a Monte-Carlo type simulation describing the texture evolution due to merging of grains, a simple functional correlation between grain coarsening and mosaicity reduction is deduced. Comparison between simulation and experiment allows one to estimate the contributions of different processes. Finally, the general significance of the present findings for other materials is discussed.

  6. Diamond as a scaffold for bone growth.

    PubMed

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

    2013-04-01

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

  7. Optical and spin coherence properties of nitrogen-vacancy centers placed in a 100 nm thick isotopically purified diamond layer.

    PubMed

    Ishikawa, Toyofumi; Fu, Kai-Mei C; Santori, Charles; Acosta, Victor M; Beausoleil, Raymond G; Watanabe, Hideyuki; Shikata, Shinichi; Itoh, Kohei M

    2012-04-11

    We have studied optical and spin properties of near-surface nitrogen-vacancy (NV) centers incorporated during chemical vapor phase growth of isotopically purified (12)C single-crystal diamond layers. The spectral diffusion-limited line width of zero-phonon luminescence from the NV centers is 1.2 ± 0.5 GHz, a considerable improvement over that of NV centers formed by ion implantation and annealing. Enhanced spin dephasing times (T(2)* ? 90 ?s, T(2) ? 1.7 ms) due to the reduction of (13)C nuclear spins persist even for NV centers placed within 100 nm of the surface. PMID:22404419

  8. 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. [Optical and Electronic Materials Unit, National Institute for Materials Science (NIMS), 1-1 Namiki, Tsukuba, Ibaraki 305-0044 (Japan); Koide, Y. [Optical and Electronic Materials Unit, National Institute for Materials Science (NIMS), 1-1 Namiki, Tsukuba, Ibaraki 305-0044 (Japan); Nanofabrication Platform, NIMS, 1-2-1 Sengen, Tsukuba, Ibaraki 305-0047 (Japan); Center of Materials Research for Low Carbon Emission, NIMS, 1-1 Namiki, Tsukuba, Ibaraki 305-0044 (Japan)

    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.

  9. Modular design of locally ordered tetrahedral structures: III. Structural mechanism of nonequilibrium fibrous and rough-layer normal growth of diamond crystals

    NASA Astrophysics Data System (ADS)

    Bul'enkov, N. A.; Zheligovskaya, E. A.

    2015-05-01

    Structural mechanisms of nontangential nonequilibrium normal growth of natural and synthetic diamond crystals with a fibrous or layered structure, formed under particularly nonequilibrium conditions, are proposed. It is shown that their growth is based on strained noncrystalline structures rapidly growing in length: 30/11 and 40/9 helices. The fibrous growth of diamond crystals along the <111> and <100> directions occurs according to the helicoidal mechanism, with helicoid axes in the form of 30/11 and 40/9 helices, respectively. Stacks of rough {110} lamellae can be formed via branching of 30/11 helices, which are then overgrown by a crystalline layer. Lamellae with orientation {100}, formed during the growth of diamond and silicon from vapor phase, also grow according to the helicoidal mechanism based on 40/9 helices via the aggregation of helicoids into these lamellae. Due to the complicated internal structure of these diamond crystals, their physical properties differ from those of diamond single crystals grown according to the tangential growth mechanism.

  10. The Release Behavior of Diamond Shocked to 15 Mbar

    NASA Astrophysics Data System (ADS)

    Gregor, M. C.; McCoy, C. A.; Polsin, D. N.; Boehly, T. R.; Meyerhofer, D. D.; Fratanduono, D. E.; Celliers, P. M.

    2014-10-01

    Ultrananocrystalline diamond (UNCD) is used as an ablator material for inertial confinement fusion experiments at the National Ignition Facility. Both the Hugoniot and the release behavior of the UNCD ablators are needed to accurately model the implosion process. The OMEGA laser was used to perform experiments in which two types of high-density carbon released into sample materials with known Hugoniots (quartz, 200 mg/cm3 SiO2 foam, liquid deuterium, and polystyrene). We present preliminary results of the release behavior of both UNCD and single-crystal diamond in the 5- to 15-Mbar regime. Models for the release isentropes of UNCD and single-crystal diamond will be developed using a Mie-Grüneisen equation of state. This material is based upon work supported by the Department of Energy National Nuclear Security Administration under Award Number DE-NA0001944.

  11. Study of optical properties of diamond-like carbon\\/porous silicon antireflective coating layers for multicrystalline silicon solar cell applications

    Microsoft Academic Search

    K. Ait-Hamouda; A. Ababou; M. Ouchabane; N. Gabouze; S. Belhousse; H. Menari; K. Beldjilali

    2007-01-01

    In this work, a study on some optical properties of diamond-like carbon (DLC) films is presented. The DLC films have been deposited by DC discharge plasma-enhanced chemical vapor deposition (PECVD). The deposited layers have been characterized by spectrophotometry, ellipsometry and Fourier transform infrared spectroscopy (FTIR) analysis. The result shows that the C–Si ratio evolves with the DLC thickness to reach

  12. 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.

  13. Development of a synthetic diamond radiation detector with a boron doped CVD diamond contact

    Microsoft Academic Search

    Junichi Kaneko; Masaki Katagiri; Yujiro Ikeda; Takeo Nishitani

    1999-01-01

    A boron doped CVD diamond contact was applied to a diamond radiation detector for suppressing a polarization phenomenon. A boron doped CVD diamond layer was grown on a synthetic type IIa single crystal diamond; it was then used as a contact. The contact was completely free from radiation damage which is unavoidable in a contact made by an ordinary ion

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

    SciTech Connect

    Araújo, D.; Alegre, M. P.; Piñero, J. C. [Dpto Ciencia de los Materiales, Facultad de Ciencias, Universidad de Cádiz, 11510 Puerto Real (Cádiz) (Spain)] [Dpto Ciencia de los Materiales, Facultad de Ciencias, Universidad de Cádiz, 11510 Puerto Real (Cádiz) (Spain); Fiori, A.; Bustarret, E. [Institut Néel, CNRS-Université Joseph Fourier, 25 av. des Martyrs, 38042 Grenoble (France)] [Institut Néel, CNRS-Université Joseph Fourier, 25 av. des Martyrs, 38042 Grenoble (France); Jomard, F. [Groupe d'Etude de la Matière Condensée (GEMaC), UMR 8635 du CNRS, UVSQ, 45 av. des Etats-Unis, 78035 Versailles Cedex (France)] [Groupe d'Etude de la Matière Condensée (GEMaC), UMR 8635 du CNRS, UVSQ, 45 av. des Etats-Unis, 78035 Versailles Cedex (France)

    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.

  15. 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.

  16. NIR and VIS-raman spectroscopy of CVD diamond films

    Microsoft Academic Search

    M. Griesser; M. Grasserbauer; R. Kellner; S. Bohr; R. Haubner; B. Lux

    1995-01-01

    Raman spectroscopy is a widely used method for the analysis of CVD diamond layers, because it enables to distinguish between different carbon phases, such as diamond, graphite, amorphous carbon and nanocrystalline carbon, which are all commonly present in CVD diamond films. A comparison of visible Raman spectroscopy and near-infrared Raman spectroscopy applied to CVD diamond layers on various substrates (Si,

  17. Accepted to Diamond and Related Materials A kinetic model of diamond nucleation and silicon carbide interlayer formation during

    E-print Network

    Dandy, David

    Accepted to Diamond and Related Materials A kinetic model of diamond nucleation and silicon carbide intermediate layers on silicon substrates during nucleation and the early stages of diamond deposition have diffusion of carbon atoms into the silicon carbide layer, and the morphology and orientation of the diamond

  18. 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.

  19. Characterisation of diamond coatings with different morphologies by Raman spectroscopy using various laser wavelengths.

    PubMed

    Rudigier, Moritz; Haubner, Roland

    2012-05-01

    Since the beginning of low-pressure diamond synthesis, Raman spectroscopy has been widely used to identify and characterise the quality of diamonds. The diamond crystal is characterised by a Raman peak at about 1,332 cm(-1). Other peaks are associated with miscellaneous carbon structures, e.g. graphite and amorphous phases. In recent years, both well-faceted crystalline diamonds and nanocrystalline and ultrananocrystalline diamonds have been investigated. For these fine-grained materials, the diamond peak at 1,332 cm(-1) disappears and the intensities of peaks at other wavelengths increase. To study the influence of the Raman laser wavelength, three lasers were used (472.681 nm, blue; 532.1 nm, green; 632.81 nm, red). For well-faceted diamonds, the Raman spectra with blue and green laser light were similar. A shift of the peak maxima and different intensities were observed. With use of the red laser, a strong luminescence peak and low peak intensities for the various carbon-related peaks occurred. When the diamond morphology changes from well-faceted to fine-grained ballas diamond, the spectra are similar for all three lasers. PMID:22362277

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

    NASA Astrophysics Data System (ADS)

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

    2015-06-01

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

  1. AlTiN layer effect on mechanical properties of Ti-doped diamond-like carbon composite coatings

    E-print Network

    Volinsky, Alex A.

    Accepted 11 February 2011 Available online 24 February 2011 Keywords: Interlayer DLC AlTiN Tribology Adhesion Ti/Ti-doped diamond-like carbon (DLC) and Ti/AlTiN/Ti-DLC composite coatings were depositedTiN interlayers have a columnar structure with 50­80 nm grains. The hardness and elastic modulus of Ti/Ti-DLC

  2. Effect of surface treatments on the electronic properties of ultra-nanocrystalline diamond films

    E-print Network

    Chen, Yang-Yuan

    .L. Dong a,b,c , S.S. Chen b,d , J.W. Chiou b,c , Y.Y. Chen a , J.-H. Guo c , H.F. Cheng e , I.N. Lin b , C.L. Chang b, a Institute of Physics, Academia Sinica, Taipei 11529, Taiwan, R.O.C. b Department of Physics, Tamkang Univeristy, Tamsui 25137, Taiwan, R.O.C. c Advanced Light Source, Lawrence Berkeley National

  3. Conflict Diamonds

    NSDL National Science Digital Library

    New from the United Nations, this short, informative site cautions against conflict diamonds, which are defined as "diamonds that originate from areas controlled by forces or factions opposed to legitimate and internationally recognized governments, and are used to fund military action in opposition to those governments." Along with general descriptions of conflict diamonds, the site briefly explains the ways in which the UN, governments, and non-governmental organizations are trying to halt the sale of these gems, including the drafting of a strict "Certificate of Origin" regime which will certify that only legitimate diamonds reach the market. Conflict Diamonds looks at the UN's anti-conflict diamond activity in two specific countries: Angola and Sierra Leone. For more information on Conflict Diamonds, please see the July 27, 2000 Scout Report for Business and Economics.

  4. Laser polishing of diamond plates

    NASA Astrophysics Data System (ADS)

    Pimenov, S. M.; Kononenko, V. V.; Ralchenko, V. G.; Konov, V. I.; Gloor, S.; Lüthy, W.; Weber, H. P.; Khomich, A. V.

    Results are reported on laser polishing of 150-400-?m-thick free-standing diamond films with either a copper vapor laser (510 nm wavelength) or an ArF excimer laser (193 nm wavelength). Studies were focused on three particular goals. First, we aimed at a choice of optimum conditions for laser polishing of thick diamond films. It was shown that the laser polishing conditions and the resulting surface roughness were controlled by varying the angle of incidence of a scanning laser beam and by polishing time. Second, the laser ablation technique was applied to remove a defective layer from the ``substrate'' side of the diamond plates in order to reduce optical losses due to absorption in this layer. Third, the structure of the laser-graphitized diamond surface was studied using UV, visible, and IR optical spectroscopy techniques in the course of the ``step-by-step'' oxidative removal of the graphitic layer with increasing temperature of the oxidation in ambient air. Once the graphitic layer was removed, the optical transmission in the UV-visible-IR spectral range of the diamond films polished under optimum conditions was measured and compared with the optical transmission of the mechanically polished diamond films. It was shown that the optical quality (in the long-wave infrared region) of the laser-polished diamond plates was sufficient to reach the transmittance value very close to the theoretical limit.

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

    SciTech Connect

    Daicho, Akira, E-mail: notevayas-tales@ruri.waseda.jp; Saito, Tatsuya; Kurihara, Shinichiro; Kawarada, Hiroshi, E-mail: kawarada@waseda.jp [School of Science and Engineering, Waseda University, 3-4-1 Okubo, Shinjuku-ku, Tokyo 169-8555 (Japan); Hiraiwa, Atsushi [Institute for Nanoscience and Nanotechnology, Waseda University, 513 Waseda-tsurumaki, Shinjuku, Tokyo 162-0041 (Japan)

    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.

  6. Extreme synthesis and chemical doping of diamond aerogel

    NASA Astrophysics Data System (ADS)

    Pauzauskie, Peter J.; Crowhurst, Jonathan C.; Worsley, Marcus A.; Laurence, Ted A.; Wang, Yinmin; Kilcoyne, A. L. D.; Weber, Peter K.; Willey, Trevor M.; Visbeck, Kenneth S.; Evans, William J.; Satcher, Joe H., Jr.

    2010-03-01

    Amorphous carbon aerogels have attracted much interest in recent years due to their low density, large intrinsic surface areas (>1000 m^2/g), large pore volume, low dielectric constant, and high strength. We use high-pressure (˜20 GPa) laser-heating (>600 C) within a diamond anvil cell (DAC) to convert the amorphous network of a low-density (40mg/cc) carbon aerogel into an ultrananocrystalline diamond aerogel. Photoluminescence spectroscopy and confocal time-correlated single-photon counting indicate the recovered material contains both negatively-charged and neutral nitrogen-vacancy (NV) complexes. Synchrotron scanning transmission x-ray microscopy (STXM) is used to compare the carbon electronic density-of-states of the amorphous starting material with the recovered diamond aerogel with ˜100 meV energy resolution. Finally, we use nanoscale secondary ion mass spectrometry to investigate doping of the resorcinol-formaldehyde starting material with the aim of chemically tuning heteroatomic point defects within this diamond material system.

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

    NASA Astrophysics Data System (ADS)

    Feldman, Albert; Holly, Sandor

    1991-12-01

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

  8. Diamond photonics

    Microsoft Academic Search

    Igor Aharonovich; Andrew D. Greentree; Steven Prawer

    2011-01-01

    Diamond, a material marvelled for its strength, beauty and perfection, was first used to polish stone axes in Neolithic times. This most ancient of materials is now being touted by many as the ideal platform for quantum-age technologies. In this Review, we describe how the properties of diamond match the requirements of the 'second quantum revolution'. We also discuss recent

  9. Diamond pixel modules

    NASA Astrophysics Data System (ADS)

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

    2011-04-01

    With the commissioning of the LHC in 2010 and upgrades expected in 2015, ATLAS and CMS are planning to upgrade their innermost tracking layers with radiation hard technologies. Chemical Vapor Deposition diamond has been used extensively in beam conditions monitors as the innermost detectors in the highest radiation areas of BaBar, Belle, CDF and all LHC experiments. This material is now being considered as a sensor material for use very close to the interaction region where the most extreme radiation conditions exist. Recently the RD42 collaboration constructed, irradiated and tested polycrystalline and single-crystal chemical vapor deposition diamond sensors to the highest fluences expected at the super-LHC. We present beam test results of chemical vapor deposition diamond up to fluences of 1.8×1016 protons/cm2 illustrating that both polycrystalline and single-crystal chemical vapor deposition diamonds follow a single damage curve. We also present beam test results of irradiated complete diamond pixel modules.

  10. CHAIRMAN'S CIRCLE DIAMOND CIRCLE

    E-print Network

    Walker, Lawrence R.

    CHAIRMAN'S CIRCLE DIAMOND CIRCLE PRESIDENTIAL CIRCLE EXECUTIVE CIRCLE OUR SPONSORS Sponsoring Host Scarff CONFERENCE SPONSORS DIAMOND CIRCLE The Venetian | The Palazzo DIAMOND CIRCLE M Resort Spa Casino

  11. Superconducting Nanowire Single Photon Detector on Diamond

    E-print Network

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

    2014-01-17

    Superconducting nanowire single photon detectors (SNSPDs) are fabricated directly on diamond substrates and their optical and electrical properties are characterized. Dark count performance and photon count rates are measured at varying temperatures for 1310nm and 632nm photons. The procedure to prepare diamond substrate surfaces suitable for the deposition and patterning of thin film superconducting layers is reported. Using this approach, diamond substrates with less than 300pm RMS surface roughness are obtained.

  12. Diamond Nanophotonics

    E-print Network

    Igor Aharonovich; Elke Neu

    2014-08-23

    The burgeoning field of nanophotonics has grown to be a major research area, primarily because of the ability to control and manipulate single quantum systems (emitters) and single photons on demand. For many years studying nanophotonic phenomena was limited to traditional semiconductors (including silicon and GaAs) and experiments were carried out predominantly at cryogenic temperatures. In the last decade, however, diamond has emerged as a new contender to study photonic phenomena at the nanoscale. Offering plethora of quantum emitters that are optically active at room temperature and ambient conditions, diamond has been exploited to demonstrate super-resolution microscopy and realize entanglement, Purcell enhancement and other quantum and classical nanophotonic effects. Elucidating the importance of diamond as a material, this review will highlight the recent achievements in the field of diamond nanophotonics, and convey a roadmap for future experiments and technological advancements.

  13. 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 ?m in a short time using a deposition rate of 70 ± 10 nm min-1. Rutherford backscattering spectrometry results showed that DLC coatings contain hydrogen up to 30 ± 3% indicating deposition of hydrogenated DLC (a-C:H) coatings. Coatings with good adhesion are achieved when using a multiple energy implantation regime. Raman spectroscopy results suggest slightly larger disordered DLC layers when using low ion energy, indicating higher sp3 bonds in DLC coatings. The results show that commercially interesting coatings can be achieved in short time.

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

    PubMed

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

    2014-08-01

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

  15. High-density fluids and the growth of monocrystalline diamonds

    NASA Astrophysics Data System (ADS)

    Weiss, Y.; Kiflawi, I.; Davies, N.; Navon, O.

    2014-09-01

    The chemical nature and composition of the growth medium of monocrystalline (MC) diamonds is still a matter of debate, partially because carbonate-bearing high-density fluids (HDFs) that are common in fibrous diamonds have not been found in MC diamonds. Here we report the first finding of HDF microinclusions in a MC octahedral diamond from Finsch, South Africa and in the MC octahedral core of a coated diamond from Kankan, Guinea; both diamonds carry nitrogen in B-centers. Numerous microinclusions in diamond Finsch_2a_cap1 are restricted to two thin layers parallel to the (1 1 1) face, ?20 and 200 ?m from the diamond rim. Low-Mg carbonatitic HDFs are found along the inner layer while the outer layer trapped saline compositions. The major and trace element compositions of the inclusions and their infrared spectra are highly similar to those of microinclusions found in fibrous diamonds. A few isolated microinclusions of saline compositions are scattered around a sulfide inclusion in the center of the octahedral core of diamond ON-KAN-383. This evidence for the involvement of oxidized fluids in the formation of MC diamonds adds to previous reports on the antiquity of HDFs in fibrous diamonds, the presence of carbonate and halide phases in inclusions in MC diamonds and the similarity of trace element pattern of a MC diamond to those of low-Mg carbonatitic HDF in fibrous diamonds. In addition, we show that the interaction of HDFs with depleted garnets can produce sinusoidal REE patterns which are one of the primary features of lherzolitic and harzburgitic garnet inclusions in MC diamonds. Together, these observations suggest that HDFs are involved in the formation of many types of diamonds from the Archaean to the Phanerozoic. HDFs are trapped in large quantities during rapid, fibrous growth, but must also be present during the growth of many MC diamonds.

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

    PubMed

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

    2011-06-15

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

  17. Diamond fiber field emitters

    DOEpatents

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

    1996-01-01

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

  18. Advanced Diamond Anvil Techniques (Customized Diamond Anvils)

    SciTech Connect

    Weir, S

    2009-02-11

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

  19. '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.

  20. Diamond-coated ZnS for improved erosion resistance

    NASA Astrophysics Data System (ADS)

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

    1997-06-01

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

  1. 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.

  2. Superconducting nanowire single photon detector on diamond

    SciTech Connect

    Atikian, Haig A.; Burek, Michael J.; Choy, Jennifer T.; Lon?ar, Marko, E-mail: loncar@seas.harvard.edu [School of Engineering and Applied Sciences, Harvard University, 33 Oxford Street, Cambridge, Massachusetts 02138 (United States); Eftekharian, Amin; Jafari Salim, A.; Hamed Majedi, A. [University of Waterloo, 200 University Ave West, Waterloo, Ontario N2L 3G1 (Canada); Institute for Quantum Computing, University of Waterloo, 200 University Ave West, Waterloo, Ontario N2L 3G1 (Canada)

    2014-03-24

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

  3. Diamond growth on polycrystalline nickel silicides

    NASA Astrophysics Data System (ADS)

    Rey, S.; Hommet, J.; Schmerber, G.; Le Normand, F.

    2000-06-01

    Nickel silicides such as NiSi 2 and Ni 3Si display adequate structural and chemical properties for the heteroepitaxial HFCVD growth of diamond on it. Therefore, polycrystalline NiSi 2 and Ni 3Si were synthesized and their behavior for diamond growth were compared with polycrystalline references of Ni and Si samples. The quality of diamond particles grown on NiSi 2 and Ni 3Si as well as Si substrates is fairly increased in comparison with the quality of diamond grown on Ni substrates. This is interpreted from XPS and AES surface characterizations, by the depletion on Ni 3Si of the graphitic layer observed on nickel which competes with diamond growth. Both on Si-rich NiSi 2 silicide and silicon, a carbide is found as a precursor phase to diamond.

  4. Epitaxial growth of europium monoxide on diamond

    NASA Astrophysics Data System (ADS)

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

    2013-11-01

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

  5. Diamond nucleation under bias conditions

    NASA Astrophysics Data System (ADS)

    Stöckel, R.; Stammler, M.; Janischowsky, K.; Ley, L.; Albrecht, M.; Strunk, H. P.

    1998-01-01

    The so-called bias pretreatment allows the growth of heteroepitaxial diamond films by plasma chemical vapor deposition on silicon (100) surfaces. We present plan-view and cross-sectional transmission electron micrographs of the substrate surface at different phases of the bias pretreatment. These observations are augmented by measurements of the etch rates of Si, SiC, and different carbon modifications under plasma conditions and the size distribution of oriented diamond crystals grown after bias pretreatment. Based on these results a new model for diamond nucleation under bias conditions is proposed. First, a closed layer of nearly epitaxially oriented cubic SiC with a thickness of about 10 nm is formed. Subplantation of carbon into this SiC layer causes a supersaturation with carbon and results in the subcutaneous formation of epitaxially oriented nucleation centers in the SiC layer. Etching of the SiC during the bias pretreatment as well as during diamond growth brings these nucleation centers to the sample surface and causes the growth of diamonds epitaxially oriented on the Si/SiC substrate.

  6. 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.

  7. Optical properties of diamond

    Microsoft Academic Search

    Michael E. Thomas; William J. Tropf

    1994-01-01

    Because of its excellent thermal-mechanical properties, diamond is a promising infrared window material. With the development of chemical vapor deposition (CVD) diamond technology, diamond windows and domes are becoming a practical reality. The infrared transmittance of type IIa and CVD diamond was characterized as a function of temperature, and the room-temperature ultraviolet transmittance of type IIa diamond was also measured.

  8. High temperature diffusion chromizing as a successful method for CVD-diamond coating of steel

    Microsoft Academic Search

    S. Schwarz; Y. Musayev; S. M. Rosiwal; C. Schaufler; R. F. Singer; H. Meerkamm

    2002-01-01

    Using chromium carbide intermediate layers, generated by a novel diffusion process, well adherent CVD-diamond coatings were deposited onto large surfaces of 41Cr4 steel substrates. The chromium carbide intermediate layers feature excellent barrier properties against the diffusion of iron from the substrate and against the diffusion of carbon from the gas phase during the diamond deposition. The diamond coatings show also

  9. Growth of single crystal diamond

    NASA Astrophysics Data System (ADS)

    Regmi, Murari

    The subject of the research presented in this dissertation is the growth of single crystal diamond by microwave plasma chemical vapor deposition (CVD). Both heteroepitaxial and homoepitaxial growth methods have been examined, with emphasis on producing large diamond crystals of high structural and chemical perfection. By heteroepitaxy, epitaxial growth on a foreign substrate, diamond was grown on (001) Ir thin-film epitaxial buffer layers deposited on (001) strontium titanate (SrTiO3) by DC magnetron sputtering. To nucleate diamond on Ir, the Ir surface was bombarded with low energy ions extracted from the hydrocarbon plasma, a process known as DC biasing or bias-enhanced nucleation. Since this critical process is poorly understood, attention was paid to the spatial and temporal evolution of the Ir surface during the bias treatment. It was discovered that the biased Ir surface is etched on a surprisingly short time scale during which highly correlated nanopillars, 3-4 nm in height with mean separation 15 nm, emerge. The etching process is spatially non-uniform, propagating from substrate center to substrate edge in minutes. Diamond grew on Ir without an intervening phase. Lattice images revealed that interfacial strain from the 7% Ir-diamond lattice mismatch is largely relieved by misfit dislocations within 1 nm of the interface. It is suggested that the high nucleation density obtained with specific bias conditions is associated with the roughened Ir surface. To grow heteroepitaxial diamond as thick films, a two-step growth method was explored. This process involved the transfer of a thin heteroepitaxial diamond film, still attached to a substrate, to a second reactor where high growth rate conditions were possible. Characterization of films grown by this approach showed that the resulting diamond had much lower levels of internal strain, suggesting that the process could be used to grow diamond crystals of structural quality similar to natural diamond. In homoepitaxy, epitaxial growth on a substrate of the same material, diamond was deposited by CVD directly onto high-pressure, high-temperature Type Ib diamond substrates. Methods for removing substrate surface damage, as well as other imperfections, were devised by use of plasma etching. The characteristics and statistics of pits formed during etching were studied. Diamond growth methods were developed with the aim of minimizing the formation of various structural and chemical defects. To accomplish this, several growth parameters were varied, including substrate temperature, feed gas concentration, growth rate, substrate surface, microwave power, and reactor geometry. Regions of parameter space were found in which the diamond (001) surface remained smooth during growth, and complete suppression of instabilities that create hillocks or non-epitaxial crystallites was demonstrated. A great deal of information was obtained by interrupting growth, removing the crystal from the reactor for optical inspection, and then resuming the process with no apparent negative effects. Diamond crystals were grown on 3 x 3 mm2 substrates with thicknesses greater than 0.5 mm. The chemical purity of the crystals was such that it was impossible to observe signatures of substitutional nitrogen at the ppm level.

  10. Plasma assisted conversion of carbon fibers to diamond

    NASA Astrophysics Data System (ADS)

    Ismat Shah, S.; Walls, D. J.; Waite, Matthew M.; Guerin, D.

    1995-11-01

    Pitch based carbon fibers have been converted to diamond through exposure to a pure hydrogen microwave plasma. The conversion depends strongly on the process pressure. At low pressure only part of the surface of the fiber was converted to diamond, however under optimum conditions a thick continuous diamond layer could be obtained. The carbon conversion efficiency to form diamond at the high pressure was at least an order of magnitude higher than is obtained in a regular CH4+H2 plasma assisted diamond deposition.

  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, fracture is studied mainly by indentation or mechanical breaking of freestanding films, e.g., by bending or bursting. It is very difficult to study the fracture mechanism, discriminating between tensile, shear, and tearing stress components (mode I-III fracture) with these partly semiquantitative methods. A novel ultrasonic laser-based technique using short nonlinear surface acoustic wave pulses, developing shock fronts during propagation, has recently been employed to study mode-resolved fractures of single-crystal silicon. This method allows the generation of finite cracks and the evaluation of the fracture strength for well-defined crystallographic configurations. Laser ultrasonics reaches the critical stress at which real diamond fails and therefore can be employed as a new tool for mechanistic studies of the fracture behavior of CVD diamond in the future.

  12. 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.

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

    DOEpatents

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

    1997-01-01

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

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

    E-print Network

    Boyer, Edmond

    Boron concentration profiling by high angle annular dark field-scanning transmission electron 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 1020 cmÀ3 were quantitatively

  15. Thermal improvement of InP wire photonic crystal laser on silicon by addition of Diamond Nanoparticles in polymer bonding layer

    Microsoft Academic Search

    A. Bazin; Y. Halioua; P. Monnier; F. Bordas; T. Karle; S. Perruchas; T. Gacoin; H. Girard; I. Sagnes; G. Roelkens; R. Raj; F. Raineri

    2010-01-01

    Diamond Nanoparticles are added to BCB polymer in order to increase the thermal dissipation of InP-based photonic crystal cavity laser bonded on silicon. Optical measurement are performed to evaluate the enhancement of the heat sinking with nanoparticles density.

  16. Optical Absorption of N-Doped Diamond

    E-print Network

    Washington at Seattle, University of - Department of Physics, Electroweak Interaction Research Group

    Optical Absorption of N- Doped Diamond Presentation by: Winnie H. Liang INT REU: University Diamond Structures · Results · Conclusion #12;Motivation Diamonds... · are fascinating · (natural Colored Diamonds · can be rare and expensive Blue Diamond (Hope Diamond) What about yellow colored diamond

  17. Attempts to p-Dope Ultrananocrystalline Diamond Films in a Hot Filament Reactor Paul William May and Matthew Hannaway

    E-print Network

    Bristol, University of

    hydrolysed to boric acid on exposure to air. These results are rationalised using a model for UNCD growth. With 40,000 ppm of B2H6, crystals of boric oxide were found on the substrate surface, which slowly

  18. Diamond/Ir/SrTiO3: A material combination for improved heteroepitaxial diamond films

    NASA Astrophysics Data System (ADS)

    Schreck, M.; Roll, H.; Stritzker, B.

    1999-02-01

    Heteroepitaxial diamond films with highly improved alignment have been realized by using the layer sequence diamond/Ir/SrTiO3(001). In a first step, epitaxial iridium films with a misorientation <0.2° have been deposited on polished SrTiO3(001) surfaces by electron-beam evaporation. Using the bias-enhanced nucleation procedure in microwave plasma chemical vapor deposition, epitaxial diamond grains with a density of 109cm-2 could be nucleated on these substrates. The orientation relationship for this layer system is diamond(001)[100]?Ir(001)[100]?SrTiO3(001)[100]. The polar and azimuthal spread for the crystal orientation of a 600 nm thick diamond film is about 1° in each case. For an 8 ?m thick diamond film a significantly improved alignment of 0.34° (polar) and 0.65° (azimuthal) has been measured. The latter values, which to the best of our knowledge are superior to those of all former reports about epitaxial diamond films on alternative substrates, indicate the high potential of the substrate Ir/SrTiO3 for the realization of large-area single-crystalline diamond films.

  19. Diamond Industry Resolves to Ban "Conflict Diamonds"

    NSDL National Science Digital Library

    Missner, Emily D.

    The 29th World Diamond Congress met last week from July 16 to July 19 in Antwerp, Belgium where the issue of "conflict diamonds," diamonds mined from warring countries including Sierra Leone and Angola, was the dominating topic. Conflict diamonds have fueled and funded wars in these countries, as well as led to the murder and mutilation of thousands of people. These conflict diamonds are estimated to account for four percent of $6.8 billion diamond production industry. On July 19, at the end of the Congress, a resolution was introduced by International Diamond Manufacturers Association (IDMA) and the World Federation of Diamond Bourses, which calls for an international system of certifying gemstones's origins, as well as a registry to monitor the sales, imports, and exports of the precious stones. The resolution was unanimously endorsed, including the approval of De Beers, the diamond trader that controls 60 percent of the entire diamond supply. The IDMA and the World Federation of Diamond Bourses believe that these measures will be implemented by the end of the year.

  20. Architecture of multilayer nanocomposite coatings with super-hard diamond-like carbon layers for wear protection at high contact loads

    Microsoft Academic Search

    A. A. Voevodin; S. D. Walck; J. S. Zabinski

    1997-01-01

    Super-hard and low-friction diamond-like carbon (DLC) coatings deposited at low temperatures are currently of great interest for wear protection and friction reduction. However, their high hardness (50–80 GPa), intrinsic stresses, and poor adhesion limit their use to applications where contact pressures are below I GPa and the coating thickness is below 0.5 ?m to prevent cracking and delamination. These negative

  1. 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.

  2. 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.

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

    SciTech Connect

    Chen, Shih-Show [Department of Physics, Tamkang University, Tamsui, New-Taipei 251, Taiwan (China); Department of Information Technology and Mobile Communication, Taipei College of Maritime Technology, Tamsui, New-Taipei 251, Taiwan (China); Chen, Huang-Chin [Department of Physics, Tamkang University, Tamsui, New-Taipei 251, Taiwan (China); Department of Materials Science and Engineering, National Tsing Hua University, Hsinchu 300, Taiwan (China); Wang, Wei-Cheng; Lin, I-Nan; Chang, Ching-Lin [Department of Physics, Tamkang University, Tamsui, New-Taipei 251, Taiwan (China); Lee, Chi-Young [Department of Materials Science and Engineering, National Tsing Hua University, Hsinchu 300, Taiwan (China); Guo Jinghua [Advanced Light Source, Lawrence Berkeley National Laboratory, Berkeley, California 94720 (United States)

    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.

  4. Polishing of single point diamond tool based on thermo-chemical reaction with copper

    Microsoft Academic Search

    Naomichi Furushiro; Masahiro Higuchi; Tomomi Yamaguchi; Shoichi Shimada; Kazushi Obata

    2009-01-01

    This paper describes a new polishing method for diamond cutting tools. The method is based on the principle of oxidization of copper and deoxidization of copper oxide by carbon. A diamond tool was brought into contact with a copper plate, heated in air to a range of 323–523K. The depth of the removed layer of diamond increased almost linearly with

  5. Diffusion of hydrogen in undoped, p-type and n-type doped diamonds

    Microsoft Academic Search

    C. Saguy; C. Cytermann; B. Fizgeer; V. Richter; Y. Avigal; N. Moriya; R. Kalish; B. Mathieu; A. Deneuville

    2003-01-01

    Hydrogen is a key impurity in diamond since it is unintentionally incorporated in all chemical vapor deposition (CVD) grown diamond layers. Its presence in the material can grossly affect its electrical and optical properties. Theoretically, hydrogen has been predicted to be present in diamond in one of the three charge states, H+, H0 and H?. Moreover it may form complexes

  6. Minimal graphene thickness for wear protection of diamond

    NASA Astrophysics Data System (ADS)

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

    2015-01-01

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

  7. Redox-couple interactions with undoped single crystalline CVD diamond

    Microsoft Academic Search

    D. Shin; H. Watanabe; C. E. Nebel

    2006-01-01

    Intrinsic CVD diamond is well known as insulator, however if the surface is hydrogen terminated, a surface conduction can be detected if exposed to air and covered by an adsorbate layer. In this paper we show that hydrogen terminated intrinsic single crystalline CVD diamond undergoes an insulator metal transition if immersed into redox electrolyte solutions with chemical potentials below the

  8. Electronic properties of graphene-single crystal diamond heterostructures

    SciTech Connect

    Zhao, Fang; Thuong Nguyen, Thuong; Golsharifi, Mohammad; Amakubo, Suguru; Jackman, Richard B., E-mail: r.jackman@ucl.ac.uk [London Centre for Nanotechnology and Department of Electronic and Electrical Engineering, University College London, 17-19 Gordon Street, London WC1H 0AH (United Kingdom); Loh, K. P. [Department of Chemistry, National University of Singapore, 3 Science Drive, Singapore 117543 (Singapore)

    2013-08-07

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

  9. '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.

  10. '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.

  11. Recent Advances in Diamond Detectors

    E-print Network

    Trischuk, W

    2008-01-01

    With the commissioning of the LHC expected in 2009, and the LHC upgrades expected in 2012, ATLAS and CMS are planning for detector upgrades for their innermost layers requiring radiation hard technologies. Chemical Vapor Deposition (CVD) diamond has been used extensively in beam conditions monitors as the innermost detectors in the highest radiation areas of BaBar, Belle and CDF and is now planned for all LHC experiments. This material is now being considered as an alternate sensor for use very close to the interaction region of the super LHC where the most extreme radiation conditions will exist. Recently the RD42 collaboration constructed, irradiated and tested polycrystalline and single-crystal chemical vapor deposition diamond sensors to the highest fluences available. We present beam test results of chemical vapor deposition diamond up to fluences of 1.8 x 10^16 protons/cm^2 showing that both polycrystalline and single-crystal chemical vapor deposition diamonds follow a single damage curve allowing one t...

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

    NASA Astrophysics Data System (ADS)

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

    2015-04-01

    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.

  13. 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 ?m 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.

  14. 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. PMID:19916418

  15. Diamonds in stone meteorites

    Microsoft Academic Search

    Harold C. Urey; Aldo Mele; Toshiko Mayeda

    1957-01-01

    A search for diamonds in the chondrites Richardton, Forest City, Holbrook. Warrenton, Indarch, Cold Bokaveld and Cape Girardeau and in the Goalpara achondrite has been made. Diamonds were found in Goalpara only.

