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1

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

NASA Astrophysics Data System (ADS)

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.

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

2014-03-01

2

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

SciTech Connect

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.

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

3

Electronic properties of ultrananocrystalline diamond surfaces.  

SciTech Connect

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

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

2010-03-04

4

Nanopatterning of ultrananocrystalline diamond thin films via block copolymer lithography.  

SciTech Connect

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.

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

2010-07-01

5

Ultra-nanocrystalline diamond electrodes: optimization towards neural stimulation applications  

NASA Astrophysics Data System (ADS)

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.

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

2012-02-01

6

Ultrananocrystalline diamond-decorated silicon nanowire field emitters.  

PubMed

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

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

2014-08-27

7

Characterization of ultrananocrystalline diamond microsensors for in vivo dopamine detection  

PubMed Central

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

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

2013-01-01

8

Characterization of ultrananocrystalline diamond microsensors for in vivo dopamine detection  

NASA Astrophysics Data System (ADS)

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.

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

2013-06-01

9

Mechanical stiffness and dissipation in ultrananocrystalline diamond micro-resonators.  

SciTech Connect

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.

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

2009-01-01

10

Planar Ultrananocrystalline Diamond Field Emitter in Accelerator RF Electron Injector: Performance Metrics  

E-print Network

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

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

2014-01-01

11

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

NASA Astrophysics Data System (ADS)

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

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

2014-07-01

12

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

NASA Astrophysics Data System (ADS)

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.

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

2014-10-01

13

Elasticity, strength, and toughness of single crystal silicon carbide, ultrananocrystalline diamond, and hydrogen-free tetrahedral amorphous  

E-print Network

crystal 3C-SiC from Case Western Reserve University10 was deposited in an atmospheric-pressure chemicalElasticity, strength, and toughness of single crystal silicon carbide, ultrananocrystalline diamond report the mechanical properties of three emerging materials in thin film form: single crystal silicon

Espinosa, Horacio D.

14

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

EPA Science Inventory

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

15

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

SciTech Connect

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.

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

16

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

NASA Astrophysics Data System (ADS)

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.

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

2014-04-01

17

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

SciTech Connect

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.

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

18

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

SciTech Connect

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

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

2001-11-01

19

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

SciTech Connect

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.

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

20

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

PubMed

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

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

2014-08-27

21

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

PubMed Central

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

2011-01-01

22

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

NASA Astrophysics Data System (ADS)

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

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

2012-01-01

23

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

DOEpatents

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

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

2013-01-15

24

Ultrananocrystalline diamond nano-pillars synthesized by microwave plasma bias-enhanced nucleation and bias-enhanced growth in hydrogen-diluted methane  

NASA Astrophysics Data System (ADS)

Bias-enhanced nucleation and growth of ultrananocrystalline diamond (UNCD) nano-pillars on silicon substrates by low-pressure microwave plasma chemical vapor deposition in a hydrogen-rich gas mixture with methane is reported. Direct-current biasing of the substrate in a constant-current mode is applied to substrates, which are pre-heated to 800 °C, to result in a negative bias voltage of greater than 350 V throughout the nucleation and growth process. Self-masking by UNCD clusters, angle dependent sputtering of UNCD clusters, and ion-assisted chemical vapor deposition by bias enhanced bombardment of energetic ions are attributed to the formation of UNCD nano-pillars. High-resolution transmission electron microscopy analysis indicates that an interfacial layer exists between the silicon substrate and the UNCD nano-pillars. The porous UNCD film with high-density nano-pillars exhibits excellent optical anti-reflectivity and improved electron field emission characteristics compared to smooth and solid UNCD films.

Chu, Yueh-Chieh; Tu, Chia-Hao; Liu, Chuan-pu; Tzeng, Yonhua; Auciello, Orlando

2012-12-01

25

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

NASA Astrophysics Data System (ADS)

Copper ion implantation and subsequent annealing at 600 °C achieved high electrical conductivity of 95.0 (?cm)-1 for ultrananocrystalline diamond (UNCD) films with carrier concentration of 2.8 × 1018 cm-2 and mobility of 6.8 × 102 cm2/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/cm2 at an applied field of 8.0 V/?m.

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

2014-02-01

26

Construction of a ultrananocrystalline diamond-based cold cathode arrays for a flat-panel x-ray source  

NASA Astrophysics Data System (ADS)

A novel cold cathode field emission array (FEA) X-ray source based on ultra-nanocrystalline diamond (UNCD) field emitters is being constructed as an alternative for detection of obscured objects and material. Depending on the geometry of the given situation the flat-panel X-ray source could be used in tomography, radiography, or tomosynthesis. Furthermore, the unit could be used as a portable X-ray scanner or an integral part of an existing detection system. UNCD field emitters show great field emission output and can be deposited over large areas as the case with carbon nanotube "forest" (CNT) cathodes. Furthermore, UNCDs have better mechanical and thermal properties as compared to CNT tips which further extend the lifetime of UNCD based FEA. This work includes the first generation of the UNCD based FEA prototype which is being manufactured at the Center for Nanoscale Materials within Argonne National Laboratory with standard microfabrication techniques. The prototype is a 3x3 pixel FEA, with a pixel pitch of 500 ?m, where each pixel is individually controllable.

Grant, E. J.; Posada, C. M.; Divan, R.; Sumant, A. V.; Rosenmann, D.; Stan, L.; Avachat, A.; Castano, C. H.; Lee, H. K.

2013-06-01

27

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

SciTech Connect

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

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

2011-12-31

28

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

SciTech Connect

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.

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

29

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

NASA Astrophysics Data System (ADS)

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

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

2012-04-01

30

High efficiency diamond solar cells  

DOEpatents

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

Gruen, Dieter M. (Downers Grove, IL)

2008-05-06

31

Origin of graphitic filaments on improving the electron field emission properties of negative bias-enhanced grown ultrananocrystalline diamond films in CH4/Ar plasma  

NASA Astrophysics Data System (ADS)

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 CH4 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/cm2 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 CH4/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.

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

2014-10-01

32

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...

33

Evidence of universality in the dynamical response of nanomechanical ultra-nanocrystalline diamond resonators at millikelvin temperatures  

E-print Network

in increased dis- sipation which limits device performance. To counter this trend it is therefore necessary (TLS) provide the dominant contribution to intrin- sic dissipation. Even though the general trend) exhibits similar properties to bulk diamond, including extremely high Young's mod- ulus and remarkable

34

Diamond layers for the protection of infrared windows  

NASA Astrophysics Data System (ADS)

In comparison with presently available LWIR (8 - 12 micrometers ) window materials, diamond has unsurpassed optical and thermomechanical properties. However, the manufacture of bulk diamond optical components is still in its infancy and many years effort are required to develop the technologies necessary to the fabrication of large windows and domes. In the short term the coating of current LWIR materials (particularly ZnS) with a protective layer of polycrystalline diamond would result in a significant improvement in performance. At GMMTL a high temperature microwave plasma assisted chemical vapor deposition (MPACVD) system has been developed which produces excellent quality diamond films on silicon. It is not so easy to apply this technique to the coating of ZnS since atomic hydrogen in the microwave plasma attacks and rapidly etches the ZnS surface and, in addition, there is a large thermal expansion mismatch between ZnS and diamond that causes decohesion of the film. To solve this problem an advanced physical vapor deposition (PVD) process has been used to deposit interlayers of various LWIR transparent materials onto ZnS to give protection from the plasma and also allow some thermal stress relief. The interlayers have been found to be extremely robust with respect to current nucleation treatments and have allowed continuous diamond films of thickness in excess of 1 micron to be formed onto ZnS. The significance of nucleation treatment and diamond morphology are discussed in the context of gaining the optimal performance both in terms of layer adhesion and IR properties.

Tossell, David A.; Costello, Mark C.; Brierley, Crofton J.

1992-12-01

35

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

NASA Astrophysics Data System (ADS)

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

Carlisle, J. A.

2009-05-01

36

Diamonds  

NSDL National Science Digital Library

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.

Brieske, Joel A.

2002-01-01

37

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

NASA Astrophysics Data System (ADS)

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.

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

38

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

E-print Network

Alumina atomic layer deposition nanocoatings on primary diamond particles using a fluidized bed particles in a scalable fluidized bed reactor. The studies of fluidization at reduced pressure show; Atomic layer deposition (ALD); Fluidized bed reactor 1. Introduction Due to its extreme hardness, diamond

George, Steven M.

39

Reaction layer formation and fracture at chemically vapor deposited diamond\\/metal interfaces  

Microsoft Academic Search

Chemically vapor deposited (CVD) diamond films have been deposited by a microwave enhanced deposition process on metal substrates including titanium, tungsten, molybdenum, and copper. Boundary reaction layers formed at the interface during the growth of the CVD diamond films have been investigated for each of these systems. In these studies, the interface has been exposed by mechanically deforming the metal

Scott S. Perry; Gabor A. Somorjai

1994-01-01

40

Reaction layer formation and fracture at chemically vapor deposited diamond/metal interfaces  

SciTech Connect

Chemically vapor deposited (CVD) diamond films have been deposited by a microwave enhanced deposition process on metal substrates including titanium, tungsten, molybdenum, and copper. Boundary reaction layers formed at the interface during the growth of the CVD diamond films have been investigated for each of these systems. In these studies, the interface has been exposed by mechanically deforming the metal substrate to cause film delamination. Where the diamond film has adhered to the substrate through the growth process, delamination procedures have been carried out under controlled conditions in order to preserve the integrity of the interfacial species. The exposed interfaces were characterized by x-ray photoelectron spectroscopy, scanning Auger microscopy, secondary electron microscopy, and Raman microprobe spectroscopy. Reaction layers composed of carbides and oxides of the native metal were detected at the interfaces of titanium, tungsten, and molybdenum while only traces of carbon and oxygen were detected at the diamond/copper interface. We believe that both the chemical composition and morphology of the interface influence the adhesive properties of the diamond coating. Correlated investigations of the interfacial surfaces reveal that fracture of the diamond/metal interface occurs discretely at the diamond nucleation plane or within a reaction layer near the diamond interface.

Perry, S.S.; Somorjai, G.A. (Department of Chemistry and Lawrence Berkeley Laboratory, University of California, Berkeley, California 94720 (United States))

1994-07-01

41

Diamond layers for the protection of infrared windows  

Microsoft Academic Search

In comparison with presently available LWIR (8 - 12 micrometers ) window materials, diamond has unsurpassed optical and thermomechanical properties. However, the manufacture of bulk diamond optical components is still in its infancy and many years effort are required to develop the technologies necessary to the fabrication of large windows and domes. In the short term the coating of current

David A. Tossell; Mark C. Costello; Crofton J. Brierley

1992-01-01

42

Formation of detonation diamond layers on silicon by the aerosol method  

NASA Astrophysics Data System (ADS)

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.

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

2014-09-01

43

n-type diamond with high room temperature electrical conductivity by deuteration of boron doped diamond layers  

Microsoft Academic Search

The conversion of the conductivity of B-doped homoepitaxially grown diamond layers from p- to n-type upon deuteration and its reconversion to p-type following annealing is extensively studied. Several B doped samples have been converted to n-type when exposed to a deuterium plasma at approximately 500 °C. The n-type features are related to D uptake of the samples. The donors, thus

C. Saguy; R. Kalish; C. Cytermann; Z. Teukam; J. Chevallier; F. Jomard; A. Tromson-Carli; J. E. Butler; C. Baron; A. Deneuville

2004-01-01

44

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

NASA Astrophysics Data System (ADS)

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.

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

2011-12-01

45

Buffer layers for deposition of superconducting YBaCuO thin film on polycrystalline diamond  

NASA Astrophysics Data System (ADS)

In an attempt to combine the properties of high temperature superconductors with the high thermal conductivity and low specific heat of diamond, we have explored the deposition of in- situ YBa(subscript 2)Cu(subscript 3)O(subscript 7-(delta) ) (YBCO) superconducting films on polycrystalline diamond thin films. We demonstrate for the first time superconducting YBCO films on diamond employing multiple layer buffer layer systems. Three different composite buffer layer systems were explored for this purpose: (1) Diamond/Zr/YSZ/YBCO, (2) Diamond/Si(subscript 3)N(subscript 4)/YSZ/YBCO, and (3) Diamond/SiO(subscript 2)/YSZ/YBCO. Adherent thin Zr films were deposited by dc sputtering on the diamond films at 450 to 820 degree(s)C. The yttria stabilized zirconia (YSZ) was deposited by reactive RF sputtering at 680 to 750 degree(s)C. The Si(subscript 3)N(subscript 4) and SiO(subscript 2) were also deposited by on-axis RF sputtering at 400 to 700 degree(s)C. YBCO films were grown on the buffer layers by off-axis RF sputtering at substrate temperatures between 690 degree(s)C and 750 degree(s)C. In all cases, the as-deposited YBCO films were superconducting above 77 K. This demonstration enables the fabrication of low heat capacity, fast response time bolometric far IR detectors and paves the way for the use of HTSC as a high frequency interconnect metallization on thick diamond film based multichip modules.