  16. A Diamond's Deep History

    NSDL National Science Digital Library

    While diamonds play a significant role in many cultures, the Earth processes that create diamonds are less familiar to many people. With the use of Macromedia Flash Player, Thirteen/NET New York educates the public about the formation of diamonds two to three billion years ago deep underground. Users can learn about indicator minerals, kimberlite chimneys, and secondary diamond deposits. Through the colorful illustrations and animations, the website offers a great introduction to the creation of this desirable stone.

  17. Diamond heteroepitaxy by bias enhanced nucleation

    NASA Astrophysics Data System (ADS)

    Jayaseelan, Vidhya Sagar

    Diamond has exceptional semiconducting and optical properties that can be used for a wide variety of new applications such as high temperature, high power devices, and optical windows. Exploitation of these properties of diamond needs the development of heteroepitaxial diamond growth process on traditional substrates such as Silicon and Silicon Carbide. Bias enhanced nucleation (BEN) followed by Plasma Enhanced Chemical vapor Deposition (PECVD) has been recognized as a promising route to achieve this goal. However, the BEN process for heteroepitaxy and its mechanism is not well understood. In this study, a system is designed and fabricated to enable the application of bias during diamond deposition in an ASTEX PECVD system, and heteroepitaxial diamond films are grown. The evolution of the oriented diamond film and its microstructure is studied by SEM, TEM, and XRD techniques revealing the formation of misoriented grains, extensive twinning and low angle grain boundaries. The effect of the BEN process conditions on the degree of orientation is investigated. It is observed that the orientation of the films improved at lower bias durations, methane flow rates and bias voltages. TEM images of the nucleation layer are analyzed, and the changes in the nucleation layer grain structure with process parameters are studied. Significant variation in the microstructure and grain size from an average of about 560 nm to about 10 nm is observed with change in process conditions. The BEN process is investigated and the nature of the deposit forming during this step is revealed using SEM, TEM and Raman spectroscopy to be predominantly a nanocrystalline diamond film along with rhombohedral and amorphous carbon. A simple model based on the formation of a nanocrystalline diamond particles during BEN, followed by their growth and coalescence under the plasma is proposed to describe the oriented film formation. The variations in microstructures and orientation are correlated with the process conditions under which they are formed.

  18. The Nature of Diamonds

    NSDL National Science Digital Library

    This Web site looks at how diamonds are created (naturally and synthetically), and how they have been used throughout history. It contains information on composition and structure, the origins and history of diamonds, mining & distribution and an overview of the many uses of diamonds and how they are grown synthetically. A bibliography provides a listing of more than 75 resources for further study.

  19. Diamond particle detectors systems in high energy physics

    NASA Astrophysics Data System (ADS)

    Oh, A.

    2015-04-01

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

  20. 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.

  1. The ATLAS Diamond Beam Monitor

    E-print Network

    Schaefer, Douglas; The ATLAS collaboration

    2015-01-01

    After the first three years of the LHC running the ATLAS experiment extracted it's 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 also install a set of beam monitoring telescopes with pixel sensors, four each in the forward and backward regions. These telescopes were assembled based on chemical vapour deposited (CVD) diamond sensors to survive in this high radiation environment without needing extensive cooling. This talk will describe the lessons learned in construction and commissioning of the ATLAS x Diamond Beam Monitor (DBM). We will show results from the construction quality assurance tests, commissioning performance, including results from cosmic ray running in early 2015 and also expected first results from LHC run 2 collisions.

  2. Hydrogen Storage in Diamond Films

    Microsoft Academic Search

    M. A. Prelas; T. K. Ghosh; S. K. Loyalka; R. V. Tompson

    2002-01-01

    Field Enhanced Diffusion with Optical Activation (FEDOA), a method developed in the authors' laboratory for adding impurities to diamond, has demonstrated that many types of impurities can be incorporated into natural diamond plates and CVD diamond films. This work reports the incorporation of hydrogen in type IIa diamond plates and CVD diamond films. The results indicate that hydrogen is attracted

  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. Diamond tool machining of materials which react with diamond

    DOEpatents

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

    1992-01-01

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

  5. Synthesis and Characterization of Multilayered Diamond Coatings for Biomedical Implants.

    PubMed

    Booth, Leigh; Catledge, Shane A; Nolen, Dustin; Thompson, Raymond G; Vohra, Yogesh K

    2011-05-01

    With incredible hardness and excellent wear-resistance, nanocrystalline diamond (NCD) coatings are gaining interest in the biomedical community as articulating surfaces of structural implant devices. The focus of this study was to deposit multilayered diamond coatings of alternating NCD and microcrystalline diamond (MCD) layers on Ti-6Al-4V alloy surfaces using microwave plasma chemical vapor deposition (MPCVD) and validate the multilayer coating's effect on toughness and adhesion. Multilayer samples were designed with varying NCD to MCD thickness ratios and layer numbers. The surface morphology and structural characteristics of the coatings were studied with X-ray diffraction (XRD), Raman spectroscopy, and atomic force microscopy (AFM). Coating adhesion was assessed by Rockwell indentation and progressive load scratch adhesion tests. Multilayered coatings shown to exhibit the greatest adhesion, comparable to single-layered NCD coatings, were the multilayer samples having the lowest average grain sizes and the highest titanium carbide to diamond ratios. PMID:21603588

  6. Synthesis and Characterization of Multilayered Diamond Coatings for Biomedical Implants

    PubMed Central

    Booth, Leigh; Catledge, Shane A.; Nolen, Dustin; Thompson, Raymond G.; Vohra, Yogesh K.

    2011-01-01

    With incredible hardness and excellent wear-resistance, nanocrystalline diamond (NCD) coatings are gaining interest in the biomedical community as articulating surfaces of structural implant devices. The focus of this study was to deposit multilayered diamond coatings of alternating NCD and microcrystalline diamond (MCD) layers on Ti-6Al-4V alloy surfaces using microwave plasma chemical vapor deposition (MPCVD) and validate the multilayer coating’s effect on toughness and adhesion. Multilayer samples were designed with varying NCD to MCD thickness ratios and layer numbers. The surface morphology and structural characteristics of the coatings were studied with X-ray diffraction (XRD), Raman spectroscopy, and atomic force microscopy (AFM). Coating adhesion was assessed by Rockwell indentation and progressive load scratch adhesion tests. Multilayered coatings shown to exhibit the greatest adhesion, comparable to single-layered NCD coatings, were the multilayer samples having the lowest average grain sizes and the highest titanium carbide to diamond ratios. PMID:21603588

  7. David Jardini President, Black Diamond

    E-print Network

    Benos, Panayiotis "Takis"

    David Jardini President, Black Diamond Investments LLC Charles Lenzner President, Lenzner Tour Products Celtic Healthcare, Inc. Clark Metal Products Diamond Wire Spring Eyetique GeoSpatial Innovations

  8. Raman Characterisation of Diamond Coatings Using Different Laser Wavelengths

    NASA Astrophysics Data System (ADS)

    Haubner, Roland; Rudigier, Moritz

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

  9. Characteristics of Impact Diamonds

    Microsoft Academic Search

    R. Skala; V. J. Bouska

    1992-01-01

    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

  10. 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.

  11. Diamond nucleation using polyethene

    DOEpatents

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

    2013-07-23

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

  12. Hexagonal AlN(0001) Heteroepitaxial Growth on Cubic Diamond (001)

    NASA Astrophysics Data System (ADS)

    Hirama, Kazuyuki; Taniyasu, Yoshitaka; Kasu, Makoto

    2010-04-01

    Structural properties of a hexagonal aluminum nitride (AlN) (0001) layer grown on a cubic diamond (001) substrate by metalorganic vapor-phase epitaxy (MOVPE) are investigated to discuss its growth mechanism. It was found that the AlN layer consists of tilted and rotated domains, which are nucleated just on diamond (001) substrates at the initial growth stage. The tilted AlN domains form on the diamond {111} facets of the pits, which are created on the diamond (001) surface during the thermal cleaning in H2. The AlN[0001] direction of the tilted domains is oriented normal to the diamond {111} facets because the atomic bonding configurations of AlN(0001) and diamond (111) planes are similar. On the other hand, two kinds of rotated AlN domains form on the diamond (001) surface. The [0001] direction of the rotated AlN domains is oriented normal to diamond (001) surface, and the AlN[1010] or [1120] direction is oriented to the diamond [110] direction. The formation of the two kinds of rotated AlN domains originates from the nucleation on two different diamond (001) terraces with one atomic layer height difference.

  13. Hexagonal AlN(0001) Heteroepitaxial Growth on Cubic Diamond (001)

    NASA Astrophysics Data System (ADS)

    Kazuyuki Hirama,; Yoshitaka Taniyasu,; Makoto Kasu,

    2010-04-01

    Structural properties of a hexagonal aluminum nitride (AlN) (0001) layer grown on a cubic diamond (001) substrate by metalorganic vapor-phase epitaxy (MOVPE) are investigated to discuss its growth mechanism. It was found that the AlN layer consists of tilted and rotated domains, which are nucleated just on diamond (001) substrates at the initial growth stage. The tilted AlN domains form on the diamond {111} facets of the pits, which are created on the diamond (001) surface during the thermal cleaning in H2. The AlN[0001] direction of the tilted domains is oriented normal to the diamond {111} facets because the atomic bonding configurations of AlN(0001) and diamond (111) planes are similar. On the other hand, two kinds of rotated AlN domains form on the diamond (001) surface. The [0001] direction of the rotated AlN domains is oriented normal to diamond (001) surface, and the AlN[10\\bar{1}0] or [11\\bar{2}0] direction is oriented to the diamond [1\\bar{1}0] direction. The formation of the two kinds of rotated AlN domains originates from the nucleation on two different diamond (001) terraces with one atomic layer height difference.

  14. 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) of oriented diamond on Ni thin films. Focused ion beam (FIB) technique was used for the sample preparation. Heteroepitaxial diamond nuclei formed at the early nucleation stage and after longer growth time were studied. A carbide interfacial layer between the diamond nuclei and Ni was observed. Diamond grew epitaxially on this interfacial layer with very few defects. All defects appeared to have propagated into the interfacial layer and consisted primarily of stacking faults and dislocations. The selected area diffraction showed a slight misorientation of the interfacial layer with the Ni film. It is believed, that the interfacial layer, which has the same crystal structure and a very close lattice constant with Ni, stabilized the sp3 carbon and facilitated diamond nucleation. A model describing the nucleation mechanism is proposed.

  15. Low-field electron emission from undoped nanostructured diamond

    PubMed

    Zhu; Kochanski; Jin

    1998-11-20

    Strong and sustained electron emission at low electric fields was observed in undoped, nanostructured diamond. Electron emission of 10 milliamperes per square centimeter was observed at applied fields of 3 to 5 volts per micrometer. These are the lowest fields ever reported for any field-emitting material at technologically useful current densities. The emitter consists of a layer of nanometer-size diamond particulates, which is heat-treated in a hydrogen plasma. These emission characteristics are attributed to the particles' high defect density and the low electron affinity of the diamond surface. Such emitters are technologically useful, because they can be easily and economically fabricated on large substrates. PMID:9822373

  16. Characterization of MPCVD diamond films grown on porous silicon

    NASA Astrophysics Data System (ADS)

    Heiderhoff, R.; Spitzl, R.; Maywald, M.; Raiko, V.; Balk, Ludwig J.; Engemann, J.

    1994-04-01

    Spectrally and temporally resolved cathodoluminescence (CL), micro-Raman spectroscopy and the investigation with a scanning force microscopy in a contact current mode (CCM-SFM) are used for characterizing the properties of diamond films. The diamond films and particles are grown by microwave plasma-assisted CVD (MPCVD) on top of monocrystalline and porous silicon (PS) surfaces. The PS layers with different thicknesses and porosity are formed on (111) and (100) silicon by anodization in 12 percent HF solution (HF : H2O equals 1 : 3) at constant current density. A 15 keV electron-beam is used for CL excitation. The CL investigations are carried out at 77 K using an optical multichannel analysis system with simultaneous resolutions of (Delta) (lambda) equals0.2 nm and (Delta) tequals1 ns. Complementary Raman analysis has shown that the synthesized films exhibit diamond structure with good crystalline quality. Diamond films on monocrystalline silicon mostly yield a Raman peak shift of 3-5 cm-1 towards higher wave numbers compared to those of natural diamond due to the presence of compressive stress. The presence of PS allows to reduce stress in diamond films up to a peak shift of 1-2 cm-1 under the same deposition conditions. Intensity and FWHM of the cathodoluminescence as well as the FWHM of the Raman spectrum on PS decrease compared to those of silicon. This indicates that PS is superior to monocrystalline silicon concerning the crystalline quality of the diamond films. High- lateral-resolution analysis, in order to correlate the surface topography with the electrical properties of these diamond films, is carried out by a CCM-SFM. From these characterization methods crucial material system parameters are deduced revealing the influence of a thin PS layer on the crystalline and electrical properties of the diamond films grown on top.

  17. Poly(naphthalenehydrocarbyne): synthesis, characterization, and application to preparation of thin diamond films

    Microsoft Academic Search

    B. M. Bulychev; T. M. Zvukova; A. I. Sizov; A. F. Aleksandrov; Yu. A. Korobov; M. V. Kanzyuba; A. V. Khomich

    2010-01-01

    The diamond phase precursor, viz., poly(naphthalenehydrocarbyne) (1), was prepared. Its disordered structure is built of CH fragments with sp3-hybridized carbon atoms, and arene fragments are inserted in the structure. The use of 1 in the process of diamond layer deposition makes it possible to prepare highly qualitative thin diamond coatings with low\\u000a roughness and good optical properties.

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

    SciTech Connect

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

    2010-01-01

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

  19. 31 CFR 592.310 - Rough diamond.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ...2012-07-01 2012-07-01 false Rough diamond. 592.310 Section 592.310 ...DEPARTMENT OF THE TREASURY ROUGH DIAMONDS CONTROL REGULATIONS General Definitions § 592.310 Rough diamond. The term rough diamond means...

  20. 31 CFR 592.310 - Rough diamond.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ...2013-07-01 2013-07-01 false Rough diamond. 592.310 Section 592.310 ...DEPARTMENT OF THE TREASURY ROUGH DIAMONDS CONTROL REGULATIONS General Definitions § 592.310 Rough diamond. The term rough diamond means...

  1. 31 CFR 592.310 - Rough diamond.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ...2014-07-01 2014-07-01 false Rough diamond. 592.310 Section 592.310 ...DEPARTMENT OF THE TREASURY ROUGH DIAMONDS CONTROL REGULATIONS General Definitions § 592.310 Rough diamond. The term rough diamond means...

  2. 31 CFR 592.310 - Rough diamond.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ...2011-07-01 2011-07-01 false Rough diamond. 592.310 Section 592.310 ...DEPARTMENT OF THE TREASURY ROUGH DIAMONDS CONTROL REGULATIONS General Definitions § 592.310 Rough diamond. The term rough diamond means...

  3. 31 CFR 592.310 - Rough diamond.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ...2010-07-01 2010-07-01 false Rough diamond. 592.310 Section 592.310 ...DEPARTMENT OF THE TREASURY ROUGH DIAMONDS CONTROL REGULATIONS General Definitions § 592.310 Rough diamond. The term rough diamond means...

  4. 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)

  5. Ekati Diamond Mine

    NSDL National Science Digital Library

    2001-01-01

    The page on the Ekati Diamond Mine, which is located in the Northwest Territories and is North America's only operating diamond mine, presents a satellite image and informational text. A detailed map of the region is also included which will allow users to compare the satellite image to what the area looks like on a map. The CCRS was last mentioned in the May 24, 2000 Scout Report for Science and engineering.

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

    NASA Astrophysics Data System (ADS)

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

    2015-04-01

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

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

    NASA Astrophysics Data System (ADS)

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

    2015-06-01

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

  8. Simulation of 1550-nm diamond VECSEL with high contrast grating

    NASA Astrophysics Data System (ADS)

    Walczak, Jaroslaw; Czyszanowski, Tomasz; Dems, Maciej; Sarzala, Robert P.; Sokol, Adam; Wasiak, Michal; Iakovlev, Vladimir

    2012-06-01

    In the following paper a simulation of optically pumped vertical external cavity surface emitting lasers (VECSEL) with a novel approach for the improvement of the heat management is presented. In recent VECSEL structures, it was common to use one top diamond heat spreader in order to decrease the thermal resistance of the device by redistributing the heat flow to the lateral regions and thus transporting heat down to the copper heat sink more efficiently. We present here further improvement of the heat management by eliminating the bottom DBR from the heat flow path and substituting it for a diamond with a High Contrast Grating (HCG). Hence the active region, which consists of 5 pairs of AlGaInAs quaternary alloy quantum wells, is sandwiched between two diamond heat spreading layers. The structure of Si HCG deposited on a diamond provides broad wavelength range in which reflectivity is close to 100% for the emitted beam for perpendicular mode polarization with respect to the direction of the HCG trenches. The HCG assures less than 20% reflection and near zero absorption of pumping light, hence it allows for on-axis bottom pumping scheme and integration of the VECSEL with the pumping laser. According to the simulations 300 ?m thick top diamond heat spreader is enough to assure effective heat dissipation mechanism. Replacing the bottom DBR with the diamond heat spreader will provide additional 10% reduction of the thermal impedance. The minimum of thermal impedance is achieved for about 450 ?m thick bottom diamond heat spreader.

  9. Utilizing of hydrocarbon contamination for prevention of the surface charge-up at electron-beam assisted chemical etching of a diamond chip

    NASA Astrophysics Data System (ADS)

    Taniguchi, Jun; Miyamoto, Iwao; Ohno, Naoto; Honda, Satoshi

    1997-01-01

    Electron beam assisted chemical etching (EBACE) with oxygen gas is not applicable for direct fine patterning of diamond devices, because the diamond is an electrical insulator and electron beam impingement of the diamond causes the surface charge-up. It is possible to form conductive layer of hydrocarbon on the diamond surface by electron beam irradiation in the atmosphere of diffusion pump oil vapors. In this paper, a scanning electron microscope (SEM) combined with oxygen gas introduction system was used for EBACE of the diamond. It was found by in-situ SEM observation that rectangular patterns with several ?m 2 area and sub-?m depth were formed on the diamond chip.

  10. Direct deposition of diamond films on steel using a three-step process

    Microsoft Academic Search

    M. Gowri; H. Li; J. J. Schermer; W. J. P. van Enckevort; J. J. ter Meulen

    2006-01-01

    Diamond coatings were successfully deposited on tool steel substrates without using any external diffusion barrier layers. The diamond film deposition was performed in a hot filament chemical vapour deposition (HFCVD) reactor. In the first step, a high substrate temperature and a high methane percentage were used to achieve a faster critical carbon concentration and hence a shorter incubation time for

  11. Development of a diamond RF switch for a pulse compression system

    Microsoft Academic Search

    Xiaoxi Xu; J. Schein; Niansheng Qi; R. R. Prasad; M. Krishnan; F. Tamura; S. Tantawi

    2000-01-01

    Summary form only given. We present a proof of principle result of an optically controlled diamond RF switch that call be used for high power RF compression systems. The switch is based on the excitation of a plasma layer within a CVD diamond wafer by a laser beam. HFSS simulations were carried out for the design of a TE10 and

  12. Mechanism of photoconductivity in intrinsic epitaxial CVD diamond studied by photocurrent spectroscopy and photocurrent decay measurements

    Microsoft Academic Search

    Z. Remes; R. Petersen; K. Haenen; M. Nesladek; M. D'Olieslaeger

    2005-01-01

    We report experimental results on photocurrent spectra and the transient decay of photocurrent in intrinsic CVD diamond films grown homoepitaxially on natural, (100) oriented, single crystal type IIa diamond substrates. The detectors fabricated from these layers were developed in the frame of the LYRA project (the LYman-alpha RAdiometer onboard the European satellite PROBA-2) and will be used in space for

  13. Negatively Charged Nitrogen-Vacancy Centers in a 5 nm Thin 12 Diamond Film

    E-print Network

    Leonardo, Degiorgi

    , isotopically enriched ([12 C] = 99.99%) diamond layer by CVD. The present method allows for the formation of NVNegatively Charged Nitrogen-Vacancy Centers in a 5 nm Thin 12 C Diamond Film K. Ohashi, T. Rosskopf,# C. L. Degen, and K. M. Itoh*, School of Fundamental Science and Technology, Keio University

  14. Surface electronic properties of H-terminated diamond in contact with adsorbates and electrolytes

    Microsoft Academic Search

    C. E. Nebel; B. Rezek; D. Shin; H. Watanabe

    2006-01-01

    A comprehensive summary of surface electronic properties of undoped hydrogen terminated diamond covered with adsorbates or in electrolyte solutions is given. The formation of a conductive layer at the surface is characterized using Hall effect, conductivity, contact potential difference (CPM), scanning electron microscopy (SEM), and cyclic voltammetry experiments. Data are from measurements on homoepitaxially grown CVD diamond films with atomically

  15. Highly Oriented Diamond Films on Heterosubstrates

    NASA Astrophysics Data System (ADS)

    Arnault, J. C.

    The potential applications of diamond in the field of electronics working under high power and high temperature (aeronautic, aerospace, etc.) require highly oriented films on heterosubstrates. This is the key motivation of the huge research efforts that have been carried out during the last ten years. Very significant progress has been accomplished and nowadays diamond films with misorientations close to 1.5° are elaborated on ?-SiC monocrystals. Moreover, an excellent crystalline quality with polar and azimuthal misalignments lower than 0.6° is reported for diamond films grown on iridium buffer layers. Unfortunately, these films are still too defective for high power electronics applications. To achieve higher crystalline quality, further improvements of the deposition methods are needed. Nevertheless, a deeper knowledge of the elemental mechanisms occurring during the early stages of growth is also essential. The first part of this paper focuses on the state of the art of the different investigated ways towards heteroepitaxy. Secondly, the present knowledge of the early stages of diamond nucleation and growth on silicon substrates for both classical nucleation and bias-assisted nucleation (BEN) is reviewed. Finally, the remaining questions concerning the understanding of the nucleation processes are discussed.

  16. Test-beam studies of diamond sensors for SLHC

    NASA Astrophysics Data System (ADS)

    Uplegger, Lorenzo; Ngadiuba, Jennifer; Alagoz, Enver; Andresen, Jeff; Arndt, Kirk; Bolla, Gino; Bortoletto, Daniela; Marie Brom, Jean; Brosius, Richard; Bubna, Mayur; Chramowicz, John; Cumalat, John; Jensen, Frank; Krzywda, Alex; Kumar, Ashish; Kwan, Simon; Lei, C. M.; Menasce, Dario; Moroni, Luigi; Obertino, Margherita; Osipenkov, Ilya; Perera, Lalith; Prosser, Alan; Rivera, Ryan; Solano, Ada; Tan, Ping; Terzo, Stefano; Tran, Nhan; Robert Wagner, Stephen

    2013-08-01

    Diamond sensors are studied as an alternative to silicon sensors to withstand the high radiation doses that are expected in future upgrades of the pixel detectors for the SLHC. Diamond pixel sensors are intrinsically radiation hard and are considered as a possible solution for the innermost tracker layers close to the interaction point where current silicon sensors cannot cope with the harsh radiation environment.An effort to study possible candidates for the upgrades is undergoing using the Fermilab test-beam facility (FTBF), where diamonds and 3D silicon sensors have been studied. Using a CMS pixel-based telescope built and installed at the FTBF, we are studying charge collection efficiencies for un-irradiated and irradiated devices bump-bonded to the CMS PSI46 pixel readout chip. A description of the test-beam effort and preliminary results on diamond sensors will be presented.

  17. Processing of functionally graded tungsten carbide-cobalt-diamond composites

    NASA Astrophysics Data System (ADS)

    Jain, Mohit

    Polycrystalline diamond compacts (PDCs) are widely used as drill bit cutters in rock drilling and as tool bits in machining non-ferrous materials. A typical PDC comprises a thin layer of sintered polycrystalline diamond bonded to a tungsten carbide-cobalt substrate. A well recognized failure mechanism is delamination at the interface between diamond and cemented carbide. High stresses at the diamond/carbide interface, due to thermal expansion and modulus mismatch, are the primary cause of in-service failure under impact loading conditions. This work was undertaken to develop a tungsten carbide-cobalt-diamond composite, which has a continuously graded interface between the diamond and tungsten carbide. The process developed comprised the following steps: (i) generation of a pore size gradient by electrochemical etching of cobalt from the surface of a partially sintered tungsten carbide-cobalt preform; (ii) chemical vapor infiltration of the porous preform with carbon by catalytic decomposition of a methane/hydrogen mixture, resulting in a graded carbon concentration; and (iii) consolidation of the carbon infiltrated preforms at 8GPa/1500°C to complete densification and to transform the carbon into diamond. Thus, the final product consists of a functionally graded WC-Co-diamond composite, with controlled distribution of the constituent phases. Tungsten carbide-cobalt powders with mean tungsten carbide particle size of 0.8mum(micro-grain) and 100 nm(nano-grain) were used as starting materials. Processing conditions were adjusted to obtain an optimal distribution of carbon in porous preforms. After high pressure/high temperature consolidation, both micro- and nano-composites showed a diffused interface between inner and outer regions of the fully dense materials. A micro-composite showed columnar-like tungsten carbide grains and faceted diamond grains in the outer region of the sintered material. The grain size of the diamond in this region was ˜2mum, and the hardness was VHN = 3700 +/- 60 kg/mm2. The inner region showed equiaxed tungsten carbide grains, with some grains having a coating of diamond-like carbon. A nano-composite showed equiaxed tungsten carbide grains and faceted diamond grains in the outer region of the sintered material. The grain size for both tungsten carbide and diamond was ˜200nm, and the hardness was VHN = 3186 +/- 300 kg/mm2.

  18. Diamond and Polycrystalline Diamond for MEMS Applications: Simulations and Experiments

    E-print Network

    Çagin, Tahir

    on Silicon and polycrystalline diamond show that this rapid wear is caused by a variety of factors, relatedDiamond and Polycrystalline Diamond for MEMS Applications: Simulations and Experiments Tahir C¸ a on Silicon. This is due to the technological know­how accumulated on manipulating, machining, manufacturing

  19. Facts about Diamond Blackfan Anemia

    MedlinePLUS

    ... Form Controls NCBDDD Cancel Submit Search The CDC Diamond Blackfan Anemia (DBA) Note: Javascript is disabled or ... Español (Spanish) Recommend on Facebook Tweet Share Compartir Diamond Blackfan anemia (DBA) is a rare blood disorder ...

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

    NASA Astrophysics Data System (ADS)

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

    2014-09-01

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

  1. 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

  2. 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.

  3. 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.

  4. 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)

  5. Diamond membranes with controlled porosity

    Microsoft Academic Search

    V. P. Mammana; R. D. Mansano; P. Verdonck; A. Pavani Filho; M. C. Salvadori

    1997-01-01

    Porous diamond membranes were fabricated using a method based on growing diamond on a patterned silicon surface. Protrusions on the silicon surface acted as molds for forming the pores on the diamond film. The membrane described here was 10 ?m thick, 15 mm in diameter, had a pore size of about 60 ?m in diameter and a nominal pore density

  6. 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.

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

    SciTech Connect

    Yogesh K. Vohra

    2005-05-12

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

  8. Photoelasticity of diamond

    Microsoft Academic Search

    G. N. Ramachandran

    1950-01-01

    Summary  The photo-elastic constants of diamonds have been redetermined and are found to beq\\u000a 11=?5·05,q\\u000a 12=+2·15,q\\u000a 44=?2·8×10?14 cm.2 dyne?1 andp\\u000a 11=?0·31,p\\u000a 12=+0·09,p\\u000a 44=?0·12. These lead to a decrease in refractive index when diamond is subjected to a hydrostatic pressure.

  9. Diamond Measuring Machine

    SciTech Connect

    Krstulic, J.F.

    2000-01-27

    The fundamental goal of this project was to develop additional capabilities to the diamond measuring prototype, work out technical difficulties associated with the original device, and perform automated measurements which are accurate and repeatable. For this project, FM and T was responsible for the overall system design, edge extraction, and defect extraction and identification. AccuGem provided a lab and computer equipment in Lawrence, 3D modeling, industry expertise, and sets of diamonds for testing. The system executive software which controls stone positioning, lighting, focusing, report generation, and data acquisition was written in Microsoft Visual Basic 6, while data analysis and modeling were compiled in C/C++ DLLs. All scanning parameters and extracted data are stored in a central database and available for automated analysis and reporting. The Phase 1 study showed that data can be extracted and measured from diamond scans, but most of the information had to be manually extracted. In this Phase 2 project, all data required for geometric modeling and defect identification were automatically extracted and passed to a 3D modeling module for analysis. Algorithms were developed which automatically adjusted both light levels and stone focus positioning for each diamond-under-test. After a diamond is analyzed and measurements are completed, a report is printed for the customer which shows carat weight, summarizes stone geometry information, lists defects and their size, displays a picture of the diamond, and shows a plot of defects on a top view drawing of the stone. Initial emphasis of defect extraction was on identification of feathers, pinpoints, and crystals. Defects were plotted color-coded by industry standards for inclusions (red), blemishes (green), and unknown defects (blue). Diamonds with a wide variety of cut quality, size, and number of defects were tested in the machine. Edge extraction, defect extraction, and modeling code were tested for multiple runs of each stone. Although there were problems with a few stones, the machine automatically completed measurements on a majority of the stones tested. A demo was performed in Lawrence for AccuGem stockholders and potential investors. The demo successfully demonstrated our technology on a random stone brought by an attendee. In conclusion, the project was successful in development of the basic technology required for a diamond measuring machine. Continued improvements in lighting control, edge and defect extraction, and an increased image depth-of-field will increase the reliability and consistency of measurements. Although additional work is needed to make the machine a commercial product, there are no foreseeable technical roadblocks in that process.

  10. Fluidized bed deposition of diamond

    DOEpatents

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

    1998-01-01

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

  11. Intergranular diamonds in Qtz-Kfs aggregates from Kokchetav UHP metamorphic rocks

    NASA Astrophysics Data System (ADS)

    Korsakov, A. V.; Theunissen, K.; Smirnova, L. V.

    2003-04-01

    Mantle-derived rocks and related placer deposits are the conventional diamond source. The occurrence of metamorphic diamond as inclusion in refractory minerals in crustal rocks, considerably enlarged the possible rock composition for its formation (from metapelites to metacarbonates). Diamond-bearing rocks within the Kokchetav massif exclusively occur within the Kumdy-Kol block, consisting of (1) Grt-Bt gneisses and interlayered carbonate rocks as main diamond containers; (2) migmatites and eclogite bodies as diamond-free sequences. Estimated peak metamorphic conditions are in the range of T=950--1000^oC and P>40 kbar. We report the first find of intergranular diamond in quartz-feldspar (Qtz-Kfs) aggregates. The diamond-bearing Qtz-Kfs aggregate is best understood as a crystallization product from a silicate melt. The high solubility of CO_2 (up to 15 wt.% according to Hermann and Green, 2002) in such melt could provide carbon for diamond/graphite precipitation under high P-T parameters. Therefore a "granitic" melt is suggested to act as crystallization-media for metamorphic diamond as well as transport-media. The preservation of intergranular diamonds within Qtz-Kfs aggregates during near-isothermal decompression confirms once more the very fast exhumation rate and weakens further the postulated "dry system" for UHP preservation. It also makes questionable the use of diamond inclusions as evidence for UHP origin of the host mineral. The highest content of intergranular diamonds, being at the contact between Grt-Bt-Qtz and Cpx ± Cal layers, this may indicate that interaction of pelite-derived "granitic" melts with metacarbonates might be a fundamental process to produce diamond-bearing Qtz-Kfs aggregates. This study was supported by the Russian Foundation for Basic Research (N 01-05-65093) and by the Belgian Government (BOSTCA).

  12. 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.

  13. Heteroepitaxial CVD diamond film growth

    NASA Astrophysics Data System (ADS)

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

    2003-03-01

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

  14. 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 nearby Eastern Sayan (south-west of the Siberian craton). Parasteresis 3 (unknown host rock type) includes yellow-orange cuboids (II type according to Orlov's classification), which occur in kimberlites in small quantities, but most common in the north-east placers of the Siberian craton. Parasteresis 4 (unknown host rock type) includes diamonds of V and VII types according to Orlov, which are entirely absent in kimberlites. Parasteresis 5 involves the so called yacutites - microcrystalline substance with the add of lonsdaleite phase, typical for diamonds from impact craters. Comparison of yacutites with diamonds from Popigay astrobleme showed up their complete similarity. This fact is evident for the relation of yacutites to the Popigay astrobleme. Thus, in the placers of the Siberian craton there are at least three groups of diamonds with the unknown host rock type. The distribution of the discriminated types of diamonds among the craton is higly uneven. Diamonds of 2,3,4 and 5 parasteresis type (supposed to be from lamprophyres, unknown sources and yacutites) predominate in the north-eastern placers of the Siberian craton, whereas the part of the kimberlitic diamonds is less then a half, in some areas they are completely absent. Early- carboniferous deposits of the Kjutungdinskij graben is the only area where kimberlitic diamonds strongly predominate. That was the case to predict mid-paleozoic kimberlitic field there. In the central part of the province the major role goes to the kimberlitic diamonds associated with the mid-paleozoic kimberlites. Roundish diamonds of the second parasteresis type are in lead on the south of the Siberian craton, and may probably associate with the lamprophyres such as Ingash complex. Mapping of distribution of the distinguished diamond parasteresises among the Siberian craton reveals the tendency of diamonds hypothetically from lamprophyres and unknown sources to associate with the precambrian protrusions - Anabar shield, Olenek rise and Eastern Sayan. This allows us to suggest that the diamonds supply of the

  15. INSTITUTE OF PHYSICS PUBLISHING JOURNAL OF PHYSICS: CONDENSED MATTER J. Phys.: Condens. Matter 16 (2004) R539R552 PII: S0953-8984(04)56693-6

    E-print Network

    Espinosa, Horacio D.

    2004-01-01

    for a new MEMS technology based on ultrananocrystalline diamond thin films Orlando Auciello1 , James BirrellMEMS.Akeychallenge for diamond MEMS is the integration of diamond films with other materials. Conventional CVD thin film diamond. We describe a new ultrananocrystalline diamond (UNCD) film technology based on a microwave plasma

  16. Diamond Film Gas Sensors for Leak Detection of Semiconductor Doping Gases

    Microsoft Academic Search

    Kazushi Hayashi; Yoshihiro Yokota; Takeshi Tachibana; Koichi Miyata; Koji Kobashi; Tetsuya Fukunaga; Tadashi Takada

    2000-01-01

    Gas sensors for leak detection of toxic semiconductor doping gases such as PH3, B2H6, and AsH3 were fabricated using diamond films. The sensors have a double-layered structure composed of undoped and B-doped polycrystalline diamond layers with Pt electrodes. The relative changes in the resistance of the sensors were typically 10-20% for 0.2 ppm PH3 in air, and the highest value

  17. Lower pressure synthesis of diamond material

    DOEpatents

    Lueking, Angela (State College, PA); Gutierrez, Humberto (State College, PA); Narayanan, Deepa (Redmond, WA); Burgess Clifford, Caroline E. (State College, PA); Jain, Puja (King Of Prussia, PA)

    2010-07-13

    Methods of synthesizing a diamond material, particularly nanocrystalline diamond, diamond-like carbon and bucky diamond are provided. In particular embodiments, a composition including a carbon source, such as coal, is subjected to addition of energy, such as high energy reactive milling, producing a milling product enriched in hydrogenated tetrahedral amorphous diamond-like carbon compared to the coal. A milling product is treated with heat, acid and/or base to produce nanocrystalline diamond and/or crystalline diamond-like carbon. Energy is added to produced crystalline diamond-like carbon in particular embodiments to produce bucky diamonds.

  18. Coalescence of Epitaxial Lateral Overgrowth-Diamond on Stripe-Patterned Nucleation on Ir/MgO(001)

    NASA Astrophysics Data System (ADS)

    Washiyama, Shun; Mita, Seiji; Suzuki, Kazuhiro; Sawabe, Atsuhito

    2011-09-01

    The coalescence of epitaxial lateral overgrowth (ELO)-diamonds from stripe-patterned diamond nucleation formed on (001) Ir/MgO has been investigated. Scanning electron microscopy showed only continuous macro steps on the coalesced ELO-diamond layers. Cross-sectional Raman mappings for the 1332 cm-1 diamond peak revealed that ELO regions including coalescence boundaries had a lower full width at half maximum value than regions vertically grown on a nucleation layer. Continuously observed strong tensile strains in ELO regions indicated that additional defect formation to relax the lattice was suppressed even after the coalescence. These results showed that the ELO diamond process could be used to obtain high crystalline diamond films by heteroepitaxy.

  19. Interfacial study of cubic boron nitride films deposited on diamond.

    PubMed

    Zhang, W J; Meng, X M; Chan, C Y; Chan, K M; Wu, Y; Bello, I; Lee, S T

    2005-08-25

    We have studied the nucleation and growth of cubic boron nitride (cBN) films deposited on silicon and diamond-coated silicon substrates using fluorine-assisted chemical vapor deposition (CVD). These comparative studies substantiate that the incubation amorphous/turbostratic BN layers, essential for the cBN nucleation on silicon, are not vital precursors for cBN nucleation on diamond, and they are inherently eliminated. At vastly reduced critical bias voltage, down to -10 V, cBN growth is still maintained on diamond surfaces, and cBN and underlying diamond crystallites exhibit an epitaxial relationship. However, the epitaxial growth is associated with stress in the cBN-diamond interfacial region. In addition, some twinning of crystallites and small-angle grain boundaries are observed between the cBN and diamond crystallites because of the slight lattice mismatch of 1.36%. The small-angle grain boundaries could be eliminated by imposing a little higher bias voltage during the initial growth stage. The heteroepitaxial growth of cBN films on different substrate materials are discussed in the view of lattice matching, surface-energy compatibility, and stability of the substrate against ion irradiation. PMID:16853031

  20. Resolution studies of single-crystal CVD diamond

    Microsoft Academic Search

    R. Hall-Wilton; M. Pernicka; E. Bartz; J. Doroshenko; D. Hits; S. Schnetzer; R. Stone; V. Halyo; B. Harrop; A. Hunt; D. Marlow; W. Bugg; M. Hollingsworth; S. Spanier; W. Johns

    2010-01-01

    The Pixel Luminosity Telescope (PLT) is a dedicated luminosity monitor, presently under construction, for the Compact Muon Solenoid (CMS) experiment at the Large Hadron Collider (LHC). It measures the particle flux in three layers of pixel diamond detectors that are aligned precisely with respect to each other and the beam direction, utilizing simultaneously performed particle track position measurements. The PLT's

  1. Simulation of Atmospheric Pressure Methane-Hydrogen Microdischarge for Diamond Like Carbon (DLC) Film Deposition

    Microsoft Academic Search

    T. Farouk; B. Farouk; A. Gutsol; A. Fridman

    2007-01-01

    Summary form only given. Plasma assisted chemical vapor (PACVD) reactors are frequently used to deposit amorphous carbon layers on materials. These layers also called diamond-like-carbon layers, can be deposited on a variety of substrates by PACVD using different kinds of plasmas, which are generally maintained at low pressure. Operating the plasma at low pressure has several drawbacks which include expensive

  2. Low Temperature Growth of Nanostructured Diamond Films on Metals

    NASA Technical Reports Server (NTRS)

    Baker, Paul A.; Catledge, Shane A.; Vohra, Yogesh K.

    2001-01-01

    The field of nanocrystalline diamond and tetrahedral amorphous carbon films has been the focus of intense experimental activity in the last few years for applications in field emission display devices, optical windows, and tribological coatings, The choice of substrate used in most studies has typically been silicon. For metals, however, the thermal expansion mismatch between the diamond film and substrate gives rise to thermal stress that often results in delamination of the film. To avoid this problem in conventional CVD deposition low substrate temperatures (less than 700 C) have been used, often with the incorporation of oxygen or carbon monoxide to the feedgas mixture. Conventionally grown CVD diamond films are also rough and would require post-deposition polishing for most applications. Therefore, there is an obvious need to develop techniques for deposition of well-adhered, smooth nano-structured diamond films on metals for various tribological applications. In our work, nanostructured diamond films are grown on a titanium alloy substrate using a two-step deposition process. The first step is performed at elevated temperature (820 C) for 30 minutes using a H2/CH4/N2 gas mixture in order to grow a thin (approx. 600 nm) nanostructured diamond layer and improve film adhesion. The remainder of the deposition involves growth at low temperature (less than 600 C) in a H2/CH4/O2 gas mixture. Laser reflectance Interferometry (LRI) pattern during growth of a nanostructured diamond film on Ti-6Al-4V alloy. The first 30 minutes are at a high temperature of 820 C and the rest of the film is grown at a low temperature of 580 T. The fringe pattern is observed till the very end due to extremely low surface roughness of 40 nm. The continuation of the smooth nanostructured diamond film growth during low temperature deposition is confirmed by in-situ laser reflectance interferometry and by post-deposition micro-Raman spectroscopy and surface profilometry. Similar experiments performed without the starting nanostructured diamond layer resulted in poorly adhered films with a more crystalline appearance and a higher surface roughness. This low temperature deposition of nanostructured diamond films on metals offers advantages in cases where high residual thermal stress leads to delamination at high temperatures.

  3. Genetics Home Reference: Diamond-Blackfan anemia

    MedlinePLUS

    ... literature OMIM Genetic disorder catalog Conditions > Diamond-Blackfan anemia On this page: Description Genetic changes Inheritance Diagnosis ... definitions Reviewed February 2012 What is Diamond-Blackfan anemia? Diamond-Blackfan anemia is a disorder of the ...

  4. Controlled synthesis of diamond and carbon nanotubes on Ni-base alloy

    NASA Astrophysics Data System (ADS)

    Li, Y. S.; Hirose, A.

    2008-12-01

    A Ni-base alloy Inconel 600 has been used as substrate for growing two typical carbon thin film materials, diamond and carbon nanotubes (CNTs), in a hot filament chemical vapor deposition reactor with methane-hydrogen mixture. Under typical deposition conditions, the deposits formed on the as-polished alloy substrate comprise duplex layers, outer diamond layer and intermediate graphite layer. An Al thin film applied as an interlayer on the Inconel alloy effectively prevented the growth of intermediate graphite, and only a dense, adherent diamond film was deposited. When the substrate was negatively biased, a glow discharge was initiated and aligned carbon nanotubes were exclusively synthesized. No diamond was formed in this case.

  5. REVIEW ARTICLE: Diamond for bio-sensor applications

    Microsoft Academic Search

    Christoph E. Nebel; Bohuslav Rezek; Dongchan Shin; Hiroshi Uetsuka; Nianjun Yang

    2007-01-01

    A summary of photo- and electrochemical surface modifications applied on single-crystalline chemical vapour deposition (CVD) diamond films is given. The covalently bonded formation of amine- and phenyl-linker molecule layers is characterized using x-ray photoelectron spectroscopy, atomic force microscopy (AFM), cyclic voltammetry and field-effect transistor characterization experiments. Amine- and phenyl-layers are very different with respect to formation, growth, thickness and molecule

  6. 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.

  7. Conversion of fullerenes to diamond

    DOEpatents

    Gruen, Dieter M. (1324 59th St., Downers Grove, IL 60515)

    1993-01-01

    A method of forming synthetic diamond on a substrate is disclosed. The method involves providing a substrate surface covered with a fullerene or diamond coating, positioning a fullerene in an ionization source, creating a fullerene vapor, ionizing fullerene molecules, accelerating the fullerene ions to energies above 250 eV to form a fullerene ion beam, impinging the fullerene ion beam on the substrate surface and continuing these steps to obtain a diamond thickness on the substrate.

  8. Conversion of fullerenes to diamond

    DOEpatents

    Gruen, Dieter M. (1324 59th St., Downers Grove, IL 60515)

    1994-01-01

    A method of forming synthetic diamond on a substrate. The method involves providing a substrate surface covered with a fullerene or diamond coating, positioning a fullerene in an ionization source, creating a fullerene vapor, ionizing fullerene molecules, accelerating the fullerene ions to energies above 250 eV to form a fullerene ion beam, impinging the fullerene ion beam on the substrate surface and continuing these steps to obtain a diamond film thickness on the substrate.

  9. Ultrafast laser processing of diamond

    NASA Astrophysics Data System (ADS)

    Salter, P. S.; Booth, M. J.

    2014-03-01

    Ultrashort pulsed lasers are used to fabricate 3D structures in single crystal CVD diamond. The interaction of the laser with diamond lattice leads to a permanent structural modification, which is highly localized at the focus. Severe spherical aberrations compromise fabrication precision below the diamond surface. We implement adaptive aberration compensation to ensure optimum fabrication performance. The nature of the structural modification is analysed for both surface and subsurface laser fabrications.

  10. Ion beam induced surface graphitization of CVD diamond for x-ray beam position monitor applications

    SciTech Connect

    Liu, Chian; Shu, D.; Kuzay, T.M. [Argonne National Lab, IL (United States). Advanced Photon Source; Wen, L.; Melendres, C.A. [Argonne National Lab., IL (United States). Materials Science Div.]|[Argonne National Lab., IL (United States). Chemical Technology Div.

    1996-12-31

    The Advanced Photon Source at ANL is a third-generation synchrotron facility that generates powerful x-ray beams on its undulator beamlines. It is important to know the position and angle of the x- ray beam during experiments. Due to very high heat flux levels, several patented x-ray beam position monitors (XBPM) exploiting chemical vapor deposition (CVD) diamond have been developed. These XBPMs have a thin layer of low-atomic-mass metallic coating so that photoemission from the x rays generate a minute but measurable current for position determination. Graphitization of the CVD diamond surface creates a very thin, intrinsic and conducting layer that can stand much higher temperatures and minimal x-ray transmission losses compared to the coated metallic layers. In this paper, a laboratory sputter ion source was used to transform selected surfaces of a CVD diamond substrate into graphite. The effect of 1-5 keV argon ion bombardment on CVD diamond surfaces at various target temperatures from 200 to 500 C was studied using Auger electron spectroscopy and in-situ electrical resistivity measurements. Graphitization after the ion bombardment has been confirmed and optimum conditions for graphitization studied. Raman spectroscopy was used to identify the overall diamond structure in the bulk of CVD diamond substrate after the ion bombardments. It was found that target temperature plays an important role in stability and electrical conductivity of the irradiated CVD diamonds.

  11. Nanocrystalline tungsten carbide: As incompressible as diamond

    SciTech Connect

    Lin, Zhijun; Wang, Lin; Zhang, Jianzhong; Mao, Ho-kwang; Zhao, Yusheng; (CIW); (LANL)

    2009-12-10

    We investigate the compressibility of nanocrystalline tungsten carbide (nano-WC) using synchrotron x-ray diffraction. Nano-WC displays a bulk modulus (452 GPa) comparable to that of diamond; it is 10%-15% larger than previously reported values for bulk WC. This finding is consistent with a generalized model of nanocrystal with a compressed surface layer. The linear bulk moduli of nano-WC along a- and c-axes were determined to be 407 and 546 GPa, respectively. First-principles density functional theory (DFT) calculations confirm the experimental observations of an anisotropic linear compressibility and a lower bulk modulus for microsized WC.

  12. Conversion of fullerenes to diamonds

    DOEpatents

    Gruen, Dieter M. (1324 59th St., Downers Grove, IL 60515)

    1995-01-01

    A method of forming synthetic diamond or diamond-like films on a substrate surface. The method involves the steps of providing a vapor selected from the group of fullerene molecules or an inert gas/fullerene molecule mixture, providing energy to the fullerene molecules consisting of carbon-carbon bonds, the energized fullerene molecules breaking down to form fragments of fullerene molecules including C.sub.2 molecules and depositing the energized fullerene molecules with C.sub.2 fragments onto the substrate with farther fragmentation occurring and forming a thickness of diamond or diamond-like films on the substrate surface.

  13. Diamond detectors for space applications

    NASA Astrophysics Data System (ADS)

    Pace, E.; De Sio, A.

    2003-11-01

    This work reviews some general results obtained by our group in the framework of a programme focused on the development and the characterisation of Vacuum-UV (VUV) CVD diamond photodetectors to address the requirements of space missions where pixel and 2-D arrays are used. We discuss the performance of detectors based on single crystal diamond films and CVD polycrystalline diamond films. The performance of these devices in the dark and under illumination was investigated and the results were compared to those from CCD and MCP detectors. The status of diamond detector technology is finally described in order to highlight its advantages over more traditional detectors and the aspects requiring further developments.

  14. DIAMOND PEAK WILDERNESS, OREGON.

    USGS Publications Warehouse

    Sherrod, David R.; Moyle, Phillip R.

    1984-01-01

    No metallic mineral resources were identified during a mineral survey of the Diamond Peak Wilderness in Oregon. Cinder cones within the wilderness contain substantial cinder resources, but similar deposits that are more accessible occur outside the wilderness. The area could have geothermal resources, but available data are insufficient to evaluate their potential. Several deep holes could be drilled in areas of the High Cascades outside the wilderness, from which extrapolations of the geothermal potential of the several Cascade wilderness could be made.

  15. Recombination Radiation from Diamond

    Microsoft Academic Search

    P. J. Dean; I. H. Jones

    1964-01-01

    The spectrum of the recombination radiation from diamond has been measured over the photon energy range 4.9-5.5 eV at 90, 160, 207, and 320°K. At 90°K, recombination emission has been detected from ten samples out of a batch of fifteen single crystals, the majority of which were known to be relatively defect free. The persistent and usually dominant spectral features

  16. 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

  17. Diamond growth on WC-Co substrates by hot filament chemical vapor deposition: Effect of filamentsubstrate separation

    E-print Network

    Bristol, University of

    (tungsten, molybdenum, silicon, etc.) [1­4]. Successful diamond deposition requires elevated substrate that of the favored substrate materials. Typically, therefore, CVD diamond coatings contain (compressive) stress which have a tendency to form an interfacial carbide layer under standard CVD conditions which serves

  18. Friction and Wear Properties of As-Deposited and Carbon Ion-Implanted Diamond Films

    NASA Technical Reports Server (NTRS)

    Miyoshi, Kazuhisa

    1996-01-01

    Recent work on the friction and wear properties of as-deposited and carbon ion-implanted diamond films was reviewed. Diamond films were produced by the microwave plasma chemical vapor deposition (CVD) technique. Diamond films with various grain sizes and surface roughnesses were implanted with carbon ions at 60 keV ion energy, resulting in a dose of 1.2 x 10(exp 17) carbon ions per cm(exp 2). Various analytical techniques, including Raman spectroscopy, proton recoil analysis, Rutherford backscattering, transmission and scanning electron microscopy, X-ray photoelectron spectroscopy, and X-ray diffraction, were utilized to characterize the diamond films. Sliding friction experiments were conducted with a polished natural diamond pin in contact with diamond films in the three environments: humid air (40% relative humidity), dry nitrogen (less than 1 percent relative humidity), and ultrahigh vacuum (10(exp -7) Pa). The CVD diamond films indeed have friction and wear properties similar to those of natural diamond in the three environments. The as-deposited, fine-grain diamond films can be effectively used as self-lubricating, wear-resistant coatings that have low coefficients of friction (0.02 to 0.04) and low wear rates (10(exp -7) to lO(exp -8) mm(exp 3) N(exp -1) m(exp -1)) in both humid air and dry nitrogen. However, they have high coefficients of friction (1.5 to 1.7) and a high wear rate (10(exp -4) mm(exp 7) N(exp -1) m(exp -1)) in ultrahigh vacuum. The carbon ion implantation produced a thin surficial layer (less than 0.1 micron thick) of amorphous, non-diamond carbon on the diamond films. In humid air and dry nitrogen, the ion-implanted, fine and coarse-grain diamond films have a low coefficient of friction (around 0.1) and a low wear rate (10(exp -7) mm(exp 3) N(exp -1) m(exp-1)). Even in ultrahigh vacuum, the presence of the non-diamond carbon layer reduced the coefficient of friction of fine-grain diamond films to 0.1 or lower and the wear rate to 10(exp -6) mm(exp 3) N(exp -1) m(exp -1). Thus, the carbon ion-implanted, fine-grain diamond films can be effectively used as wear-resistant, self-lubricating coatings not only in air and dry nitrogen, but also in ultrahigh vacuum.

  19. 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.

  20. Microwave plasma enhanced chemical vapor deposition of nanocrystalline diamond films by bias-enhanced nucleation and bias-enhanced growth

    SciTech Connect

    Chu, Yueh-Chieh [Institute of Microelectronics, National Cheng Kung University No.1, University Road, Tainan 701, Taiwan (China); Tzeng, Yonhua, E-mail: tzengyo@mail.ncku.edu.tw [Institute of Microelectronics, National Cheng Kung University No.1, University Road, Tainan 701, Taiwan (China); Advanced Optoelectronics Technology Center, National Cheng Kung University No.1, University Road, Tainan 701, Taiwan (China); Auciello, Orlando [Department of Materials Science and Engineering and Bioengineering, University of Texas in Dallas, 800 W. Campbell Rd, Richardson, Texas 75080 (United States)

    2014-01-14

    Effects of biasing voltage-current relationship on microwave plasma enhanced chemical vapor deposition of ultrananocrystalline diamond (UNCD) films on (100) silicon in hydrogen diluted methane by bias-enhanced nucleation and bias-enhanced growth processes are reported. Three biasing methods are applied to study their effects on nucleation, growth, and microstructures of deposited UNCD films. Method A employs 320?mA constant biasing current and a negative biasing voltage decreasing from ?490?V to ?375?V for silicon substrates pre-heated to 800?°C. Method B employs 400?mA constant biasing current and a decreasing negative biasing voltage from ?375?V to ?390?V for silicon pre-heated to 900?°C. Method C employs ?350?V constant biasing voltage and an increasing biasing current up to 400?mA for silicon pre-heated to 800?°C. UNCD nanopillars, merged clusters, and dense films with smooth surface morphology are deposited by the biasing methods A, B, and C, respectively. Effects of ion energy and flux controlled by the biasing voltage and current, respectively, on nucleation, growth, microstructures, surface morphologies, and UNCD contents are confirmed by scanning electron microscopy, high-resolution transmission-electron-microscopy, and UV Raman scattering.

  1. Improving nanocrystalline diamond coatings for micro end mills

    NASA Astrophysics Data System (ADS)

    Heaney, Patrick J.

    A new method is presented for coating 300 mum diameter tungsten carbide (WC) micro end mills with diamond using a hot filament chemical vapor deposition (HF-CVD) method. This method has been developed to create uniform, conformal and continuous diamond coatings. Initial work is shown to prove the feasibility and concept of the project. This was the first work known to coat and evaluate the machining performance WC micro end mills. The performance of uncoated and coated micro end mills was evaluated by dry machining channels in 6061-T6 aluminum. The test results showed a 75% and 90% decrease in both cutting and trust forces for machining, respectfully. The coated tools produced a more predictable surface finish with no burring. These improved results are due to the superior tribological properties of diamond against aluminum. Initial results indicated severe problems with coating delamination causing complete tool failure. After proving the initial concept, new methods for optimizing the coating and improving performance were studied. Each optimization step is monitored through surface analysis techniques to monitor changes in coating morphology and diamond quality. Nucleation density was increased by improving the seed method, using ultra dispersed diamond (UDD) seed. The increase in nucleation density allowed the synthesis of coatings as thin as 60 nm. The adhesion of the coating to the tool was improved through carbon ion implantation (CII). CII is a different surface preparation technique that deactivates the effect of Co, while not weakening the tool. CII also creates a great nucleation layer which diamond can directly grow from, allowing the diamond coating to chemically bond to the substrate improving adhesion and eliminating the need for a seed layer. These thin coatings were shown to be of high quality sp3 trigonaly bonded diamond that resulted in lower machining forces with less delamination. The 90% reduction in machining forces that thin conformal diamond coatings can achieve for micro end mills directly influences the accuracy of parts and the speed with which they can be made. A 50% reduction in forces could be used to double the material removal rate, cutting the part machining cost in half.

  2. Growth defects in diamond films

    Microsoft Academic Search

    D. Shechtman; J. L. Hutchison; L. H. Robins; E. N. Farabaugh; A. Feldman

    1993-01-01

    Growth defects in diamond films grown by plasma-assisted chemical vapor deposition (CVD) were studied by high resolution electron microscopy. Several features of the microstructure were resolved and their importance to the growth of the diamond film was evaluated. The observations included various twin boundaries of the type Sigma = 3, as well as Sigma = 9, Sigma = 27, and

  3. ‘BLACK DIAMOND’ THORNLESS TRAILING BLACKBERRY

    Technology Transfer Automated Retrieval System (TEKTRAN)

    The U.S. Department of Agriculture-Agricultural Research Service (USDA-ARS), the Oregon Agricultural Experiment Station, and the Washington Agricultural Research Center have released 'Black Diamond', a thornless (botanically “spineless”) blackberry for the processing and fresh market. 'Black Diamond...

  4. Electrical conductivity of heteroepitaxial diamond

    NASA Astrophysics Data System (ADS)

    Behravan, Mahdokht

    The purpose of this research is to understand the electrical conduction mechanisms of heteroepitaxial diamond by performing direct current (DC) electrical measurements. Of particular interest is the temperature dependence of the DC conductivity. The project takes advantage of recent advances at Michigan State University in the growth of diamond by chemical vapor deposition on lattice-matched substrates, i.e., by heteroepitaxy. This investigation represents the first detailed study of an electrical transport property of heteroepitaxial diamond. The characterization of the electrical properties of a wide bandgap, high resistivity material such as diamond requires low current, high temperature measurements. A number of new techniques were developed to perform reliable electronic measurements at elevated temperatures. The magnitude of the DC conductivity of heteroepitaxial diamond was found to be remarkably similar to that of high-purity, Type IIa natural diamond. Heteroepitaxial diamond exhibits thermally activated conductivity, with a single activation energy of 1.40+/-0.03 eV from 250 °C to 550 °C. This result is similar to previous measurements by other workers on Type Ila natural diamond, suggesting the presence of electronic states at comparable concentrations in materials of completely different origin.

  5. REVIEW ARTICLE: Diamond for bio-sensor applications

    NASA Astrophysics Data System (ADS)

    Nebel, Christoph E.; Rezek, Bohuslav; Shin, Dongchan; Uetsuka, Hiroshi; Yang, Nianjun

    2007-10-01

    A summary of photo- and electrochemical surface modifications applied on single-crystalline chemical vapour deposition (CVD) diamond films is given. The covalently bonded formation of amine- and phenyl-linker molecule layers is characterized using x-ray photoelectron spectroscopy, atomic force microscopy (AFM), cyclic voltammetry and field-effect transistor characterization experiments. Amine- and phenyl-layers are very different with respect to formation, growth, thickness and molecule arrangement. We detect a single-molecular layer of amine-linker molecules on diamond with a density of about 1014 cm-2 (10% of carbon bonds). Amine molecules are bonded only on initially H-terminated surface areas to carbon. In the case of electrochemical deposition of phenyl-layers, multi-layer formation is detected due to three-dimensional (3D) growths. This gives rise to the formation of typically 25 Å thick layers. The electrochemical grafting of boron-doped diamond works on H-terminated and oxidized surfaces. After reacting such films with hetero-bifunctional crosslinker molecules, thiol-modified ss-DNA markers are bonded to the organic system. Application of fluorescence and AFM on hybridized DNA films shows dense arrangements with densities of up to 1013 cm-2. The DNA is tilted by an angle of about 35° with respect to the diamond surface. Shortening the bonding time of thiol-modified ss-DNA to 10 min causes a decrease of DNA density to about 1012 cm-2. Application of AFM scratching experiments shows threshold removal forces of around 75 nN for DNA bonded on phenyl-linker molecules and of about 45 nN for DNA bonded to amine-linker molecules. DNA sensor applications using Fe(CN6)3-/4- mediator redox molecules, impedance spectroscopy and DNA-field effect transistor devices performances are introduced and discussed.

  6. Magnetic properties of polycrystalline diamonds

    NASA Astrophysics Data System (ADS)

    Collinson, D. W.

    1998-09-01

    The remanent magnetism and bulk magnetic properties of polycrystalline diamonds have been investigated. The diamonds are of two distinct types, those occurring together with gem-grade diamonds in kimberlite pipes in S Africa, and carbonados, found in placer deposits notably in Brazil and the Central African Republic. Both types generally possess measurable remanent magnetization, the former stronger than the latter, and stability tests indicate the presence of primary and secondary components. Magnetite is the dominant carrier of NRM in the kimberlite diamonds, but the very small content of magnetic mineral in the carbonados makes identification of the carrier difficult. Possible contributors are tetrataenite, native iron and cohenite. Anomalous acquisition of isothermal remanence occurs in some carbonados, saturation being unachievable in applied fields in excess of 1 T. The ratio of saturation remanence to initial NRM is anomalously low in some of the kimberlite diamonds, and the possibility of magnetic contamination is investigated.

  7. Field emission from diamond particles studied by scanning field emission microscopy.

    PubMed

    Watanabe, Akihiko; Deguchi, Masahiro; Kitabatake, Makoto; Kono, Shozo

    2003-01-01

    Field emission properties from diamond particles (DPs) are studied. The DPs with thin chemically vapor deposited (CVD) diamond overcoat, dispersed onto metal substrate, essentially exhibit negative electron affinity (NEA). Field emission, approximately 1mA/cm(2) under a macroscopic electric field of 3.5kV/mm are observed. Microscopic electrical properties were studied by scanning tunneling microscopy/spectroscopy. Most parts of the DP surface exhibit narrow gap and p-type characteristics. The localized regions, which have wide gap like bulk diamond properties, are randomly distributed near the top of DP. The field emission current distribution depicted by scanning field emission microscopy (SFEM) show that the electron emission is originating from a localized region on the selected DPs. We found, through SFEM measurement, some favorable field emission spots ("hot spots") where measured emission current is several orders higher than that of the other DPs ("normal spots"). Field emission spectroscopy (FES) results suggest that a poorly conducting layer is present along the electron path from the metal electrode to vacuum.We propose two models for field emission from "hot spots", which involve two main mechanisms. One is electron injection from the metal substrate to the DP, which is attributed to the electric field enhancement at intrinsic non-doped diamond (i-diamond) layer sandwiched between the metal substrate and the surface conductive layer (p-diamond) of the CVD diamond overcoat on the DP. The other is electron emission at the top site of NEA DP through the local i-diamond region or the depletion region of the p-diamond, which is caused by the applied electric field. PMID:12535558

  8. Status review of the science and technology of Ultrananoscrystalline Diamond (UNCD (sup {trademark}) films and application to multifunctional devices.

    SciTech Connect

    Auciello, O.; Sumant, A. V.

    2010-07-01

    This review focuses on a status report on the science and technology of ultrananocrystalline diamond (UNCD) films developed and patented at Argonne National Laboratory. The UNCD material has been developed in thin film form and exhibit multifunctionalities applicable to a broad range of macro to nanoscale multifunctional devices. UNCD thin films are grown by microwave plasma chemical vapor deposition (MPCVD) or hot filament chemical vapor deposition (HFCVD) using new patented Ar-rich/CH4 or H2/CH4 plasma chemistries. UNCD films exhibit a unique nanostructure with 2-5 nm grain size (thus the trade name UNCD) and grain boundaries of 0.4-0.6 nm for plain films, and grain sizes of 7-10 nm and grain boundaries of 2-4 nm when grown with nitrogen introduced in the Ar-rich/CH4 chemistry, to produce UNCD films incorporated with nitrogen, which exhibit electrical conductivity up to semi-metallic level. This review provides a status report on the synthesis of UNCD films via MPCVD and integration with dissimilar materials like oxides for piezoactuated MEMS/NEMS, metal films for contacts, and biological matter for a new generation of biomedical devices and biosensors. A broad range of applications from macro to nanoscale multifunctional devices is reviewed, such as coatings for mechanical pumps seals, field-emission cold cathodes, RF MEMS/NEMS resonators and switches for wireless communications and radar systems, NEMS devices, biomedical devices, biosensors, and UNCD as a platform for developmental biology, involving biological cells growth on the surface. Comparisons with nanocrystalline diamond films and technology are made when appropriate.

  9. Friction and Wear Properties of As-deposited and Carbon Ion-implanted Diamond Films

    NASA Technical Reports Server (NTRS)

    Miyoshi, Kazuhisa

    1994-01-01

    Recent work on the friction and wear properties of as-deposited and carbon ion-implanted diamond films was reviewed. Diamond films were produced by the microwave plasma chemical vapor deposition (CVD) technique. Diamond films with various grain sizes and surface roughnesses were implanted with carbon ions at 60 ke V ion energy, resulting in a dose of 1.2310(exp 17) carbon ions/cm(exp 2). Various analytical techniques, including Raman spectroscopy, proton recoil analysis, Rutherford backscattering, transmission and scanning electron microscopy, x-ray photoelectron spectroscopy, and x-ray diffraction, were utilized to characterize the diamond films. Sliding friction experiments were conducted with a polished natural diamond pin in contact with diamond films in the three environments: humid air (40 percent relative humidity), dry nitrogen (less than 1 percent relative humidity), and ultrahigh vacuum (10(exp -7) Pa). The CVD diamond films indeed have friction and were properties similar to those of natural diamond in the three environments. The as-deposited, fine-grain diamond films can be effectively used as self-lubricating, wear-resistant coatings that have low coefficients of friction (0.02 to 0.04) and low wear rates (10(exp -7) to 10(exp -8)mm(exp 3)/N-m) in both humid air and dry nitrogen. However, they have high coefficients of friction (1.5 to 1.7) and a high wear rate (10(exp -4)mm(exp 3/N-m) in ultrahigh vacuum. The carbon ion implanation produced a thin surficial layer (less than 0.1 micron thick) of amorphous, nondiamond carbon on the diamond films. In humid air and dry nitrogen, the ion-implanted, fine- and coarse-grain diamond films have a low coefficient of friction (around 0.1) and a low wear rate (10(exp -7)mm(exp 3/N-m). Even in ultrahigh vacuum, the presence of the nondiamond carbon layer reduced the coefficient of friction of fine-grain diamond films to 0.1 or lower and the wear rate to 10(exp -6)mm(exp 3)/N-m. Thus, the carbon ion-implanted, fine-grain diamond films can be effectively used as wear-resistant, self-lubricating coatings not only in air and dry nitrogen, but also in ultrahigh vacuum. The wear mechanism of diamond films is that of small fragments chipping off the surface. The size of wear particles is related to the extent of wear rates.

  10. Acoustic wave properties of CVD diamond

    Microsoft Academic Search

    Colm M Flannery; Michael D Whitfield; Richard B Jackman

    2003-01-01

    Diamond is a material which displays exceptional electronic, thermal, tribological, elastic and acoustic properties. These exceptional properties make diamond extremely difficult to characterize. In particular, diamond displays the highest acoustic velocities of any material making it an ideal candidate for acoustic wave devices. The acoustic properties of CVD diamond have not been successfully characterized by conventional acoustic techniques. This has

  11. Recent results on CVD diamond radiation sensors

    Microsoft Academic Search

    P. Weilhammer; W. Adam; C. Bauer; E. Berdermann; F. Bogani; E. Borchi; M. Bruzzi; C. Colledani; J. Conway; W. Dabrowski; P. Delpierre; A. Deneuville; W. Dulinski; R. v. d. Eijk; B. van Eijk; A. Fallou; D. Fish; M. Fried; K. K. Gan; E. Gheeraert; E. Grigoriev; G. Hallewell; R. Hall-Wilton; S. Han; F. Hartjes; J. Hrubec; D. Husson; H. Kagan; D. Kania; J. Kaplon; R. Kass; K. T. Knopfle; M. Krammer; P. F. Manfredi; D. Meier; LeNormand; L. S. Pan; H. Pernegger; M. Pernicka; R. Plano; V. Re; J. L. Riester; S. Roe; Roff; A. Rudge; M. Schieber; S. Schnetzer; S. Sciortino; V. Speziali; H. Stelzer; R. Stone; R. J. Tapper; R. Tesarek; G. B. Thomson; M. Trawick; W. Trischuk; R. Turchetta

    1998-01-01

    CVD diamond radiation sensors are being developed for possible use in trackers in the LHC experiments. The diamond promises to be radiation hard well beyond particle fluences that can be tolerated by Si sensors. Recent results from the RD 42 collaboration on charge collection distance and on radiation hardness of CVD diamond samples will be reported. Measurements with diamond tracking

  12. Development of CVD diamond radiation detectors

    Microsoft Academic Search

    W Adam; C Bauer; E Berdermann; F Bogani; E Borchi; Mara Bruzzi; C Colledani; J Conway; W Dabrowski; P A Delpierre; A Deneuville; W Dulinski; B van Eijk; A Fallou; D Fisch; F Foulon; M Friedl; K K Gan; E Gheeraert; E A Grigoriev; G D Hallewell; R Hall-Wilton; S Han; F G Hartjes; Josef Hrubec; D Husson; H Kagan; D R Kania; J Kaplon; R Kass; K T Knöpfle; Manfred Krammer; P F Manfredi; D Meier; M Mishina; F Le Normand; L S Pan; H Pernegger; Manfred Pernicka; S Pirollo; V Re; J L Riester; S Roe; D G Roff; A Rudge; S R Schnetzer; S Sciortino; V Speziali; H Stelzer; R Stone; R J Tapper; R J Tesarek; G B Thomson; M L Trawick; W Trischuk; R Turchetta; A M Walsh; R Wedenig; Peter Weilhammer; H J Ziock; M M Zoeller

    1998-01-01

    Diamond is a nearly ideal material for detecting ionizing radiation. Its outstanding radiation hardness, fast charge collection and low leakage current allow a diamond detector to be used in high ra diation, high temperature and in aggressive chemical media. We have constructed charged particle detectors using high quality CVD diamond. Characterization of the diamond samples and various detect ors are

  13. Application of Diamond in High Technology

    Microsoft Academic Search

    A. A. Altukhov; M. S. Afanas'ev; V. B. Kvaskov; V. E. Lyubchenko; A. Yu. Mityagin; E. N. Murav'ev; L. A. Pomortsev; V. A. Potapov; B. V. Spitsyn

    2004-01-01

    This review focuses on the critical issues and future directions in the application of diamond in high technology. Diamond nuclear radiation detectors, photosensors, photoemitters, spectral windows, active and passive microelectronic components, and microelectromechanical systems are discussed in detail. In Russia, high-technology diamond applications have not yet moved toward the manufacturing stage, even though Russia possesses immense resources of natural diamond

  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. Adhesion of diamond coatings synthesized by oxygen-acetylene flame CVD on tungsten carbide

    SciTech Connect

    Marinkovic, S.; Stankovic, S. [Institute of Nuclear Sciences, Belgrade (Yugoslavia); Dekanski, A. [Institute for Electrochemistry, Belgrade (Yugoslavia)

    1995-12-31

    The results of a study concerned with chemical vapor deposition of diamond on tungsten carbide cutting tools using an oxygen-acetylene flame in a normal ambient environment are presented. Effects of preparation conditions on the adhesion of the coating have been investigated, including different surface treatment, different position of the flame with respect to the coated surface, effect of an intermediate poorly crystalline diamond layer, etc. In particular, effect of polishing and ultrasonic lapping with diamond powder was compared with that of a corresponding treatment with SiC powder.

  16. Competitive graphitization and diamond growth on hot-dip aluminized carbon steel substrate

    NASA Astrophysics Data System (ADS)

    Li, Y. S.; Ma, H. T.; Yang, L. Z.; Zhang, C. Z.; Feng, R. F.; Yang, Q.; Hirose, A.

    2014-09-01

    When carbon steel is directly exposed in 99%H2-1%CH4 gas mixture for plasma enhanced CVD deposition of diamond coatings, an intermediate graphite layer is preferentially formed on the substrate surface, and the substrate is subjected to a severe internal carburization attack. The diamond coatings formed easily delaminate from the steel substrate. Hot dip aluminizing treatment of the carbon steel has markedly promoted diamond nucleation, growth and interfacial adhesion. The formation of graphite intermediate phase on the substrate surface is effectively inhibited and the substrate carburization is also suppressed. The possible mechanism of this transition is discussed based on a series of analytical techniques.

  17. Deposition of cBN on silicon substrates coated with diamond thin films

    Microsoft Academic Search

    Q. He; Chengming Li; Craig Frankel; Lawrence Pilione; Bill Drawl; Fanxiu Lu; Russell Messier

    2005-01-01

    By controlling the pretreatment processes and deposition parameters on silicon substrates, diamond thin films with different surface roughness and sp2\\/sp3 ratio were used as an interlayer for subsequent c-BN (cubic boron nitride) thin film deposition studies. The diamond interlayers were prepared by microwave plasma chemical vapor deposition (CVD), while the c-BN top layers were prepared by unbalanced magnetron sputtering physical

  18. Near-surface spectrally stable nitrogen vacancy centres engineered in single crystal diamond.

    PubMed

    Stacey, Alastair; Simpson, David A; Karle, Timothy J; Gibson, Brant C; Acosta, Victor M; Huang, Zhihong; Fu, Kai Mei C; Santori, Charles; Beausoleil, Raymond G; McGuinness, Liam P; Ganesan, Kumaravelu; Tomljenovic-Hanic, Snjezana; Greentree, Andrew D; Prawer, Steven

    2012-07-01

    A method for engineering thin (<100 nm) layers of homoepitaxial diamond containing high quality, spectrally stable, isolated nitrogen-vacancy (NV) centres is reported. The photoluminescence excitation linewidth of the engineered NVs are as low as 140 MHz, at temperatures below 12 K, while the spin properties are at a level suitable for quantum memory and spin register applications. This methodology of NV fabrication is an important step toward scalable and practical diamond based photonic devices suitable for quantum information processing. PMID:22628048

  19. Building Diamond-free Posets Aaron Dutle

    E-print Network

    Biro, Csaba

    Building Diamond-free Posets Aaron Dutle AMS Southeastern Sectional October 5, 2013 Joint with ´Eva Czabarka, Travis Johnston, and L´aszl´o Sz´ekely Dutle Building Diamond-free Posets #12;The Diamond Johnston, and L´aszl´o Sz´ekely Dutle The Diamond Conjecture is False #12;#12;Building Diamond-free Posets

  20. 76 FR 37684 - Airworthiness Directives; Diamond Aircraft Industries GmbH Model (Diamond) DA 40 Airplanes...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2011-06-28

    ...RIN 2120-AA64 Airworthiness Directives; Diamond Aircraft Industries GmbH Model (Diamond) DA 40 Airplanes Equipped With Certain Cabin...found during maintenance inspections of the Diamond Model DA 40 airplanes equipped with a...