Beetz, Charles P.; Cui, G. J.; Lincoln, B. A.; Kirlin, Peter S.

1992-09-01

46

Thick diamond layers angled by polishing to reveal defect and impurity depth profiles  

Microsoft Academic Search

Diamond layers were grown top a thickness of 25 to 35 ?m either on type-Ib synthetic or type-IIa natural diamond substrates by using high or low microwave-power densities. To evaluate defects and impurities depth profiles, the samples were angled by polishing and characterized by cathodoluminescence. The first important finding is that boron, nitrogen and structural defects seem to be concentrated in

A. Tallaire; M. Kasu; K. Ueda

2008-01-01

47

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

SciTech Connect

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.

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

48

Plasma-activated direct bonding of diamond-on-insulator wafers to thermal oxide grown silicon wafers  

E-print Network

Plasma-activated direct bonding of diamond-on-insulator wafers to thermal oxide grown silicon microscopy, profilometer and wafer bow measurements. Plasma-activated direct bonding of DOI wafers to thermal September 2010 Keywords: Diamond-on-insulator Plasma activation Ultrananocrystalline diamond Direct bonding

Akin, Tayfun

49

Hybrid sensors based on colour centres in diamond and piezoactive layers  

NASA Astrophysics Data System (ADS)

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

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

2014-06-01

50

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

NASA Astrophysics Data System (ADS)

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

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

2014-01-01

51

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

NASA Astrophysics Data System (ADS)

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.

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

52

Mechanical Properties of Ultrananocrystalline Diamond Thin Films for MEMS Applications  

E-print Network

showed fracture strength to vary from 3.95 to 5.03 GPa when seeding was performed with ultrasonic are grown using a microwave plasma chemical vapor deposition technique involving a novel CH4/Ar chemistry effects in each that hinder accurate property measurements. EXPERIMENTAL PROCEDURE Two types of specimens

Espinosa, Horacio D.

53

Polarization dependent asymmetric magneto-resistance features in nanocrystalline diamond films  

NASA Astrophysics Data System (ADS)

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.

Bhattacharyya, Somnath; Churochkin, Dmitry

2014-08-01

54

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

PubMed

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

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

2003-07-15

55

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

DOEpatents

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.

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

56

The p-to-n-type conversion of boron-doped diamond layers by deuteration: New findings  

Microsoft Academic Search

The p-to-n-type conversion of particular B-doped homoepitaxially grown diamond layers upon deuterium plasma treatment was discovered three years ago. However, many questions regarding the reproducibility of the effect for samples of different origins remain unanswered up to now, in particular the role of the electrical contacts and the possibility of a surface inversion layer being responsible for the n-type conductivity,

C. Saguy; R. Kalish; J. Chevallier; F. Jomard; C. Cytermann; B. Philosoph; T. Kociniewski; D. Ballutaud; C. Baron; A. Deneuville

2007-01-01

57

Growth and properties of nanocrystalline diamond films  

NASA Astrophysics Data System (ADS)

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

Williams, Oliver A.; Nesládek, Milo

2006-10-01

58

Theoretical investigation of surface acoustic wave in the new, three-layered structure: ZnO\\/AlN\\/diamond  

Microsoft Academic Search

The new layered structure, ZnO\\/AlN\\/diamond, for surface acoustic wave (SAW) devices is investigated for gigahertz-band applications. This structure combines the advantages of both piezoelectric materials, with a high electromechanical coupling coefficient (K2) of ZnO and high acoustic velocity of AlN. Theoretical results show that Rayleigh mode SAWs with large phase velocities up to 12,200 m\\/s and large K2 from 1

Mohamed El Hakiki; Omar Elmazria; Patrick Alnot

2007-01-01

59

Structured polymer grafts on diamond.  

SciTech Connect

In this work, a facile method for the preparation of structured and functional polymer grafts on diamond surfaces is described. Uniform poly(styrene) (PS) grafts with a thickness of {approx}110 nm were created directly onto oxidized ultrananocrystalline diamond (UNCD) surfaces by the self-initiated photografting and photopolymerization of bulk styrene with UV irradiation. The stable covalent bonding of the PS grafts allows polymer analogue reactions with drastic reaction conditions without noticeable detachment of the polymer coating. Thus, various functionalities, such as nitro, sulfonic, and aminomethyl groups have been successfully incorporated to the polymer grafts. Furthermore, the reactivity contrast between hydrogenated and oxidized UNCD surfaces allows for the preparation of structured polymer grafts. Finally, we have demonstrated the good reactivity and accessibility of the incorporated pendant functional groups.

Steenackers, M.; Lud, S. Q.; Niedermeier, M.; Bruno, P.; Gruen, D. M.; Feulner, P.; Stutzmann, M.; Garrido, J. A.; Jordan, R.; Materials Science Division; Technische Univ. Munchen

2007-11-01

60

Crystalline quality and residual stresses in diamond layers by Raman and x-ray diffraction analyses  

NASA Astrophysics Data System (ADS)

A major problem for diamond coating applications is that diamond films tend to exhibit poor adherence on many substrates and typically disbond at thicknesses of the order of a few micrometers principally because of residual stresses. Residual stresses are composed of thermal mismatch stresses and intrinsic tensile film stresses induced during film growth. Diamond films were deposited in a classical tubular microwave plasma reactor from hydrocarbon-hydrogen-oxygen gas mixtures. The stress level was investigated as a function of the gaseous composition (especially oxygen concentration) and deposition temperature (700-900 °C). Thermal stress was directly calculated from Hooke's law using a biaxial Young's modulus value of 1230 GPa for polycrystalline diamond. Total diamond film stress was directly determined by the radius of curvature method and by x-ray diffraction using the sin2 ? method. The microdistorsions and the size of the coherently diffracting domains have been determined from the broadening of the diffraction peak. When coupled also with a Raman study, these investigations allow discussion of the origin of intrinsic stress.

Rats, D.; Bimbault, L.; Vandenbulcke, L.; Herbin, R.; Badawi, K. F.

1995-10-01

61

Young's modulus, fracture strength, and Poisson's ratio of nanocrystalline diamond films  

NASA Astrophysics Data System (ADS)

Young's modulus, fracture stress, and Poisson's ratio are important mechanical characteristics for micromechanical devices. The Poisson's ratio of a material is a good measure to elucidate its mechanical behavior and generally is the negative ratio of transverse to axial strain. A nanocrystalline (NCD) and an ultrananocrystalline (UNCD) diamond sample with grain boundaries of different chemical and structural constitutions have been investigated by an ultrasonic resonance method. For both samples, the elastic moduli are considerably reduced, compared with the elastic modulus of single crystal diamond (sc-diamond). Depending on the chemical and structural constitution of grain boundaries in nano- and ultrananocrystalline diamond different values for Poisson's ratio and for the fracture strength are observed. We found a Poisson's ratio of 0.201 ± 0.041 for the ultrananocrystalline sample and 0.034 ± 0.017 for the nanocrystalline sample. We discuss these results on the basis of a model for granular media. Higher disorder in the grain boundary leads to lower shear stiffness between the single grains and ultimately results in a decrease of Young's and shear modulus and possibly of the fracture strength of the material.

Mohr, Markus; Caron, Arnaud; Herbeck-Engel, Petra; Bennewitz, Roland; Gluche, Peter; Brühne, Kai; Fecht, Hans-Jörg

2014-09-01

62

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

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.

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

63

Shallow donors with high n-type electrical conductivity in homoepitaxial deuterated boron-doped diamond layers  

Microsoft Academic Search

Diamond is a unique semiconductor for the fabrication of electronic and opto-electronic devices because of its exceptional physical and chemical properties. However, a serious obstacle to the realization of diamond-based devices is the lack of n-type diamond with satisfactory electrical properties. Here we show that high-conductivity n-type diamond can be achieved by deuteration of particularly selected homo-epitaxially grown (100) boron-doped

Zéphirin Teukam; Jacques Chevallier; Cécile Saguy; Rafi Kalish; Dominique Ballutaud; Michel Barbé; François Jomard; Annie Tromson-Carli; Catherine Cytermann; James E. Butler; Mathieu Bernard; Céline Baron; Alain Deneuville

2003-01-01

64

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

PubMed

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

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

2012-05-01

65

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

NASA Astrophysics Data System (ADS)

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

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

2011-02-01

66

Role of interfacial transition layers in VO2/Al2O3 heterostructures H. Zhou, M. F. Chisholm, Tsung-Han Yang, S. J. Pennycook, and J. Narayan  

E-print Network

of spray pyrolysis deposited nano-crystalline BiFeO3 films AIP Advances 1, 042140 (2011) X) Ultrathin ultrananocrystalline diamond film synthesis by direct current plasma-assisted chemical vapor-energy minimization process of accommodating the symmetry mismatch between the substrate and the film

Pennycook, Steve

67

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

NASA Astrophysics Data System (ADS)

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

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

2013-11-01

68

Dielectric properties of hydrogen-incorporated chemical vapor deposited diamond thin films  

NASA Astrophysics Data System (ADS)

Diamond thin films with a broad range of microstructures from a ultrananocrystalline diamond (UNCD) form developed at Argonne National Laboratory to a microcrystalline diamond (MCD) form have been grown with different hydrogen percentages in the Ar /CH4 gas mixture used in the microwave plasma enhanced chemical vapor deposition (CVD) process. The dielectric properties of the CVD diamond thin films have been studied using impedance and dc measurements on metal-diamond-metal test structures. Close correlations have been observed between the hydrogen content in the bulk of the diamond films, measured by elastic recoil detection (ERD), and their electrical conductivity and capacitance-frequency (C-f) behaviors. Addition of hydrogen gas in the Ar /CH4 gas mixture used to grow the diamond films appears to have two main effects depending on the film microstructure, namely, (a) in the UNCD films, hydrogen incorporates into the atomically abrupt grain boundaries satisfying sp2 carbon dangling bonds, resulting in increased resistivity, and (b) in MCD, atomic hydrogen produced in the plasma etches preferentially the graphitic phase codepositing with the diamond phase, resulting in the statistical survival and growth of large diamond grains and dominance of the diamond phase, and thus having significant impact on the dielectric properties of these films.

Liu, Chao; Xiao, Xingcheng; Wang, Jian; Shi, Bing; Adiga, Vivekananda P.; Carpick, Robert W.; Carlisle, John A.; Auciello, Orlando

2007-10-01

69

Diamond crown bit  

SciTech Connect

This patent describes a diamond crown bit, comprising: a body; a matrix secured on one of the end faces of the body; mud discharge ports subdividing the matrix into sections separated from one another; each sector consisting of: a weld-on layer on the one end face of the body where the sectors are held to the body; a diamond-impregnated layer shaped as a parelleleipiped and held to the weld-on layer to have its front and rear faces inclined; and an insert shaped as a triangular prism having side face rigidly held to the weld-on layer and its face face rigidly held to the inclined rear face of the diamond-impregnated layer.

Aubakirov, M.T.; Limanov, E.L.; Syzdykov, A.K.; Abdrazakov, R.S.; Tleuov, M.G.; Khazhuer, V.S.; Buzdov, R.D.; Khashirov, V.K.

1987-07-21

70

Mechanical Properties of Ultrananocrystalline Diamond Thin Films Relevant to MEMS/NEMS Devices  

E-print Network

the microcantilever-based tests. Tests were performed on UNCD specimens grown by both micro and nano wafer- seeding, fracture, size effects Introduction Silicon has been the dominant material in the micro- electronics using a microwave plasma chemical vapor deposition (CVD) technique involving a new CH4/Ar chem- istry

Espinosa, Horacio D.

71

Ex situ variable angle spectroscopic ellipsometry studies on chemical vapor deposited boron-doped diamond films: Layered structure and modeling aspects  

NASA Astrophysics Data System (ADS)

We report the optical property measurements on boron-doped diamond (BDD) films which were synthesized by microwave plasma-assisted chemical vapor deposition technique on Si (100) using methane in high hydrogen dilution and trimethylboron as precursors with varying boron concentration such that [B]/[C]gas=100, 500, 1000, 2000, 4000, and 6467ppm. These BDD films were investigated using a rotating analyzer variable angle spectroscopic ellipsometry (SE) from the near IR to UV range (830-193nm). By applying the conventional Bruggeman effective medium approximation and linear regression analyses to the raw SE data that is, [?(?i),?(?i)] and pseudodielectric function (??r(?i)?,??i(?i)?), we determined the most appropriate model fit. The SE modeling was performed through the normal and point-by-point fit methods combined with the coupled and uncoupled bulk and surface layer approaches providing the details about the thin films' microstructure in terms of the (a) multilayer (component and surface) structure and component layer thickness of the films, (b)volume fraction of constituents [fsp3C, fsp2C and void (fv) in the component layer], (c) inhomogeneity of the structure along the growth axis and its variation with boron concentration, and (iv) surface roughness layer thickness (ds) with dimensions less than the optical wavelength that is not otherwise available. A simplified three-layer structural model consisting of an interfacial layer, an intermediate (or bulk) layer, and a top surface roughness layer has been proposed, which simulates the ellipsometry data reasonably well with coupled point-by-point method. An estimator, i.e., mean squared error (?2), is used to assess the accuracy of the model fit. The results (surface roughness and constituents' fraction) obtained through SE modeling are also compared with those from atomic force microscopy (AFM) and Raman spectroscopy to validate the layered model employed. Typically, high surface roughness values around 6nm were found for films grown under different boron concentrations which is almost five times smaller than determined from AFM. In this context, we determined an approximate linear relationship between these two variables. The relatively smaller surface roughness for BDD films indicates the combined role of boron-hydrogen (B, H) in diamond (C) while keeping the substrate temperature constant. We also discussed the variation of (fv and fnd) for the bulk and surface layers with increasing boron concentration.

Gupta, S.; Dudipala, A.; Williams, O. A.; Haenen, K.; Bohannan, E.

2008-10-01

72

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.

73

Diamond photonics  

Microsoft Academic Search

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

Igor Aharonovich; Andrew D. Greentree; Steven Prawer

2011-01-01

74

Diamond for biosensor applications  

Microsoft Academic Search

A summary of photo- and electrochemical surface modifications applied on single- crystalline chemical vapor deposition (CVD) diamond films is given. The covalently bonded formation of amine- and phenyl-linker molecule layers are characterized using X-ray photoelectron spectroscopy (XPS), 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

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

75

Extreme ultraviolet transmission of a synthetic diamond thin film  

NASA Technical Reports Server (NTRS)

Measurements are presented of a thin film of synthetic diamond at various wavelengths in the extreme ultraviolet. The synthetic diamond combines the transmission properties of carbon with the strength, density, and ruggedness of a natural diamond. The Extreme Ultraviolet Transmission (EUV) of a film of the synthetic diamond has shown the existence of a thin surface layer of silicon, probably in the form of silicon carbide, which is not a contaminant layer.

Vallerga, John V.; Gibson, J. L.; Knowles, J. L.

1991-01-01

76

Diamond Nanophotonics  

E-print Network

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.

Igor Aharonovich; Elke Neu

2014-08-23

77

Diamond Nanophotonics  

E-print Network

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.

Aharonovich, Igor

2014-01-01

78

Diamond fiber field emitters  

DOEpatents

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.

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

79

Diamond coatings exposure to fusion-relevant plasma conditions  

NASA Astrophysics Data System (ADS)

Several types of diamond layers have been deposited on molybdenum tiles by chemical vapour deposition techniques, and exposed under erosion-dominated conditions in the SOL of TEXTOR in order to assess them as a suitable candidate for plasma-facing material. Post-exposure characterisation of physical properties and surface modification induced by the plasma was performed by SEM imaging, investigation of diamond surface by micro-Raman spectroscopy and deuterium retention measurements by NRA. The analyses evidenced that lightly boron-doped micro-crystalline diamond is performing better than undoped and heavily doped samples, and nano-crystalline diamond and diamond-like carbon, as it showed lower surface modification, lower presence of arcing traces at the surface and lower deuterium retention. High concentration of boron in the layers led to higher retention of deuterium, whereas undoped (insulating) diamond showed increased arcing activity. Nano-crystalline diamond and diamond-like carbon layers generally showed poorer mechanical properties.

Porro, S.; Temmerman, G. De; Lisgo, S.; Rudakov, D. L.; Litnovsky, A.; Petersson, P.; John, P.; Wilson, J. I. B.

2011-08-01

80

Advanced Diamond Anvil Techniques (Customized Diamond Anvils)  

SciTech Connect

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.

Weir, S

2009-02-11

81

Nanocrystalline diamond for medicine  

NASA Astrophysics Data System (ADS)

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

Mitura, Stanislaw

1997-06-01

82

High-density fluids and the growth of monocrystalline diamonds  

NASA Astrophysics Data System (ADS)

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.

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

2014-09-01

83

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)

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.

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

2014-08-01

84

Amorphous-diamond electron emitter  

DOEpatents

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

Falabella, Steven (Livermore, CA)

2001-01-01

85

Superconducting nanowire single photon detector on diamond  

NASA Astrophysics Data System (ADS)

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.

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

2014-03-01

86

Epitaxial growth of europium monoxide on diamond  

NASA Astrophysics Data System (ADS)

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.

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

87

Conversion of p-type to n-type diamond by exposure to a deuterium plasma  

Microsoft Academic Search

The lack of a shallow donor in diamond with reasonable room temperature conductivity has been a major obstacle, until now, for the realization of many diamond based electronic devices. Most recently it has been shown that exposure of p-type (B doped) homoepitaxial diamond layers to a deuterium plasma can result in the formation of n-type diamond with a shallow donor

R. Kalish; C. Saguy; C. Cytermann; J. Chevallier; Z. Teukam; F. Jomard; T. Kociniewski; D. Ballutaud; J. E. Butler; C. Baron; A. Deneuville

2004-01-01

88

Growth of single crystal diamond  

NASA Astrophysics Data System (ADS)

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.

Regmi, Murari

89

Study of diamond film growth and properties  

NASA Technical Reports Server (NTRS)

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

Albin, Sacharial

1990-01-01

90

Below-Band-Gap Laser Ablation Of Diamond For TEM  

NASA Technical Reports Server (NTRS)

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

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

1995-01-01

91

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

Microsoft Academic Search

Synthesis of silicon carbide and diamond nanoparticles is studied during short-pulse implantation of carbon ions and protons into a silicon target. The experiments are carried out using a TEMP source of pulsed powerful ion beams based on a magnetically insulated diode with radial magnetic field B r . The beam parameters are as follows: the ion energy is 300 keV,

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

2009-01-01

92

Formation of nanosized particles of silicon carbide and diamonds in surface layer of silicon target during short-pulsed implantation of carbon ions  

Microsoft Academic Search

In the paper the study results of silicon carbide and diamond nanosized particle synthesis during short-pulsed implantation of carbon ions and protons into the silicon target are presented. The experiments have been performed at the source of high-power pulsed ion beams “TEMP” based on the magnetically isolated diode with Br field. The beam parameters are the following: ion energy is

G. E. Remnev; Yu. F. Ivanov; E. P. Naiden; M. S. Saltymakov; A. V. Stepanov; V. F. Shtanko

2008-01-01

93

Optical and Other Properties of MPACVD Diamond  

NASA Astrophysics Data System (ADS)

The exceptional properties of diamond have stimulated a considerable research effort into the low pressure synthesis of diamond thin films for a diverse range of applications including:- tribological coatings, semiconductor heat sinks and (as in this work) protective optical coatings. Numerous deposition techniques have been reported in the literature including Microwave Plasma Assisted CVD (MPACVD). This paper briefly describes the MPACVD deposition system used at Plessey Research Caswell Ltd and outlines the effects of important deposition parameters on the growth morphology of diamond crystallites and thin films. Techniques including SEM, TEM and X-ray diffraction have been used to study the growth mechanisms of MPACVD diamond. IR and Raman spectroscopy have been used to characterise the deposited films and an IR reflection technique is described for studying the infrared properties of the layers. The effect of deposition parameters on the properties of diamond thin films is discussed with regard to the use of these films for protecting IR windows and domes.

Wort, Christopher J.; Lettington, Alan H.; Smith, C. J.; Hetherington, A. V.

1990-04-01

94

Plasma spraying method for forming diamond and diamond-like coatings  

DOEpatents

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.

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

1997-01-01

95

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

Microsoft Academic Search

Synthesis of silicon carbide and diamond nanoparticles is studied during short-pulse implantation of carbon ions and protons\\u000a into a silicon target. The experiments are carried out using a TEMP source of pulsed powerful ion beams based on a magnetically\\u000a insulated diode with radial magnetic field B\\u000a \\u000a r\\u000a . The beam parameters are as follows: the ion energy is 300 keV,

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

2009-01-01

96

Molecular Structure of diamond  

NSDL National Science Digital Library

Diamonds were first mined over 4,000 years ago in India. During this period, however, diamonds were of no use as jewelry. Louis de Berqueur, was the first who discovered how to cut facets of a diamond, changing the world of fine jewelry. The diamond is not only found in India but also in South Africa, Brazil, Russia, Austria, and Arkansas. A diamond can be used for several things. The most obvious includes a gemstone for jewelry purposes. It is also used for various industrial functions, such as cutting, grinding, and polishing. These characteristics make the diamond "a girl's best friend."

2002-08-23

97

Fabrication of thin diamond membranes for quantum information processing  

NASA Astrophysics Data System (ADS)

Coupling of nano-photonic devices to color centers in diamond offers exceptional opportunities to enhance our understanding of light-matter interactions. The formation of thin single crystal diamond membranes containing such centers, is an important prerequisite for the fabrication of diamond based devices. However, there are challenges in forming such membranes in ways that do not compromise the quality of the cavities or the optical properties of the emitters. Here we report the formation of optically active diamond membranes and the subsequent fabrication of optical cavities. In our approach, 1.7 ?m thick diamond membranes were generated by forming a sacrificial layer using ion implantation, followed by thermal annealing. These membranes then served as templates for the epitaxial overgrowth of ˜ 300 nm of diamond using CVD. Remarkably, the regrown films reveal the presence of optically active defects which were not present in the template, such as silicon-vacancy (SiV) or nitrogen vacancy centers. Microdisk cavities were then formed from the regrown single crystal diamond membranes. Whispering gallery modes (WGMs) with quality factors of ˜ 3000 were measured from the diamond cavities. Spectral overlap of WGMs with the zero phonon line of SiV centers was observed and lifetime reduction of the coupled emitter -- cavity system was measured. The demonstration of coupling between diamond emitters and a single crystal diamond cavity is a crucial step towards diamond integrated nano-photonic networks.

Aharonovich, Igor; Lee, Jonathan; Magyar, Andrew; Hu, Evelyn

2012-02-01

98

Ion implantation of diamond: Damage, doping, and lift-off  

SciTech Connect

In order to make good quality economical diamond electronic devices, it is essential to grow films and to dope these films to obtain n- and p- type conductivity. This review talk discuss first doping by ion implantation plus annealing of the implantation damage, and second flow to make large area single crystal diamonds. C implantation damage below an estimated Frenkel defect concentration of 7% could be recovered almost completely by annealing at 950C. For a defect concentration between 7 and 10%, a stable damage form of diamond (``green diamond``) was formed by annealing. At still higher damage levels, the diamond graphitized. To introduce p-type doping, we have co-implanted B and C into natural diamond at 77K, followed by annealing up to 1100C. The resulting semiconducting material has electrical properties similar to those of natural B-doped diamond. To create n-type diamond, we have implanted Na{sup +}, P+ and As{sup +} ions and have observed semiconducting behavior. This has been compared with carbon or noble element implantation, in an attempt to isolate the effect of radiation damage. Recently, in order to obtain large area signal crystals, we have developed a novel technique for removing thin layers of diamond from bulk or homoepitaxial films. This method consists of ion implantation, followed by selective etching. High energy (4--5 MeV) implantation of carbon or oxygen ions creates a well-defined layer of damaged diamond buried at a controlled depth. This layer is graphitized and selectivity etched either by heating at 550C in an oxygen ambient or by electrolysis. This process successfully lifts off the diamond plate above the graphite layer. The lift-off method, combined with well-established homoepitaxial growth processes, has potential for fabrication of large area single-crystal diamond sheets.