  1. 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

    2015-07-01

    The fabrication of an all-diamond microprobe is demonstrated for the first time. This ME (microelectrode) assembly consists of an inner boron doped diamond (BDD) layer and an outer undoped diamond layer. Both layers were grown on a sharp tungsten tip by chemical vapor deposition (CVD) in a stepwise manner within a single deposition run. BDD is a material with proven potential as an electrochemical sensor. Undoped CVD diamond is an insulating material with superior chemical stability in comparison to conventional insulators. Focused ion beam (FIB) cutting of the apex of the ME was used to expose an electroactive BDD disk. By cyclic voltammetry, the redox reaction of ferrocenemethanol was shown to take place at the BDD microdisk surface. In order to ensure that the outer layer was nonelectrically conductive, a diffusion barrier for boron atoms was established seeking the formation of boron-hydrogen complexes at the interface between the doped and the undoped diamond layers. The applicability of the microelectrodes in localized corrosion was demonstrated by scanning amperometric measurements of oxygen distribution above an Al-Cu-CFRP (Carbon Fiber Reinforced Polymer) galvanic corrosion cell. PMID:26057348

  2. Conversion of fullerenes to diamond

    DOEpatents

    Gruen, Dieter M. (1324 59th St., Downers Grove, IL 60515)

    1994-01-01

    A method of forming synthetic hydrogen defect free diamond or diamond like films on a substrate. The method involves providing vapor containing fullerene molecules with or without an inert gas, providing a device to impart energy to the fullerene molecules, fragmenting at least in part some of the fullerene molecules in the vapor or energizing the molecules to incipient fragmentation, ionizing the fullerene molecules, impinging ionized fullerene molecules on the substrate to assist in causing fullerene fragmentation to obtain a thickness of diamond on the substrate.

  3. Tailoring nanocrystalline diamond film properties

    DOEpatents

    Gruen, Dieter M. (Downers Grove, IL); McCauley, Thomas G. (Somerville, MA); Zhou, Dan (Orlando, FL); Krauss, Alan R. (Naperville, IL)

    2003-07-15

    A method for controlling the crystallite size and growth rate of plasma-deposited diamond films. A plasma is established at a pressure in excess of about 55 Torr with controlled concentrations of hydrogen up to about 98% by volume, of unsubstituted hydrocarbons up to about 3% by volume and an inert gas of one or more of the noble gases and nitrogen up to about 98% by volume. The volume ratio of inert gas to hydrogen is preferably maintained at greater than about 4, to deposit a diamond film on a suitable substrate. The diamond film is deposited with a predetermined crystallite size and at a predetermined growth rate.

  4. CVD Diamond Dielectric Accelerating Structures

    NASA Astrophysics Data System (ADS)

    Schoessow, P.; Kanareykin, A.; Gat, R.

    2009-01-01

    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 TM01 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.

  5. Growth of twin-free heteroepitaxial diamond on Ir/YSZ/Si(111)

    NASA Astrophysics Data System (ADS)

    Fischer, M.; Brescia, R.; Gsell, S.; Schreck, M.; Brugger, T.; Greber, T.; Osterwalder, J.; Stritzker, B.

    2008-12-01

    Heteroepitaxial nucleation and growth of twin-free diamond on Ir(111) is reported. The bias enhanced nucleation (BEN) technique was applied in a microwave plasma chemical vapor deposition setup to induce diamond nucleation on the new multilayer stack Ir/YSZ/Si(111). We demonstrate that the gathering of the diamond nuclei in so-called "domains," a pattern formation process unique for diamond nucleation on iridium, is also present on Ir(111). The 1-2 nm thick carbon layer deposited by BEN does not show any crystalline diamond structures in electron diffraction and high resolution lattice imaging microscopy. In contrast, x-ray photoelectron diffraction (XPD) measurements yield C 1s diffractograms with clear threefold symmetry. The main features are comparable to measurements on diamond (111) single crystal surfaces. The weaker fine structure in the XPD patterns of the BEN layers is attributed to some disorder due to the harsh ion bombardment. However, this ion bombardment did not induce any measurable amount of twinning as deduced from the threefold symmetry. After 3 h diamond growth, the signal due to twins in the x-ray diffraction pole figures is still below the noise level of ˜1%. Negligible twinning and the low mosaic spread of 0.96° (tilt) and 1.85° (twist) indicate that these films mark a breakthrough toward heteroepitaxial diamond films with (111) orientation. They provide interesting growth substrates, e.g., for phosphorous doped diamond or for the formation of heterojunction devices by deposition of wurtzite-type wide band gap semiconductor materials.

  6. 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.

  7. Toward a Universal Anti-Stick Layer for Nanoimprint Lithography Imprinters: Ultra-Thin F-DLC

    E-print Network

    Krchnavek, Robert R.

    Toward a Universal Anti-Stick Layer for Nanoimprint Lithography Imprinters: Ultra-Thin F-DLC Ryan W of the nanoscale pattern. Previous work on thick (>100 nm) diamond-like carbon (DLC) layers indicates fluorinated diamond-like carbon (F-DLC) provides a durable anti-wear, anti-stick layer. In this work, a process

  8. 16 CFR 23.13 - Disclosure of treatments to diamonds

    Code of Federal Regulations, 2011 CFR

    2011-01-01

    ...2011-01-01 false Disclosure of treatments to diamonds 23.13 Section 23.13 Commercial Practices...INDUSTRIES § 23.13 Disclosure of treatments to diamonds A diamond is a gemstone product. Treatments to diamonds...

  9. 16 CFR 23.13 - Disclosure of treatments to diamonds

    Code of Federal Regulations, 2010 CFR

    2010-01-01

    ...2010-01-01 false Disclosure of treatments to diamonds 23.13 Section 23.13 Commercial Practices...INDUSTRIES § 23.13 Disclosure of treatments to diamonds A diamond is a gemstone product. Treatments to diamonds...

  10. Helium and carbon isotopes in Indian diamonds

    NASA Astrophysics Data System (ADS)

    Wiens, R.; Lal, D.; Craig, H.

    1990-09-01

    Helium and carbon isotope measurements in Indian diamonds (from Andhra Pradesh) were carried out using samples that included mined diamonds from primary kimberlite source rocks and alluvial diamonds from river gravel. The He and C isotope concentrations in diamonds from these two sources were compared, and the Indian diamonds were compared to those from other regions. Results indicate that most of the He-3 in the alluvial diamonds is of cosmogenic origin and that the alluvial diamonds may also have a significant He-4 component due to alpha particles implanted during storage in a secondary matrix. One diamond, a mined kimberlite specimen, was found to have the lowest He-4 content (0.018 microcc/g) so far recorded in diamonds.

  11. 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.

  12. Method of dehalogenation using diamonds

    SciTech Connect

    Farcasiu, Malvina (Roslyn Harbor, NY); Kaufman, Phillip B. (Lafayette, LA); Ladner, Edward P. (Pittsburgh, PA); Anderson, Richard R. (Brownsville, PA)

    2000-01-01

    A method for preparing olefins and halogenated olefins is provided comprising contacting halogenated compounds with diamonds for a sufficient time and at a sufficient temperature to convert the halogenated compounds to olefins and halogenated olefins via elimination reactions.

  13. Electronic properties of CVD diamond

    Microsoft Academic Search

    C E Nebel

    2003-01-01

    The electronic properties of chemical vapour deposited (CVD) diamond are reviewed based on data measured by transient and spectrally resolved photoconductivity experiments, photo-thermal deflection spectroscopy (PDS) and electron paramagnetic resonance (EPR) where substitutional nitrogen (P1-centre) and carbon defects (H1-centre) are detected. The results show that nominally undoped high quality polycrystalline CVD diamond is a n-type semiconductor due to the presence

  14. Neutron Detectors Based Upon Artificial Single Crystal Diamond

    Microsoft Academic Search

    Maurizio Angelone; Giulio Aielli; Salvatore Almaviva; Roberto Cardarelli; Daniele Lattanzi; Marco Marinelli; Enrico Milani; Giuseppe Prestopino; Mario Pillon; Rinaldo Santonico; Aldo Tucciarone; Claudio Verona; Gianluca Verona-Rinati

    2009-01-01

    This paper reports about state-of-the-art artificial Single Crystal Diamond (SCD) neutron detectors based on a multilayered structure and grown by chemical vapour deposition (CVD) technique. Multilayered SCD detectors covered with a thin layer of 6LiF allow the simultaneous detection of both slow and fast neutrons and can operate in pulse and current mode. These detectors can also be produced with

  15. Carbon onions as nanoscopic pressure cells for diamond formation

    Microsoft Academic Search

    F. Banhart; P. M. Ajayan

    1996-01-01

    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

  16. 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

    ...2013-07-01 2013-07-01 false Portland Harbor, Portland, Maine (between Little Diamond Island and Great Diamond Island...Special Anchorage Areas § 110.6 Portland Harbor, Portland, Maine (between Little Diamond Island and Great Diamond...

  17. 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

    ...2014-07-01 2014-07-01 false Portland Harbor, Portland, Maine (between Little Diamond Island and Great Diamond Island...Special Anchorage Areas § 110.6 Portland Harbor, Portland, Maine (between Little Diamond Island and Great Diamond...

  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

    ...2012-07-01 2012-07-01 false Portland Harbor, Portland, Maine (between Little Diamond Island and Great Diamond Island...Special Anchorage Areas § 110.6 Portland Harbor, Portland, Maine (between Little Diamond Island and Great Diamond...

  19. 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

    ...Portland Harbor, Portland, Maine (between Little Diamond Island and Great Diamond Island). 110.6 Section 110.6 Navigation...Portland Harbor, Portland, Maine (between Little Diamond Island and Great Diamond Island)....

  20. 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

    ...Portland Harbor, Portland, Maine (between Little Diamond Island and Great Diamond Island). 110.6 Section 110.6 Navigation...Portland Harbor, Portland, Maine (between Little Diamond Island and Great Diamond Island)....

  1. Discussion on the research of CVD diamond tools

    Microsoft Academic Search

    Zhu Zhenghong; Qian Zhengwang

    2011-01-01

    Diamond cutting tools are increasingly wide application, this is a review about CVD diamond tools, with the most highest cost-effective in synthetic diamond. We introduce CVD diamond and CVD synthesis technology, the key technology of CVD diamond coated tools and some related problems here. Summarize the newest technical developments of CVD diamond at home and abroad. Make a summary for

  2. Simulations of chemical vapor deposition diamond film growth using a kinetic Monte Carlo model and two-dimensional models of microwave plasma and hot filament chemical vapor deposition reactors

    NASA Astrophysics Data System (ADS)

    May, P. W.; Harvey, J. N.; Allan, N. L.; Richley, J. C.; Mankelevich, Yu. A.

    2010-12-01

    A one-dimensional kinetic Monte Carlo (KMC) model has been developed to simulate the chemical vapor deposition of a diamond (100) surface under conditions used to grow single-crystal diamond (SCD), microcrystalline diamond (MCD), nanocrystalline diamond (NCD), and ultrananocrystalline diamond (UNCD) films. The model considers adsorption, etching/desorption, lattice incorporation and surface migration but not defect formation or renucleation processes. Two methods have been devised for estimation of the gas phase concentrations of species at the growing diamond surface, and are used to determine adsorption rates for C1Hx hydrocarbons for the different conditions. The rate of migration of adsorbed carbon species is governed by the availability of neighboring radical sites, which, in turn, depend upon the rates of H abstraction and of surface-radical migration. The KMC model predicts growth rates and surface roughness for each of diamond types consistent with experiment. In the absence of defect formation and renucleation the average surface diffusion length, ?, is a key parameter controlling surface morphology. When ? <2, surface migration is limited by the lack of availability of surface radical sites, and the migrating surface species simply hop back and forth between two adjacent sites but do not travel far beyond their initial adsorption site. Thus, Eley-Rideal processes dominate the growth, leading to the rough surfaces seen in NCD and UNCD. The maximum or "intrinsic" surface roughness occurs for nominally zero-migration conditions (? =0) with an rms value of approximately five carbon atoms. Conversely, when migration occurs over greater distances (? >2), Langmuir-Hinshelwood processes dominate the growth producing the smoother surfaces of MCD and SCD. By extrapolation, we predict that atomically smooth surfaces over large areas should occur once migrating species can travel approximately five sites (? ˜5). ?-scission processes are found to be unimportant for MCD and SCD growth conditions, but can remove up to 5% of the adsorbing carbon for NCD and UNCD growth. C1Hx insertion reactions also contribute <1% to the growth for nearly all conditions, while C2Hx (x <2) insertion reactions are negligible due their very low concentrations at the surface. Finally, the predictions for growth rate and morphology for UNCD deposition in a microwave system were found to be anomalous compared to those for all the other growth conditions, suggesting that carbonaceous particulates created in these plasmas may significantly affect the gas chemistry.

  3. Diamonds: Exploration, mines and marketing

    NASA Astrophysics Data System (ADS)

    Read, George H.; Janse, A. J. A. (Bram)

    2009-11-01

    The beauty, value and mystique of exceptional quality diamonds such as the 603 carat Lesotho Promise, recovered from the Letseng Mine in 2006, help to drive a multi-billion dollar diamond exploration, mining and marketing industry that operates in some 45 countries across the globe. Five countries, Botswana, Russia, Canada, South Africa and Angola account for 83% by value and 65% by weight of annual diamond production, which is mainly produced by four major companies, De Beers, Alrosa, Rio Tinto and BHP Billiton (BHPB), which together account for 78% by value and 72% by weight of annual diamond production for 2007. During the last twelve years 16 new diamond mines commenced production and 4 re-opened. In addition, 11 projects are in advanced evaluation and may begin operations within the next five years. Exploration for diamondiferous kimberlites was still energetic up to the last quarter of 2008 with most work carried out in Canada, Angola, Democratic Republic of the Congo (DRC) and Botswana. Many kimberlites were discovered but no new economic deposits were outlined as a result of this work, except for the discovery and possible development of the Bunder project by Rio Tinto in India. Exploration methods have benefitted greatly from improved techniques of high resolution geophysical aerial surveying, new research into the geochemistry of indicator minerals and further insights into the formation of diamonds and the relation to tectonic/structural events in the crust and mantle. Recent trends in diamond marketing indicate that prices for rough diamonds and polished goods were still rising up to the last quarter of 2008 and subsequently abruptly sank in line with the worldwide financial crisis. Most analysts predict that prices will rise again in the long term as the gap between supply and demand will widen because no new economic diamond discoveries have been made recently. The disparity between high rough and polished prices and low share prices of publicly traded diamond companies may be due to investors losing patience with the slow pace or absence of new promising discoveries and switching into shares of base metals and fertilizers for agriculture (potash and phosphates).

  4. Fabrication and characterization of an all-diamond tubular flow microelectrode for electroanalysis.

    PubMed

    Hutton, Laura A; Vidotti, Marcio; Iacobini, James G; Kelly, Chris; Newton, Mark E; Unwin, Patrick R; Macpherson, Julie V

    2011-07-15

    The development of the first all-diamond hydrodynamic flow device for electroanalytical applications is described. Here alternate layers of intrinsic (insulating), conducting (heavily boron doped), and intrinsic polycrystalline diamond are grown to create a sandwich structure. By laser cutting a hole through the material, it is possible to produce a tubular flow ring electrode of a characteristic length defined by the thickness of the conducting layer (for these studies ?90 ?m). The inside of the tube can be polished to 17 ± 10 nm surface roughness using a diamond impregnanted wire resulting in a coplanar, smooth, all-diamond surface. The steady-state limiting current versus volume flow rate characteristics for the one electron oxidation of FcTMA(+) are in agreement with those expected for laminar flow in a tubular electrode geometry. For dopamine detection, it is shown that the combination of the reduced fouling properties of boron doped diamond, coupled with the flow geometry design where the products of electrolysis are washed away downstream of the electrode, completely eradicates fouling during electrolysis. This paves the way for incorporation of this flow design into online electroanalytical detection systems. Finally, the all diamond tubular flow electrode system described here provides a platform for future developments including the development of ultrathin ring electrodes, multiple apertures for increased current response, and multiple, individually addressable ring electrodes incorporated into the same flow tube. PMID:21644592

  5. Epitaxy of cubic boron nitride on (001)-oriented diamond.

    PubMed

    Zhang, X W; Boyen, H-G; Deyneka, N; Ziemann, P; Banhart, F; Schreck, M

    2003-05-01

    Cubic boron nitride (c-BN), although offering a number of highly attractive properties comparable to diamond, like hardness, chemical inertness and a large electronic bandgap, up to now has not found the attention it deserves. This mostly has to do with preparational problems, with easy chemical routes not available and, instead, the necessity to apply ion-bombardment-assisted methods. Hence, most of the c-BN samples prepared as thin films have been nanocrystalline, making the prospect of using this material for high-temperature electronic applications an illusion. Although heteroepitaxial nucleation of c-BN on diamond substrates has been demonstrated using the high-pressure-high-temperature technique, none of the low-pressure methods ever succeeded in the epitaxial growth of c-BN on any substrate. Here, we demonstrate that heteroepitaxial c-BN films can be prepared at 900 degrees C on highly (001)-oriented diamond films, formed by chemical vapour deposition, using ion-beam-assisted deposition as a low-pressure technique. The orientation relationship was found to be c-BN(001)[100]||diamond(001)[100]. High-resolution transmission electron microscopy additionally proved that epitaxy can be achieved without an intermediate hexagonal BN layer that is commonly observed on various substrates. PMID:12692532

  6. Epitaxy of cubic boron nitride on (001)-oriented diamond

    NASA Astrophysics Data System (ADS)

    Zhang, X. W.; Boyen, H.-G.; Deyneka, N.; Ziemann, P.; Banhart, F.; Schreck, M.

    2003-05-01

    Cubic boron nitride (c-BN), although offering a number of highly attractive properties comparable to diamond, like hardness, chemical inertness and a large electronic bandgap, up to now has not found the attention it deserves. This mostly has to do with preparational problems, with easy chemical routes not available and, instead, the necessity to apply ion-bombardment-assisted methods. Hence, most of the c-BN samples prepared as thin films have been nanocrystalline, making the prospect of using this material for high-temperature electronic applications an illusion. Although heteroepitaxial nucleation of c-BN on diamond substrates has been demonstrated using the high-pressure-high-temperature technique, none of the low-pressure methods ever succeeded in the epitaxial growth of c-BN on any substrate. Here, we demonstrate that heteroepitaxial c-BN films can be prepared at 900 °C on highly (001)-oriented diamond films, formed by chemical vapour deposition, using ion-beam-assisted deposition as a low-pressure technique. The orientation relationship was found to be c-BN(001)[100]||diamond(001)[100]. High-resolution transmission electron microscopy additionally proved that epitaxy can be achieved without an intermediate hexagonal BN layer that is commonly observed on various substrates.

  7. 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. PMID:19375336

  8. CVD diamond nucleation enhanced by ultrasonic pretreatment using diamond and mixture of diamond and TaC powders

    Microsoft Academic Search

    S. G Wang; Qing Zhang; S. F Yoon; J Ahn; Q Wang; D. J Yang; Q. F Huang; Rusli; W. Z Tang; F. X Lu

    2002-01-01

    Effects of ultrasonic pretreatment on chemical vapor deposition (CVD) diamond nucleation on Si substrates were systematically studied. Pure 1.5–40 ?m-diamond powder and mixtures of 1.5–5 ?m-diamond as well as 5–20 ?m-Tantalum Carbide (TaC) powder were used in ultrasonic pretreatment. The root-mean-square (Rms) surface roughness of the pretreated substrates, residual diamond and TaC powders left on the substrates were examined using

  9. Diamond and Related Materials 9 (2000) 12631269 www.elsevier.com/locate/diamond

    E-print Network

    Bristol, University of

    2000-01-01

    technology was adapted to be used to seed diamond nano-grit onto silicon. Patterned, boron-doped diamond pads with in situ boron-doping, dots (85 mm in diameter) containing poly-crystals in the nanometre range deposition; Diamond seeding; Electron emitters; Boron-doped; CVD diamond 1. Introduction Selected area

  10. Welcome to Diamond Light Source Parking Visitors can park outside Diamond

    E-print Network

    Crowther, Paul

    Welcome to Diamond Light Source Parking ­ Visitors can park outside Diamond House, or if that is full, in the Visitor car park. Users should park around the ring. On Arrival ­ Diamond does not have 8500). Then take a seat 2 and wait for your Diamond contact to collect you. Users ­ Fast track users

  11. 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.

  12. Molecular orientation of lead phthalocyanine on (100) oriented single crystal diamond surfaces.

    PubMed

    Dexters, Wim; Bourgeois, Emilie; Nesládek, Milos; D'Haen, Jan; Goovaerts, Etienne; Haenen, Ken

    2015-04-21

    Lead phthalocyanine (PbPc) thin films of 5 and 50 nm have been deposited on hydrogen and oxygen terminated single crystal diamond (SCD) using organic molecular beam deposition. Atomic force microscopy and X-ray diffraction (XRD) studies showed that PbPc grown on the hydrogen terminated SCD forms layers with a high degree of crystallinity, dominated by the monoclinic (320) orientation parallel to the diamond surface. The oxygen terminated diamond led to a randomly oriented PbPc film. Absorption and photocurrent measurements indicated the presence of both polymorphs of PbPc, however, the ratio differed depending on the termination of the SCD. Finally, polarized Raman spectroscopy was used to determine the orientation of the molecules of the thin film. The results confirmed the random orientation on the O-terminated diamond. On SCD:H, the PbPc molecules are lying down in accordance with the XRD results. PMID:25779759

  13. Crystal tilting of diamond heteroepitaxially grown on vicinal Ir/SrTiO3(001)

    NASA Astrophysics Data System (ADS)

    Gsell, S.; Schreck, M.; Stritzker, B.

    2004-08-01

    In the present study SrTiO3 crystals with vicinal (001) surfaces inclined 3° and 5° towards [110] and [100], respectively, have been used to deposit iridium layers and subsequently epitaxial diamond films. The iridium grows on top of the vicinal SrTiO3(001) with a perfect cube-on-cube registry. In contrast, the diamond films on the iridium show a strong additional tilting of up to 2°. A model is proposed which explains the effect by the preferential incorporation of misfit dislocations due to the stress anisotropy on the vicinal substrate planes taking into account the lattice misfit and the islandlike growth mode of diamond. The experimental observations and their explanation suggest that the epitaxial diamond alignment on iridium takes place during lateral growth within the first few nanometers.

  14. Structure, magnetic, and electronic properties of hydrogenated two-dimensional diamond films

    NASA Astrophysics Data System (ADS)

    Li, Jia; Li, Hongdong; Wang, Zhigang; Zou, Guangtian

    2013-02-01

    In this paper, we study the effects of semi-hydrogenation (SH) and full-hydrogenation (FH) on the structural evolution and properties of two-dimensional (2D) diamond nanofilms by first-principles calculations. Both the hydrogenation processes play an important role in stabilizing the 2D diamond structures. For the FH cases, the direct bandgaps are localized in the region of 2.54-3.55 eV and decreased following an inverse law with layer number (n). For the SH cases, a ferrimagnetism characteristic is presented determining by the unpaired electrons on the un-hydrogenated side, and the spin-related bandgaps are in an infrared region of 0.74-1.17 eV, which are strongly dependent on n. As a result, the hydrogenation is favorable for tuning the electronic and magnetic properties of 2D diamond nanofilms to achieve high performance diamond-based nanodevices.

  15. 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.

  16. Genesis of Diamond-bearing and Diamond-free Podiform Chromitites in the Luobusa Ophiolite, Tibet

    NASA Astrophysics Data System (ADS)

    Yang, J.; Xiong, F.; Xu, X.; Robinson, P. T.; Dilek, Y.; Griffin, W. L.

    2014-12-01

    Micro-diamonds, moissanite and many highly reduced minerals, such as native Fe, Cr, Ni, Si, Al, and metallic alloys, have been reported previously from podiform chromitites and peridotites of the Luobusa ophiolite in the eastern segment of the Yarlung-Zangbo suture of southern Tibet.. Similar mineral associations have now been confirmed in mantle peridotites or chromitites of 11 other ophiolites in 5 orogenic belts, in Tibet, Myanmar, North China and the Polar Urals. However, detailed studies of the Luobusa ophiolite show that not all chromitites contain these UHP and highly reduced minerals. Diamond-bearing chromitites are chiefly massive bodies composed of over 95 modal% magnesiochromite with Cr#s [100Cr/(Cr+Al)] of 77-83 and Mg#s [100Mg/(Mg+Fe)] of 71-82. Most of these bodies have sharp contacts with the host harzburgites and are only rarely enclosed in dunite envelopes. Many magnesiochromite grains in the massive chromitites contain inclusions of forsterite and pyroxene. Forsterite inclusions have Fo numbers of 97-99 and NiO contents of 1.11-1.29 wt%. Mg#s of clinopyroxene inclusions are 96-98 and those of orthopyroxene are 96-97. X-ray studies show that the olivine inclusions have very small unit cells and short cation-oxygen bond distances, suggesting crystallization at high pressure. In contrast, diamond-free chromitites typically occur as layers within thick dunite sequences or as irregular patches surrounded by dunite envelopes. They consist of variable proportions of magnesiochromite (Cr# = 76-78; Mg# = 58-61) and olivine, and have banded, nodular and disseminated textures. The dunite envelopes consist chiefly of granular olivine with a few relatively large, amoeboidal grains of magnesiochromite, and typically grade into the host peridotites with increasing pyroxene. Unlike those in the massive ores, magnesiochromite grains in nodular and disseminated chromitites lack pyroxene inclusions, and their olivine inclusions have relatively low Fo (94-96) and NiO (0.35-0.58 wt%). We propose that the diamond-bearing chromitite ores formed within the deeper parts of the upper mantle and were emplaced at an oceanic spreading ridge, whereas the diamond-free chromitites formed at shallow levels by melt/rock reaction, most likely in a SSZ environment.

  17. 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.

  18. Diamond photodiodes for x-ray application

    SciTech Connect

    Distel, James R [Los Alamos National Laboratory; Smedley, John [BNL; Keister, Jeffrey W [BNL; Muller, Erik [STONY BROOK UNIV.; Jordan - Sweet, Jean [WATSON RESEARCH CENTER; Bohon, Jen [CASE WESTERN RESERVE UNIV.; Dong, Bin [NON LANL

    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.

  19. Spectroscopic ellipsometry of homoepitaxial diamond multilayers and delta-doped structures

    SciTech Connect

    Bousquet, J.; Chicot, G.; Eon, D.; Bustarret, E. [Univ. Grenoble Alpes, Inst. NEEL, F-38042 Grenoble (France); CNRS, Inst. NEEL, F-38042 Grenoble (France)

    2014-01-13

    The optimization of diamond-based unipolar electronic devices such as pseudo-vertical Schottky diodes or delta-doped field effect transistors relies in part on the sequential growth of nominally undoped (p{sup –}) and heavily boron doped (p{sup ++}) layers with well-controlled thicknesses and steep interfaces. Optical ellipsometry offers a swift and contactless method to characterize the thickness, roughness, and electronic properties of semiconducting and metallic diamond layers. We report ellipsometric studies carried out on delta-doped structures and other epitaxial multilayers with various boron concentrations and thicknesses (down to the nanometer range). The results are compared with Secondary Ion Mass Spectroscopy and transport measurements.

  20. 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.

  1. Diamond-integrated optomechanical circuits.

    PubMed

    Rath, Patrik; Khasminskaya, Svetlana; Nebel, Christoph; Wild, Christoph; Pernice, Wolfram H P

    2013-01-01

    Diamond offers unique material advantages for the realization of micro- and nanomechanical resonators because of its high Young's modulus, compatibility with harsh environments and superior thermal properties. At the same time, the wide electronic bandgap of 5.45 eV makes diamond a suitable material for integrated optics because of broadband transparency and the absence of free-carrier absorption commonly encountered in silicon photonics. Here we take advantage of both to engineer full-scale optomechanical circuits in diamond thin films. We show that polycrystalline diamond films fabricated by chemical vapour deposition provide a convenient wafer-scale substrate for the realization of high-quality nanophotonic devices. Using free-standing nanomechanical resonators embedded in on-chip Mach-Zehnder interferometers, we demonstrate efficient optomechanical transduction via gradient optical forces. Fabricated diamond resonators reproducibly show high mechanical quality factors up to 11,200. Our low cost, wideband, carrier-free photonic circuits hold promise for all-optical sensing and optomechanical signal processing at ultra-high frequencies. PMID:23575694

  2. 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.

  3. Modular dynamics in diamonds

    E-print Network

    Romeo Brunetti; Valter Moretti

    2010-09-25

    We investigate the relation between the actions of Tomita-Takesaki modular operators for local von Neumann algebras in the vacuum for free massive and massless bosons in four dimensional Minkowskian spacetime. In particular, we prove a long-standing conjecture that says that the generators of the mentioned actions differ by a pseudo-differential operator of order zero. To get that, one needs a careful analysis of the interplay of the theories in the bulk and at the boundary of double cones (a.k.a. diamonds). After introducing some technicalities, we prove the crucial result that the vacuum state for massive bosons in the bulk of a double cone restricts to a KMS state at its boundary, and that the restriction of the algebra at the boundary does not depend anymore on the mass. The origin of such result lies in a careful treatment of classical Cauchy and Goursat problems for the Klein-Gordon equation as well as the application of known general mathematical techniques, concerning the interplay of algebraic structures related with the bulk and algebraic structures related with the boundary of the double cone, arising from quantum field theories in curved spacetime. Our procedure gives explicit formulas for the modular group and its generator in terms of integral operators acting on symplectic space of solutions of massive Klein-Gordon Cauchy problem.

  4. Geochemical Characteristics of Southern African Diamonds

    Microsoft Academic Search

    P. Deines; J. W. Harris

    2002-01-01

    The question whether significant differences in the carbon isotopic composition of diamonds and the chemistry of their inclusions exist among diamonds from different kimberlites, is examined with 1350 diamond samples from kimberlites on the Kaapvaal Craton (Premier, Finsch, Roberts Victor, Koffiefontein) towards the margin of the craton (Jagersfontein) and the Limpopo Mobile Belt (Jwaneng, Orapa, Venetia). The carbon isotope distributions

  5. 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.…

  6. Diamond semiconductor technology for RF device applications

    Microsoft Academic Search

    Yasar Gurbuz; Onur Esame; Ibrahim Tekin; Weng P. Kang; Jimmy L. Davidson

    2005-01-01

    This paper presents a comprehensive review of diamond electronics from the RF perspective. Our aim was to find and present the potential, limitations and current status of diamond semiconductor devices as well as to investigate its suitability for RF device applications. While doing this, we briefly analysed the physics and chemistry of CVD diamond process for a better understanding of

  7. Traditionally configured prawn trawls contain small diamond-

    E-print Network

    434 Traditionally configured prawn trawls contain small diamond- shaped meshes in the codend, and small diamond-mesh sections. A strategically located panel of 85-mm netting was inserted on the bar with a conventional diamond-mesh codend (control) showed that both square-mesh designs significantly re- duced

  8. Pro-Q Diamond Phosphoprotein Gel Stain

    E-print Network

    Lebendiker, Mario

    Pro-Q Diamond Phosphoprotein Gel Stain In-gel Detection Technology for Protein Phosphorylation and phosphoproteomics, the Pro-Q Diamond phos- phoprotein gel stain is a breakthrough technology that provides a simple phosphoproteins, the Pro-Q Diamond signal is linear over three orders of magnitude and the strength of the signal

  9. Diamond-free Families Jerrold R. Griggs

    E-print Network

    Griggs, Jerrold R.

    Diamond-free Families Jerrold R. Griggs Wei-Tian Li Linyuan Lu August 28, 2011 Abstract Given. For k 2 let Dk denote the k-diamond poset {A that continues to stymie all interested researchers is the diamond poset on four elements. We present a better

  10. Performance of a new Diamond Drill Bit

    Microsoft Academic Search

    C. R. Ivie; J. E. Wood

    1984-01-01

    Early in 1984 a new type of synthetic diamond drill bit was introduced. The bits, know as ballaset diamond bits, are designed for and work well in medium to hard, moderately abrasive formations such as limestones, dolomites, hard brittle shales, and sandstones. Two years of field tests, many in the overthrust belt, have proven that ballaset diamond bits offer faster

  11. High-fluence Si-implanted diamond: Optimum implantation temperature for SiC formation

    SciTech Connect

    Weishart, H.; Eichhorn, F.; Heera, V.; Pecz, B.; Barna, A.; Skorupa, W. [Institute of Ion Beam Physics and Materials Research, Forschungszentrum Rossendorf, P.O. Box 510119, D-01314 Dresden (Germany); Research Institute for Technical Physics and Materials Science, Hungarian Academy of Sciences, P.O. Box 49, H-1525 Budapest (Hungary); Institute of Ion Beam Physics and Materials Research, Forschungszentrum Rossendorf, P.O. Box 510119, D-01314 Dresden (Germany)

    2005-08-15

    In this paper the authors investigate the effect of implantation temperature on the structural properties of diamond implanted with high fluences of Si between 5.3x10{sup 17} Si cm{sup -2} and 1x10{sup 18} Si cm{sup -2}. In order to reduce radiation-induced damage and to enhance SiC formation the implantations were performed at elevated temperatures in the range from 900 to 1200 deg. C. Subsequently, all samples were annealed for 10 min at 1500 deg. C in a rf-heated furnace. X-ray diffraction revealed the formation of cubic SiC nanocrystallites in a buried layer inside the implanted diamond. The implantation-induced damage was assessed by analyzing graphitization of the surface-near layer using Raman spectroscopy. With increasing Si fluence the implantation-induced damage rises and the nearly perfect alignment of the formed SiC crystallites within the host diamond lattice deteriorates. However, raising the implantation temperature from 900 to 1000 deg. C reduces the damage in the diamond and increases the amount, size, and epitaxial alignment of the crystalline SiC precipitates. Further increase of the implantation temperature gives no improvement in the quality of the SiC-rich layer. Instead, the damaged diamond converts into graphite and the formation of SiC crystallites is obstructed.

  12. 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.

  13. 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 for the past 500 Ma between and among superchrons, subchrons, kimberlites and entrained diamonds weigh heavily in favor of the following scenario: solid core growth, the consequent release of Si, O, C, H, S, K and possibly N and B to D'', disruption of D'' at some critically unstable threshold thickness (200-300 km), enhanced core convection and the stabilization of a constant non-reversing magnetic dipole field, rising plumes and subsequent volcanism. If protokimberlitic magma and entrainment begin at the core-mantle boundary, a number of geochemical and mineralogical anomalies in diamonds are at present best satisfied if D'' is invoked. These include but are not limited to intensely reduced (i.e., oxygen deficient) SiC, metallic Fe, an abundance of sulfides, silicate perovskite and wuestite-periclase mineral inclusions in diamonds.

  14. Friction and wear performance of boron doped, undoped microcrystalline and fine grained composite diamond films

    NASA Astrophysics Data System (ADS)

    Wang, Xinchang; Wang, Liang; Shen, Bin; Sun, Fanghong

    2015-01-01

    Chemical vapor deposition (CVD) diamond films have attracted more attentions due to their excellent mechanical properties. Whereas as-fabricated traditional diamond films in the previous studies don't have enough adhesion or surface smoothness, which seriously impact their friction and wear performance, and thus limit their applications under extremely harsh conditions. A boron doped, undoped microcrystalline and fine grained composite diamond (BD-UM-FGCD) film is fabricated by a three-step method adopting hot filament CVD (HFCVD) method in the present study, presenting outstanding comprehensive performance, including the good adhesion between the substrate and the underlying boron doped diamond (BDD) layer, the extremely high hardness of the middle undoped microcrystalline diamond (UMCD) layer, as well as the low surface roughness and favorable polished convenience of the surface fine grained diamond (FGD) layer. The friction and wear behavior of this composite film sliding against low-carbon steel and silicon nitride balls are studied on a ball-on-plate rotational friction tester. Besides, its wear rate is further evaluated under a severer condition using an inner-hole polishing apparatus, with low-carbon steel wire as the counterpart. The test results show that the BD-UM-FGCD film performs very small friction coefficient and great friction behavior owing to its high surface smoothness, and meanwhile it also has excellent wear resistance because of the relatively high hardness of the surface FGD film and the extremely high hardness of the middle UMCD film. Moreover, under the industrial conditions for producing low-carbon steel wires, this composite film can sufficiently prolong the working lifetime of the drawing dies and improve their application effects. This research develops a novel composite diamond films owning great comprehensive properties, which have great potentials as protecting coatings on working surfaces of the wear-resistant and anti-frictional components.