Parikh, N.R.; McGucken, E.; Swanson, M.L. [North Carolina Univ., Chapel Hill, NC (United States). Dept. of Physics and Astronomy; Hunn, J.D.; White, C.W.; Zuhr, R.A. [Oak Ridge National Lab., TN (United States)

1993-09-01

99

Diamond nonlinear photonics  

NASA Astrophysics Data System (ADS)

Despite progress towards integrated diamond photonics, studies of optical nonlinearities in diamond have been limited to Raman scattering in bulk samples. Diamond nonlinear photonics, however, could enable efficient, in situ frequency conversion of single photons emitted by diamond's colour centres, as well as stable and high-power frequency microcombs operating at new wavelengths. Both of these applications depend crucially on efficient four-wave mixing processes enabled by diamond's third-order nonlinearity. Here, we have realized a diamond nonlinear photonics platform by demonstrating optical parametric oscillation via four-wave mixing using single-crystal ultrahigh-quality-factor (1 × 106) diamond ring resonators operating at telecom wavelengths. Threshold powers as low as 20 mW are measured, and up to 20 new wavelengths are generated from a single-frequency pump laser. We also report the first measurement of the nonlinear refractive index due to the third-order nonlinearity in diamond at telecom wavelengths.

Hausmann, B. J. M.; Bulu, I.; Venkataraman, V.; Deotare, P.; Lon?ar, M.

2014-05-01

100

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.

101

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

NASA Astrophysics Data System (ADS)

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 ^oC with a 2% mixture of CH4 in H, resulting in extremely high doping levels ˜ 10^20/cm^3) 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.

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

2013-03-01

102

Diffusion of sulfur into natural diamond: Characterization and applications in radiation detection  

NASA Astrophysics Data System (ADS)

A "second generation" doping reactor has been constructed, tested, and used to diffuse sulfur into polished, natural diamond plates. Different sulfur sources have been used for the incorporation of sulfur into the diamond lattice. Diffusion coefficients in the range of 10-15 cm2/s to 10-14 cm2 /s have been calculated for sulfur into natural diamond. The small decrease in optical transmission (5%) of the diamond samples after doping and the ohmic nature of the diffused layer indicate that the sulfur-doping of diamond may be a useful technique for the formation of electrical contacts on diamond-based radiation detectors.

West, Matthew Keith

103

Diamond bio electronics.  

PubMed

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

Linares, Robert; Doering, Patrick; Linares, Bryant

2009-01-01

104

Lift-off technique of homoepitaxial CVD diamond films by deep implantation and selective etching  

Microsoft Academic Search

We report on the replication of diamond substrates and the production of thin free-standing monocrystalline diamond films by applying a “lift-off” technique as suggested by Parikh et al. A diamond substrate is first deeply implanted in order to create a damaged subsurface layer that is selectively etched after overgrowth. In this process incomplete delamination and chipping appeared to be a

R. Locher; D. Behr; H. Güllich; N. Herres; P. Koidl; R. Samlenski; R. Brenn

1997-01-01

105

The Nature of Diamonds  

NASA Astrophysics Data System (ADS)

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

Harlow, George E.

1997-10-01

106

Protein-modified nanocrystalline diamond thin films for biosensor applications  

NASA Astrophysics Data System (ADS)

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

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

2004-10-01

107

Synthesis and morphology of CVD diamond on Ta and TaC film  

NASA Astrophysics Data System (ADS)

Synthetic diamond films have been deposited on the Si(111) surface, polycrystalline Ta plate, TaC/Si, and TaC/Ta substrates using an electron assisted chemical vapor deposition (EACVD) method. The effects of substrate pretreatment and existence of carbide layer on the diamond nucleation, subsequent growth and morphology have been studied. The substrate pretreatment, scratching by diamond powder, affects nucleation behavior, subsequent growth and morphology of diamond. Existence of carbide layer and formation of carbide on the substrate affects nucleation density, growth rate and morphology of diamond.

Togashi, Fumitaka; Kobayashi, Ken; Mitsuhashi, Masahiko; Karasawa, Shiro; Ohya, Seishiro; Watanabe, Takeshi

1993-03-01

108

Determining the composition of high-pressure mantle melts using diamond aggregates  

Microsoft Academic Search

We present a new experimental technique for circumventing the quenching problems that have plagued high-pressure peridotite melting studies. A thin layer of ~50 m diamonds is placed above a layer of peridotite powder. Partial melt extracted from the peridotite layer collects in the pore spaces between the diamonds and equilibrates diffusively with the residual peridotite mineralogy. Isolated from the crystalline

Michael B. Baker; Edward M. Stolper

1994-01-01

109

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

PubMed

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

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

2008-05-14

110

Diamond tool machining of materials which react with diamond  

DOEpatents

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.

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

1992-01-01

111

Effect of diamond nucleation process on propagation losses of AlN/diamond SAW filter.  

PubMed

In this work, the effect of a diamond nucleation process on freestanding aluminium nitride (AlN)/diamond surface acoustic wave (SAW) device performances was studied. Before diamond deposition, silicon (Si) substrates have been mechanically nucleated, using an ultrasonic vibration table with submicron diamond slurry, and bias-enhanced nucleated (BEN). Freestanding diamond layers obtained on mechanically scratched Si substrates exhibit a surface roughness of R(MS) = 13 nm, whereas very low surface roughness (as low as R(MS) < or = 1 nm) can be achieved on a freestanding BEN diamond layer. Propagation losses have been measured as a function of the operating frequency for the two nucleation techniques. Dispersion curves of phase velocities and electromechanical coupling coefficient (K2) were determined experimentally and by calculation as a function of normalized thickness AlN film (kh(AlN) = 2pi h(AlN)/lambda). Experimental results show that the propagation losses strongly depend on the nucleation technique, and that these losses are weakly increased with frequency when the BEN technique is used. PMID:15690731

Elmazria, Omar; El Hakiki, Mohamed; Mortet, Vincent; Assouar, Badreddine M; Nesládek, Milos; Vanecek, Milan; Bergonzo, Philippe; Alnot, Patrick

2004-12-01

112

Influence of boron on diamond growth on WC-Co hardmetals  

Microsoft Academic Search

Diamond coatings were produced by the hot-filament method, adding B(C2H5)3 to the gas phase. We compared the results on WC-Co hardmetal and Si substrates. SIMS-measurements revealed high B contents in diamond layers on WC-Co substrates accompanied by high amounts of Co. TEM showed CoB and CO2B inclusions in the diamond layer. Furthermore, B-diffusion in the WC-Co bulk was shown. On

P. Wurzinger

1996-01-01

113

Diamond nucleation using polyethene  

DOEpatents

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.

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

2013-07-23

114

The carbonado diamond conundrum  

Microsoft Academic Search

The reviewer presents the results of a literature search on the enigmatic occurrences of carbonado; a form (but not the only form) of polycrystalline diamond, which is mined for industrial diamonds. The principal occurrences are in Brazil, the Central African Republic (CAR) and Siberia (Yakutia). In the latter the name yakutite has been coined, but, though there are differences between

G. J. H. McCall

2009-01-01

115

Diamond films: Historical perspective  

SciTech Connect

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

Messier, R. [Pennsylvania State Univ., University Park (United States)

1993-01-01

116

Is sulfur a donor in diamond?  

NASA Astrophysics Data System (ADS)

Homoepitaxial diamond layers grown by chemical-vapor deposition in the presence of H2S, which were published to exhibit n-type conductivity, are carefully analyzed both electrically and structurally. Hall-effect measurements as a function of temperature clearly show the samples to exhibit p-type conduction, with an activation energy, carrier concentrations, and mobilities which very much resemble those of B-doped p-type diamond. Secondary-ion-mass spectroscopy confirms that indeed the samples, previously claimed to be n type due to a donor state attributed to sulfur, contain enough unintentional boron to explain the observed p-type features.

Kalish, R.; Reznik, A.; Uzan-Saguy, C.; Cytermann, C.

2000-02-01

117

Diamond Ages and Lithosphere Evolution - Applications to Diamond Exploration  

Microsoft Academic Search

Combinations of studies on diamonds, diamond inclusions, diamond bearing mantle and ultra-high pressure (UHP) metamorphic crustal rocks, kimberlites and lamproites have been successful in delivering insights into major processes such as plate tectonics, craton accretion, the effects of large magmatic events as well as contributing to a better understanding of diamond formation and preservation over an extended period of earth

H. H. Helmstaedt; J. J. Gurney; S. H. Richardson

2009-01-01

118

Preparation of Diamond Mold Using Electron Beam Lithography for Application to Nanoimprint Lithography  

Microsoft Academic Search

Diamond molds were fabricated by two types of fabrication processes, both of which use a conductive intermediate layer between the diamond surface and polymethylmethacrylate (PMMA) resist to prevent surface charge-up. Using a PtPd intermediate layer, electron beam lithography and ion beam etching, a denting line pattern of 600 nm width and 70 nm depth was fabricated. Using a carbon intermediate

Jun Taniguchi; Yuji Tokano; Iwao Miyamoto; Masanori Komuro; Hiroshi Hiroshima; Kazuhiko Kobayashi; Takeshi Miyazaki; Hideyuki Ohyi

2000-01-01

119

Diamond and diamond-like carbon films for advanced electronic applications  

SciTech Connect

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

Siegal, M.P.; Friedmann, T.A.; Sullivan, J.P. [and others

1996-03-01

120

Growth of oriented diamond on nickel wafers and thin films  

NASA Astrophysics Data System (ADS)

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.

Liu, Wei

2000-10-01

121

Mechanical stresses and amorphization of ion-implanted diamond  

NASA Astrophysics Data System (ADS)

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

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

2013-06-01

122

Software optimization for electrical conductivity imaging in polycrystalline diamond cutters  

NASA Astrophysics Data System (ADS)

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

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

2014-02-01

123

Instrumentation development for electrical conductivity imaging in polycrystalline diamond cutters  

NASA Astrophysics Data System (ADS)

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

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

2013-01-01

124

Amorphous diamond films  

DOEpatents

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.

Falabella, S.

1998-06-09

125

Ekati Diamond Mine  

NSDL National Science Digital Library

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.

2001-01-01

126

Fracture of synthetic diamond  

Microsoft Academic Search

The fracture behavior of synthetic diamond has been investigated using indentation methods and by the tensile testing of pre-notched fracture-mechanics type samples. Specifically, the fracture toughness of free-standing diamond plates, grown by chemically-vapor deposited (CVD) methods, was measured using Vickers indentations and by the use of disk-shaped compact-tension specimens; the latter method provides an evaluation of the through-thickness fracture properties,

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

1995-01-01

127

Diamond rotating bit  

SciTech Connect

An improved rotating diamond bit for earth boring is devised by incorporating generally triangular, prismatically shaped synthetic polycrystalline diamond elements in the teeth of the boring bit. The polycrystalline diamond elements are set on lands defined on the bit face such that two opposing triangular faces of the prismatic diamond element form a dihedral angle in the direction of travel of the element defined by the bit rotation. The polycrystalline diamond element is thus inclined with respect to the direction of linear travel of the element when the bit rotates. In other words, the normal to the parallel opposing triangular faces of the diamond element is acutely inclined with respect to the direction of travel of the element. A shoulder-to-gage transition pattern of the junk slot, waterway and collector is arranged to uniformly distribute the flow of fluid across the shoulder to guage transition. Further, the distribution of fluid from the central conduit within the longitudinal core of the bit to a plurality of nozzles which merge with corresponding waterways on the bit face is arranged such that fluid is preferentially delivered to a radially innermost nozzle and thereafter in a graduated series of steps in lesser amounts to a series of sequenced nozzles more radially disposed from the center of the rotating bit.

Link, H. D.

1985-11-05

128

Characterization of MPCVD diamond films grown on porous silicon  

NASA Astrophysics Data System (ADS)

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.

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

1994-04-01

129

Microinclusions in polycrystalline diamonds: insights into processes of diamond formation  

Microsoft Academic Search

Polycrystalline diamond aggregates (framesites) contain silicates of eclogitic and peridotitic affinity (e.g. Kurat and Dobosi, 2000). The minerals occur mostly in interstices and are intimately intergrown with the diamonds, indicating contemporaneous crystallization within the diamond stability field in the Earth's mantle. In addition to silicates, rarer phases such as Fe-carbide can sometimes be found in framesites that record unusually low

D. E. Jacob; R. Wirth; F. Enzmann; J. O. Schwarz; A. Kronz

2009-01-01

130

Shock Diamonds and Mach Disks  

NSDL National Science Digital Library

The article presents and explains the diamond-shaped pattern that appears in the rocket engine and jet engine exhausts. Several photographs illustrate this phenomenon, and images show how crisscrossing shock waves produce the diamond shapes.

2010-06-03

131

High-Voltage Diamond Vertical Schottky rectifiers  

Microsoft Academic Search

We have designed, simulated and experimentally demonstrated high-voltage vertical diamond Schottky rectifiers. The rectifiers were fabricated on free-standing homo-epi films with remarkably low p-type doping using a lift-off process. Theoretical calculations have been performed to determine the thickness and doping concentration of the drift region. Devices with 20mum epi layer have been shown to block 3.7kV and conduct 0.6 A\\/cm2

W. Huang; T. P. Chow; J. Yang; J. E. Butler

2005-01-01

132

The Diamond Makers  

NASA Astrophysics Data System (ADS)

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.

Hazen, Robert M.

1999-08-01

133

Making Diamond in the Laboratory  

ERIC Educational Resources Information Center

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)

Strong, Herbert

1975-01-01

134

Radiation Physics with Diamonds  

NASA Astrophysics Data System (ADS)

Some salient features and examples of the numerous results obtained during the last decade in close collaboration with Friedel Sellschop in a Bonn/Darmstadt/Erlangen/Kharkov/ Munich/Rossendorf/Wits Collaboration at the superconducting Darmstadt electron linear accelerator (S-DALINAC) on the interaction of relativistic electrons with diamonds are presented. These studies started with investigations of channeling radiation (CR) and were later on extended into the field of parametric X radiation (PXR), with the main aim to possibly develop a tunable radiation source with a small bandwidth. But also basic properties of these types of radiations, like e.g. coherence and occupation lengths, linewidths, polarization and interference with coherent bremsstrahlung have been investigated as well as special properties of diamonds. An example for such a measurement is the susceptibility of diamond through PXR. Lately CR has also been explored in the context of a new acceleration mechanism.

Richter, A.

2001-09-01

135

Process for making diamonds  

NASA Technical Reports Server (NTRS)

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

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

1973-01-01

136

Rare Diamond Confirms that Earth's Mantle Holds an Ocean's Worth of Water  

E-print Network

Rare Diamond Confirms that Earth's Mantle Holds an Ocean's Worth of Water The diamond contains a longheld theory: Earth's mantle holds an ocean's worth of water. "It's actually the confirmation that there is a very, very large amount of water that's trapped in a really distinct layer in the deep Earth," said

Machel, Hans

137

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

SciTech Connect

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

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

2009-01-01

138

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

NASA Astrophysics Data System (ADS)

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.

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

2014-09-01

139

Diamond/AlN Thin Films for Optical Applications  

SciTech Connect

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

Knoebber, F.; Bludau, O.; Williams, O. A.; Sah, R. E.; Kirste, L.; Baeumler, M.; Nebel, C. E.; Ambacher, O.; Cimalla, V.; Lebedev, V. [Fraunhofer Institute for Applied Solid State Physics, Tullastr. 72, 79108 Freiburg (Germany); Leopold, S.; Paetz, D. [IMN MacroNano registered , Ilmenau University of Technology, PF 100565, 98684 Ilmenau (Germany)

2010-11-01

140

Lower pressure synthesis of diamond material  

DOEpatents

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.

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

141

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

PubMed Central

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

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

2010-01-01

142

Helium and carbon isotopes in Indian diamonds  

Microsoft Academic Search

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

R. Wiens; D. Lal; H. Craig

1990-01-01

143

Mechanism of diamond formation on substrates abraded with a mixture of diamond and metal powders  

Microsoft Academic Search

In this work we report a study of CVD diamond formation on silicon substrates abraded with diamond, metal, and a mixture of diamond and metal powders. It was found that the deposited diamond particles density (DPD) obtained after abrasion with diamond powder can be enhanced by a few orders of magnitude by abrasion with a mixed metal\\/diamond slurry, whereas no

Y. Chakk; R. Brener; A. Hoffman

1996-01-01

144

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

DOEpatents

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

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

2012-07-24

145

Raman investigation of diamond films  

SciTech Connect

Extensive Raman investigations were conducted on a wide range of diamond films whose structures were dilineated by optical and confocal microscopy. The Raman Spectra from one extreme of this range indicates a very intense 1331 cm{sup {minus}1} line diagnostic of bulk crystalline diamond. Microscopy of the corresponding film shows the presence of many large true diamond crystallite. The 1331 cm{sup {minus}1} Raman line at the other extreme of the range, however, is virtually absent. It is replaced, at this extreme, by a very broad Raman contour whose maxima occur near 1355 cm{sup {minus}1} and 1575 cm{sup {minus}1}. Optical microscopy now reveals a complete lack of diamond crystallites. The ratio of the integrated Raman intensity of the 1331 cm{sup {minus}1} diamond line to the integral of the entire broad contour extending from {approx}1200 cm{sup {minus}1} to 1800 cm{sup {minus}1}, with maxima near 1355 cm{sup {minus}1} and 1575 cm{sup {minus}1}, was determined. This ratio rises with increasing diamond crystallite size, and it decreases as true diamond crystallites are replaced by diamond-like, but amorphous, hard carbon, which produces the broad Raman contour. The measured intensity ratio was analyzed in terms of a differential equation related to phonon coupling. The increase of the intensity ratio of the 1331 cm{sup {minus}1} diagnostic diamond peak is due to phono-phonon coupling between the diamond crystallites, as the concentration of the amorphous diamond-like carbon decreases. Confocal microscopy indicates many amorphous-like regions interspersed between diamond crystallites which account for the intensity loss, and agree with the Raman intensity measurements. These Raman measurements crystallinity versus amorphous hard-carbon character of thin diamond film.

Feng, Li-Ming

1993-12-31

146

South Africa, Namibia Diamond Deposits  

NASA Technical Reports Server (NTRS)

This radar image covers a portion of the Richtersveld National Park and Orange River (top of image) in the Northern Cape Province of the Republic of South Africa. The Orange River marks the boundary between South Africa to the south and Namibia to the north. This is an area of active mining for diamonds, which were washed downstream from the famous Kimberley Diamond Area, millions of years ago when the river was much larger. The mining is focused on ancient drainages of the Orange River which are currently buried by think layers of sand and gravel. Scientists are investigating whether these ancient drainages can be seen with the radar's ability to penetrate sand cover in extremely dry regions. A mine, shown in yellow, is on the southern bank of the river in an abandoned bend which is known as an 'oxbow.' The small bright circular areas (left edge of image) west of the mine circles are fields of a large ostrich farm that are being watered with pivot irrigation. The large dark area in the center of the image is the Kubus Pluton, a body of granite rock that broke through the surrounding rocks about 550 million years ago. North is toward the upper right. The area shown is about 55 by 60 kilometers (34 by 37 miles) centered at 28.4 degrees south latitude, 16.8 degrees east longitude. Colors are assigned to different radar frequencies and polarizations as follows: red is L-band horizontally transmitted and horizontally received; green is L-band horizontally transmitted and vertically received; blue is C-band horizontally transmitted and vertically received. The image was acquired on April 18, 1994 by the Spaceborne Imaging Radar-C/X-band Synthetic Aperture (SIR-C/X-SAR) imaging radar when it flew aboard the space shuttle Endeavour. SIR-C/X-SAR is a joint mission of the U.S./German and Italian space agencies.

1998-01-01

147

Thermal diffusivity of diamond films using a laser pulse technique  

NASA Technical Reports Server (NTRS)

Polycrystalline diamond films were deposited using a microwave plasma-enhanced chemical vapor deposition process. A laser pulse technique was developed to measure the thermal diffusivity of diamond films deposited on a silicon substrate. The effective thermal diffusivity of a diamond film on silicon was measured by observing the phase and amplitude of the cyclic thermal waves generated by laser pulses. An analytical model is presented to calculate the effective in-plane (face-parallel) diffusivity of a two-layer system. The model is used to reduce the effective thermal diffusivity of the diamonds/silicon sample to a value for the thermal diffusivity and conductivity of the diamond film. The average effective diffusivity values are 1.47 + or - 0.03 and 1.83 + or - 0.10 yielding thermal diffusivity values of 7.46 + or - 0.90 and 7.33 + or - 0.70 sq cm/s respectively, for the two samples; the calculated thermal con ductivity values are 13.50 and 13.28 W/cmK, which are better than that of type 1a natural diamond. The phase and amplitude measurements give similar results.

Albin, Sacharia; Winfree, William P.; Crews, B. Scott

1990-01-01

148

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 ...

149

Conversion of fullerenes to diamond  

DOEpatents

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.

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

1994-01-01

150

Diamond films for laser hardening  

NASA Technical Reports Server (NTRS)

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.

Albin, S.; Watkins, L.; Ravi, K.; Yokota, S.

1989-01-01

151

Diamond Ages and Lithosphere Evolution - Applications to Diamond Exploration  

NASA Astrophysics Data System (ADS)

Combinations of studies on diamonds, diamond inclusions, diamond bearing mantle and ultra-high pressure (UHP) metamorphic crustal rocks, kimberlites and lamproites have been successful in delivering insights into major processes such as plate tectonics, craton accretion, the effects of large magmatic events as well as contributing to a better understanding of diamond formation and preservation over an extended period of earth history. The crystal structure of diamond ensures that mineral inclusions in natural diamonds, whether fluid or solid, may be maintained as closed systems over extended periods of geological time and provide useful information about key processes in the mantle, as far back as 3.5 Ga and possibly further. Available diamond ages suggest that all macrodiamonds in economically significant kimberlites and lamproites are xenocrystic and have formed in pre-existing upper mantle assemblages, predominantly peridotite, eclogite and websterite in the sub-continental lithospheric mantle (SCLM) and occasionally in higher-pressure equivalents of such rocks, for example majorite. Diamond ages also suggest that conditions favorable for diamond formation in the SCLM have been episodic, can be repeated in the same pre-existing host rocks at significantly different times and that all investigated ore bodies have more than one population of xenocrystic diamonds contributing to run-of-mine production. Evidence is accumulating as well that diamond forming processes are metasomatic, though this is more conclusively demonstrated for young rather than old diamonds. Given that both diamond formation events and transportation into the crust are episodic and span from the Paleoarchean to the Cenozoic, diamond geology, mineralogy, and chemistry provide a unique opportunity to contribute to knowledge about the evolution of the earth's continental lithosphere through a major part of earth history. While the processes of formation and preservation of diamonds in the cratonic roots are a function of Archean and post-Archean craton evolution and have operated worldwide, the timing of individual diamond-forming events and of their transport to the surface are craton specific. The formation of diamondiferous carbonated, G- 10 garnet-bearing harzburgitic domains in Mesoarchean mantle roots represents the earliest lithospheric- diamond-forming event so far discovered in the Kaapvaal, Zimbabwe, Slave, and Siberian diamond fields. Not only is it the earliest, it remains of primary importance as a contributor to the diamond budget in many of the on-craton deposits. Ideally, exploration for kimberlites containing the G-10 bearing harzburgitic diamond component should concentrate on the Mesoarchean nuclei of Archean cratons or tectonically buried parts thereof. The ancient harzburgitic component makes a lesser or no contribution to the diamond budget of craton-margin and off-craton primary deposits (e.g., the Argyle and Ellendale lamproites, the Colorado/Wyoming State Line kimberlites, the Carolina kimberlite in northwestern Brazil, the kimberlites of the North Lesotho area, and Jagersfontein. This is in accord with the low grade of all these deposits, except Argyle. The presentation will stress that modern exploration should make use of the increasing evidence that diamond formation ages can be correlated with Archean and Proterozoic craton evolution events.

Helmstaedt, H. H.; Gurney, J. J.; Richardson, S. H.

2009-05-01

152

DIAMOND SECONDARY EMITTER  

SciTech Connect

We present the design and experimental progress on the diamond secondary emitter as an electron source for high average power injectors. The design criteria for average currents up to 1 A and charge up to 20 nC are established. Secondary Electron Yield (SEY) exceeding 200 in transmission mode and 50 in emission mode have been measured. Preliminary results on the design and fabrication of the self contained capsule with primary electron source and secondary electron emitter will also be presented.

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

2005-10-09

153

Diamond turning of glass  

SciTech Connect

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

Blackley, W.S.; Scattergood, R.O.