  15. Diamond Molecules Found in Petroleum

    NASA Astrophysics Data System (ADS)

    Carlson, R. M. K.; Dahl, J. E. P.; Liu, S. G.; Olmstead, M. M.; Buerki, P. R.; Gat, R.

    We recently reported [1,2] the discovery and isolation of new members of the hydrogen-terminated diamond series, ˜1 to ˜2 nm sized higher diamondoids from petroleum. Crystallographic studies [1,2] revealed a wealth of diamond molecules that are nanometer-sized rods, helices, discs, pyramids, etc. Highly rigid, well-defined, readily derivatizable structures make them valuable molecular building blocks for nanotechnology. We now produce certain higher diamondoids in gram quantities. Although more stable than graphite particles of comparable size, higher diamondoids are extraordinarily difficult to synthesize. Attempts to synthesize them were abandoned in the 1980's. We examined extracts of diamond-containing materials synthesized by CO2 laser-induced gas-phase synthesis [3] and commercial CVD in an attempt to detect diamantane to undecamantane. However, high-sensitivity GCMS detected no diamondoids in these materials.

  16. Method for machining steel with diamond tools

    DOEpatents

    Casstevens, John M. (Greenville, TX)

    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.

  17. The ATLAS Diamond Beam Monitor : Luminosity Detector on the LHC

    E-print Network

    Schaefer, Douglas; The ATLAS collaboration

    2015-01-01

    After the first three years of the LHC running the ATLAS experiment extracted it's 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 also install a set of beam monitoring telescopes with pixel sensors, four each in the forward and backward regions. These telescopes were assembled based on chemical vapour deposited (CVD) diamond sensors to survive in this high radiation environment without needing extensive cooling. This talk will describe the lessons learned in construction and commissioning of the ATLAS x Diamond Beam Monitor (DBM). We will show results from the construction quality assurance tests, commissioning performance, including results from cosmic ray running in early 2015 and also expected first results from LHC run 2 collisions.

  18. Zr/oxidized diamond interface for high power Schottky diodes

    SciTech Connect

    Traoré, A., E-mail: aboulaye.traore@neel.cnrs.fr; Muret, P.; Fiori, A.; Eon, D.; Gheeraert, E. [Univ. Grenoble Alpes, Inst NEEL, F-38042 Grenoble (France); CNRS, Inst NEEL, F-38042 Grenoble (France); Pernot, J., E-mail: julien.pernot@neel.cnrs.fr [Univ. Grenoble Alpes, Inst NEEL, F-38042 Grenoble (France); CNRS, Inst NEEL, F-38042 Grenoble (France); Institut Universitaire de France, 103 Boulevard Saint-Michel, F-75005 Paris (France)

    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.

  19. Diamond Wars? Conflict Diamonds and Geographies of Resource Wars

    Microsoft Academic Search

    Philippe Le Billon

    2008-01-01

    In the late 1990s, natural resources such as oil, diamonds, and timber came under increased scrutiny by conflict analysts and media outlets for their purported role in many contemporary wars. This article discusses some of the limitations of conventional arguments linking wars and resources. Dominated by econometric approaches and rational choice theory interpretations, arguments pertaining to “resource wars” often oversimplify

  20. Waveguide Diamond Vacuum Windows with HELICOFLEX® Seals

    NASA Astrophysics Data System (ADS)

    Doane, J. L.

    2003-02-01

    Since brazing to diamond can be difficult, time-consuming and expensive, we have designed windows sealed for high vacuum by two Helicoflex® metal seals on opposing faces of a diamond disk. To prevent excessive stress on the diamond, the seals must be well aligned and external forces on the window assembly must not be transmitted to the diamond. We describe the main features of these windows. Calculations of the temperature rises and stresses in the diamond are presented. Tests with heat sources indicate that the thermal conduction through the seals is very good. A window in 31.75 mm corrugated waveguide with a diamond disk 0.75 mm thick for 84 GHz has been operated up to 300 kW in 3 s pulses. The temperature rise measured in thermocouples touching the edges of the diamond disks was very small. Water cooling channels were provided but have not been needed.

  1. High temperature diffusion chromizing as a successful method for CVD-diamond coating of steel—Part II

    Microsoft Academic Search

    S. Schwarz; S. M. Rosiwal; Y. Musayev; R. F. Singer

    2003-01-01

    Well adherent CVD-diamond coatings were deposited onto 41Cr4 steel substrates using chromium carbide diffusion interlayers. The influence of coating parameters on microstructure and composition of chromium carbide layer and substrate was investigated. In situ heat treatment allows for a variation of physical and mechanical properties of the substrate. We assume that the adhesion of CVD-diamond coatings depends inter alia on

  2. Limiting processes for diamond epitaxial alignment on silicon

    NASA Astrophysics Data System (ADS)

    Thürer, K.-H.; Schreck, M.; Stritzker, B.

    1998-06-01

    For the heteroepitaxial deposition of diamond on silicon using the bias-enhanced nucleation procedure, several different processes contributing to the final misalignment of the layers can be identified: (i) The interface of Si/diamond or Si/SiC and SiC/diamond, respectively. (ii) The growth of individual grains during the biasing process. (iii) The growth competition between differently oriented grains and their coalescence during the growth of thick films. X-ray-diffraction texture studies revealed that the azimuthal alignment is essentially determined by the nucleation step. Oriented nucleation is only possible within a defined time window. Within this time window the azimuthal misalignment shows a characteristic variation depending on the absolute value of the bias voltage. The alignment of the SiC interlayer as measured by synchrotron radiation cannot explain the observed variation. In contrast, texture measurements of thick oriented films after exposure to the bias conditions suggest that the limitation of the process time window for oriented nucleation as well as the variation of misorientation with biasing time can be traced back to the detrimental effect of bias-assisted growth. Based on this mechanism, a model is proposed which allows one (a) to describe the temporal development of the azimuthal misorientation within the process time window, and (b) to estimate the contribution of bias-assisted growth on the misorientation. Finally, some epitaxial diamond films have been deposited on high-quality ?-SiC layers. A minimum value of 2.9° for the width of the azimuthal distribution has been found.

  3. Self-Lubricating, Wear-Resistant Diamond Films Developed for Use in Vacuum Environment

    NASA Technical Reports Server (NTRS)

    1996-01-01

    Diamond's outstanding properties--extreme hardness, chemical and thermal inertness, and high strength and rigidity--make it an ideal material for many tribological applications, such as the bearings, valves, and engine parts in the harsh environment found in internal-combustion engines, jet engines, and space propulsion systems. It has been demonstrated that chemical-vapor-deposited diamond films have low coefficients of friction (on the order of 0.01) and low wear rates (less than 10(sup -7) mm (sup 3/N-m)) both in humid air and dry nitrogen but that they have both high coefficients of friction (greater than 0.4) and high wear rates (on the order of 1(sup -4) mm sup 3/N-m)) in vacuum. It is clear that surface modifications that provide acceptable levels of friction and wear properties will be necessary before diamond films can be used for tribological applications in a space-like, vacuum environment. Previously, it was found that coatings of amorphous, non-diamond carbon can provide low friction in vacuum. Therefore, to reduce the friction and wear of diamond film in vacuum, carbon ions were implanted in an attempt to form a surface layer of amorphous carbon phases on the diamond films.

  4. Pulsed ion beam methods for in situ characterization of diamond film deposition processes

    SciTech Connect

    Krauss, A.R.; Smentkowski, V.S.; Zuiker, C.D.; Gruen, D.M. [Argonne National Lab., IL (United States); Im, J. [Argonne National Lab., IL (United States)]|[Northwestern Univ., Evanston, IL (United States). Dept. of Materials Science and Engineering; Schultz, J.A.; Waters, K. [Ionwerks Corp., Houston, TX (United States); Chang, R.P.H. [Northwestern Univ., Evanston, IL (United States). Dept. of Materials Science and Engineering

    1995-06-01

    Diamond and diamond-like carbon (DLC) have properties which in principle make them ideally suited to a wide variety of thin-film applications. Their widespread use as thin films, however, has been limited for a number of reasons related largely to the lack of understanding and control of the nucleation and growth processes. Real-time, in situ studies of the surface of the growing diamond film are experimentally difficult because these films are normally grown under a relatively high pressure of hydrogen, and conventional surface analytical methods require an ultrahigh vacuum environment. It is believed, however, that the presence of hydrogen during growth is necessary to stabilize the corrugated diamond surface structure and thereby prevent the formation of the graphitic phase. Pulsed ion beam-based analytical methods with differentially pumped ion sources and particle detectors are able to characterize the uppermost atomic layer of a film during, growth at ambient pressures 5-7 orders of magnitude higher than other surface-specific analytical methods. We describe here a system which has been developed for the purpose of determining the hydrogen concentration and bonding sites on diamond surfaces as a function of sample temperature and ambient hydrogen pressure under hot filament CVD growth conditions. It is demonstrated that as the hydrogen partial pressure increases, the saturation hydrogen coverage of the surface of a CVD diamond film increases, but that the saturation level depends on the atomic hydrogen concentration and substrate temperature.

  5. 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.

  6. Twin quintuplets in CVD diamond

    Microsoft Academic Search

    D. Shechtman; A. Feldman; J. L. Hutchison

    1992-01-01

    The atomic structure of twin quintuplets in a chemical vapor deposited (CVD) diamond film was - investigated by high resolution transmission electron microscopy (HRTEM). We conclude that the twin quintuplets have two main morphologies. The first consists of four Sigma = 3 twin boundaries and one Sigma = 81 twin boundary. The Sigma = 81 twin boundary contains the dislocations

  7. Diamond-like amorphous carbon

    Microsoft Academic Search

    J. Robertson

    2002-01-01

    Diamond-like carbon (DLC) is a metastable form of amorphous carbon with significant sp3 bonding. DLC is a semiconductor with a high mechanical hardness, chemical inertness, and optical transparency. This review will describe the deposition methods, deposition mechanisms, characterisation methods, electronic structure, gap states, defects, doping, luminescence, field emission, mechanical properties and some applications of DLCs. The films have widespread applications

  8. Diamond studded traveling wave tube

    Microsoft Academic Search

    J. A. Dayton; G. T. Mearini; H. Chen; C. L. Kory

    2004-01-01

    Summary form only given.. A novel method of mm wave traveling wave tube (TWT) slow wave circuit fabrication, employing laser micromachining and the in situ growth of diamond studs as an insulating dielectric, is being developed, which would enable a new class of very wideband, low distortion, high efficiency amplifiers. Because the slow wave circuit is supported by an array

  9. 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.

  10. Diamond Nanophotonics and Quantum Optics

    NASA Astrophysics Data System (ADS)

    Barclay, Paul

    2011-10-01

    The diamond nitrogen-vacancy (NV) center is an optically active impurity whose ``atom-like'' properties make it a promising solid state qubit, in which well-defined optical transitions are used to control the quantum state of single NV electron and nuclear spins. These properties have led to impressive demonstrations of quantum information storage in single NV nuclear spins, entanglement between NV electron spins and single photons, and implementations of high resolution optical magnetometers using single NVs. A missing ingredient for implementing quantum information processing architectures with NVs is creating scalable coherent coupling between them. Nanophotonic circuits, in which waveguides function as a ``quantum bus'' between NVs embedded in optical microcavities, offer a chip-based solution to this hurdle. In my talk I will review recent advances in realizing nanophotonic devices in diamond based materials. I will present results demonstrating Purcell enhanced coupling between optical nanocavities and NVs in single crystal diamond, and will discuss opportunities and challenges which lay ahead for diamond quantum optics.

  11. The characteristics of inorganic electroluminescent devices with an amorphous diamond film as cathode material

    Microsoft Academic Search

    Sea-Fue Wang; Jui-Chen Pu; James C. Sung

    2009-01-01

    Diamond like carbon (DLC) thin films were used as the cathode layers of inorganic alternating current driven thick dielectric electroluminescent devices. The results indicated that electroluminescent (EL) devices with DLC cathode has superior brightness over the EL with Al or Cr-doped DLC cathodes. Cr-doping in DLC thin film can increase the electrical conductivity, but degrades the EL properties. Also, the

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

    DOEpatents

    Westerfield, Curtis L. (Espanola, NM); Morris, John S. (Los Alamos, NM); Agnew, Stephen F. (Los Alamos, NM)

    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.

  13. Hot-iron-metal polishing machine for CVD diamond films and characteristics of the polished surfaces

    Microsoft Academic Search

    Masanori Yoshikawa; Fuminori Okuzumi

    1997-01-01

    We developed a technique to examine the presence of a damaged layer on a CVD diamond surface, caused by polishing, using etching in hydrogen plasma. Based on the results we developed an apparatus for polishing the flank face of a cutting insert edge using a hot-iron-metal method. Further, we carried out experiments to examine the cutting performance of cutting inserts

  14. Diamond Growth on Haynes 214 Alloy

    NASA Astrophysics Data System (ADS)

    Mihec, Damian F.; Baek, Sung Hyun; Metson, James B.

    A major target in diamond deposition is the growth of heteroepitaxial diamond films that are free from impurities, grain boundaries and defects for use in electronic applications. Nickel has been identified as a material with a close lattice match to diamond that minimises defect formation in diamond films but as a substrate, nickels' higher thermal expansion coefficient with respect to diamond, and the interfacial formation of amorphous and graphitic carbon before nucleation of diamond, leads to a weakened diamond/metal bond. Haynes 214 alloy is a nickel-based alloy used in high-temperature environments. Regions within this alloy contain amounts of aluminium known to affect the ability of nickel to stabilise amolphous carbon and graphite. Areas rich in aluminium discourage the formation of sp2 carbon, creating a barrier to carbon diffusion and allowing diamond nucleation to occur on the metal surface. Diamond deposition on Haynes 214 alloy using combustion assisted chemical vapour deposition (CACVD) rapidly produced a well structured, polycrystalline diamond film that typically delaminated with sample cooling. The film exhibited areas that were transparent corresponding to areas on the substrate rich in aluminium and dark areas matching nickel rich areas of the substrate surface catalysing the formation of amorphous and graphitic carbon.

  15. Multiple Diamond Anvil (MDA) apparatus using nano-polycrystalline diamond

    NASA Astrophysics Data System (ADS)

    Irifune, T.; Kunimoto, T.; Tange, Y.; Shinmei, T.; Isobe, F.; Kurio, A.; Funakoshi, K.

    2011-12-01

    Thanks to the great efforts by Dave Mao, Bill Bassett, Taro Takahashi, and their colleagues at the University of Rochester through 1960s-70s, diamond anvil cell (DAC) became a major tool to investigate the deep Earth after its invention by scientists at NBS in 1958. DAC can now cover almost the entire pressure and temperature regimes of the Earth's interior, which seems to have solved the longstanding debate on the crystal structure of iron under the P-T conditions of the Earth's inner core. In contrast, various types of static large-volume presses (LVP) have been invented, where tungsten carbide has conventionally been used as anvils. Kawai-type multianvil apparatus (MA), which utilize 6 first-stage harden steel and 8 tungsten carbide anvils, is the most successful LVP, and has been used for accurate measurements of phase transitions, physical properties, element partitioning, etc. at high pressure and temperature. However, pressures using tungsten carbide as the second-stage anvils have been limited to about 30 GPa due to significant plastic deformation of the anvils. Efforts have been made to expand this pressure limit by replacing tungsten carbide anvils with harder sintered diamond (SD) anvils over the last two decades, but the pressures available in KMA with SD anvils have still been limited to below 100 GPa. We succeeded to produce nano-polycrystalline diamond (NPD or HIME-Diamond) in 2003, which is known to have ultrahigh hardness, very high toughness and elastic stiffness, high transmittance of light, relatively low thermal conductivity. These properties are feasible for its use as anvils, and some preliminary experiments of application of NPD anvils to laser heated DAC have successfully made in the last few years. We are now able to synthesize NPD rods with about 1cm in both diameter and length using a newly constructed 6000-ton KMA at Geodynamics Research Center, Ehime University, and have just started to apply this new polycrystalline diamond as anvils for multianvil apparatus. Various versions of the Multiple Diamond Anvil (MDA) apparatus with NPD anvils (Fig.1), amalgamated forms of MA and DAC, are currently being tested for experiments under Mbar regimes without sacrificing the advantages of MA over DAC.

  16. Medical applications of diamond particles and surfaces.

    SciTech Connect

    Narayan, R. J.; Boehm, R. D.; Sumant, A. V. (Center for Nanoscale Materials); (Univ. of California)

    2011-04-01

    Diamond has been considered for use in several medical applications due to its unique mechanical, chemical, optical, and biological properties. In this paper, methods for preparing synthetic diamond surfaces and particles are described. In addition, recent developments involving the use of diamond in prostheses, sensing, imaging, and drug delivery applications are reviewed. These developments suggest that diamond-containing structures will provide significant improvements in the diagnosis and treatment of medical conditions over the coming years. Diamond is an allotrope of carbon that is being considered for use in several medical applications. Ramachandran determined that the crystal structure of diamond consists of two close packed interpenetrating face centered cubic lattices; one lattice is shifted with respect to the other along the elemental cube space diagonal by one-quarter of its length. If one approximates carbon atoms as equal diameter rigid spheres, the filling of this construction is 34%. Due to the carbon-carbon distance (1.54 {angstrom}), diamond crystal exhibits the highest atomic density (1.76 x 10{sup 23} cm{sup -3}) of any solid. The very high bond energy between two carbon atoms (83 kcal/mol) and the directionality of tetrahedral bonds are the main reasons for the high strength of diamond. Diamond demonstrates the highest Vickers hardness value of any material (10,000 kg/mm{sup 2}). The tribological properties of diamond are also impressive; the coefficient of friction of polished diamond is 0.07 in argon and 0.05 in humid air. Diamond is resistant to corrosion except in an oxygen atmosphere at temperatures over 800 C. In addition, type IIa diamond exhibits the highest thermal conductivity of all materials (20 W cm{sup -1} K{sup -1} at room temperature).

  17. 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 other suitable flow controller. When the liquid enters the low-pressure environment inside the chamber, it evaporates to form a vapor mixture of the same chemical composition. In addition to the inlet for the feedstock liquid, the chamber is fitted with an outlet connected to a vacuum pump (not shown) through a throttle valve (also not shown) that is automatically controlled to keep the pressure at or near the required value throughout the deposition process. Inside the chamber, a spiral filament made of tungsten, tantalum, graphite, or other high-melting-temperature material is electrically heated to a temperature >2,000 C high enough to cause dissociation of vapor molecules into the aforementioned radicals. A deposition substrate typically, a diamond-polished silicon wafer about 2.5 cm square is positioned about 2 cm away from the filament. The exact location of the substrate is chosen so that the substrate becomes heated by the filament to a deposition temperature in the approximate range of 800 to 1,000 C.

  18. Network-Aware Partitioning of Computation in Diamond

    E-print Network

    Network-Aware Partitioning of Computation in Diamond Alex Nizhner1 Larry Huston2 Peter Steenkiste Pittsburgh, PA 15213 Abstract The Diamond storage architecture enables efficient interactive search efficient use of resources under dynamic conditions, Diamond adaptively partitions computation among

  19. 78 FR 25363 - Airworthiness Directives; Diamond Aircraft Industries Airplanes

    Federal Register 2010, 2011, 2012, 2013, 2014

    2013-05-01

    ...2120-AA64 Airworthiness Directives; Diamond Aircraft Industries Airplanes AGENCY...new airworthiness directive (AD) for Diamond Aircraft Industries Model DA 40 NG airplanes...information identified in this AD, contact Diamond Aircraft Industries GmbH, N.A....

  20. 76 FR 48047 - Airworthiness Directives; Diamond Aircraft Industries Powered Sailplanes

    Federal Register 2010, 2011, 2012, 2013, 2014

    2011-08-08

    ...2120-AA64 Airworthiness Directives; Diamond Aircraft Industries Powered Sailplanes...new airworthiness directive (AD) for Diamond Aircraft Industries Model H-36 ``DIMONA...brake control system torsion tube on a Diamond (formerly Hoffman) H 36 powered...

  1. 76 FR 64793 - Airworthiness Directives; Diamond Aircraft Industries Powered Sailplanes

    Federal Register 2010, 2011, 2012, 2013, 2014

    2011-10-19

    ...2120-AA64 Airworthiness Directives; Diamond Aircraft Industries Powered Sailplanes...new airworthiness directive (AD) for Diamond Aircraft Industries Model H-36 ``DIMONA...brake control system torsion tube on a Diamond (formerly Hoffman) H 36 powered...

  2. Laser damage threshold of diamond films

    NASA Technical Reports Server (NTRS)

    Albin, Sacharia; Cropper, Andre D.; Watkins, Linwood C.; Byvik, Charles E.; Buoncristiani, A. Martin

    1989-01-01

    The possibility that diamond films may inhibit laser-induced damage to optical components in laser systems films was investigated by measuring laser damage thresholds of free-standing diamond film windows, diamond films deposited on silicon substrates, and bare silicon substrate. Polycrystalline diamond films were deposited using a dc plasma-enhanced CVD process. It was found that free-standing diamond films had the highest laser damage threshold at 1064 nm. For a diamond film of 630 nm, the damage threshold was found to be 7 J/sq cm, as compared to a damage threshold of 4.5 J/sq cm for bare silicon, and a low value of 1.5 J/sq cm for the film/substrate combination. The damage mechanism is considered to involve melting or dielectric breakdown induced by laser radiation. The low value of the film/substrate combination is attributed to film stress and conditions of film deposition.

  3. High crystalline quality single crystal chemical vapour deposition diamond

    NASA Astrophysics Data System (ADS)

    Martineau, P. M.; Gaukroger, M. P.; Guy, K. B.; Lawson, S. C.; Twitchen, D. J.; Friel, I.; Hansen, J. O.; Summerton, G. C.; Addison, T. P. G.; Burns, R.

    2009-09-01

    Homoepitaxial chemical vapour deposition (CVD) on high pressure, high temperature (HPHT) synthetic diamond substrates allows the production of diamond material with controlled point defect content. In order to minimize the extended defect content, however, it is necessary to minimize the number of substrate extended defects that reach the initial growth surface and the nucleation of dislocations at the interface between the CVD layer and its substrate. X-ray topography has indicated that when type IIa HPHT synthetic substrates are used, the density of dislocations nucleating at the interface can be less than 400 cm-2. X-ray topography, photoluminescence imaging and birefringence microscopy of HPHT grown synthetic type IIa diamond clearly show that the extended defect content is growth sector dependent. lang111rang sectors contain the highest concentration of both stacking faults and dislocations but lang100rang sectors are relatively free of both. It has been shown that HPHT treatment of such material can significantly reduce the area of stacking faults and cause dislocations to move. This knowledge, coupled with an understanding of how growth sectors develop during HPHT synthesis, has been used to guide selection and processing of substrates suitable for CVD synthesis of material with high crystalline perfection and controlled point defect content.

  4. Friction between silicon and diamond at the nanoscale

    NASA Astrophysics Data System (ADS)

    Bai, Lichun; Sha, Zhen-Dong; Srikanth, Narasimalu; Pei, Qing-Xiang; Wang, Xu; Srolovitz, David J.; Zhou, Kun

    2015-06-01

    This work investigates the nanoscale friction between diamond-structure silicon (Si) and diamond via molecular dynamics simulation. The interaction between the interfaces is considered as strong covalent bonds. The effects of load, sliding velocity, temperature and lattice orientation are investigated. Results show that the friction can be divided into two stages: the static friction and the kinetic friction. During the static friction stage, the load, lattice orientation and temperature dramatically affects the friction by changing the elastic limit of Si. Large elastic deformation is induced in the Si block, which eventually leads to the formation of a thin layer of amorphous Si near the Si-diamond interface and thus the beginning of the kinetic friction stage. During the kinetic friction stage, only temperature and velocity have an effect on the friction. The investigation of the microstructural evolution of Si demonstrated that the kinetic friction can be categorized into two modes (stick-slip and smooth sliding) depending on the temperature of the fracture region.

  5. Halogen geochemistry of mantle fluids in diamond

    Microsoft Academic Search

    R. Burgess; G. Turner

    1995-01-01

    Argon and halogens (Cl, Br and I) have been measured, using 40Ar-39 Ar stepped heating method, in diamonds from Jwaneng, Orapa (both in Botswana) and Zaire. The samples analysed included cubic (coated) stones and polycrystalline diamonds of eclogitic association. Both these types of diamond contain H2O, CO2, carbonate and silicate inclusions. Coated stones have relatively constant 40Ar*\\/Cl and Br\\/Cl, show

  6. The equilibrium boundary between grahite and diamond

    Microsoft Academic Search

    C. Scott Kennedy; George C. Kennedy

    1976-01-01

    The equilibrium boundary between diamond and graphite has been determined over the temperature interval 1100°C-1625°C. A piston-cylinder apparatus and a ''zero-friction'' cell were used. Pressures were computed by force\\/area measurements and are independent of any calibration points. Visual observations of diamond dissolution or diamond growth were used in fixing the position of the boundary. Our newly determined boundary has the

  7. High sensitivity thermal sensors on insulating diamond

    Microsoft Academic Search

    R. Job; A. V. Denisenko; A. M. Zaitsev; A. A. Melnikov; M. Werner; W. R. Fahrner

    1996-01-01

    Diamond is a promising material to develop sensors for applications in harsh environments. To increase the sensitivity of diamond temperature sensors the effect of thermionic hole emission (TE) over an energetic barrier formed in the interface between highly boron-doped p-type and intrinsic insulating diamond areas has been suggested. To study the TE of holes a p-i-p diode has been fabricated

  8. Ultraviolet photoresponse characteristics of diamond diodes

    NASA Astrophysics Data System (ADS)

    Marchywka, M.; Goldberg, R. T.; Hochedez, J. F.; Geis, M. W.; Socker, D. G.; Moses, D.

    1991-12-01

    It is suggested that the passive diamond surface should allow a stable VUV response, thus eliminating a serious shortcoming of existing solid-state VUV detectors. The mechanical superiority and electrical similarity of diamond compared to silicon suggest that 2D imagers of this type may be feasible. Three different devices were investigated: an Al-diamond Schottky diode, and two structures believed to be np diodes. Photoresponse measurements were made, and favorable results were obtained.

  9. Interlayers for diamond deposition on tool materials

    Microsoft Academic Search

    I. Endler; A. Leonhardt; H.-J. Scheibe; R. Born

    1996-01-01

    The direct deposition of diamond on such tool materials as hard metals and steels is difficult because graphitization occurs and adhesion is poor. The following hard coatings have been investigated concerning their suitability as interlayers for diamond growth: TiN, TiC, Si3N4, SiC, SiCxNy, (Ti, Si)Nx and pulsed arc deposited a-C (laser-arc). The diamond deposition was performed by hot-filament CVD. A

  10. Strength properties of diamond-metal strip

    Microsoft Academic Search

    V. K. Sorokin

    1977-01-01

    1.It has been established that the principal factors determining the strength of 40-to 80-µ-thick diamond-metal strip with a copper-tin-nickel binder after strengthening consisting of quenching, plastic working, and aging are the diamond powder concentration and strip thickness.2.It is shown that the strength of metal strip containing a diamond powder without a metal coating can be calculated with the equations proposed

  11. Diamond coated inserts, drills, and end mills

    SciTech Connect

    Suzuki, T.; Hattori, T.; Endo, A. [Toshiba Tungaloy Co., Ltd., Kawasaki (Japan)] [and others

    1995-12-31

    Current status of chemical vapor deposition (CVD) diamond for the application to cutting tools was briefly summarized, focused on microstructures, adhesion strength and cutting performance. Diamond-coated cemented carbide inserts, drills and end mills were tested against Al-Si alloys and problems for expanding tool market were also discussed. Further, the potential use of thick diamond films for replacing with PCD was described.

  12. 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.

  13. RAPID COMMUNICATION: Nanostructured diamond film deposition on curved surfaces of metallic temporomandibular joint implant

    NASA Astrophysics Data System (ADS)

    Fries, Marc D.; Vohra, Yogesh K.

    2002-10-01

    Microwave plasma chemical vapour deposition of nanostructured diamond films was carried out on curved surfaces of Ti-6Al-4V alloy machined to simulate the shape of a temporomandibular joint (TMJ) dental implant. Raman spectroscopy shows that the deposited films are uniform in chemical composition along the radius of curvature of the TMJ condyle. Thin film x-ray diffraction reveals an interfacial carbide layer and nanocrystalline diamond grains in this coating. Nanoindentation hardness measurements show an ultra-hard coating with a hardness value of 60+/-5 GPa averaged over three samples.

  14. 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.

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

    DOEpatents

    Pern, Fu-Jann (Golden, CO); Touryan, Kenell J. (Indian Hills, CO); Panosyan, Zhozef Retevos (Yerevan, AM); Gippius, Aleksey Alekseyevich (Moscow, RU)

    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.

  16. Nano-crystalline tungsten carbide: As incompressible as diamond

    SciTech Connect

    Lin, Zhijun; Wang, Lin; Zhang, Jianzhong; Mao, Ho-kwang; Zhao, Yusheng

    2009-01-01

    We investigate the compressibility of nanocrystalline tungsten carbide (nano-WC) using synchrotron x-ray diffraction. Nano-WC displays a bulk modulus (452 GPa) comparable to that of diamond; it is 10%–15% larger than previously reported values for bulk WC. This finding is consistent with a generalized model of nanocrystal with a compressed surface layer. The linear bulk moduli of nano-WC along a- and c-axes were determined to be 407 and 546 GPa, respectively. First-principles density functional theory (DFT) calculations confirm the experimental observations of an anisotropic linear compressibility and a lower bulk modulus for microsized WC.

  17. Diamond Theory: Symmetry in Binary Spaces

    NSDL National Science Digital Library

    Cullinane, Steven.

    This Web site provides detailed discussions of Diamond Theory, and is intended for college math students or mathematicians. Diamond Theory, according to the author, is best classified in the subject of "finite automorphism groups of algebraic, geometric, or combinatorial structures." The main focus of the material is the technical aspects of the concept, but there are some references to its philosophical beginnings. Despite having extensive information on this site, the author also includes several links to offsite resources. The "Diamond 16 Puzzle" is a curious challenge that might be easier after learning about the Diamond Theory.

  18. Electrochemical patterning of amorphous carbon on diamond

    NASA Technical Reports Server (NTRS)

    Marchywka, Mike; Pehrsson, Pehr E.; Binari, Steven C.; Moses, Daniel

    1993-01-01

    The ability to pattern ion-implantation damaged or other nondiamond carbon on a diamond substrate is useful for fabricating a variety of devices. We accomplished such patterning by an unmasked implantation into a diamond substrate followed by photolithography and a selective electrochemical etch. The use of a high resistivity medium coupled with applied biases over 50 V permitted etching without requiring contact between the substrate and an electrode. Many electrolytes gave etches that exhibit high selectivity for nondiamond carbon over both diamond and dielectrics such as photoresist. Optical, electrical, and Raman spectroscopic measurements elucidate the effects of the etch on the implanted diamond surface.

  19. Whole cell environmental biosensor on diamond.

    PubMed

    Chong, Kwok Feng; Loh, Kian Ping; Ang, Kailian; Ting, Yen Peng

    2008-06-01

    A whole-cell environmental biosensor was fabricated on a diamond electrode. Unicellular microalgae Chlorella vulgaris was entrapped in the bovine serum albumin (BSA) membrane and immobilized directly onto the surface of a diamond electrode for heavy metal detection. We found that the unique surface properties of diamond reduce the electrode fouling problem commonly encountered with metal electrodes. The cell-based diamond biosensor can attain a detection limit of 0.1 ppb for Zn(2+) and Cd(2+), and exhibits higher detection sensitivity and stability compared to platinum electrodes. PMID:18493672

  20. Crystallographic relationships between diamond and its inclusions

    NASA Astrophysics Data System (ADS)

    Nimis, Paolo; Nestola, Fabrizio; Angel, Ross J.; Milani, Sula; Alvaro, Matteo; Anzolini, Chiara; Schiazza, Mariangela; Bruno, Marco; Prencipe, Mauro; Harris, Jeff W.; Hutchison, Mark T.

    2015-04-01

    The study of the crystallographic orientations of minerals included in diamonds can provide an insight into the mechanisms of their incorporation and the timing of their formation relative to the host diamond. The reported occurrence of non-trivial orientations for some minerals in some diamonds, suggesting an epitactic relationship, has long been considered to reflect contemporaneous growth of the diamond and the inclusion (= syngenesis). Correct interpretation of such orientations requires (i) a statistically significant data set, i.e. crystallographic data for single and multiple inclusions in a large number of diamonds, and (ii) a robust data-processing method, capable of removing ambiguities derived from the high symmetry of the diamond and the inclusion. We have developed software which performs such processing, starting from crystallographic orientation matrixes obtained by X-ray diffractometry. Preliminary studies indicate a wide variety of trends in the orientations of different inclusion phases in diamonds. In contrast to previous claims, olivine inclusions in lithospheric diamonds from Udachnaya do not show any preferred orientations with respect to their diamond hosts, but multiple inclusions in a single diamond often show very similar orientations within a few degrees (Nestola et al. 2014). Chromite (spinel) inclusions exhibit a strong tendency for a single (111) plane of each inclusion to be parallel to a (111) plane of their diamond host, but without any statistically significant orientation of the crystallographic axes a, b, and c. By contrast, 7 inclusions of ferropericlase studied in 2 different super deep diamonds (four inclusions in one diamond and three inclusions in the second diamond) from Brazil all exhibit the same orientation with their axes practically coincident with those of diamonds regardless of the position and the shape of the inclusions. The implications of these observations for the mechanisms of diamond growth will be explored. This work was supported by ERC starting grant 307322 to F. Nestola and Alfred P. Sloan Foundation's Deep Carbon Observatory project to P. Nimis. Nestola F., et al. (2014) Int Geol Rev, 56,1658-1667.

  1. Electrical properties of diamond nanostructures

    NASA Astrophysics Data System (ADS)

    Bevilacqua, M.

    Nanocrystalline diamond films (NCD) can potentially be used in a large variety of applications such as electrochemical electrodes, tribology, cold cathodes, and corrosion resistance. A thorough knowledge of the electrical properties of NCD films is therefore critical to understand and predict their performance in various applications. In the present work the electrical properties of NCD films were analysed using Impedance Spectroscopy and Hall Effect measurements. Impedance Spectroscopy permits to identify and single out the conduction paths within the films tested. Such conduction paths can be through grain interiors and/or grain boundaries. Hall measurements, carried out on Boron doped NCD, permits determination of the mobility of the films. Specific treatments were devised to enhance the properties of the NCD films studied. Detonation nanodiamond (DND) is becoming an increasingly interesting material. It is already used as abrasive material or component for coatings [1], but its potential applications can extend far beyond these. It is therefore essential to understand the structure and electrical properties of DND in order to exploit the full potential of this material. In the present work, electrical properties of DND were studied using Impedance Spectroscopy. The results obtained suggest that DND could be used to manufacture devices able to work as Ammonia detectors. Another major area of study in this work was ultra-violet diamond photodetectors. Using high quality CVD single-crystal diamond, UV photodetection devices were built using standard lithographic techniques. Following the application of heat treatments, the photoconductive properties of these devices were highly enhanced. The devices represent the state-of-the-art UV diamond photodetectors.

  2. 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.

  3. Diamond Detectors as Beam Monitors

    E-print Network

    Dehning, B; Dobos, D; Pernegger, H; Griesmayer, E

    2010-01-01

    CVD diamond particle detectors are already in use in the CERN experiments ATLAS, CMS, LHCb and ALICE and at various particle accelerator laboratories in USA and Japan. This is a proven technology with high radiation tolerance and very fast signal read-out. It can be used for measuring single-particles as well as for high-intensity particle cascades, for timing measurements on the nanosecond scale and for beam protection systems. The radiation tolerance is specified with 10 MGy.

  4. Surface passivation in diamond nucleation

    NASA Astrophysics Data System (ADS)

    Lee, C. H.; Lin, Z. D.; Shang, N. G.; Liao, L. S.; Bello, I.; Wang, N.; Lee, S. T.