1988-12-01

154

Diamond - A novel sensing material  

NASA Astrophysics Data System (ADS)

The present development status evaluation of diamond-deposition processes gives attention to turbulent flow regime CVD processes, which can enhance deposition rates, and to hybrid microelectronic, optoelectronic, and similar devices based on CVD diamond. A preliminary theoretical computation is presented for comparing the power dissipation vs gate-propagation delay for diamond-based, Si-based, and GaAs-based devices. Thermal interactions of semiconductor devices due to close-spaced arraying are addressed; it is shown that diamond-based devices can withstand higher operating temperatures.

Vaseashta, Ashok K.; Desu, Seshu B.

1993-01-01

155

Achieving ultra-hard surface of mechanically polished diamond crystal by thermo-chemical refinement  

NASA Astrophysics Data System (ADS)

In the present work, we propose a novel thermo-chemical post-processing method for refining the mechanically polished surface of natural diamond crystal. The deformation mechanisms of diamond crystal during mechanical polishing are elucidated by Raman Spectroscopy corroborated by molecular dynamics simulations. Moreover, the surface mechanical properties of diamond crystal are qualitatively characterized by nanoindentation tests. Our results reveal that under mechanical polishing there are phase transformations from diamond carbons to layered graphite, amorphous sp3 and sp2 hybrided structures occurred in the topmost surface layer, which consequently deteriorates the intrinsic surface strength of diamond crystal. In the following thermo-chemical refinement, the polishing-induced amorphous carbons, layered graphite and internal stress are largely removed through the weak oxidation reaction. It is found that the formation of considerable graphene structures in the topmost surface layer results in an ultra-hard diamond crystal surface with dramatically enhanced hardness and Young's modulus. Our findings shed light on the preparation of natural diamond crystal surface with superior mechanical properties.

Zong, Wenjun; Zhang, Junjie; Liu, Yue; Sun, Tao

2014-10-01

156

Ohmic contacts to boron-doped diamond  

NASA Astrophysics Data System (ADS)

Two types of contacts, namely Au and Au/Ta, were fabricated on B-doped diamond films by rf sputtering deposition. I- V measurements show that our Au and Au/Ta contacts have exhibited good ohmic characteristics in their as-deposited states. Upon annealing, their ohmic behaviors were improved to different extent. Compared with Au contact, Au/Ta contact has lower specific contact resistance value and better adhesion. X-ray photoelectron spectroscopy (XPS) analyses indicate that there is an obvious interdiffusion between Au and diamond film in Au contact. The interdiffusion was enhanced by annealing. This interdiffusion layer may be the reason why Au contacts are ohmic in the as-deposited and annealed states. As for Au/Ta contacts, XPS analyses show the formation of TaC at the interface between Ta and diamond film in the as-deposited state, there is an increase of TaC in the annealed contact. The presence of TaC promotes our Au/Ta contacts to have better ohmic characteristic.

Zhen, Congmian; Wang, Yinyue; He, Shanhu; Guo, Qiufen; Yan, Zhijun; Pu, Yuejiao

2003-07-01

157

Influence of diamond surface termination on thermal boundary conductance between Al and diamond  

SciTech Connect

The effect of diamond surface treatment on the Thermal Boundary Conductance (TBC) between Al and diamond is investigated. The treatments consist in either of the following: exposition to a plasma of pure Ar, Ar:H and Ar:O, and HNO{sub 3}:H{sub 2}SO{sub 4} acid dip for various times. The surface of diamond after treatment is analyzed by X-ray Photoelectron Spectroscopy, revealing hydrogen termination for the as-received and Ar:H plasma treated samples, pure sp{sup 2} termination for Ar treated ones and oxygen (keton-like) termination for the other treatments. At ambient, all the specific treatments improve the TBC between Al and diamond from 23 {+-} 2 MW m{sup -2} K{sup -1} for the as-received to 65 {+-} 5, 125 {+-} 20, 150 {+-} 20, 180 {+-} 20 MW m{sup -2} K{sup -1} for the ones treated by Ar:H plasma, acid, pure Ar plasma, and Ar:O plasma with an evaporated Al layer on top, respectively. The effect of these treatments on temperature dependence are also observed and compared with the most common models available in the literature as well as experimental values in the same system. The results obtained show that the values measured for an Ar:O plasma treated diamond with Al sputtered on top stay consistently higher than the values existing in the literature over a temperature range from 78 to 290 K, probably due a lower sample surface roughness. Around ambient, the TBC values measured lay close to or even somewhat above the radiation limit, suggesting that inelastic or electronic processes may influence the transfer of heat at this metal/dielectric interface.

Monachon, Christian; Weber, Ludger [Laboratoire de Metallurgie Mecanique, Ecole Polytechnique Federale de Lausanne, Lausanne (Switzerland)] [Laboratoire de Metallurgie Mecanique, Ecole Polytechnique Federale de Lausanne, Lausanne (Switzerland)

2013-05-14

158

Stable metallization for diamond and other materials  

NASA Technical Reports Server (NTRS)

An adherent and metallurgically stable metallization system for diamond is presented. The big improvement in metallurgical stability is attributed to the use of a ternary, amorphous Ti--Si--N diffusion barrier. No diffusion between the layers and no delamination of the metallization was observed after annealing the schemes at 400.degree. C. for 100 hours and at 900.degree. C. for 30 minutes. Thermal cycling experiments in air from -65 to 155.degree. C. and adhesion tests were performed. Various embodiments are disclosed.

Bachli, Andreas (Inventor); Kolawa, Elzbieta (Inventor); Nicolet, Marc-Aurele (Inventor); Vandersande, Jan W. (Inventor)

2000-01-01

159

Diamonds: Exploration, mines and marketing  

Microsoft Academic Search

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%

George H. Read

2009-01-01

160

The Ideal Strength of Diamond  

NASA Astrophysics Data System (ADS)

We present calculations of both the ideal shear and tensile strengths of diamond using pseudopotential density functional theory, within the local density approximation. Our calculations show a transition to a graphitic state under large shear stress, as has recently been seen in nanoindentation studies. We also compare the ideal shear strength with the maximum shear stress observed in diamond anvil cell experiments.

Roundy, David; Cohen, Marvin L.

2001-03-01

161

Photo- and thermionic emission of MWPECVD nanocrystalline diamond films  

NASA Astrophysics Data System (ADS)

Nanocrystalline diamond (NCD) films with and without a diamond buffer layer (BL) have been grown on p-type silicon substrates by microwave plasma enhanced chemical vapor deposition technique at different values of deposition temperature (652-884 °C). The photo- and thermionic electron emission properties of NCD films have been investigated, illustrated and explained by analyzing the surface morphology and the grain shape determined by atomic force microscopy, the chemical-structural properties by Raman spectroscopy and nanocrystallites size by X-ray diffraction. The NCD films with BL grown at the highest deposition temperature have shown the highest photo- and thermionic emission currents.

Cicala, G.; Magaletti, V.; Valentini, A.; Nitti, M. A.; Bellucci, A.; Trucchi, D. M.

2014-11-01

162

Boron-doped superlattices and Bragg mirrors in diamond  

NASA Astrophysics Data System (ADS)

A periodic modulation of the boron doping level of single crystal diamond multilayers over more than three orders of magnitude during epitaxial growth by microwave plasma-enhanced chemical vapor deposition is shown to yield Bragg mirrors in the visible. The thicknesses and doping level of the individual layers were controlled by in situ spectroscopic ellipsometry, enabling to tune the reflectance peak to the wavelength range of diamond color centers, such as NV0 or NV-. The crystalline quality, periodicity, and sharpness of the doping transitions in these doping superlattices over tens of periods were confirmed by high resolution X-ray diffraction.

Fiori, A.; Bousquet, J.; Eon, D.; Omnès, F.; Bellet-Amalric, E.; Bustarret, E.

2014-08-01

163

Surface and pseudo-surface acoustic waves piezoelectrically excited in diamond-based structures  

NASA Astrophysics Data System (ADS)

Surface and pseudo-surface acoustic plane waves generated in two- and three-layer AlN/Diamond and AlN/Diamond/? -TiAl structures by a point electric source are analyzed in the mathematical framework based on the Green's matrix integral representation and guided wave asymptotics derived using the residue technique. The attention is focused on the effect of pseudo-surface-to-surface wave degeneration at certain discrete values of h /? (h is the thickness of the piezoelectric layer and ? is the wave-length). Earlier such optimal ratios were discovered and experimentally verified for the first pseudo-surface (Sezawa) wave mode in the AlN/Diamond structure. The present research reveals this effect for higher modes as well as examines its manifestation for three-layer structures with different diamond-to-AlN thickness ratios H/h.

Glushkov, Evgeny; Glushkova, Natalia; Zhang, Chuanzeng

2012-09-01

164

Surface treatment of diamond films with Ar and O 2 cluster ion beams  

NASA Astrophysics Data System (ADS)

Irradiation effects of Ar and O 2 cluster ion beams were studied on Chemical Vapor Deposition (CVD) diamond films. When the acceleration energy of the O 2 cluster ion was 20 keV, the sputtering yield was 400 atoms/cluster which is 13 times higher than that of Ar cluster ions because of the enhancement by chemical reactions. The average roughness of the diamond surface decreased with Ar cluster ion beams. This smoothing is attributed to the physical sputtering effect. However, a thin graphite layer was formed on the surface by contamination of monomer ion in the cluster beam, which decreases the optical transmittance of the diamond films. In contrast, the surface roughness was not improved but no graphite layer was formed with O 2 cluster ions. By using both Ar and O 2 cluster ion beams, a very flat diamond surface without a graphite layer on the surface can be fabricated.

Toyoda, N.; Hagiwara, N.; Matsuo, J.; Yamada, I.

1999-01-01

165

REVIEW ARTICLE: Diamond for bio-sensor applications  

Microsoft Academic Search

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

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

2007-01-01

166

Diamond and other forms of elemental carbon in Saturn’s deep atmosphere  

NASA Astrophysics Data System (ADS)

The energetic lightning storms in the Saturn atmosphere will dissociate molecules into atoms, ions and plasma. Specifically, methane will be dissociated into elemental carbon, most probably in an amorphous form, such as fluffy turbostratic carbon or irregular soot particles. Once formed, this non-crystalline carbon sinks down through the atmosphere reaching an altitude of similar density. Amorphous carbon is converted to graphite under pressure. Graphite has a density of ~2.2 g/cc at room temperature. The density of diamond is ~3.3 g/cc at STP. However, at much higher pressures, the density of diamond increases dramatically, up to 9 grams/cm3 at P=1500 GPa (15 Mbar). As carbon descends through the atmosphere, amorphous carbon becomes graphite which then is converted into diamond, creating various strata of carbon allotropes according to their densities. Densities of the planets increase with depth. Eventually, at great depths, diamond will melt, forming liquid diamond. The melting point of diamond varies with pressure, reaching a high of ~ 8000 K at 500 GPa (5 Mbar). Using updated adiabats and equation-of-state data from Nettelmann et al. (2011), we determined the altitude at which diamond reaches its melting point on each planet. Combining these adiabats with new data for the carbon phase diagram from high-pressure shockwave experiments indicates that diamond may be a stable layer in the atmospheres of Jupiter and Saturn. Previously, only Uranus and Neptune were thought to have conditions in their interiors that would allow the formation of diamond at their cores. It appears that the interior of Jupiter gets hot enough to reach the liquid diamond region of the carbon phase diagram, whereas the interior of Saturn includes regions of temperature and pressure where carbon could exist as solid diamond. At the boundaries (locations of sharp increases in density) on Jupiter and Saturn, there may be diamond rain or diamond oceans sitting as a layer. However, in Uranus and Neptune, the temperatures never reach as high as 8000 K. The cores are ~5000K, too cold for diamond to melt on these planets. Therefore, it appears that diamonds are forever on Uranus and Neptune but not on Jupiter and Saturn.

Delitsky, M. L.; Baines, K. H.

2013-10-01

167

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

NASA Astrophysics Data System (ADS)

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.

Chu, Yueh-Chieh; Tzeng, Yonhua; Auciello, Orlando

2014-01-01

168

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

SciTech Connect

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.

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

169

Ultrathin W-Al dual interlayer approach to depositing smooth and adherent nanocrystalline diamond films on stainless steel.  

PubMed

The adherence of diamond coated on steel is commonly low and needs to be strengthened with thick intermediate layers. In this paper, a nanoscale W-Al dual metal interlayer has been applied on SS304 substrates to facilitate deposition of continuous, adherent and smooth diamond thin films. During the microwave plasma-enhanced chemical vapor deposition process, the Al inner layer 30 nm thick diffuses into steel surface inhibiting carbon diffusion and graphitization. The W outer layer 20 nm thick is transformed into W carbides, both preventing carbon diffusion and enhancing diamond nucleation. The diamond films synthesized are of high purity and have smooth surfaces and dense structures. Indentation and shear deformation tests indicate high delaminating tolerance of the diamond films. PMID:20356176

Li, Y S; Tang, Y; Yang, Q; Maley, J; Sammynaiken, R; Regier, T; Xiao, C; Hirose, A

2010-02-01

170

The EKATI - Kimberlite - Diamond - Mine in Canada  

Microsoft Academic Search

This paper deals with the kimberlites and diamonds of the Ekati Diamond Mine, NWT, Canada, which lies in the central part of the canadian slave craton and is operated by the BHP Billiton Diamond Inc.. 150 kimberlites were discovered at Ekati and five of them are mined for diamonds. The most Ekati kimberlites are pipe-like bodies and their age rang

Janine Mundt

171

Properties of diamond grown from CO2 containing gas chemistries  

NASA Astrophysics Data System (ADS)

The structural, optical and mechanical properties of CVD diamond grown using chemistries on the H-CO tie line have been investigated. A microwave plasma CVD system has been used with methane and ethylene containing gas chemistries to grow free standing optical quality diamond layers. When these feed stock gases are combined with carbon dioxide and hydrogen they enable the H-CO tie line to be traversed up to the central region of the Bachmann growth diagram. The structural properties were assessed using SEM, cathodoluminescence, Raman spectroscopy and x-ray diffraction techniques. The optical properties were assessed using several techniques including measurements of spectral emissivity over a range of temperatures and the role of nitrogen impurities identified. The trends in the optical characteristics will be discussed in relation to differences in mechanical properties with a view of evaluating the viability of using oxygen-based chemistries for the fabrication of diamond components.

Mollart, Tim P.; Lewis, Keith L.; Williams, G. M.

1999-07-01

172

Analysis of temperature distribution and performance of polycrystalline diamond compact bits under field drilling conditions  

SciTech Connect

Analysis of laboratory tests on full-scale fieldworn polycrystalline diamond compact (PDC) bits showed the frictional heat at the rock/bit interface to be largely generated at the diamond cutting edges of the PDCs. Inspection of the observed wear of the PDCs together with the analysis revealed that the diamond layer attacks the formation at a large negative rake angle and that rock flour accumulates under the cutting edge during drilling, forming a stable buildup edge. The results showed that for effective cooling of the PDCs fluid velocities of at least 50 m/s are required along the diamond surfaces when drilling with oil-based fluids. With water-based drilling fluids, higher velocities should be used to prevent bit balling or boiling of the drilling fluid at the diamond surface of the PDCs.

Zijsling, O.H.

1984-09-01

173

Boron-doped diamond films on silicon studied by Raman and infrared spectroscopies  

NASA Astrophysics Data System (ADS)

Boron doped diamond films were deposited onto (100) orientated Si substrates using a thermal filament CVD method. Boron trioxide was used as a doping source and samples with boron to carbon (B/C) ratios of 0, 10, 100, and 1000 ppm were prepared for the optical measurements. The infrared (IR) results reveal the formation of an ultrathin SiC layer at the interface between Si and diamond. Furthermore, the IR data confirm the resistivity data obtained from electrical measurements. Raman spectroscopy was used to probe the quality and homogeneity of the diamond films. Upon increasing B/C ratio the diamond phonon line shifts to lower frequency and is also broadened revealing a softening of the diamond. In addition, the optical absorption was found to increase strongly with increasing B/c ratio.

Okano, Ken; Kurosu, Tateki; Iida, Masamori; Eickhoff, Thomas; Wilhelm, Hans; Zahn, Dietrich R. T.

1990-08-01

174

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

NASA Astrophysics Data System (ADS)

The internal structure and growth history of six macro-diamonds from kimberlite pipes in Yakutia (Russia) were investigated with cathodoluminescence imaging and coupled carbon isotope and nitrogen abundance analyses along detailed core to rim traverses. The diamonds are characterised by octahedral zonation with layer-by-layer growth. High spatial resolution SIMS profiles establish that there is no exchange of the carbon isotope composition across growth boundaries at the ?m scale and that isotopic variations observed between (sub)zones within the diamonds are primary. The macro-diamonds have ?13C values that vary within 2‰ of -5.3‰ and their nitrogen contents range between 0-1334 at. ppm. There are markedly different nitrogen aggregation states between major growth zones within individual diamonds that demonstrate Yakutian diamonds grew in multiple growth events. Growth intervals were punctuated by stages of dissolution now associated with <10 ?m wide zones of nitrogen absent type II diamond. Across these resorption interfaces carbon isotope ratios and nitrogen contents record shifts between 0.5-2.3‰ and up to 407 at. ppm, respectively. Co-variation in ?13C value-nitrogen content suggests that parts of individual diamonds precipitated in a Rayleigh process from either oxidised or reduced fluids/melts, with two single diamonds showing evidence of both fluid types. Modelling the co-variation establishes that nitrogen is a compatible element in diamond relative to its growth medium and that the nitrogen partition coefficient is different between oxidised (3-4.1) and reduced (3) sources. The reduced sources have ?13C values between -7.3‰ and -4.6‰, while the oxidised sources have higher ?13C values between -5.8‰ and -1.8‰ (if grown from carbonatitic media) or between -3.8‰ and +0.2‰ (if grown from CO2-rich media). It is therefore concluded that individual Yakutian diamonds originate from distinct fluids/melts of variable compositions. The diamond-forming fluids within the cratonic mantle beneath the Siberian Craton record significant variations in composition and volume and include both oxidised and reduced sources. These observations suggest that dating diamond inclusions using an isochron approach will best provide geologically meaningful ages if inclusions can be shown to be genetically (spatially) related.

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

2013-01-01

175

2D photonic crystals fabricated in wide bandgap nanocrystalline diamond  

NASA Astrophysics Data System (ADS)

Chemical vapor deposited (CVD) nanocrystalline diamond films and novel lithography techniques were used to fabricate short wavelength photonic slab crystals (PhC) with feature sizes below 100 nm. CVD diamond was chosen as a promising material for photonic structures due to a large bandgap (5.45 eV) and high index of refraction (2.38). Two methods of fabricating diamond PhC, both based on electron-beam lithography, have been developed. For structures with a high filling coefficient, the best results were obtained with an organic-inorganic bilayer negative resist structure utilizing a polymer-based resist as the bottom layer and a flowable oxide (FOx-12) as the top layer. After E-beam exposure and developing, the FOx pattern was used as a mask for dry etching the bottom resist layer. The resulting structure provides rigid overhang with very fine feature size control that is not affected by the surface roughness of the diamond film. A metal mask was deposited over the patterned bilayer resist followed by lift-off. The remaining metal pattern was used as a protective mask for a highly anisotropic oxygen plasma etch of the nanodiamond film. With the proper choice of the metal mask, this method can be applied to a wide range of materials and feature sizes. Relatively thin nanodiamond structures with a low filling coefficient can be fabricated in a simpler process that utilizes E-beam patterned FOx-12 as an etch mask. Freely suspended PhC slabs were formed by wet etch removal of the sacrificial oxide layer underneath the diamond film. We will present fabrication techniques, experimental data of the mechanical properties of the nanodiamond resonator, and analysis of the optical bandgap of the nanodiamond PhC.

Baldwin, Jeffrey W.; Zalalutdinov, Maxim; Butler, James E.; Feygelson, Tatyana; Houston, Brian H.

2005-11-01

176

Chemical Vapor-Deposited (CVD) Diamond Films for Electronic Applications  

NASA Technical Reports Server (NTRS)

Diamond films have a variety of useful applications as electron emitters in devices such as magnetrons, electron multipliers, displays, and sensors. Secondary electron emission is the effect in which electrons are emitted from the near surface of a material because of energetic incident electrons. The total secondary yield coefficient, which is the ratio of the number of secondary electrons to the number of incident electrons, generally ranges from 2 to 4 for most materials used in such applications. It was discovered recently at the NASA Lewis Research Center that chemical vapor-deposited (CVD) diamond films have very high secondary electron yields, particularly when they are coated with thin layers of CsI. For CsI-coated diamond films, the total secondary yield coefficient can exceed 60. In addition, diamond films exhibit field emission at fields orders of magnitude lower than for existing state-of-the-art emitters. Present state-of-the-art microfabricated field emitters generally require applied fields above 5x10^7 V/cm. Research on field emission from CVD diamond and high-pressure, high-temperature diamond has shown that field emission can be obtained at fields as low as 2x10^4 V/cm. It has also been shown that thin layers of metals, such as gold, and of alkali halides, such as CsI, can significantly increase field emission and stability. Emitters with nanometer-scale lithography will be able to obtain high-current densities with voltages on the order of only 10 to 15 V.

1995-01-01

177

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

NASA Technical Reports Server (NTRS)

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.

Miyoshi, Kazuhisa

1994-01-01

178

Tailoring nanocrystalline diamond film properties  

DOEpatents

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.

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

2003-07-15

179

Investigation of nucleation and growth processes of diamond films by atomic force microscopy  

NASA Technical Reports Server (NTRS)

The nucleation and growth of plasma enhanced chemical vapor deposited (PECVD) polycrystalline diamond films were studied using atomic force microscopy (AFM). AFM images were obtained for: (1) nucleated diamond films produced from depositions that were terminated during the initial stages of growth, (2) the silicon substrate-diamond film interface side of diamond films (1-4 micrometers thick) removed from the original surface of the substrate, and (3) cross-sectional fracture surface of the film, including the Si/diamond interface. Pronounced tip effects were observed for early-stage diamond nucleation attributed to tip convolution in the AFM images. AFM images of the films cross-section and interface however were not affected by tip convolution, and the images indicate that the surface of the silicon substrate is initially covered by small grained polycrystalline-like film and the formation of this precursor film is followed by nucleation of the diamond film on top of this layer. X-ray photoelectron spectroscoy (XPS) spectra indicates that some silicon carbide is present in the precursor layer.

George, M. A.; Burger, A.; Collins, Warren E.; Hu, Z.

1995-01-01

180

Investigation of nucleation and growth processes of diamond films by atomic force microscopy  

NASA Technical Reports Server (NTRS)

The nucleation and growth of plasma-enhanced chemical-vapor deposited polycrystalline diamond films were studied using atomic force microscopy (AFM). AFM images were obtained for (1) nucleated diamond films produced from depositions that were terminated during the initial stages of growth, (2) the silicon substrate-diamond film interface side of diamond films (1-4 micrometers thick) removed from the original surface of the substrate, and (3) the cross-sectional fracture surface of the film, including the Si/diamond interface. Pronounced tip effects were observed for early-stage diamond nucleation attributed to tip convolution in the AFM images. AFM images of the film's cross section and interface, however, were not highly affected by tip convolution, and the images indicate that the surface of the silicon substrate is initially covered by a small grained polycrystalline-like film and the formation of this precursor film is followed by nucleation of the diamond film on top of this layer. X-ray photoelectron spectroscopy spectra indicate that some silicon carbide is present in the precursor layer.

George, M. A.; Burger, A.; Collins, W. E.; Davidson, J. L.; Barnes, A. V.; Tolk, N. H.

1994-01-01

181

Fabrication of amorphous diamond films  

DOEpatents

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.

Falabella, S.

1995-12-12

182

Quantum computing: Three of diamonds  

NASA Astrophysics Data System (ADS)

Quantum computers require error correction protocols to repair the state of the quantum bits. This has now been demonstrated using a 'majority voting' protocol among a cluster of three defect spins in diamond.

Morton, John J. L.; Elzerman, Jeroen

2014-03-01

183

Application of Conditional Simulation to Quantify Uncertainty and to Classify a Diamond Deflation Deposit  

Microsoft Academic Search

Since the early 1900’s diamonds have been known to occur in aeolian placers in south western Namibia. At Namdeb’s Elizabeth\\u000a Bay Mine diamonds are extracted from the fine to coarse grit layers in a sequence of stratigraphic horizons formed during\\u000a periods of vigorous wind action. Significant capital expenditure is required to extend the life of mine at Elizabeth Bay and,

Sean Duggan; Roussos Dimitrakopoulos

184

Shallow donor induced n-type conductivity in deuterated boron-doped diamond  

Microsoft Academic Search

We show that deuteration of a series of boron-doped (100) diamond epitaxial layers can lead to a p-type to n-type conversion. The n-type diamond epilayers have electrical conductivities of a few S\\/cm at 300 K. These values are a factor 103-105 higher than the n-type conductivities achieved with phosphorus doping. This is a consequence of the shallow donor character of

J. Chevallier; Z. Teukam; C. Saguy; R. Kalish; C. Cytermann; F. Jomard; M. Barbé; T. Kociniewski; J. E. Butler; C. Baron; A. Deneuville

2004-01-01

185

Diamonds: Exploration, mines and marketing  

NASA Astrophysics Data System (ADS)

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).