    2000-12-01

    Surface passivation is introduced to suppress the deleterious effect of Si surface oxides and thus enhance diamond heteroepitaxial nucleation. Surface composition and diamond nucleation and growth on H-, Br-, and I-passivated Si surfaces were studied. X-ray photoelectron spectroscopy showed that the passivated Si surfaces were free of silicon oxides and carbides. Remarkable enhancement in nucleation was achieved on passivated surfaces and the nucleation density obtained on a Br-passivated Si surface reached 1010 cm-2. Programmable temperature desorption revealed that the adsorbate desorption temperature increased in the order of H, I, and Br passivation. The same order of increase was also observed in the saturation value of electron emission current from the passivated surfaces, which was related to the degree of nucleation. Nucleation enhancement was shown to be greater when the adsorbate desorption temperature is closer to the nucleation temperature, so that more adsorbate- and oxide-free Si surface area would be available for nucleation. The study established that surface passivation is potentially an effective approach for diamond heteroepitaxial nucleation.

  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. Formation of silicon-on-diamond by direct bonding of plasma-synthesized diamond-like carbon to silicon

    SciTech Connect

    Zhu Ming; Chu, Paul K; Shi Xuejie; Wong Man; Liu Weili; Lin Chenglu [Department of Physics and Materials Science, City University of Hong Kong, Tat Chee Avenue, Kowloon, Hong Kong (China); Department of Electrical and Electronic Engineering, The Hong Kong University of Science and Technology, Clear Water Bay, Kowloon, Hong Kong (China); Research Center of Functional Semiconductor Film Engineering and Technology, Shanghai Institute of Microsystem and Information Technology, Chinese Academy of Sciences, 865 Changning Road, 200050 Shanghai (China)

    2004-09-27

    We propose to replace the buried SiO{sub 2} layer in silicon-on-insulator with a plasma synthesized diamond-like-carbon (DLC) thin film to mitigate the self-heating effects. The DLC films synthesized on silicon by a plasma immersion ion implantation and deposition process exhibit outstanding surface topography, and excellent insulating properties are maintained up to an annealing temperature of 900 deg. C. Hence, the degree of graphitization in our DLC materials is insignificant during thin-film transistor processing and even in most annealing steps in conventional complementary metal oxide silicon processing. Using Si/DLC direct bonding and the hydrogen-induced layer transfer method, a silicon-on-diamond structure has been fabricated. Cross-sectional high-resolution transmission electron microscopy reveals that the bonded interface is abrupt and the top Si layer exhibits nearly perfect single crystalline quality. A model is postulated to describe the reactions occurring at the interface during the annealing steps in Si-DLC wafer bonding.

  7. PREFACE: Science's gem: diamond science 2009 Science's gem: diamond science 2009

    NASA Astrophysics Data System (ADS)

    Mainwood, Alison; Newton, Mark E.; Stoneham, Marshall

    2009-09-01

    Natural diamond has been valued for its appearance and mechanical properties for at least two thousand years. As a gem stone diamond is unsurpassed. However, scientific work, especially in the last 20 years, has demonstrated that diamond has numerous surprising properties and many unique ones. Some of the extreme properties have been known for many years, but the true scale of diamond's other highly desirable features is still only coming to light as control in the synthesis of diamond, and hence material perfection, improves. The ultimate prize for man-made diamond is surely not in the synthesis of gem stones, but in delivering technological solutions enabled by diamond to the challenges facing our society today. If the special properties are to be exploited to their full potential, at least four crucial factors must be considered. First, there must be sufficient scientific understanding of diamond to make applications effective, efficient and economical. Secondly, the means of fabrication and control of properties have to be achieved so that diamond's role can be optimised. Thirdly, it is not enough that its properties are superior to existing materials: they must be so much better that it is worth initiating new technologies to exploit them. Finally, any substantial applications will have to address the society's major needs worldwide. The clear technology drivers for the 21st century come from the biomedical technologies, the demand for energy subject to global constraints, and the information technologies, where perhaps diamond will provide the major enabling technology [1]. The papers in this volume concern the solid state physics of diamond, and primarily concern the first two factors: understanding, and control of properties. They address many of the outstanding basic problems, such as the identification of existing defects, which affect the material's properties, both desirable and less so. Regarding future substantial applications, one paper discusses diamond's exceptional properties for quantum information processing [2], a topic on which there have been many recent papers, and where a diamond colour centre single photon source is already commercially available. Biomedical applications of diamond are recognised, partly tribological and partly electrochemical, but lie outside the present group of papers. Processing and controlling diamond surfaces and interfaces with other materials in their environment are critical steps en route to exploitation. Boron-doped diamond has already found application in electro-analysis and in the bulk oxidation of dissolved species in solution [3]. Energy-related applications—ranging from high-power electronics [3] to a potential first wall of fusion reactors [4]—are further exciting potential applications. Even small and ugly diamonds have value. Their mechanical properties [5] dominate, with significant niche applications such as thermal sinks. The major applications for diamond to date exploit only a fraction of diamond's special properties: visual for status diamonds, and mechanical for working diamonds. Diamond physics reaches well beyond the usual laboratory, to the geological diamond formation processes in the Earth's mantle. Characterization of natural gem diamonds [6, 7] is one part of the detective story that allows us to understand the conditions under which they formed. It was only half a century ago that the scientific and technological challenges of diamond synthesis were met systematically. Today, most of the recent research on diamond has concentrated on synthetics, whether created using high pressure, high temperature (HPHT) techniques or chemical vapour deposition (CVD). The HPHT synthesis of diamond has advanced dramatically [8, 9] to the extent that dislocation birefringence [10] can be largely eliminated. In silicon technology, the elimination of dislocations was a major step in microelectronics. Now, even diamond can be synthesised containing virtually no dislocations. The understanding of the critical processes that are involved in CVD diamond growth are

  8. 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: ?13C 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 ?13C 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 ?13C with decreasing residence temperature (proxy for decreasing depth) is interpreted to reflect diamond formation from a carbonate-bearing metasomatic fluid/melt that isotopically evolves as it percolates upward through the lithosphere.

  9. Growth and characterization of Eu:Y{sub 2}O{sub 3} thin-film phosphors on silicon and diamond-coated silicon substrates

    SciTech Connect

    Cho, K.G.; Kumar, D.; Jones, D.L.; Lee, D.G.; Holloway, P.H.; Singh, R.K. [Univ. of Florida, Gainesville, FL (United States). Dept. of Materials Science and Engineering

    1998-10-01

    Europium-activated yttrium oxide (Eu:Y{sub 2}O{sub 3}) phosphor films have been grown in situ on (100) bare silicon and diamond-coated silicon substrates using a pulsed laser deposition technique. Diamond-coated silicon substrates were prepared by hot filament chemical vapor deposition onto (100) silicon wafers. Measurements of photoluminescence and cathodoluminescence properties of Eu:Y{sub 2}O{sub 3} films have shown that the films grown on diamond-coated silicon substrates are brighter than the films grown on bare silicon substrates under identical deposition conditions. The improved brightness of the Eu:Y{sub 2}O{sub 3} films on diamond-coated silicon substrates is attributed to reduced internal reflection, low photon energy absorption by substrate, and enhanced scattering of incident beam with lattice. All these effects are primarily brought about by the presence of a rough diamond interfacial layer between the phosphor films and substrates.

  10. Diamond Growth in the Subduction Factory

    NASA Astrophysics Data System (ADS)

    Bureau, H.; Frost, D. J.; Bolfan-Casanova, N.; Leroy, C.; Estève, I.

    2014-12-01

    Natural diamonds are fabulous probes of the deep Earth Interior. They are the evidence of the deep storage of volatile elements, carbon at first, but also hydrogen and chlorine trapped as hydrous fluids in inclusions. The study of diamond growth processes in the lithosphere and mantle helps for our understanding of volatile elements cycling between deep reservoirs. We know now that inclusion-bearing diamonds similar to diamonds found in nature (i.e. polycrystalline, fibrous and coated diamonds) can grow in hydrous fluids or melts (Bureau et al., GCA 77, 202-214, 2012). Therefore, we propose that the best environment to promote such diamonds is the subduction factory, where highly hydrous fluids or melts are present. When oceanic plates are subducted in the lithosphere, they carry an oceanic crust soaked with seawater. While the slabs are traveling en route to the mantle, dehydration processes generate saline fluids highly concentrated in NaCl. In the present study we have experimentally shown that diamonds can grow from the saline fluids (up to 30 g/l NaCl in water) generated in subducted slabs. We have performed multi-anvil press experiments at 6-7 GPa and from 1300 to 1400°C during 6:00 hours to 30:00 hours. We observed large areas of new diamond grown in epitaxy on pure diamond seeds in salty hydrous carbonated melts, forming coated gems. The new rims are containing multi-component primary inclusions. Detailed characterizations of the diamonds and their inclusions have been performed and will be presented. These experimental results suggest that multi-component salty fluids of supercritical nature migrate with the slabs, down to the deep mantle. Such fluids may insure the first stage of the deep Earth's volatiles cycling (C, H, halogen elements) en route to the transition zone and the lower mantle. We suggest that the subduction factory may also be a diamond factory.

  11. 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.

  12. Microstructure and mechanical properties of diamond films on titanium-aluminum-vanadium alloy

    NASA Astrophysics Data System (ADS)

    Catledge, Shane Aaron

    The primary focus of this dissertation is the investigation of the processing-structure-property relationships of diamond films deposited on Ti-6Al-4V alloy by microwave plasma chemical vapor deposition (MPCVD). By depositing a well-adhered protective layer of diamond on an alloy component, its hardness, wear-resistance, performance, and overall lifetime could be significantly increased. However, due to the large thermal expansion mismatch between the diamond film and metal (and the corresponding residual stress induced in the film), film adhesion is typically unsatisfactory and often results in immediate delamination after processing. Therefore, it is a major goal of this research to improve adhesion of the diamond film to the alloy substrate. Through the use of innovative processing techniques involving MPCVD deposition conditions and methane (CH4), nitrogen (N2), and hydrogen (H2) chemistry, we have achieved diamond films which consistently adhere to the alloy substrate. In addition, we have discovered that, with the appropriate choice of deposition conditions, the film structure can be tailored to range from highly crystalline, well-faceted diamond to nanocrystalline diamond with extremely low surface roughness (as low as 27 nm). The relationship between processing and structure was studied using in-situ optical emission spectroscopy, micro-Raman spectroscopy, surface profilometry, glancing-angle x-ray diffraction, and scanning electron microscopy. We observe that when nitrogen is added to the H2/CH4 feedgas mixture, a carbon-nitrogen (CN) emission band arises and its relative abundance to the carbon dimer (C2) gas species is shown to have a pronounced influence on the diamond film structure. By appropriate choice of deposition chemistry and conditions, we can tailor the diamond film structure and its corresponding properties. The mechanical properties of interest in this thesis are those relating to the integrity of the film/substrate interface, as well as the hardness, wear resistance, residual stress, and elastic modulus of the film. The mechanical properties of the diamond coatings were characterized by indentation and wear testing instruments. Finally, we developed a model based on fundamental thermodynamic and optical principles for extracting the time dependence of film thickness and surface roughness using optical pyrometry for the case of an absorbing substrate. This model provides a convenient way to determine film thickness during growth in CVD systems as well as a reliable estimate of surface roughness.

  13. Heteroepitaxial growth of cubic boron nitride films on single-crystalline (001) diamond substrates

    NASA Astrophysics Data System (ADS)

    Zhang, X. W.; Boyen, H.-G.; Ziemann, P.; Banhart, F.

    2005-02-01

    Heteroepitaxial cubic boron nitride (c-BN) films of significantly improved crystalline quality have successfully been deposited on (001) diamond single crystals using an ion beam assisted preparation method. The results of various characterization techniques prove that films containing 100% pure c-BN phase were nucleated directly on top of diamond without any intermediate hexagonal BN layer. Epitaxially grown, 500-nm-thick c-BN films are mechanically stable even under ambient conditions, though they still exhibit a compressive stress of 5 GPa. Their rocking angles of 0.2°, as observed by X-ray diffraction, point to a hitherto unprecedented quality of the films. Their surface smoothness, the magnitude of their Young’s modulus as well as their ultrahardness corroborate the outstanding quality of these epitaxially grown c-BN films on single-crystalline diamond.

  14. Thermal Conduction in Suspended Graphene Layers

    Microsoft Academic Search

    A. A. Balandin; S. Ghosh; D. L. Nika; E. P. Pokatilov

    2010-01-01

    We review the results of our experimental and theoretical investigation of heat conduction in suspended graphene layers. Through direct measurements using a noncontact optical technique, we established that the thermal conductivity of the suspended graphene flakes is extremely high, and exceeds that of diamond and carbon nanotubes. By invoking Klemens' theoretical model, we explained the physical mechanisms behind such unusual

  15. Diamond film growth from fullerene precursors

    DOEpatents

    Gruen, Dieter M. (Downers Grove, IL); Liu, Shengzhong (Woodridge, IL); Krauss, Alan R. (Naperville, IL); Pan, Xianzheng (Woodridge, IL)

    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.

  16. Double bevel construction of a diamond anvil

    DOEpatents

    Moss, William C. (San Mateo, CA)

    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.

  17. Diamond film growth argon-carbon plasmas

    DOEpatents

    Gruen, Dieter M. (Downers Grove, IL); Krauss, Alan R. (Naperville, IL); Liu, Shengzhong (Canton, MI); Pan, Xianzheng (Wuhan Hubei, CN); Zuiker, Christopher D. (LaGrange, IL)

    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.

  18. The Larger Diamonds of South Africa

    Microsoft Academic Search

    L. J. Spencer

    1911-01-01

    HE inquiry that I have recently made into the weight of the 'Cul- )inau diamond 1 has led me to clear up, as far as possible, various discrepancies in the published statements respecting the other large diamonds of South Africa. Although a knowledge of the exact weights of these stones is a matter of only trivial scientific importance, yet it

  19. Fluorinated diamond bonded in fluorocarbon resin

    DOEpatents

    Taylor, Gene W. (Los Alamos, NM)

    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.

  20. Heteroepitaxy of nickel and copper on diamond

    NASA Astrophysics Data System (ADS)

    Evlashin, S. A.; Martovitskii, V. P.; Khmel'nitskii, R. A.; Stepanov, A. S.; Suetin, N. V.; Pashchenko, P. V.

    2012-05-01

    Crystalline nickel and copper possess bcc lattices, the parameters of which are 1.2 and 1.35% smaller than that of diamond. Heteroepitaxial Ni and Cu films have been grown by magnetron sputtering on polished and then thermally annealed and etched {100} and {110} surfaces of natural diamond. The films exhibit island morphology and possess a highly perfect crystalline structure.

  1. Single Color Centers Implanted in Diamond Nanostructures

    E-print Network

    Birgit J. M. Hausmann; Thomas M. Babinec; Jennifer T. Choy; Jonathan S. Hodges; Sungkun Hong; Irfan Bulu; A. Yacoby; M. D. Lukin; Marko Lon?ar

    2010-09-21

    The development of materials processing techniques for optical diamond nanostructures containing a single color center is an important problem in quantum science and technology. In this work, we present the combination of ion implantation and top-down diamond nanofabrication in two scenarios: diamond nanopillars and diamond nanowires. The first device consists of a 'shallow' implant (~20nm) to generate Nitrogen-vacancy (NV) color centers near the top surface of the diamond crystal. Individual NV centers are then isolated mechanically by dry etching a regular array of nanopillars in the diamond surface. Photon anti-bunching measurements indicate that a high yield (>10%) of the devices contain a single NV center. The second device demonstrates 'deep' (~1\\mu m) implantation of individual NV centers into pre-fabricated diamond nanowire. The high single photon flux of the nanowire geometry, combined with the low background fluorescence of the ultrapure diamond, allows us to sustain strong photon anti-bunching even at high pump powers.

  2. Integrated diamond networks for quantum nanophotonics

    E-print Network

    Birgit J. M. Hausmann; Brendan Shields; Qimin Quan; Patrick Maletinsky; Murray McCutcheon; Jennifer T. Choy; Tom M. Babinec; Alexander Kubanek; Amir Yacoby; Mikhail D. Lukin; Marko Loncar

    2012-01-05

    Diamond is a unique material with exceptional physical and chemical properties that offers potential for the realization of high-performance devices with novel functionalities. For example diamond's high refractive index, transparency over wide wavelength range, and large Raman gain are of interest for the implementation of novel photonic devices. Recently, atom-like impurities in diamond emerged as an exceptional system for quantum information processing, quantum sensing and quantum networks. For these and other applications, it is essential to develop an integrated nanophotonic platform based on diamond. Here, we report on the realization of such an integrated diamond photonic platform, diamond on insulator (DOI), consisting of a thin single crystal diamond film on top of an insulating silicon dioxide/silicon substrate. Using this approach, we demonstrate diamond ring resonators that operate in a wide wavelength range, including the visible (630nm) and near-infrared (1,550nm). Finally, we demonstrate an integrated, on-chip quantum nanophotonic network, consisting of ring resonators coupled to low loss waveguides with grating couplers, that enables the generation and efficient routing of single photons at room temperature.

  3. Comparisons of Scintillating Fiber, Diamond Particle Detector

    E-print Network

    McDonald, Kirk

    _AB_note.pdf guard ring electrode #12;Response of diamond particle detector using injection 241Am @ 5.5 MeV 241Am detector using 193 nm ArF laser laser illumination location #12;Response of diamond particle detector using

  4. Diamond-Based Dielectric Loaded Accelerating Structures

    NASA Astrophysics Data System (ADS)

    Antipov, Sergey; Schoessow, Paul; Kanareykin, Alexei; Jing, Chunguang; Altmark, Alexander; Gai, Wei

    2010-11-01

    Diamond is an excellent material for dielectric loaded accelerating structures. It has a high breakdown threshold, very low dielectric losses and an extremely high coefficient of thermal conductance. In this paper we review progress on the design and development of diamond—based accelerating structures in the GHz—THz frequency range.

  5. 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)

  6. Energy Harvesting Diamond Channel with Energy Cooperation

    E-print Network

    Ulukus, Sennur

    Energy Harvesting Diamond Channel with Energy Cooperation Berk Gurakan Sennur Ulukus Department@umd.edu Abstract--We consider the energy harvesting diamond channel, where the source and two relays harvest energy the option of wirelessly transferring some of its energy to the relays via energy cooperation. We find

  7. Precision micromachining of CVD diamond films

    Microsoft Academic Search

    J. K Park; V. M Ayres; J Asmussen; K Mukherjee

    2000-01-01

    The laser ablation technique has been extensively recognized to be a unique method for the micromachining and designing of micro components. Chemical vapor deposited (CVD) diamond films have been processed by various types of pulsed lasers for this purpose. Nanosecond pulsed excimer lasers, and recently femtosecond pulsed lasers have been used for the micromachining of diamond films. Even though the

  8. CVD diamond coated cemented carbide cutting tools

    Microsoft Academic Search

    J. Karner; M. Pedrazzini; I. Reineck; E. Bergmann

    1996-01-01

    The development of CVD diamond coated cutting tools has faced several challenges since the commencement of the low pressure synthesis of diamond coatings from a vapor mixture of hydrogen and a carbon containing gas based on the original work by Derjaguin and Fedoseev.The reason for the fairly slow progress can be attributed to a number of problems. For example, obtaining

  9. ORIGINAL PAPER Nanocrystalline Diamond Thin Films Synthesis

    E-print Network

    Qin, Qinghua

    ­4]. They have been synthesized by various CVD technologies, such as DCPJCVD [5, 6], Pulsed laser deposition (PLD, 17] only synthesized small size micron level curved surface diamond thin films by HF-CVD. This mightORIGINAL PAPER Nanocrystalline Diamond Thin Films Synthesis on Curved Surface Duosheng Li · Qing H

  10. Radiation hardness studies of CVD diamond detectors

    Microsoft Academic Search

    C. Bauer; I. Baumann; C. Colledani; J. Conway; P. Delpierre; F. Djama; W. Dulinski; A. Fallou; K. K. Gan; R. S. Gilmore; E. Grigoriev; G. Hallewell; S. Han; T. Hessing; K. Honschied; J. Hrubec; D. Husson; H. Kagan; D. Kania; R. Kass; W. Kinnison; K. T. Knöpfle; M. Krammer; T. J. Llewellyn; P. F. Manfredi; L. S. Pan; H. Pernegger; M. Pernicka; R. Plano; V. Re; S. Roe; A. Rudge; M. Schaeffer; S. Schnetzer; S. Somalwar; V. Speziali; R. Stone; R. J. Tapper; R. Tesarek; W. Trischuk; R. Turchetta; G. B. Thomson; R. Wagner; P. Weilhammer; C. White; H. Ziock; M. Zoeller

    1995-01-01

    The inherent properties of diamond make it an ideal material for tracking detectors especially in the high rate, high radiation environments of future colliders such as the LHC. In order to survive in this environment, detectors must be radiation hard. We have constructed charged particle detectors using high quality CVD diamond and performed radiation hardness tests on them. The signal

  11. Microstrip sensors based on CVD diamond

    Microsoft Academic Search

    W. Adam; E Berdermann; P Bergonzo; G Bertuccio; F Bogani; E Borchi; A Brambilla; Mara Bruzzi; C Colledani; J Conway; P D'Angelo; W Dabrowski; P A Delpierre; A Deneuville; W Dulinski; B van Eijk; A Fallou; F Fizzotti; F Foulon; M Friedl; K. K Gan; E Gheeraert; G D Hallewell; S Han; F G Hartjes; Josef Hrubec; D Husson; H Kagan; D R Kania; J Kaplon; R Kass; T W Koeth; Manfred Krammer; A Logiudice; R Lu; L mac Lynne; C Manfredotti; D Meier; M Mishina; L Moroni; A Oh; L. S Pan; Manfred Pernicka; A Peitz; L P Perera; S Pirollo; M Procario; J. L Riester; S Roe; L Rousseau; A Rudge; J Russ; S Sala; M Sampietro; S R Schnetzer; S Sciortino; H Stelzer; R Stone; B Suter; R. J Tapper; R J Tesarek; W Trischuk; D Tromson; E Vittone; A. M Walsh; R Wedenig; Peter Weilhammer; M Wetstein; C White; W Zeuner; M M Zoeller

    2000-01-01

    In this article we present the performance of recent chemical vapour deposition (CVD) diamond micro-strip sensors in beam tests. In addition, we present the first comparison of a CVD diamond micro-strip sensor before and after proton irradiation.

  12. Diamond for high heat flux applications

    Microsoft Academic Search

    Clifford J. Robinson; Thomas M. Hartnett; Richard P. Miller; Charles B. Willingham; John E. Graebner; Donald T. Morelli

    1993-01-01

    In polycrystalline CVD diamond of useful macroscopic dimensions, which may be considered for high heat flux applications, thermal conductivity parameters are largely determined by grain size resulting from growth morphology, defects and impurities in the material. Thermal conductivity has been measured in a number of state-of-the-art diamond samples, by the steady state technique, over the temperature range 6 to 400

  13. Diamond radiation sensors for medical applications

    Microsoft Academic Search

    Frank Blum; A. Denisenko; R. Job; D. Borchert; W. R. Fahrner

    1998-01-01

    Applicability of commercial CVD diamond films for radiation detector application was studied. The CVD diamonds obtained from different sources were characterised by different optical techniques such as Raman and photoluminescence spectroscopy, cathodoluminescence (CL) and optical absorption. The samples were used for fabrication of MIM sandwich type radiation detectors. The detectors were exposed to ?-exposure (60Co source) of a low dose-rate.

  14. Creation of deep blue light emitting nitrogen-vacancy center in nanosized diamond

    SciTech Connect

    Himics, L., E-mail: himics.laszlo@wigner.mta.hu; Tóth, S.; Veres, M.; Koós, M. [Institute for Solid State Physics and Optics, Wigner Research Center for Physics, Hungarian Academy of Sciences, H-1525 Budapest, P.O. Box 49 (Hungary); Balogh, Z. [Uzhhorod National University, 88000 Uzhhorod (Ukraine)

    2014-03-03

    This paper reports on the formation of complex defect centers related to the N3 center in nanosized diamond by employing plasma immersion and focused ion beam implantation methods. He{sup +} ion implantation into nanosized diamondlayer” was performed with the aim of creating carbon atom vacancies in the diamond structure, followed by the introduction of molecular N{sub 2}{sup +} ion and heat treatment in vacuum at 750?°C to initiate vacancy diffusion. To decrease the sp{sup 2} carbon content of nanosized diamond formed during the implantation processes, a further heat treatment at 450?°C in flowing air atmosphere was used. The modification of the bonding properties after each step of defect creation was monitored by Raman scattering measurements. The fluorescence measurements of implanted and annealed nanosized diamond showed the appearance of an intensive and narrow emission band with fine structures at 2.98?eV, 2.83?eV, and 2.71?eV photon energies.

  15. 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 ?m 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

  16. Morphological phenomena of CVD diamond (Part II)

    NASA Astrophysics Data System (ADS)

    Zhu, Wei; Messier, Russell F.; Badzian, Andrzej R.

    1991-12-01

    The morphological evolution on the (1 1 1 } and (100 } faces of CVD diamond proceeded overwhelmingly through a two-dimensional layer mechanism. However, experimental evidence on defect-facilitated renucleation on the {1 1 1} faces and direct atom attachment to the lattice on the {100} faces was also found which resulted in one-dimensional growth. The {100)-oriented films were developed through a typical competitive, evolutionary selection process with sufficient surface diffusion which leaded to the formation of the pronounced <100> textured columnar structure, whereas the {1 1 1}-faceted crystals were produced under conditions of very high adatom mobility with periodical renucleation, the preferential growth direction of which was along the <110>. On the other hand, films produced at high carbon supersaturations possessed a randomly oriented columnar structure with ball shaped clustered surface, the growth process of which was dominated by constant renucleation. While the {1 1 1}-faceted crystals were usually highly defective in their internal structure, the {100}-oriented crystals were generally planar-defect free.

  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. Carbon transport in diamond anvil cells

    SciTech Connect

    Prakapenka, V.B.; Shen, G.; Dubrovinsky, L.S. (Bayerisches Geoinstitut); (UC)

    2010-11-10

    High-pressure-induced carbon transport from diamond anvils into the pressure chamber of diamond anvil cells (DACs) was studied by micro-Raman spectroscopy. Depending on experimental conditions (temperature and pressure), various carbon phases (amorphous carbon, diamond, microcrystalline or nanocrystalline graphite) were detected in the originally carbon-free samples. Temperature-induced growth of a graphite phase at the sample/diamond interface was observed in situ at high pressure in an externally heated DAC. In laser-heated samples inside the pressure-transmitting medium, at pressures above 6 GPa there was transport of carbon from the diamond culet surface into the heated part of the sample. These observations suggest that account should be taken of possible carbon diffusion in high-pressure research with DACs, such as high-pressure melting, element partitioning, phase transformations, chemical reactions, and electrical resistivity.

  19. Geochemical Characteristics of Southern African Diamonds

    NASA Astrophysics Data System (ADS)

    Deines, P.; Harris, J. W.

    2002-05-01

    The question whether significant differences in the carbon isotopic composition of diamonds and the chemistry of their inclusions exist among diamonds from different kimberlites, is examined with 1350 diamond samples from kimberlites on the Kaapvaal Craton (Premier, Finsch, Roberts Victor, Koffiefontein) towards the margin of the craton (Jagersfontein) and the Limpopo Mobile Belt (Jwaneng, Orapa, Venetia). The carbon isotope distributions of diamonds from these kimberlites are either unimodal (Premier, Finsch, Dan Carl, Koffiefontein, Venetia), bimodal, (Roberts Victor, Jagersfontein) or show a broad range of values (Orapa, Jwaneng). Major inclusion parageneses that have been recognized are peridotitic (P-Type) and eclogitic (E-Type). There is no differences in the carbon isotope distribution between P- and E-Type diamonds in the case of Premier, Finsch, Koffiefontein and only a slight (0.5 %) 13C depletion in E-type compared to P-Type diamonds for Venetia. P- and E-Type diamonds show very similar carbon isotopic composition ranges in samples from Jagersfontein, Jwaneng, and Orapa, however, in these particular kimberlites, E- Type diamonds are more frequently depleted in 13C than P-Type diamonds. A simple division of the carbon isotope distributions into craton vs. mobile belt or P-Type vs. E-Type is not possible. Within individual kimberlites systematic relationships between the carbon isotopic composition of the diamonds and the chemical composition of the associated silicates are observed. Similar trends can be found in different kimberlites. Within the eclogitic and peridotitic parageneses groups of diamonds of similar nitrogen concentration, carbon isotopic, and mineral inclusion composition can be recognized, suggesting distinct growth environments for them. For example diamonds from the Jwaneng kimberlite formed in at least seven distinct mantle environments, over a time interval which may have lasted as long as 3 Ga. Variations in the carbon isotopic composition with mantle depth can be inferred for several of the kimberlites studied. Beneath Jagersfontein the relative abundance of low 13C-content diamonds may be higher in the asthenosphere than in the lithosphere. In contrast, in the nearby Koffiefontein kimberlite asthenospheric and lithospheric diamonds are indistinguishable in their carbon isotopic composition. Hence, within kimberlites groups of diamonds of distinct geochemistry can be recognized. The differences and similarities in the geochemistry of diamonds among the 8 kimberlites were examined by comparing the average chemistry of the P-type olivine, orthopyroxene, garnet and chromite and E-Type garnet and clinopyroxene inclusions and the average carbon isotopic composition of their hosts. Among the 8 kimberlites significant differences in the geochemical characteristics (SiO2, TiO2, Al2O3, Cr2O, FeO, MnO, MgO, CaO, carbon isotopic composition) of diamonds are observed. However, the nature these differences can vary for a given kimberlite-pair comparison among different inclusion types. For example, while the orthopyroxen inclusion compositions may differ significantly between two kimberlites this may or may not be the case for the olivine or garnet inclusions. This confirms the conclusion that the diamond suites represent multiple growth environments which may or may not be similar for a particular inclusion suite or set of kimberlites. Hence, while diamonds from the different kimberlites can be geochemically distinct, their variability is complex. No simple diagnostic pattern which could be used to link diamonds, on the basis of their geochemistry, unambiguously to a particular kimberlite could be established.

  20. Diamond as an inert substrate of graphene

    SciTech Connect

    Hu Wei; Li Zhenyu; Yang Jinlong [Hefei National Laboratory for Physical Sciences at Microscale, University of Science and Technology of China, Hefei, Anhui 230026 (China)

    2013-02-07

    Interaction between graphene and semiconducting diamond substrate has been examined with large-scale density functional theory calculations. Clean and hydrogenated diamond (100) and (111) surfaces have been studied. It turns out that weak van der Waals interactions dominate for graphene on all these surfaces. High carrier mobility of graphene is almost not affected, except for a negligible energy gap opening at the Dirac point. No charge transfer between graphene and diamond (100) surfaces is detected, while different charge-transfer complexes are formed between graphene and diamond (111) surfaces, inducing either p-type or n-type doping on graphene. Therefore, diamond can be used as an excellent substrate of graphene, which almost keeps its electronic structures at the same time providing the flexibility of charge doping.

  1. Diamonds in the chemical products of detonation

    SciTech Connect

    Greiner, N.R. (Los Alamos National Lab., NM (USA))

    1989-01-01

    Diamonds have been found among the solid carbonaceous chemical products of high-explosive detonations. Explosives are fuel-oxidizer systems premixed on a molecular scale. This talk discusses some aspects of the chemical and hydrodynamic environment in which these diamonds form and some characteristics of the diamonds recovered. Diamonds have been recovered from detonations of composite explosives composed of trinitrotoluene (TNT) mixed with other powdered solid explosives, such as cyclo-trimethylenetrinitramine (RDX), triaminotrinitrobenzene (TATB), ammonium nitrate (AN), and nitroguanidine (NQ). The detonations were carried out in a 1.5-m{sup 3} tank, usually filled with 1 atm of Ar gas. Other explosive composites and one-component explosives have also been investigated. The diamonds have been characterized by transmission electron microscopy, x-ray diffraction, and various chemical means.

  2. Diamonds in the chemical products of detonation

    SciTech Connect

    Greiner, N.R.

    1988-01-01

    Diamonds have been found among the solid carbonaceous chemical products of high-explosive detonations. Explosives are fuel-oxidizer systems premixed on a molecular scale. This talk discusses some aspects of the chemical and hydrodynamic environment in which these diamonds form and some characteristics of the diamonds recovered. Diamonds have been recovered from detonations of composite explosives composed of trinitrotoluene (TNT) mixed with other powdered solid explosives, such as cyclo-trimethylenetrinitramine (RDX), triaminotrinitrobenzene (TATB), ammonium nitrate (AN), and nitroguanidine (NQ). The detonations were carried out in a 1.5-m/sup 3/ tank, usually filled with 1 atm of Ar gas. Other explosive composites and one-component explosives have also been investigated. The diamonds have been characterized by transmission electron microscopy, x-ray diffraction, and various chemical means. 8 refs., 3 figs.

  3. Shock properties of diamond and kimberlite

    NASA Astrophysics Data System (ADS)

    Willmott, G. R.; Proud, W. G.; Field, J. E.

    2003-09-01

    Plate impact experiments have been performed on diamond and the igneous diamond-bearing matrix kimberlite. Longitudinal and lateral stresses within kimberlite have been measured in the uniaxial strain regime using embedded manganin stress gauges. The shock Hugoniot of the kimberlite has been characterised, and the elastic limit and shear strength have been studied. An experimental technique has been developed to observe the shock loading of transparent particles of dimension 5 mm embedded in a matrix of lower shock impedance. The destruction of a diamond sample has been observed using high-speed photography with an inter-frame time of 100 ns. A crack within the diamond was found to propagate at 10 ± km s^{-l}, which is close to the Rayleigh wave velocity in diamond.

  4. Toroidal plasma enhanced CVD of diamond films

    SciTech Connect

    Zvanya, John, E-mail: zvanya03@students.rowan.edu; Cullen, Christopher, E-mail: cullen38@students.rowan.edu; Morris, Thomas, E-mail: morris1j@students.rowan.edu; Krchnavek, Robert R., E-mail: krchnavek@rowan.edu [Department of Electrical and Computer Engineering, Rowan University, Glassboro, New Jersey 08028 (United States); Holber, William, E-mail: b.holber@plasmability.com; Basnett, Andrew, E-mail: abasnett54@yahoo.com; Basnett, Robert, E-mail: b.basnett@plasmability.com [Plasmability LLC, Austin, Texas 78732 (United States); Hettinger, Jeffrey, E-mail: hettinger@rowan.edu [Department of Physics and Astronomy, Rowan University, Glassboro, New Jersey 08028 (United States)

    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.

  5. Diamond Provenance Through Shape, Colour, Surface Features and Value

    Microsoft Academic Search

    J. Harris

    2002-01-01

    The physical properties of diamond provide a possible means by which run-of-mine productions may be identified. Such properties as shape, the regularity and angularity of the crystal form, the level of transparency, colour, syngenetic inclusion content and surface feature characteristics, all as a function of diamond size, can classify diamond productions. In early work, up to 1500 diamonds in specific

  6. Appendix A SIMS profiles of hydrogen and deuterium in diamond

    E-print Network

    Goddard III, William A.

    127 Appendix A SIMS profiles of hydrogen and deuterium in diamond A.1 Introduction A diamond sample ion­beam doping. Impurity levels were profiled as a function of depth from the diamond surface using­type reactor, consisting of a quartz tube with diamond­coated quartz substrate holder. The substrate

  7. Understanding diamond pricing using unconditional quantile regressions Nicolas Vaillant*

    E-print Network

    Paris-Sud XI, Université de

    Understanding diamond pricing using unconditional quantile regressions Nicolas Vaillant* François of diamonds and their weight in carats. For this purpose, we use a unique sample of 112,080 certified diamonds collected from www.info-diamond.com during the first week of July 2011. We find substantial differences

  8. Vibrational Raman characterization of hard-carbon and diamond films

    Microsoft Academic Search

    Joel W. Ager; D. K. Veirs; Bruno Marchon; Namhee Cho; Gerd M. Rosenblatt

    1991-01-01

    Amorphous 'hard carbon' and microcrystalline diamond films are being investigated and characterized using high-sensitivity and spatial-profiling Raman spectroscopy. The 'hard carbon' films have broad Raman spectra with no diamond line while higher quality diamond films show only a single sharp diamond line. Features in the Raman spectra of the amorphous 'hard carbon' films correlate with the rates of specific types

  9. Machining of electrically conductive CVD diamond tool blanks using EDM

    Microsoft Academic Search

    R. H. Olsen; R. C. Dewes; D. K. Aspinwall

    2004-01-01

    The paper reviews the manufacture, microstructure and physical\\/mechanical properties of thick film chemical vapour deposited (CVD) diamond in relation to its use for cutting tools. In contrast to polycrystalline diamond (PCD), CVD diamond contains no metallic second phase, its microstructure comprising solely of columnar diamond grains. Experimental research involving an L27 Taguchi orthogonal array is presented relating to the electrical

  10. Precision and micro CVD diamond-coated grinding tools

    Microsoft Academic Search

    Jan Gäbler; Sven Pleger

    2010-01-01

    Both for ultra-precision and for micro-machining diamond is used very often as tool material. The reason is the very high dimensional stability of diamond due to its extreme hardness. Diamond is used for two kinds of machining processes: for cutting, like turning, drilling or milling, as well as for abrasive processes, like grinding. Diamond cutting tools can be made with

  11. CVD diamond: a new technology for the Paul W. May

    E-print Network

    Bristol, University of

    CVD diamond: a new technology for the future? Paul W. May Diamond exhibits a unique range a Royal Society Research Fellow, working at Bristol on all aspects of CVD diamond research. 0 1995 exotic than a hydrocarbon gas (typically methane) in an excess of hydrogen. This CVD diamond can show

  12. Electrical discharge machining of conductive CVD diamond tool blanks

    Microsoft Academic Search

    R. H. Olsen; D. K. Aspinwall; R. C. Dewes

    2004-01-01

    The paper reviews the manufacture, physical\\/mechanical properties and cutting tool applications of chemical vapour deposited (CVD) diamond and makes comparisons with polycrystalline diamond (PCD). The morphology of CVD diamond is significantly different from that of PCD, the former exhibiting continuous columnar grains extending from nucleation sites, whereas the latter involves an agglomeration of intergrown diamond crystals with a minor secondary

  13. 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. PMID:25280853

  14. Proposed method of producing large optical mirrors Single-point diamond crushing followed by polishing with a small-area tool

    NASA Technical Reports Server (NTRS)

    Wright, G.; Bryan, J. B.

    1986-01-01

    Faster production of large optical mirrors may result from combining single-point diamond crushing of the glass with polishing using a small area tool to smooth the surface and remove the damaged layer. Diamond crushing allows a surface contour accurate to 0.5 microns to be generated, and the small area computer-controlled polishing tool allows the surface roughness to be removed without destroying the initial contour. Final contours with an accuracy of 0.04 microns have been achieved.

  15. Excimer laser-induced diamond graphitization for high-energy nuclear applications

    NASA Astrophysics Data System (ADS)

    Alemanno, E.; Caricato, A. P.; Chiodini, G.; Martino, M.; Ossi, P. M.; Spagnolo, S.; Perrino, R.

    2013-12-01

    In this work, we have studied the structure and the morphology of a graphite layer induced on the surface of a polycrystalline thermal grade CVD diamond by focusing a pulsed excimer laser operating at KrF (wavelength 248 nm) and ArF (wavelength 193 nm) mixtures. By micro-Raman and photoluminescence spectroscopies, as well as scanning electron microscopy, we reported the synthesis of a turbostratic t-graphite layer after irradiation with ArF laser. By contrast, irradiating with a KrF laser beam, we obtained a disordered graphite layer with 10 laser shots, while 200 consecutive laser pulses resulted in target ablation.

  16. Extending Quantum Coherence in Diamond

    E-print Network

    C. A. Ryan; J. S. Hodges; D. G. Cory

    2010-08-18

    We experimentally demonstrate over two orders of magnitude increase in the coherence time of nitrogen vacancy centres in diamond by implementing decoupling techniques. We show that equal pulse spacing decoupling performs just as well as non-periodic Uhrig decoupling and has the additional benefit that it allows us to take advantage of "revivals" in the echo (due to the coherent nature of the bath) to explore the longest coherence times. At short times, we can extend the coherence of particular quantum states out from T_2*=2.7 us out to an effective T_2 > 340 us. For preserving arbitrary states we show the experimental importance of using pulse sequences, that through judicious choice of the phase of the pulses, compensate the imperfections of individual pulses for all input states. At longer times we use these compensated sequences to enhance the echo revivals and show a coherence time of over 1.6 ms in ultra-pure natural abundance 13C diamond.

  17. Nitrogen-doped diamond films

    NASA Astrophysics Data System (ADS)

    Baranauskas, V.; Li, B. B.; Peterlevitz, A.; Tosin, M. C.; Durrant, S. F.

    1999-05-01

    We found that very high concentrations (up to 20% vol) of nitrogen in the ethanol/hydrogen gas mixture do not prejudice the diamond quality as determined by Raman spectroscopy. Nitrogen addition also increases the diamond growth rate, as was previously reported at low nitrogen concentrations. We observed that after a second heating cycle in air at temperatures between 300 and 673 K the electrical resistance versus temperature curves of the as-grown films presented a bulk semiconductor behavior. This stabilization was due to the oxidation of the as-grown hydrogenated surface. The electrical ionization energy Ed was found to be in the range of 1.62-1.90 eV corresponding to films produced with 0 to 20% vol nitrogen in the feed. The room temperature photoluminescence spectra of films produced at low nitrogen concentration suggest that Ed results from pure electronic transitions in the nitrogen-vacancy neutral defects; for samples produced with nitrogen concentrations in the range 15-20% vol the Ed values may be due to, among others, GR1 "vibronic" transitions and charged nitrogen-vacancy defects.

  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 termination (e.g., azide), and surface boron sites (hydrazine) could all affect the electroactivity for diamond thin-films.

  19. 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.

  20. Diamond field effect transistors with a high-dielectric constant Ta2O5 as gate material

    NASA Astrophysics Data System (ADS)

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

    2014-06-01

    A Ta2O5/Al2O3 bilayer gate oxide with a high-dielectric constant (high-k) has been successfully applied to a hydrogenated-diamond (H-diamond) metal-insulator-semiconductor field effect transistor (MISFET). The Ta2O5 layer is prepared by a sputtering-deposition (SD) technique on the Al2O3 buffer layer fabricated by an atomic layer deposition (ALD) technique. The ALD-Al2O3 plays an important role to eliminate plasma damage for the H-diamond surface during SD-Ta2O5 deposition. The dielectric constants of the SD-Ta2O5/ALD-Al2O3 bilayer and single SD-Ta2O5 are as large as 12.7 and 16.5, respectively. The k value of the single SD-Ta2O5 in this study is in good agreement with that of the SD-Ta2O5 on oxygen-terminated diamond. The capacitance-voltage characteristic suggests low interfacial trapped charge density for the SD-Ta2O5/ALD-Al2O3/H-diamond MIS diode. The MISFET with a gate length of 4 µm has a drain current maximum and an extrinsic transconductance of -97.7 mA mm-1 (normalized by gate width) and 31.0 ± 0.1 mS mm-1, respectively. The effective mobility in the H-diamond channel layer is found to be 70.1 ± 0.5 cm2 V-1 s-1.

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

    SciTech Connect

    Ji, Gang, E-mail: gang.ji@univ-lille1.fr [Unité Matériaux et Transformations, UMR CNRS 8207, Bâtiment C6, Université Lille 1, 59655 Villeneuve d'Ascq (France); Electron Microscopy for Materials Science (EMAT), University of Antwerp, Groenenborgerlaan 171, 2020 Antwerp (Belgium); Tan, Zhanqiu [State Key Laboratory of Metal Matrix Composites, Shanghai Jiao Tong University, Shanghai 200240 (China); Shabadi, Rajashekhara [Unité Matériaux et Transformations, UMR CNRS 8207, Bâtiment C6, Université Lille 1, 59655 Villeneuve d'Ascq (France); Li, Zhiqiang [State Key Laboratory of Metal Matrix Composites, Shanghai Jiao Tong University, Shanghai 200240 (China); Grünewald, Wolfgang [Leica Mikrosysteme GmbH, Physikneubau, Reichenhainer Straße 70, DE-09126 Chemnitz (Germany); Addad, Ahmed [Unité Matériaux et Transformations, UMR CNRS 8207, Bâtiment C6, Université Lille 1, 59655 Villeneuve d'Ascq (France); Schryvers, Dominique [Electron Microscopy for Materials Science (EMAT), University of Antwerp, Groenenborgerlaan 171, 2020 Antwerp (Belgium); Zhang, Di [State Key Laboratory of Metal Matrix Composites, Shanghai Jiao Tong University, Shanghai 200240 (China)

    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.

  2. Diamond Surface Modification to Enhance Interfacial Thermal Conductivity in Al/Diamond Composites

    NASA Astrophysics Data System (ADS)

    Caccia, Mario; Rodríguez, Alejandro; Narciso, Javier

    2014-06-01

    Diamond/metal composites are very attractive materials for electronics because their excellent thermal properties make them suitable for use as heat sink elements in multifunctional electronic packaging systems. To enlarge the potential applications of these composites, current efforts are mainly focused on investigating different ways to improve the contact between metal and diamond. In the present work, a theoretical study has been carried out to determine the differences between the interfacial thermal conductance of aluminum/diamond and aluminum/graphite interfaces. Additionally, diamond particles were surface modified with oxygen to observe how it affects the quality of the diamond surface. The characterization of the surface of diamonds has been performed using different surface analysis techniques, especially x-ray photoelectron spectroscopy and temperature-programmed desorption.

  3. Microstructure and thermal properties of diamond\\/aluminum composites with TiC coating on diamond particles

    Microsoft Academic Search

    H. Feng; J. K. Yu; W. Tan

    2010-01-01

    A titanium carbide coating on the surface of diamond particles was proposed to improve the interfacial bonding between diamond particles and aluminum alloy for diamond\\/aluminum composites. The diamond\\/aluminum composites with the TiC coating on diamond particles were fabricated by gas pressure infiltration. The composites were characterized with optical microscope and scanning electron microscopy and by measuring thermal properties, including thermal

  4. Micrometer-scale cavities in fibrous and cloudy diamonds — A glance into diamond dissolution events

    Microsoft Academic Search

    Ofra Klein-Bendavid; Richard Wirth; Oded Navon

    2007-01-01

    Micrometer sized internal cavities in diamonds preserve evidence of diamond dissolution events. Combining the methods of focused ion beam (FIB) sample preparation and transmission electron microscopy (TEM) enables these features to be studied in detail.Micrometer-scale cavities are found in the inner parts of fibrous and cloudy kimberlitic diamonds. Their filling consists of amorphous matrix, secondary nano-crystals, volatiles and in some

  5. Bonding Diamond To Metal In Electronic Circuits

    NASA Technical Reports Server (NTRS)

    Jacquez, Andrew E.

    1993-01-01

    Improved technique for bonding diamond to metal evolved from older technique of soldering or brazing and more suitable for fabrication of delicate electronic circuits. Involves diffusion bonding, developed to take advantage of electrically insulating, heat-conducting properties of diamond, using small diamond bars as supports for slow-wave transmission-line structures in traveling-wave-tube microwave amplifiers. No fillets or side coats formed because metal bonding strips not melted. Technique also used to mount such devices as transistors and diodes electrically insulated from, but thermally connected to, heat sinks.

  6. Nucleation and growth of heteroepitaxial diamond

    NASA Astrophysics Data System (ADS)

    Bednarski-Meinke, Connie Rebecca

    This thesis describes the growth of single crystal diamond by low-pressure microwave plasma-enhanced chemical vapor deposition (CVD). Although diamond in the form of polycrystalline thin films has been deposited by CVD methods in the past, it has proven difficult to devise methods that induce the diamond crystallites to align and to coalesce into a single crystal. The method adopted here is based on heteroepitaxy, the single crystal growth of a desired material on a chemically distinct substrate. Two heteroepitaxial steps, carried out in sequence, were required. Epitaxial films of metallic iridium (Ir) metal were grown on lattice-matched single crystal oxides, principally SrTiO3 and alpha-Al2O3 (sapphire). Heteroepitaxial diamond was then grown on Ir, which provides a good match to the lattice parameter of diamond and is resistant to the high temperature methane-hydrogen plasma. Since diamond does not nucleate spontaneously at high densities, methods were used to stimulate its nucleation on Ir. Low-energy ions, attracted to the substrate from the plasma by a voltage bias, produced conditions favorable for diamond nucleation with densities approaching 1012 cm -2 across the entire substrate. By terminating the biasing at a series of time intervals, the sample temperature was quenched and the evolution of diamond film formation could be followed. Scanning electron microscopy was used to image individual diamond nuclei and crystallites, their pattern formation, and coalescence on scales from 10 nm to 10 mum. After 60 minutes of growth, extremely smooth, continuous films of single crystal diamond were obtained with dimensions the size of the substrate growth region, an area 3.5 mm in dia. By growing for extended periods, to a maximum of 48 hr, diamond plates of thickness 35 mum were produced. Freestanding crystals exhibited (111) cleavage surfaces, the same as natural diamond, and were transparent in visible light. Characterization of the material by x-ray diffraction, electron backscattering diffraction, and Raman scattering confirmed the presence of (001) oriented single crystal diamond. By optimizing the CVD reactor geometry, this research has led to the highest density of oriented nuclei yet reported. Coalescence therefore occurs at an early stage, leading to greatly improved crystalline perfection and homogeneity. The discovery that sapphire can be used as a substrate to grow (001) epitaxial Ir and diamond promises to lead to improvements in diamond quality. Sapphire has high thermal stability coupled with remarkably good crystalline perfection, and is available as large area substrates. This thesis encompasses studies of substrates, epitaxial growth of electron-beam evaporated Ir, systematic optimization of biasing procedures, exploration of the vast parameter space of the CVD reactor, description of characterization tools, and the results of more than 300 diamond growth experiments. Some new ideas, presented as a model of diamond nucleation and early growth, may help explain the major improvements obtained here.

  7. First principles study of Fe in diamond: A diamond-based half metallic dilute magnetic semiconductor

    SciTech Connect

    Benecha, E. M. [Department of Physics, University of South Africa, P.O. Box 392, UNISA 0003 Pretoria (South Africa); Lombardi, E. B., E-mail: lombaeb@unisa.ac.za [College of Graduate Studies, University of South Africa, P.O. Box 392, UNISA 0003 Pretoria (South Africa)

    2013-12-14

    Half-metallic ferromagnetic ordering in semiconductors, essential in the emerging field of spintronics for injection and transport of highly spin polarised currents, has up to now been considered mainly in III–V and II–VI materials. However, low Curie temperatures have limited implementation in room temperature device applications. We report ab initio Density Functional Theory calculations on the properties of Fe in diamond, considering the effects of lattice site, charge state, and Fermi level position. We show that the lattice sites and induced magnetic moments of Fe in diamond depend strongly on the Fermi level position and type of diamond co-doping, with Fe being energetically most favorable at the substitutional site in p-type and intrinsic diamond, while it is most stable at a divacancy site in n-type diamond. Fe induces spin polarized bands in the band gap, with strong hybridization between Fe-3d and C-2s,2p bands. We further consider Fe-Fe spin interactions in diamond and show that substitutional Fe{sup +1} in p-type diamond exhibits a half-metallic character, with a magnetic moment of 1.0??{sub B} per Fe atom and a large ferromagnetic stabilization energy of 33?meV, an order of magnitude larger than in other semiconductors, with correspondingly high Curie temperatures. These results, combined with diamond's unique properties, demonstrate that Fe doped p-type diamond is likely to be a highly suitable candidate material for spintronics applications.

  8. Deposition of CVD diamond onto GaN P.W. May a,*, H.Y. Tsai b

    E-print Network

    Bristol, University of

    thermal conductivity, diamond is currently one of the most promising materials for use in electronic of liquid Ga droplets [3]. These three reactions are perhaps one of the reasons why, to date, there have substrate using an AlN nucleation layer and a metal-organic chemical vapour deposi- tion (MOCVD) method

  9. Enhancement of secondary electron emission by annealing and microwave hydrogen plasma treatment of ion-beam-damaged diamond films

    NASA Astrophysics Data System (ADS)

    Laikhtman, A.; Hoffman, A.

    2002-02-01

    In this work we investigate the influence of annealing and microwave (MW) hydrogen plasma exposure of ion-beam-irradiated diamond film surfaces. In particular, we are interested in the recovery of secondary electron emission (SEE) and negative electron affinity (NEA) by removal of the damaged layer. To this aim, we correlate the SEE of variously treated Xe+ ion-damaged diamond films with their bonding structure in the near-surface region, as identified by near-edge x-ray absorption fine structure (NEXAFS) spectroscopy and x-ray photoelectron spectroscopy. The 30 keV Xe+ ion bombardment of hydrogenated polycrystalline diamond films to a dose of 2×1015 cm-2 results in the transformation of the near-surface region of a diamond film to sp2-bonded amorphous carbon, increased oxygen adsorption, shift of the electron affinity from negative to positive, and strong degradation of its electron emission properties, although it does not induce a pronounced depletion of hydrogen. Exposure of the ion-bombarded films to MW hydrogen plasma treatment for 30 min produces NEA diamond surfaces, but only partially regenerates SEE properties, retains some imperfection in the near-surface atomic layers, as determined by NEXAFS, and the concentration of oxygen remains relatively high. Subsequent annealing to 610 °C produces oxygen-free diamond films and somewhat increases their SEE. Annealing to 1000 °C results in desorption of the surface hydrogen, formation of positive electron affinity surfaces, and drastically degrades their electron emission properties. Prolonged (up to three hours) MW hydrogen plasma treatment of as-implanted diamond films gradually improves their crystal quality and results in a further increase of SEE intensity. The SEE intensity after three hours MW hydrogen plasma exposure of the ion-beam-irradiated films was found to be ˜50% above the value obtained for the as-deposited diamond films. This treatment does not, however, substantially reduce the concentration of oxygen in the previously damaged diamond, indicating its bulk diffusion during or after ion bombardment. Our results show that removal of damage from a highly disordered diamond surface and recovery of its electron emission properties are possible by MW hydrogen plasma. However, it is a slow process. This is most likely due to the very low etching rate of the low-level damage at the end of the ion beam range.

  10. Negatively charged nitrogen-vacancy centers in a 5 nm thin 12C diamond film.

    PubMed

    Ohashi, K; Rosskopf, T; Watanabe, H; Loretz, M; Tao, Y; Hauert, R; Tomizawa, S; Ishikawa, T; Ishi-Hayase, J; Shikata, S; Degen, C L; Itoh, K M

    2013-10-01

    We report successful introduction of negatively charged nitrogen-vacancy (NV(-)) centers in a 5 nm thin, isotopically enriched ([(12)C] = 99.99%) diamond layer by CVD. The present method allows for the formation of NV(-) in such a thin layer even when the surface is terminated by hydrogen atoms. NV(-) centers are found to have spin coherence times of between T2 ~ 10-100 ?s at room temperature. Changing the surface termination to oxygen or fluorine leads to a slight increase in the NV(-) density, but not to any significant change in T2. The minimum detectable magnetic field estimated by this T2 is 3 nT after 100 s of averaging, which would be sufficient for the detection of nuclear magnetic fields exerted by a single proton. We demonstrate the suitability for nanoscale NMR by measuring the fluctuating field from ~10(4) proton nuclei placed on top of the 5 nm diamond film. PMID:24020334

  11. Detection and analysis of diamond fingerprinting feature and its application

    NASA Astrophysics Data System (ADS)

    Li, Xin; Huang, Guoliang; Li, Qiang; Chen, Shengyi

    2011-01-01

    Before becoming a jewelry diamonds need to be carved artistically with some special geometric features as the structure of the polyhedron. There are subtle differences in the structure of this polyhedron in each diamond. With the spatial frequency spectrum analysis of diamond surface structure, we can obtain the diamond fingerprint information which represents the "Diamond ID" and has good specificity. Based on the optical Fourier Transform spatial spectrum analysis, the fingerprinting identification of surface structure of diamond in spatial frequency domain was studied in this paper. We constructed both the completely coherent diamond fingerprinting detection system illuminated by laser and the partially coherent diamond fingerprinting detection system illuminated by led, and analyzed the effect of the coherence of light source to the diamond fingerprinting feature. We studied rotation invariance and translation invariance of the diamond fingerprinting and verified the feasibility of real-time and accurate identification of diamond fingerprint. With the profit of this work, we can provide customs, jewelers and consumers with a real-time and reliable diamonds identification instrument, which will curb diamond smuggling, theft and other crimes, and ensure the healthy development of the diamond industry.

  12. Hydrogen chemisorption on diamond surfaces. Final report

    SciTech Connect

    Daley, R.; Musket, R.

    1994-09-01

    Previously we demonstrated the ability to measure submonolayer quantities of surface hydrogen on insulating glasses. The present study builds on this by examining hydrogen coverages on another insulating material: the technologically important diamond (100) surface. The information to be obtained in the present study will allow us to deduce the correct structures for the diamond (100)-(1X1) and -(2X1) surface phases and provide information on the kinetics of hydrogen desorption from the (100) surface. Such experiments are essential for a complete understanding of hydrogen surface chemistry during the chemical vapor deposition of thin diamond films. This report summarizes progress made in FY93 for measuring surface hydrogen concentrations on the diamond (100) surface. Although the available LDRD resources were insufficient to finish this study in FY93, completion of the study is planned using other resources and this detailed report as a reference.

  13. Diamond coated silicon field emitter array

    SciTech Connect

    S. Albin; W. Fu; A. Varghese; A. C. Lavarias; G. R. Myneni

    1999-07-01

    Diamond coated silicon tip arrays, with and without a self-aligned gate, were fabricated, and current-voltage characteristics of 400 tips were measured. Diamond films were grown uniformly on Si tips using microwave plasma after nucleation with 10 nm diamond suspension and substrate bias. An emission current of 57 ?A was obtained at 5 V from the ungated array tips separated from an anode at 2 ?m. In the case of the gated arrays with 1.5 ?m aperture, an emission current of 3.4 ?A was measured at a gate voltage of 80 V for an anode separation of 200 ?m. The turn-on voltages for these two types of devices were 0.2 and 40 V, respectively. Diamond coated Si tip arrays have potential applications in field emission based low voltage vacuum electronic devices and microsensors.

  14. Diamond Analyzed by Secondary Electron Emission Spectroscopy

    NASA Technical Reports Server (NTRS)

    Krainsky, Isay L.

    1998-01-01

    Diamond is a promising semiconductor material for novel electronic applications because of its chemical stability and inertness, heat conduction properties, and so-called negative electron affinity (NEA). When a surface has NEA, electrons generated inside the bulk of the material are able to come out into the vacuum without any potential barrier (work function). Such a material would have an extremely high secondary electron emission coefficient o, very high photoelectron (quantum) yield, and would probably be an efficient field emitter. Chemical-vapor-deposited (CVD) polycrystalline diamond films have even more advantages than diamond single crystals. Their fabrication is relatively easy and inexpensive, and they can be grown with high levels of doping--consequently, they can have relatively high conductivity. Because of these properties, diamond can be used for cold cathodes and photocathodes in high-power electronics and in high-frequency and high-temperature semiconductor devices.

  15. CVD diamond substrate for microelectronics. Final report

    SciTech Connect

    Burden, J. [Allied Signal, Inc., Kansas City, MO (United States). Federal Mfg. and Technologies; Gat, R. [Applied Science and Technology, Inc., Woburn, MA (United States)

    1996-11-01

    Chemical Vapor Deposition (CVD) of diamond films has evolved dramatically in recent years, and commercial opportunities for diamond substrates in thermal management applications are promising. The objective of this technology transfer initiative (TTI) is for Applied Science and Technology, Inc. (ASTEX) and AlliedSignal Federal Manufacturing and Technologies (FM&T) to jointly develop and document the manufacturing processes and procedures required for the fabrication of multichip module circuits using CVD diamond substrates, with the major emphasis of the project concentrating on lapping/polishing prior to metallization. ASTEX would provide diamond films for the study, and FM&T would use its experience in lapping, polishing, and substrate metallization to perform secondary processing on the parts. The primary goal of the project was to establish manufacturing processes that lower the manufacturing cost sufficiently to enable broad commercialization of the technology.

  16. Multifrequency spin resonance in diamond

    SciTech Connect

    Childress, Lilian; McIntyre, Jean [Department of Physics and Astronomy, Bates College, 44 Campus Ave, Lewiston, Maine 04240 (United States)

    2010-09-15

    Magnetic resonance techniques provide a powerful tool for controlling spin systems, with applications ranging from quantum information processing to medical imaging. Nevertheless, the behavior of a spin system under strong excitation remains a rich dynamical problem. In this paper, we examine spin resonance of the nitrogen-vacancy center in diamond under conditions outside the regime where the usual rotating-wave approximation applies, focusing on effects of multifrequency excitation and excitation with orientation parallel to the spin quantization axis. Strong-field phenomena such as multiphoton transitions and coherent destruction of tunneling are observed in the spectra and analyzed via numerical and analytic theory. In addition to illustrating the response of a spin system to strong multifrequency excitation, these observations may inform techniques for manipulating electron-nuclear spin quantum registers.

  17. Diamond film growth from fullerene precursors

    DOEpatents

    Gruen, D.M.; Liu, S.; Krauss, A.R.; Pan, X.

    1997-04-15

    A method and system are disclosed 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. 10 figs.

  18. Diamond-Shaped Regions as Microcosmoi

    E-print Network

    Pedro Lauridsen Ribeiro

    2010-10-25

    We give a geometrically intrinsic construction of a global time function for relatively compact diamond-shaped regions in arbitrary spacetimes. In the case of Minkowski spacetime, the flow of diffeomorphisms associated to a suitably normalized gradient of this time function becomes the conformal isotropy subgroup of the diamond. In full generality, this time function is elegantly expressed in terms of the Lorentzian distance function, and it has an asymptotic behavior at large absolute times similar to the one in Minkowski spacetime.

  19. Stress measurement of CVD diamond films

    Microsoft Academic Search

    H. Windischmann; K. J. Gray

    1995-01-01

    A review of common stress measurement techniques as related to CVD diamond is presented. A correction to the commonly applied Stoney thin film equation for the substrate curvature technique is presented for coatings with a large stiffness mismatch with the substrate. The difficulties associated with the sin2? and peak width broadening X-ray diffraction techniques in highly oriented, X-ray transparent diamond

  20. Diamond-studded helical traveling wave tube

    Microsoft Academic Search

    James A. Dayton; Gerald T. Mearini; Hsiung Chen; Carol L. Kory

    2005-01-01

    A novel method of millimeter-wave traveling wave tube (TWT) slow-wave circuit fabrication, employing laser micromachining and the in situ growth of diamond studs as an insulating dielectric, has been developed, which would enable a new class of very wideband, low distortion, high-efficiency amplifiers. Because the slow-wave circuit is supported by an array of diamond studs, rather than the conventional dielectric

  1. On the possible origins of natural diamonds

    Microsoft Academic Search

    A R Patel; Kuruvilla A Cherian

    1984-01-01

    A brief survey of the current theories of formation of diamonds in nature leads to the hypothesis which suggests the possibility\\u000a of natural diamonds having formed metastably—a hypothesis which has not been enjoying much experimental support in its favour.\\u000a The authors present briefly some aspects of the investigations which have resulted in demonstrating a new process whereby\\u000a the dissolution and

  2. Effective placement of detectors at diamond interchanges 

    E-print Network

    Prabhakar, Dayakar

    1994-01-01

    the interaction among individually- characterized driver-vehicle units as they approach and pass through the two closely spaced at-grade intersections of a conventional diamond interchange having one-way tragic on diagonal ramps that form the two opposite legs... of each intersection (14). ~ot Figure 7. Typical Detector Placement and Numbering Scheme of TEXAS Model ~14 . 25 Terminology of TEXAS Model In the TEXAS Model, the diamond interchange is configured as two adjacent, three-leg, at-grade intersections...

  3. DESIGN OF THE FARADAY CUPS IN DIAMOND

    Microsoft Academic Search

    A. F. D. Morgan

    2005-01-01

    This paper details the work done on the design of the faraday cups for the DIAMOND light source. Diamond has faraday cups in positions covering the complete energy range of the machine from the 90keV gun to the 3GeV stor- age ring. The Linac cups were modified from an existing design, while the higher energy designs were done using Monte

  4. Origin of brown coloration in diamond

    Microsoft Academic Search

    L. S. Hounsome; R. Jones; P. M. Martineau; D. Fisher; M. J. Shaw; P. R. Briddon; S. Öberg

    2006-01-01

    Measurements of the absorption spectra of brown natural type IIa diamond as well as brown nitrogen-doped CVD diamond are reported. These are largely featureless and increase almost monotonically from about 1- 5.5eV . It is argued that the brown coloration is due to an extended defect and not to a point defect. First principles modeling studies demonstrate that the spectra

  5. Effect of substitutional N on the diamond CVD growth process: A theoretical approach

    Microsoft Academic Search

    T. Van Regemorter; K. Larsson

    2008-01-01

    For both (111) and (100) diamond surface orientations, one C atom within the first or second surface carbon layer has substitutionally been replaced by an N atom. The effects of this impurity on CH3 adsorption and H abstraction from a newly adsorbed CH3 have been carefully investigated by using ultra-soft pseudo-potential density functional theory (DFT) under periodic boundary conditions. The

  6. Ultramicrohardness cross-profiling of CVD diamond\\/steel brazed junctions

    Microsoft Academic Search

    A. J. S Fernandes; M. J Fonseca; F. M Costa; R. F Silva; M. H Nazaré

    1999-01-01

    Thick microwave plasma chemical vapour deposition (MPCVD) diamond films (240, 480, 1000?m) were grown, laser cut and vacuum brazed to steel bars with an Ag\\/Cu\\/Ti (100?m) reactive filler metal. Displacement sensing indentation experiments using a dynamic ultramicrohardness tester on the brazing layer were performed on different samples. A calibration curve for the residual depth values was made by linear regression

  7. 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 called IRAS 16594-4656. Like the others, it's a carbon-rich star now in the process of dying. It has been blasting out huge amounts of material over the last thousand years, becoming enclosed within a shell of dust hundreds of times larger than the Solar System --a structure called a "protoplanetary nebula". It was in this dust -- very cold and therefore invisible to non-infrared telescopes-- that the Spanish group using ISO's SWS and LWS spectrometers detected the signature of the carbonaceous compound, in the form of a broad emission band at the wavelength of 21 micron. "We searched for the compound in twenty candidate stars and only this one had it. It is a real textbook case, with one of the strongest emissions ever detected. It gets us closer to solving the mystery and will help us to understand how the "chemical factories" of the Universe work", says ESA astronomer Pedro Garcia-Lario at the ISO Data Centre in Villafranca, Madrid. His group published their results in the March 10 issue of the Astrophysical Journal. They favour the fullerene option. Fullerenes would get formed during decomposition of the solid carbon grains condensed out of the material emitted by the star. The Canadian group obtained high-resolution ISO spectra of seven other stars in this class, and also detected a weak emission of the carbonaceous compound in a new one. They present their data in the May 11 issue of the Astrophysical Journal Letters. "Diamonds, graphite, coal and fullerenes are different forms of carbon. It is quite possible that the 21 micron feature arises from any one of these forms, although not exactly like they are on Earth", says main author Sun Kwok, at the University of Calgary. His group detected the carbonaceous compound a decade ago, for the first time, with the earlier infrared satellite IRAS. Meanwhile, results from the French group led by Louis d'Hendecourt, at the Institut d'Astrophysique Spatiale, in Paris, are adding to the debate. They isolated very tiny diamonds --a million times smaller

  8. Secondary Electron Emission Spectroscopy of Diamond Surfaces

    NASA Technical Reports Server (NTRS)

    Krainsky, Isay L.; Asnin, Vladimir M.; Petukhov, Andre G.

    1999-01-01

    This report presents the results of the secondary electron emission spectroscopy study of hydrogenated diamond surfaces for single crystals and chemical vapor-deposited polycrystalline films. One-electron calculations of Auger spectra of diamond surfaces having various hydrogen coverages are presented, the major features of the experimental spectra are explained, and a theoretical model for Auger spectra of hydrogenated diamond surfaces is proposed. An energy shift and a change in the line shape of the carbon core-valence-valence (KVV) Auger spectra were observed for diamond surfaces after exposure to an electron beam or by annealing at temperatures higher than 950 C. This change is related to the redistribution of the valence-band local density of states caused by hydrogen desorption from the surface. A strong negative electron affinity (NEA) effect, which appeared as a large, narrow peak in the low-energy portion of the spectrum of the secondary electron energy distribution, was also observed on the diamond surfaces. A fine structure in this peak, which was found for the first time, reflected the energy structure of the bottom of the conduction band. Further, the breakup of the bulk excitons at the surface during secondary electron emission was attributed to one of the features of this structure. The study demonstrated that the NEA type depends on the extent of hydrogen coverage of the diamond surface, changing from the true type for the completely hydrogenated surface to the effective type for the partially hydrogenated surface.

  9. Electron Emission from a Heteroepitaxial Diamond Planar Emitter

    NASA Astrophysics Data System (ADS)

    Yamada, Takatoshi; Maede, Jun; Sawabe, Atsuhito

    1999-08-01

    Heteroepitaxial diamond (100) with relatively smooth surface morphology is grown on iridium thin film by direct current plasma chemical vapor deposition, and its electron emission is discussed by comparing the electron emission of polycrystalline diamond with the various surface morphology. From the results of electron emission measurements, the emission property from heteroepitaxial diamond is independent of the measurement point, while that from polycrystalline diamond strongly depends on the measurement points. In addition, electron emission from heteroepitaxial diamond was observed at lower voltage compared to that from polycrystalline diamond.

  10. Distinct ribosome maturation defects in yeast models of Diamond Blackfan anemia and Shwachman Diamond syndrome

    Microsoft Academic Search

    Joseph B. Moore; Jason E. Farrar; Robert J. Arceci; Johnson M. Liu; Steven R. Ellis

    Background Diamond Blackfan anemia (DBA) and Shwachman Diamond syndrome (SDS) are inherit- ed bone marrow failure syndromes linked to defects in ribosome synthesis. The purpose of this study was to determine if yeast models for DBA and SDS differed in the mecha- nism by which ribosome synthesis was affected. Design and Methods Northern blotting, pulse-chase analysis, and polysome profiling were

  11. EXELFS analysis of natural diamond and diamond films on Si substrates

    SciTech Connect

    Moller, A.D. [Centro de Investigacion Cientifica y de Educacion Superior de Ensenada (Mexico); Araiza, L.C.; Borja, M.A. [Universidad Nacional Autonoma de Mexico, Ensenada (Mexico)

    1996-12-31

    In this work, we report the EXELFS results obtained from a polycrystalline diamond film grown on smooth silicon substrates using the Hot Filament Chemical Vapor Deposition (HF-CVD) technique in a two-step deposition process published elsewhere. In order to evaluate the quality of the thin film obtained, these results were compared with results obtained from natural diamond.

  12. Refractory two-dimensional hole gas on hydrogenated diamond surface

    SciTech Connect

    Hiraiwa, Atsushi [Institute for Nanoscience and Nanotechnology, Waseda University, 513 Waseda-tsurumaki, Shinjuku, Tokyo 162-0041 (Japan); Daicho, Akira; Kurihara, Shinichiro; Yokoyama, Yuki; Kawarada, Hiroshi [Faculty of Science and Engineering, Waseda University, 3-4-1 Okubo, Shinjuku, Tokyo 169-8555 (Japan)

    2012-12-15

    Use of two-dimensional hole gas (2DHG), induced on a hydrogenated diamond surface, is a solution to overcoming one of demerits of diamond, i.e., deep energy levels of impurities. This 2DHG is affected by its environment and accordingly needs a passivation film to get a stable device operation especially at high temperature. In response to this requirement, we achieved the high-reliability passivation forming an Al{sub 2}O{sub 3} film on the diamond surface using an atomic-layer-deposition (ALD) method with an H{sub 2}O oxidant at 450 Degree-Sign C. The 2DHG thus protected survived air annealing at 550 Degree-Sign C for an hour, establishing a stable high-temperature operation of 2DHG devices in air. In part, this achievement is based on high stability of C-H bonds up to 870 Degree-Sign C in vacuum and above 450 Degree-Sign C in an H{sub 2}O-containing environment as in the ALD. Chemically, this stability is supported by the fact that both the thermal decomposition of C-H bonds and reaction between C-H bonds and H{sub 2}O are endothermic processes. It makes a stark contrast to the instability of Si-H bonds, which decompose even at room temperature being exposed to atomic hydrogen. In this respect, the diamond 2DHG devices are also promising as power devices expectedly being free from many instability phenomena, such as hot carrier effect and negative-bias temperature instability, associated with Si devices. As to adsorbate, which is the other prerequisite for 2DHG, it desorbed in vacuum below 250 Degree-Sign C, and accordingly some new adsorbates should have adsorbed during the ALD at 450 Degree-Sign C. As a clue to this question, we certainly confirmed that some adsorbates, other than those at room temperature, adsorbed in air above 100 Degree-Sign C and remained at least up to 290 Degree-Sign C. The identification of these adsorbates is open for further investigation.

  13. Effect Of Chromium Underlayer On The Properties Of Nano-Crystalline Diamond Films

    SciTech Connect

    Garratt, Elias; AlFaify, Salem; Yoshitake, T.; Katamune, Yuki; Bowden, Mark; Nandasiri, Manjula I.; Ghantasala, S.; Mancini, D. C.; Thevuthasan, Suntharampillai; Kayani, A.

    2013-01-11

    This paper investigated the effect of chromium underlayer on the structure, microstructure and composition of the nano-crystalline diamond films. Nano-crystalline diamond thin films were deposited at high temperature in microwave-induced plasma diluted with nitrogen, on silicon substrate with a thin film of chromium as an underlayer. The composition, structure and microstructure of the deposited layers were analyzed using non-Rutherford Backscattering Spectrometry, Raman Spectroscopy, Near-Edge X-Ray Absorption Fine Structure, X-ray Diffraction and Atomic Force Microscopy. Nanoindentation studies showed that the films deposited on chromium underlayer have higher hardness values compared to those deposited on silicon without an underlayer. Diamond and graphitic phases of the films evaluated by x-ray and optical spectroscopic analysis determined consistency between sp2 and sp3 phases of carbon in chromium sample to that of diamond grown on silicon. Diffusion of chromium was observed using ion beam analysis which was correlated with the formation of chromium complexes by x-ray diffraction.

  14. Nucleation and adhesion of diamond films on Co cemented tungsten carbide

    SciTech Connect

    Polini, R.; Santarelli, M.; Traversa, E.

    1999-12-01

    Diamond deposits were grown using hot filament chemical vapor deposition (CVD) on pretreated Co cemented tungsten carbide (WC-Co) substrates with an average grain size of 6 {micro}m. Depositions were performed with 0.5 or 1.0% methane concentration and with substrate temperatures ranging from 750 to 1,000 C. Diamond nucleation densities were measured by scanning electron microscopy. Scratched and bias-enhanced nucleation pretreated substrates showed the larger nucleation densities. Etching of the WC performed by Murakami's reagent, followed by surface-Co dissolution (MP pretreatment), led to a roughened but scarcely nucleating surface. The performance of a scratching prior to the MP pretreatment allowed one to increase the nucleation density, due scratching-induced defects, confined in the outermost layer of WC grains, which act as nucleation sites. Smaller nucleation densities were observed with increasing the substrate temperature and reducing the methane concentration, confirming that diamond nucleates via a heterogeneous process. The adhesion of continuous films was evaluated by the reciprocal of the slope of crack radius-indentation load functions. The substrate pretreatments mainly affected the film adhesion, while the influence of CVD process conditions was minor. The two main factors that improve the diamond film adhesion are the coating-substrate contact area and the surface-Co removal.

  15. Selected Topics in CVD Diamond Research

    NASA Astrophysics Data System (ADS)

    Koizumi, Satoshi; Nebel, Christoph E.; Nesladek, Milos

    2006-10-01

    Since the discovery of Chemical Vapor Deposition (CVD) diamond growth in 1976, the steady scientific progress often resulted in surprising new discoveries and breakthroughs. This brought us to the idea to publish the special issue Selected Topics in CVD Diamond Research in physica status solidi (a), reflecting such advancements and interesting results at the leading edge of diamond research.The present issue summarizes this progress in the CVD diamond field by selecting contributions from several areas such as superconductivity, super-excitonic radiation, quantum computing, bio-functionalization, surface electronic properties, the nature of phosphorus doping, transport properties in high energy detectors, CVD growth and properties of nanocrystalline diamond. In all these directions CVD diamond appears to be very competitive in comparison with other semiconducting materials.As Editors of this special issue, we must admit that the selection is biased by our opinion. Nonetheless, we are sure that each contribution introduces new ideas and results which will improve the understanding of the current level of physics and chemistry of this attractive wide-bandgap semiconductor and which will help to bring it closer to applications.All submissions were invited based on the contributions of the authors to their specific research field. The Feature Articles have the format of topical reviews to give the reader a comprehensive summary. Partially, however, they are written in research paper style to report new results of ongoing research.We hope that this issue will attract the attention of a broad community of scientists and engineers, and that it will facilitate the utilization of diamond in electronic applications and technologies of the future.

  16. ‘The Diamond’: a structure for simulation debrief

    PubMed Central

    Jaye, Peter; Thomas, Libby; Reedy, Gabriel

    2015-01-01

    Background Despite debriefing being found to be the most important element in providing effective learning in simulation-based medical education reviews, there are only a few examples in the literature to help guide a debriefer. The diamond debriefing method is based on the technique of description, analysis and application, along with aspects of the advocacy-inquiry approach and of debriefing with good judgement. It is specifically designed to allow an exploration of the non-technical aspects of a simulated scenario. Context The debrief diamond, a structured visual reminder of the debrief process, was developed through teaching simulation debriefing to hundreds of faculty members over several years. The diamond shape visually represents the idealised process of a debrief: opening out a facilitated discussion about the scenario, before bringing the learning back into sharp focus with specific learning points. Debriefing is the most important element in providing effective learning in simulation-based medical education reviews Innovation The Diamond is a two-sided prompt sheet: the first contains the scaffolding, with a series of specifically constructed questions for each phase of the debrief; the second lays out the theory behind the questions and the process. Implication The Diamond encourages a standardised approach to high-quality debriefing on non-technical skills. Feedback from learners and from debriefing faculty members has indicated that the Diamond is useful and valuable as a debriefing tool, benefiting both participants and faculty members. It can be used by junior and senior faculty members debriefing in pairs, allowing the junior faculty member to conduct the description phase, while the more experienced faculty member leads the later and more challenging phases. The Diamond gives an easy but pedagogically sound structure to follow and specific prompts to use in the moment. PMID:26009951

  17. 21 CFR 872.4535 - Dental diamond instrument.

    Code of Federal Regulations, 2014 CFR

    2014-04-01

    ...2014-04-01 2014-04-01 false Dental diamond instrument. 872.4535 ...HEALTH AND HUMAN SERVICES (CONTINUED) MEDICAL DEVICES DENTAL DEVICES Surgical Devices § 872.4535 Dental diamond instrument. (a)...

  18. 21 CFR 872.4535 - Dental diamond instrument.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ...2010-04-01 2010-04-01 false Dental diamond instrument. 872.4535 ...HEALTH AND HUMAN SERVICES (CONTINUED) MEDICAL DEVICES DENTAL DEVICES Surgical Devices § 872.4535 Dental diamond instrument. (a)...

  19. 21 CFR 872.4535 - Dental diamond instrument.

    Code of Federal Regulations, 2013 CFR

    2013-04-01

    ...2013-04-01 2013-04-01 false Dental diamond instrument. 872.4535 ...HEALTH AND HUMAN SERVICES (CONTINUED) MEDICAL DEVICES DENTAL DEVICES Surgical Devices § 872.4535 Dental diamond instrument. (a)...

  20. 21 CFR 872.4535 - Dental diamond instrument.

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ...2011-04-01 2011-04-01 false Dental diamond instrument. 872.4535 ...HEALTH AND HUMAN SERVICES (CONTINUED) MEDICAL DEVICES DENTAL DEVICES Surgical Devices § 872.4535 Dental diamond instrument. (a)...

  1. 21 CFR 872.4535 - Dental diamond instrument.

    Code of Federal Regulations, 2012 CFR

    2012-04-01

    ...2012-04-01 2012-04-01 false Dental diamond instrument. 872.4535 ...HEALTH AND HUMAN SERVICES (CONTINUED) MEDICAL DEVICES DENTAL DEVICES Surgical Devices § 872.4535 Dental diamond instrument. (a)...

  2. 1. GENERAL VIEW OF THE DIAMOND MINEYARD LOOKING NORTHWEST SHOWING ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    1. GENERAL VIEW OF THE DIAMOND MINEYARD LOOKING NORTHWEST SHOWING THE DRIES ON THE LEFT, TAR STORAGE AND TOILET FACILITIES IN THE CENTER, AND A ROPE CLEANING HOUSE ON THE RIGHT - Butte Mineyards, Diamond Mine, Butte, Silver Bow County, MT

  3. FRONT ELEVATION, HOUSE AT NORTHWEST CORNER OF SEVENTEENTH AND DIAMOND ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    FRONT ELEVATION, HOUSE AT NORTHWEST CORNER OF SEVENTEENTH AND DIAMOND STREETS AND THE ATTACHED INTERIOR UNIT (NOS. 1701 AND 1703). - 1700 Block Diamond Street (Houses), North & south sides between Seventeenth & Eighteenth Streets, Philadelphia, Philadelphia County, PA

  4. 17. VIEW OF THE DIAMOND MINEYARD LOOKING NORTHEAST. THE DRIES ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    17. VIEW OF THE DIAMOND MINEYARD LOOKING NORTHEAST. THE DRIES ARE ON THE LEFT, WITH THE TAR HOUSE, TOILET, AND ROPE CLAMP CLEANING BUILDING TO THE RIGHT - Butte Mineyards, Diamond Mine, Butte, Silver Bow County, MT

  5. Epitaxial diamond growth on sapphire in an oxidizing environment

    NASA Astrophysics Data System (ADS)

    Yoshimoto, Mamoru; Yoshida, Kenji; Maruta, Hideaki; Hishitani, Yoshiko; Koinuma, Hideomi; Nishio, Shigeru; Kakihana, Masato; Tachibana, Takeshi

    1999-05-01

    Thin films of diamond are of interest for technological applications such as hard coatings, heat sinks in electronic devices and miniaturized vacuum diodes. They are typically produced by chemical vapour deposition, and the presence of atomic hydrogen has been considered crucial for the growth of the diamond crystals. Some studies have claimed diamond film growth in a hydrogen-free environment, but questions remained about the growth conditions in those cases. Here we report the nucleation and growth of diamond by vapour deposition in a hydrogen-free, pure oxygen environment to form crystals that are heteroepitaxially aligned on a single-crystal sapphire substrate. In other words, we are able to achieve diamond growth under conditions where the oxidative `etching' of carbon must compete with its deposition. By choosing a temperature range that results in preferential oxidation of non-diamond (graphitic) carbon species to that of diamond, we are able to achieve the accumulation of diamond.

  6. Prospects for the synthesis of large single-crystal diamonds

    NASA Astrophysics Data System (ADS)

    Khmelnitskiy, R. A.

    2015-02-01

    The unique properties of diamond have stimulated the study of and search for its applications in many fields, including optics, optoelectronics, electronics, biology, and electrochemistry. Whereas chemical vapor deposition allows the growth of polycrystalline diamond plates more than 200 mm in diameter, most current diamond application technologies require large-size (25 mm and more) single-crystal diamond substrates or films suitable for the photolithography process. This is quite a challenge, because the largest diamond crystals currently available are 10 mm or less in size. This review examines three promising approaches to fabricating large-size diamond single crystals: growing large-size single crystals, the deposition of heteroepitaxial diamond films on single-crystal substrates, and the preparation of composite diamond substrates.

  7. OUT Success Stories: Diamond-Cutter Drill Bits

    SciTech Connect

    Burr, R.

    2000-08-31

    DOE contributed markedly to the geothermal, oil, and gas industries through the development of the advanced polycrystalline diamond compact (PDC) drill bit. Diamond-cutter drill bits cut through tough rock quicker, reducing the cost of drilling for energy resources.

  8. For Parents of Children with Diamond Blackfan Anemia

    MedlinePLUS

    ... Disorders For Parents of Children with Diamond Blackfan Anemia Parenting Corner Q&A When your child is ... Starlight Children’s Foundation www.starlight.org Diamond Blackfan Anemia Foundation (DBAF) http://www.dbafoundation.org/ DBA Nurse ...

  9. Simulating Ramp Compression of Diamond

    NASA Astrophysics Data System (ADS)

    Godwal, B. K.; Gonzàlez-Cataldo, F. J.; Jeanloz, R.

    2014-12-01

    We model ramp compression, shock-free dynamic loading, intended to generate a well-defined equation of state that achieves higher densities and lower temperatures than the corresponding shock Hugoniot. Ramp loading ideally approaches isentropic compression for a fluid sample, so is useful for simulating the states deep inside convecting planets. Our model explicitly evaluates the deviation of ramp from "quasi-isentropic" compression. Motivated by recent ramp-compression experiments to 5 TPa (50 Mbar), we calculate the room-temperature isotherm of diamond using first-principles density functional theory and molecular dynamics, from which we derive a principal isentrope and Hugoniot by way of the Mie-Grüneisen formulation and the Hugoniot conservation relations. We simulate ramp compression by imposing a uniaxial strain that then relaxes to an isotropic state, evaluating the change in internal energy and stress components as the sample relaxes toward isotropic strain at constant volume; temperature is well defined for the resulting hydrostatic state. Finally, we evaluate multiple shock- and ramp-loading steps to compare with single-step loading to a given final compression. Temperatures calculated for single-step ramp compression are less than Hugoniot temperatures only above 500 GPa, the two being close to each other at lower pressures. We obtain temperatures of 5095 K and 6815 K for single-step ramp loading to 600 and 800 GPa, for example, which compares well with values of ~5100 K and ~6300 K estimated from previous experiments [PRL,102, 075503, 2009]. At 800 GPa, diamond is calculated to have a temperature of 500 K along the isentrope; 900 K under multi-shock compression (asymptotic result after 8-10 steps); and 3400 K under 3-step ramp loading (200-400-800 GPa). Asymptotic multi-step shock and ramp loading are indistinguishable from the isentrope, within present uncertainties. Our simulations quantify the manner in which current experiments can simulate the deep interiors of planetary bodies, including super-giant extra-Solar planets.

  10. Investigation of Surface Magnetic Noise by Shallow Spins in Diamond

    NASA Astrophysics Data System (ADS)

    Rosskopf, T.; Dussaux, A.; Ohashi, K.; Loretz, M.; Schirhagl, R.; Watanabe, H.; Shikata, S.; Itoh, K. M.; Degen, C. L.

    2014-04-01

    We present measurements of spin relaxation times (T1, T1?, T2) on very shallow (?5 nm) nitrogen-vacancy centers in high-purity diamond single crystals. We find a reduction of spin relaxation times up to 30 times compared to bulk values, indicating the presence of ubiquitous magnetic impurities associated with the surface. Our measurements yield a density of 0.01-0.1?B/nm2 and a characteristic correlation time of 0.28(3) ns of surface states, with little variation between samples and chemical surface terminations. A low temperature measurement further confirms that fluctuations are thermally activated. The data support the atomistic picture where impurities are associated with the top carbon layers, and not with terminating surface atoms or adsorbate molecules. The low spin density implies that the presence of a single surface impurity is sufficient to cause spin relaxation of a shallow nitrogen-vacancy center.

  11. Diamond Provenance Through Shape, Colour, Surface Features and Value

    NASA Astrophysics Data System (ADS)

    Harris, J.

    2002-05-01

    The physical properties of diamond provide a possible means by which run-of-mine productions may be identified. Such properties as shape, the regularity and angularity of the crystal form, the level of transparency, colour, syngenetic inclusion content and surface feature characteristics, all as a function of diamond size, can classify diamond productions. In early work, up to 1500 diamonds in specific sizes ranging from just under 2mm up to 6mm were evaluated. Using this procedure, most of the diamonds from the main mines in southern Africa have now been classified. Within South Africa, the mine at Swartruggens is the only one to have measurable levels of cube-shaped diamonds and an absence of the spinel twin form of diamond, more commonly known as the macle. In Botswana, the proportion of cube related forms at Jwaneng is about four times that at Orapa. Whilst the common diamond colours, colourless, yellow and brown, occur in most mines, there is a marked change in the proportion of transparent green-coated diamonds with depth in mines such as Finsch and Jwaneng. Individual mines may also have very small proportions of distinctive diamond colours, such as pinks at the Argyle mine in Australia and blues in the Premier mine in South Africa. More recently, classification emphasis has shifted away from large numbers of diamonds examined and particular attention has been paid to surface features, which reflect changes to the diamond either whilst still in the kimberlite, or subsequently during transport to an alluvial source. A classification of diamonds at the Venetia mine, South Africa, for example, showed that the proportion of diamonds with the feature referred to as corrosion sculpture, was distinctive between kimberlite types within the mine. With alluvial diamonds, transport causes further defects, particularly a general increase in the proportion of diamonds with surface features referred to as percussion marks and edge abrasion. The above observational information may also be combined with the observational methods normally used to characterise diamonds during typical sorting procedures prior to sale. These procedures have well-defined and very specific categories such as gem/near gem, sawable/makeable and are linked particularly to diamond colour. By combining the geological techniques with that of diamond value, a very powerful means of defining diamond to a particular source, may be created. For the purpose of identifying conflict diamonds, such observational evidence may prove very useful. Identification would become more difficult if parcels are small or mixed in some way. A major drawback, however, both to the observational approach outline above and to any analytical techniques, is that there are no database of conflict diamonds against which to set the results.

  12. Field electron emission based on resonant tunneling in diamond/CoSi2/Si quantum well nanostructures

    PubMed Central

    Gu, Changzhi; Jiang, Xin; Lu, Wengang; Li, Junjie; Mantl, Siegfried

    2012-01-01

    Excellent field electron emission properties of a diamond/CoSi2/Si quantum well nanostructure are observed. The novel quantum well structure consists of high quality diamond emitters grown on bulk Si substrate with a nanosized epitaxial CoSi2 conducting interlayer. The results show that the main emission properties were modified by varying the CoSi2 thickness and that stable, low-field, high emission current and controlled electron emission can be obtained by using a high quality diamond film and a thicker CoSi2 interlayer. An electron resonant tunneling mechanism in this quantum well structure is suggested, and the tunneling is due to the long electron mean free path in the nanosized CoSi2 layer. This structure meets most of the requirements for development of vacuum micro/nanoelectronic devices and large-area cold cathodes for flat-panel displays. PMID:23082241

  13. Alluvial Diamond Resource Potential and Production Capacity Assessment of Ghana

    USGS Publications Warehouse

    Chirico, Peter G.; Malpeli, Katherine C.; Anum, Solomon; Phillips, Emily C.

    2010-01-01

    In May of 2000, a meeting was convened in Kimberley, South Africa, and attended by representatives of the diamond industry and leaders of African governments to develop a certification process intended to assure that rough, exported diamonds were free of conflictual concerns. This meeting was supported later in 2000 by the United Nations in a resolution adopted by the General Assembly. By 2002, the Kimberley Process Certification Scheme (KPCS) was ratified and signed by both diamond-producing and diamond-importing countries. Over 70 countries were included as members at the end of 2007. To prevent trade in 'conflict' diamonds while protecting legitimate trade, the KPCS requires that each country set up an internal system of controls to prevent conflict diamonds from entering any imported or exported shipments of rough diamonds. Every diamond or diamond shipment must be accompanied by a Kimberley Process (KP) certificate and be contained in tamper-proof packaging. The objective of this study was to assess the alluvial diamond resource endowment and current production capacity of the alluvial diamond-mining sector in Ghana. A modified volume and grade methodology was used to estimate the remaining diamond reserves within the Birim and Bonsa diamond fields. The production capacity of the sector was estimated using a formulaic expression of the number of workers reported in the sector, their productivity, and the average grade of deposits mined. This study estimates that there are approximately 91,600,000 carats of alluvial diamonds remaining in both the Birim and Bonsa diamond fields: 89,000,000 carats in the Birim and 2,600,000 carats in the Bonsa. Production capacity is calculated to be 765,000 carats per year, based on the formula used and available data on the number of workers and worker productivity. Annual production is highly dependent on the international diamond market and prices, the numbers of seasonal workers actively mining in the sector, and environmental conditions, which influence seasonal farming.

  14. Nanostructure TEM analysis of diamond cold cathode field emitters

    SciTech Connect

    Wade, Travis S. [Vanderbilt University; Ghosh, Nikkon [Vanderbilt University; Wittig, James Edward [ORNL; Kang, Weng [Vanderbilt University; Allard Jr, Lawrence Frederick [ORNL; Unocic, Kinga A [ORNL; Davidson, James [Vanderbilt University; Tolk, Norman H. [Vanderbilt University

    2012-01-01

    Diamond cold cathode devices have demonstrated significant potential as electron field emitters. Ultra-sharp diamond pyramidal tips (~5nm tip radius) have been fabricated and show improvement in emission when compared to conventional field emitters. However, the emission mechanisms in these complex diamond nanostructures are not well understood. Transmission electron microscopy performed in this study provides new insight into tip structure and composition with implications for field emission and diamond growth.

  15. CVD-diamond technologies for dry drilling applications

    Microsoft Academic Search

    Y. Kevin Chou; Raymond G. Thompson; Ashok Kumar

    2010-01-01

    CVD-diamond for dry drilling applications is reported. Specifically, the fabrication of nanostructured diamond-coated drills is outlined. Tool life is evaluated by dry drilling of aluminum alloy and nanostructured diamond-coated drills show a superior performance to uncoated drills. In addition, different surface treatments have been studied with the effects on diamond film deposition and delamination investigated. Moreover, drill edge geometry has

  16. The Petrography of Meteoritic Nano-Diamonds

    NASA Technical Reports Server (NTRS)

    Dai, Z. R.; Bradley, J. P.; Brownlee, D. E.; Joswiak, D. J.

    2003-01-01

    At least some meteoritic nanodiamonds are likely of presolar origin because of their association with anomalous Xe-HL and Te isotopic components indicative of a supernova (SN) origin. But the abundance of Xe is such that only approx. 1 in 10(exp 6) nano-diamonds contains a Xe atom, and the bulk C-13/C-12 composition of nano-diamond acid residues is chondritic (solar). Therefore, it is possible that a significant fraction of meteoritic nano-diamonds formed within the solar nebula. Nano-diamonds have recently been detected for the first time within the accretion discs of young stars by the Infrared Space Observatory (ISO). No comparable evidence of nanodiamonds in the interstellar medium has yet been found. We have identified nano-diamonds in acid etched thin-sections of meteorites, polar micrometeorites, and interplanetary dust particles (IDPs) with the goal of determining their distribution as a function of heliocentric distance. (It is assumed the meteorites and the polar micrometeorites are from asteroids at 2-4 AU and at least some of the IDPs are from comets at >50AU). We found that nano-diamonds are heterogeneously distributed throughout carbon-rich meteoritic materials (we identified them in some IDPs and not in others), and that their abundance may actually decrease with heliocentric distance, consistent with the hypothesis that some of them formed within the inner solar system and not in a presolar (SN) environment. In order to gain further insight about the origins of meteoritic nano-diamonds we are currently investigating their distribution in unetched thin-sections. We have examined a chondritic cluster IDP (U220GCA), fragments of the Tagish Lake (CM1) meteorite, and a SN graphite spherule (KE3d8) isolated from the Murchison (CM) meteorite. We selected U220GCA because its nano-diamond abundance (in acid etched thin-sections) appears to be as much as approx. 10X higher than in Murchison matrix, Tagish Lake because it has a higher reported nano-diamond abundance than other carbonaceous chondrites (approx. 3650-4330 ppm), and KE3d8 because it is a carbon spherule with an isotopic composition suggesting that it is a bone fide presolar SN grain.

  17. Single crystal diamond nanobeam waveguide optomechanics

    E-print Network

    Behzad Khanaliloo; Harishankar Jayakumar; Aaron C. Hryciw; David P. Lake; Hamidreza Kaviani; Paul E. Barclay

    2015-04-28

    Optomechanical devices sensitively transduce and actuate motion of nanomechanical structures using light. Single--crystal diamond promises to improve the performance of optomechanical devices, while also providing opportunities to interface nanomechanics with diamond color center spins and related quantum technologies. Here we demonstrate dissipative waveguide--optomechanical coupling exceeding 35 GHz/nm to diamond nanobeams supporting both optical waveguide modes and mechanical resonances, and use this optomechanical coupling to measure nanobeam displacement with a sensitivity of $9.5$ fm/$\\sqrt{\\text{Hz}}$ and optical bandwidth $>150$nm. The nanobeams are fabricated from bulk optical grade single--crystal diamond using a scalable undercut etching process, and support mechanical resonances with quality factor $2.5 \\times 10^5$ at room temperature, and $7.2 \\times 10^5$ in cryogenic conditions (5K). Mechanical self--oscillations, resulting from interplay between photothermal and optomechanical effects, are observed with amplitude exceeding 200 nm for sub-$\\mu$W absorbed optical power, demonstrating the potential for optomechanical excitation and manipulation of diamond nanomechanical structures.

  18. Lubrication by Diamond and Diamondlike Carbon Coatings

    NASA Technical Reports Server (NTRS)

    Miyoshi, Kazuhisa

    1997-01-01

    Regardless of environment (ultrahigh vacuum, humid air, dry nitrogen, or water), ion-beam-deposited diamondlike carbon (DLC) and nitrogen-ion-implanted, chemical-vapor-deposited (CVD) diamond films had low steady-state coefficients of friction (less than 0.1) and low wear rates (less than or equal to 10(exp -6)cu mm/N(dot)m). These films can be used as effective wear-resistant, self-lubricating coatings regardless of environment. On the other hand, as-deposited, fine-grain CVD diamond films; polished, coarse-grain CVD diamond films; and polished and then fluorinated, coarse-grain CVD diamond films can be used as effective wear-resistant, self-lubricating coatings in humid air, in dry nitrogen, and in water, but they had a high coefficient of friction and a high wear rate in ultrahigh vacuum. The polished, coarse-grain CVD diamond film revealed an extremely low wear rate, far less than 10(exp 10) cu mm/N(dot)m, in water.

  19. Investigation of applications of diamond film

    NASA Astrophysics Data System (ADS)

    Jassowski, D. M.

    1989-11-01

    The unique properties of synthetic diamond prepared by chemical vapor deposition suggest potential aerospace applications of interest to the Air Force. The status of the rapidly developing technology of low-pressure diamond film synthesis has been determined by contacts with 76 research groups active in the field. Information on six synthetic techniques and a list of 112 active groups are included. Updated diamond film properties are presented based on the survey, literature data, and the measurements made in this program. Measurements were made of hydrogen diffusion resistance, hardness, thermal shock resistance, rupture strength, and propellant compatibility. A comprehensive screen of 200 potential Air Force applications is presented. These were reduced to a 4 high-value applications: bearing surfaces, barriers for hydrogen diffusion, barriers for propellant corrosion protection, and thermal protection for surfaces with localized high heat flux. Initial reports of unusually high tensile strength for diamond films cannot be supported by detailed analysis of test data, eliminating some structural applications. Technology development plans are presented for obtaining better properties data for demonstrating the application of diamond films to bearings.

  20. Ultradispersity of diamond at the nanoscale.

    PubMed

    Raty, Jean-Yves; Galli, Giulia

    2003-12-01

    Nanometre-sized diamond has been found in meteorites, protoplanetary nebulae and interstellar dusts, as well as in residues of detonation and in diamond films. Remarkably, the size distribution of diamond nanoparticles seems to be peaked around 2-5 nm, and to be largely independent of preparation conditions. We have carried out ab initio calculations of the stability of nanodiamond as a function of surface hydrogen coverage and of size. We have found that at about 3 nm, and for a broad range of pressures and temperatures, particles with bare, reconstructed surfaces become thermodynamically more stable than those with hydrogenated surfaces, thus preventing the formation of larger grains. Our findings provide an explanation of the size distribution of extraterrestrial and of terrestrial nanodiamond found in ultradispersed and ultracrystalline diamond films. They also provide an atomistic structural model of these films, based on the topology and structure of 2-3-nm dimond clusters consisting of a diamond core surrounded by a fullerene-like carbon network. PMID:14634641

  1. Auger Spectroscopy of Hydrogenated Diamond Surfaces

    NASA Technical Reports Server (NTRS)

    Krainsky, I. L.; Asnin, V. M.; Petukhov, A. G.; Foygel, M.

    1997-01-01

    An energy shift and a change of the line shape of the carbon core-valence-valence Auger spectra are observed for diamond surfaces after their exposure to an electron beam, or annealing at temperatures higher then 950 C. The effect is studied for both natural diamond crystals and chemical-vapor-deposited diamond films. A theoretical model is proposed for Auger spectra of hydrogenated diamond surfaces. The observed changes of the carbon Auger line shape are shown to be related to the redistribution of the valence-band local density of states caused by the hydrogen desorption from the surface. One-electron calculation of Auger spectra of diamond surfaces with various hydrogen coverages are presented. They are based on self-consistent wave functions and matrix elements calculated in the framework of the local-density approximation and the self-consistent linear muffin-tin orbital method with static core-hole effects taken into account. The major features of experimental spectra are explained.

  2. Cobalt lung in diamond polishers.

    PubMed

    Demedts, M; Gheysens, B; Nagels, J; Verbeken, E; Lauweryns, J; van den Eeckhout, A; Lahaye, D; Gyselen, A

    1984-07-01

    Five diamond polishers with interstitial lung disease attributed to cobalt not alloyed to carbides of hard metals are described. The exposure originated from high-speed grinding tools with a polishing surface of microdiamonds cemented in very fine cobalt. Mineralogic analysis of lung tissue, lavage fluid, filtered air, and exhaust dust in the work environment revealed cobalt as the only toxic agent. Complaints consisted of work-related rhinitis, cough, chest tightness, dyspnea, anorexia, and weight loss, and were intensified in the absence of an adequate exhaust ventilation. Three subjects were in a rather subacute stage, as documented by open lung biopsy in 2 of them, and had a severe restrictive defect and markedly decreased diffusing capacity. Two patients presented a more chronic histologic pattern and had a less decreased diffusing capacity. Open lung biopsies showed in these 4 a fibrosing alveolitis, mainly of the centrilobular zones. In the former 2 patients, subacute lesions consisting of a mural mononuclear cell infiltrate, marked intra-alveolar desquamation, and multinucleated giant cells were found, whereas in the latter 2, centrilobular fibrosis with some microcyst formation was also already seen. Multiple multinucleated giant cells were present in the bronchoalveolar lavage fluid. Interruption of the exposure, with or without corticotherapy, caused a rapid regression of the complaints and a partial improvement of lung function. PMID:6742597

  3. Raman Microscopic Characterization of Proton-Irradiated Polycrystalline Diamond Films

    NASA Technical Reports Server (NTRS)

    Newton, R. L.; Davidson, J. L.; Lance, M. J.

    2004-01-01

    The microstructural effects of irradiating polycrystalline diamond films with proton dosages ranging from 10(exp 15) to 10(exp 17) H(+) per square centimeter was examined. Scanning Electron Microscopy and Raman microscopy were used to examine the changes in the diamond crystalline lattice as a function of depth. Results indicate that the diamond lattice is retained, even at maximum irradiation levels.

  4. Chemical heterogeneity in carbonado, an enigmatic polycrystalline diamond

    Microsoft Academic Search

    Subarnarekha De; Peter J. Heaney; Edward P. Vicenzi; Jianhua Wang

    2001-01-01

    Carbonado, a polycrystalline variety of diamond, is characterized by unusual carbon isotope compositions with bulk ?13C values clustered tightly between ?23 and ?30‰ (relative to PDB). These values are significantly lighter than harzburgitic diamond (with a range in ?13C from ?1 to ?10‰) and fall near the lower extreme for eclogitic diamond (ranging from +3 to ?34‰). In combination with

  5. Integrated models of diamond formation and craton evolution

    Microsoft Academic Search

    Steven B. Shirey; Stephen H. Richardson; Jeffrey W. Harris

    2004-01-01

    Two decades of diamond research in southern Africa allow the age, average N content and carbon composition of diamonds, and the dominant paragenesis of their syngenetic silicate and sulfide inclusions to be integrated on a cratonwide scale with a model of craton formation. Individual eclogitic sulfide inclusions in diamonds from the Kimberley area kimberlites, Koffiefontein, Orapa and Jwaneng have Re–Os

  6. WEAK DIAMOND AND OPEN COLORINGS JUSTIN TATCH MOORE

    E-print Network

    Moore, Justin Tatch

    WEAK DIAMOND AND OPEN COLORINGS JUSTIN TATCH MOORE Abstract. The purpose of this article are not order iso- morphic. Since items 1-3 are all consequences of weak diamond (an equivalent of 2 @0 | see [4]) this suggests the question of whether OCA is relatively consistent with weak diamond

  7. DIAMOND CLOSURE by Melvin Hochster and Juan D. V' elez

    E-print Network

    Hochster, Melvin

    DIAMOND CLOSURE by Melvin Hochster and Juan D. V' elez Section 1. INTRODUCTION Throughout, all closure theory and related topics. The theory that is obtained from the notion of diamond closure The notion of diamond closure is based on defining certain ``powers'' of ideals I hni (a fixed choice

  8. World-leading lab opens new frontiers in diamond

    E-print Network

    Machel, Hans

    World-leading lab opens new frontiers in diamond research Canada Excellence Research Chair in Arctic Resources opens new lab devoted to developing technologies to expand diamond industry. By Bryan frontiers in diamond research in Canada's Arctic with one of the largest and best- equipped labs

  9. Diamond graphs and superreflexivity # William B. Johnson + and Gideon Schechtman #

    E-print Network

    Johnson, William B.

    Diamond graphs and super­reflexivity # William B. Johnson + and Gideon Schechtman # Abstract The main result is that a Banach space X is not super­reflexive if and only if the diamond graphs D n and Charikar proved that the diamond graphs D n , which were known ([GNRS]) to Lipschitz embed into # 1

  10. Diamond Field Effect Transistors with high-k gate insulator

    E-print Network

    Ku?el, Petr

    Diamond Field Effect Transistors with high-k gate insulator Yasuo Koide Seminá odd. 26 Tenkých), Japan Diamond has an attractive interest as one of next-generation power electronics materials. Since the sheet hole density in the hydrogenated-diamond surface was reported to be as high as 1E14 cm-2 which

  11. Diamond-free families of the Boolean lattice Ryan Martin

    E-print Network

    Biro, Csaba

    Diamond-free families of the Boolean lattice Ryan Martin Iowa State University Joint work Meeting (#1092) Kramer-Martin-Young (Iowa State U.) Diamond-free families 05 October 2013 1 / 16 #12;Joint-Martin-Young (Iowa State U.) Diamond-free families 05 October 2013 2 / 16 #12;The Boolean lattice Definition For any

  12. Network-Aware Partitioning of Computation in Diamond

    E-print Network

    Network-Aware Partitioning of Computation in Diamond Alex Nizhner 1 Larry Huston 2 Peter Steenkiste Pittsburgh, PA 15213 Abstract The Diamond storage architecture enables eÆcient interactive searchÆcient use of resources under dynamic conditions, Diamond adaptively partitions computation among the storage

  13. WEAK DIAMOND AND OPEN COLORINGS JUSTIN TATCH MOORE

    E-print Network

    Moore, Justin Tatch

    WEAK DIAMOND AND OPEN COLORINGS JUSTIN TATCH MOORE Abstract. The purpose of this article of weak diamond (an equivalent of 20 is relatively consistent with weak diamond. In this paper I will show that this is indeed the case. I will also

  14. Diamond Lattice Model of Semicrystalline Polyethylene in the Amorphous Region

    E-print Network

    Aluffi, Paolo

    Diamond Lattice Model of Semicrystalline Polyethylene in the Amorphous Region Zhong­Hui Duan computed, modeling the chains as random walks on a diamond lattice with two absorbing boundaries four neighbors --- the lattice of the diamond (also silicon) crystal. We shall model the chains

  15. Diamond Channel with Partially Separated Relays Ravi Tandon Sennur Ulukus

    E-print Network

    Ulukus, Sennur

    Diamond Channel with Partially Separated Relays Ravi Tandon Sennur Ulukus Department of Electrical--We consider diamond channels with a general broadcast channel p(y, z|x), with outputs Z and Y at relays 1 the capacity. We next give an upper bound for the capacity of the class of diamond channels with a physically

  16. WEAK DIAMOND AND OPEN COLORINGS JUSTIN TATCH MOORE

    E-print Network

    Moore, Justin Tatch

    WEAK DIAMOND AND OPEN COLORINGS JUSTIN TATCH MOORE- morphic. Since items 1-3 are all consequences of weak diamond (an equivalent of 2@0 ]) this suggests the question of whether OCA is relatively consistent with weak diamond. In this paper I

  17. Diamond graphs and super-reflexivity William B. Johnson

    E-print Network

    Johnson, William B.

    Diamond graphs and super-reflexivity William B. Johnson and Gideon Schechtman Abstract The main result is that a Banach space X is not super-reflexive if and only if the diamond graphs Dn Lipschitz and Charikar proved that the diamond graphs Dn, which were known ([GNRS]) to Lipschitz embed into 1

  18. Diamond turning of aspheric steel molds for optics replication

    Microsoft Academic Search

    F. Klocke; O. Dambon; B. Bulla

    2010-01-01

    Diamond turning of steel parts is conventionally not possible due to the high tool wear. However this process would enable several different application with high economical innovative potential. One technology that enables the direct manufacturing of steel components with monocrystalline diamond is the ultrasonic assisted diamond turning process. This technology has been investigated over years within the Fraunhofer IPT and

  19. 78 FR 57104 - Airworthiness Directives; Diamond Aircraft Industries Airplanes

    Federal Register 2010, 2011, 2012, 2013, 2014

    2013-09-17

    ...2120-AA64 Airworthiness Directives; Diamond Aircraft Industries Airplanes AGENCY: Federal...airworthiness directive (AD) for Diamond Aircraft Industries Model DA 40 and DA 40 F Airplanes...in this proposed AD, contact Diamond Aircraft Industries GmbH, N.A....

  20. Delaunay and Diamond Triangulations Contain Spanners of Bounded Degree

    E-print Network

    Smid, Michiel

    Delaunay and Diamond Triangulations Contain Spanners of Bounded Degree Prosenjit Bose Michiel Smid satisfying the diamond property, then for a specific range of values of dependent on the angle of the diamonds, we show that G is a t-spanner of V (for some constant t) whose maximum degree is bounded