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

2009-11-01

186

Structural and Electrical Properties of Nanocrystalline Diamond based Barium Strontium Titanate Varactors  

Microsoft Academic Search

Barium strontium titanate (BST) varactors fabricated on silicon substrates experience reliability and yield issues due to the defects induced in the interdiffusion of the layers in the bottom electrode stack. The structural and electrical properties of BST varactors fabricated on nanocrystalline diamond (NCD) films as the diffusion barrier layer are reported here. The structural properties and the quality of the

Venkataramanan Gurumurthy; Sathyaharish Jeedigunta; Sam Baylis; Priscila Spagnol; John Bumgarner; Ashok Kumar; Thomas Weller

2008-01-01

187

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

Microsoft Academic Search

Densifying non-mined diamond powder precursors with diamond produced by chemical vapor infiltration (CVI) is an attractive approach for forming thick diamond deposits that avoids many potential manufacturability problems associated with predominantly chemical vapor deposition (CVD) processes. The authors have developed two techniques: electrophoretic deposition and screen printing, to form nonmined diamond powder precursors on substrates. They then densify these precursors

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

1993-01-01

188

Three-dimensional cathodoluminescence imaging and electron backscatter diffraction: tools for studying the genetic nature of diamond inclusions  

NASA Astrophysics Data System (ADS)

As a step towards resolving the genesis of inclusions in diamonds, a new technique is presented. This technique combines cathodoluminescence (CL) and electron backscatter diffraction (EBSD) using a focused ion beam-scanning electron microscope (FIB-SEM) instrument with the aim of determining, in detail, the three-dimensional diamond zonation adjacent to a diamond inclusion. EBSD reveals that mineral inclusions in a single diamond have similar crystallographic orientations to the host, within ±0.4°. The chromite inclusions record a systematic change in Mg# and Cr# from core to the rim of the diamond that corresponds with a ~80°C decrease of their formation temperature as established by zinc thermometry. A chromite inclusion, positioned adjacent to a boundary between two major diamond growth zones, is multi-faceted with preferred octahedral and cubic faces. The chromite is surrounded by a volume of non-luminescent diamond (CL halo) that partially obscures any diamond growth structures. The CL halo has apparent crystallographic morphology with symmetrically oriented pointed features. The CL halo is enriched in ~200 ppm Cr and ~80 ppm Fe and is interpreted to have a secondary origin as it overprints a major primary diamond growth structure. The diamond zonation adjacent to the chromite is complex and records both syngenetic and protogenetic features based on current inclusion entrapment models. In this specific case, a syngenetic origin is favoured with the complex form of the inclusion and growth layers indicating changes of growth rates at the diamond-chromite interface. Combined EBSD and 3D-CL imaging appears an extremely useful tool in resolving the ongoing discussion about the timing of inclusion growth and the significance of diamond inclusion studies.

Wiggers de Vries, D. F.; Drury, M. R.; de Winter, D. A. M.; Bulanova, G. P.; Pearson, D. G.; Davies, G. R.

2011-04-01

189

New Technique Produces 10-carat Diamond  

NSF Publications Database

... half-inch thick single-crystal diamonds at rapid growth rates (100 micrometers per hour) using a ... Congress in Argonne, Ill., May 18, 2005. "The rapid synthesis of large, single-crystal diamond is a ...

190

Performance of MSGC on diamond-coated glass  

NASA Astrophysics Data System (ADS)

A microstrip detector on ionic conducting glass suffers from the irreversible modifications of the substrate, which leads to changes of the gas amplification, and more seriously the amplification becomes rate-dependent. A recent solution consists in coating ionic conducting glasses with a layer of diamond like carbon (DLC). In this contribution, results are reported on the stability and rate capability of plates coated either before or after the lithography (under and overcoating) process.

Cicognani, G.; Guerard, B.; Oed, A.

1997-02-01

191

Detector assembly with a diamond detector for recording neutrons  

Microsoft Academic Search

The BDPN-1K detector assembly for neutron radiation comprises the detector and a preamplifier connected by a 10-m-long cable. The detector can be disassembled. Before the sensitive surface of the diamond there is placed a cover with a converter disk cemented to it; this disk is a UâOâ layer applied to an aluminum foil. Since the detector can be disassembled, the

A. E. Luchanskii; S. S. Martynov; V. S. Khrunov; V. A. Chekhlaev

1988-01-01

192

Diamond formation on carbon\\/carbon composite  

Microsoft Academic Search

A carbon\\/carbon composite was used as substrate for low-pressure diamond deposition. To enhanced diamond nucleation on carbon\\/carbon composites, a total of ten surface preparation methods have been investigated. These methods involved the use of atomic hydrogen etching, mechanical polishing, sonication, or coating. Diamond nucleation was found to occur on either the defects of the carbon\\/carbon composite substrates or diamond particulate

Jyh-Ming Ting

1995-01-01

193

Polycrystalline diamond films for optical applications  

NASA Astrophysics Data System (ADS)

The applicability of CVD diamond films in optics is investigated. Emphasis is put on the role of the surface roughness as the most critical parameter influencing the optical quality of polycrystalline diamond films. In particular we report on the preparation of optically smooth, thin diamond films, on the in situ analysis of the optical quality, on the coating of large area substrates, and on the growth of thick, free-standing diamond wafers with flat surfaces.

Wild, C.; Mueller-Sebert, W.; Eckermann, T.; Koidl, P.

194

Ultimate Atomic Bling: Nanotechnology of Diamonds  

SciTech Connect

Diamonds exist in all sizes, from the Hope Diamond to minuscule crystals only a few atoms across. The smallest of these diamonds are created naturally by the same processes that make petroleum. Recently, researchers discovered that these 'diamondoids' are formed in many different structural shapes, and that these shapes can be used like LEGO blocks for nanotechnology. This talk will discuss the discovery of these nano-size diamonds and highlight current SLAC/Stanford research into their applications in electronics and medicine.

Dahl, Jeremy

2010-05-25

195

Thermal neutron dosimeter by synthetic single crystal diamond devices.  

PubMed

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

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

2009-07-01

196

The Diamond Mines of South Africa  

Microsoft Academic Search

A life-long friend of Cecil Rhodes, Garner F. Williams (1842–1922) was the first general manager of the De Beers Consolidated Mines, which once produced 95% of the diamond yield of the world. First published in 1902, this work opens with a chapter on notable historical diamonds, and goes on to describe the initial discovery of diamonds in South Africa, the

Gardner F. Williams

197

Diamond Drilling Specification Manual and Course Outline.  

ERIC Educational Resources Information Center

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.…

British Columbia Dept. of Education, Victoria.

198

Technical Characteristics of Diamond Reinforced Epoxy Composites  

Microsoft Academic Search

Diamond reinforced polymeric composites are becoming ever more applied in wear resistant tools. The performance of these composites depends on their mechanical properties in association with the hard diamond particle interaction with the soft polymeric matrix. In the present work, epoxy matrix composites, with different phr, reinforced with 10, 20 and 30 wt.% diamond particles were investigated through mechanical tests

Sergio N. Monteiro; Gustavo W. de Menezes; Ruben Jesus; S. Rodriguez; Guerold S. Bobrovnitchii; Ana Lucia; D. Skury

2005-01-01

199

Nanoindentation of diamond, graphite and fullerene films  

Microsoft Academic Search

The recently developed method of nanoindentation is applied to various forms of carbon materials with different mechanical properties, namely diamond, graphite and fullerite films. A diamond indenter was used and its actual shape determined by scanning force microscopy with a calibration grid. Nanoindentation performed on different surfaces of synthetic diamond turned out to be completely elastic with no plastic contributions.

Asta Richter; Ronald Ries; Roger Smith; Matthias Henkel; Bodo Wolf

2000-01-01

200

Underground at Black Diamond Mines  

SciTech Connect

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

Higgins, C.T.

1989-10-01

201

Diamond photodiodes for x-ray application  

SciTech Connect

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.

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

202

Atomic-structure determination of diamond using Auger-electron diffraction  

NASA Astrophysics Data System (ADS)

The surface structure of diamond is determined by comparing angle-resolved Auger-electron spectroscopy data to a theoretical model of electron diffraction in a cluster. The diffraction pattern of carbon KVV Auger-electron emission at 265 eV from a diamond(100) surface was obtained in an ultrahigh vacuum chamber. The polar scan curves of the experimental data at azimuthal angles 0°, 15°, 30°, and 45° are compared to theoretical predictions obtained using a single scattering cluster model. The calculated polar intensity distributions are a fairly sensitive function of surface structure. Optimal agreement with experiment occurs when there is a (2×1) reconstruction at the diamond surface and there is a perpendicular expansion of 0.015(+/-0.001) Å between layers 1 and 2, 0.010(+/-0.003) Å between layers 2 and 3 and 0.005(+/-0.005) Å between layers 3 and 4.

Yue, F.; Swineford, R. S.; Pappas, D. P.

1996-03-01

203

YBa2Cu3O7 thin films on nanocrystalline diamond films for HTSC bolometer  

NASA Technical Reports Server (NTRS)

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.

Cui, G.; Beetz, C. P., Jr.; Boerstler, R.; Steinbeck, J.

1993-01-01

204

Diamond nanowires for highly sensitive matrix-free mass spectrometry analysis of small molecules.  

PubMed

This paper reports on the use of boron-doped diamond nanowires (BDD NWs) as an inorganic substrate for matrix-free laser desorption/ionization mass spectrometry (LDI-MS) analysis of small molecules. The diamond nanowires are prepared by reactive ion etching (RIE) with oxygen plasma of highly boron-doped (the boron level is 10(19) B cm(-3)) or undoped nanocrystalline diamond substrates. The resulting diamond nanowires are coated with a thin silicon oxide layer that confers a superhydrophilic character to the surface. To minimize droplet spreading, the nanowires were chemically functionalized with octadecyltrichlorosilane (OTS) and then UV/ozone treated to reach a final water contact angle of 120°. The sub-bandgap absorption under UV laser irradiation and the heat confinement inside the nanowires allowed desorption/ionization, most likely via a thermal mechanism, and mass spectrometry analysis of small molecules. A detection limit of 200 zeptomole for verapamil was demonstrated. PMID:22080363

Coffinier, Yannick; Szunerits, Sabine; Drobecq, Hervé; Melnyk, Oleg; Boukherroub, Rabah

2012-01-01

205

Diamond nanowires for highly sensitive matrix-free mass spectrometry analysis of small molecules  

NASA Astrophysics Data System (ADS)

This paper reports on the use of boron-doped diamond nanowires (BDD NWs) as an inorganic substrate for matrix-free laser desorption/ionization mass spectrometry (LDI-MS) analysis of small molecules. The diamond nanowires are prepared by reactive ion etching (RIE) with oxygen plasma of highly boron-doped (the boron level is 1019 B cm-3) or undoped nanocrystalline diamond substrates. The resulting diamond nanowires are coated with a thin silicon oxide layer that confers a superhydrophilic character to the surface. To minimize droplet spreading, the nanowires were chemically functionalized with octadecyltrichlorosilane (OTS) and then UV/ozone treated to reach a final water contact angle of 120°. The sub-bandgap absorption under UV laser irradiation and the heat confinement inside the nanowires allowed desorption/ionization, most likely via a thermal mechanism, and mass spectrometry analysis of small molecules. A detection limit of 200 zeptomole for verapamil was demonstrated.

Coffinier, Yannick; Szunerits, Sabine; Drobecq, Hervé; Melnyk, Oleg; Boukherroub, Rabah

2011-12-01

206

Diamond Wars? Conflict Diamonds and Geographies of Resource Wars  

Microsoft Academic Search

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

Philippe Le Billon

2008-01-01

207

Diamond radiation detectors II. CVD diamond development for radiation detectors  

SciTech Connect

Interest in radiation detectors has supplied some of the impetus for improving the electronic properties of CVD diamond. In the present discussion, we will restrict our attention to polycrystalhne CVD material. We will focus on the evolution of these materials over the past decade and the correlation of detector performance with other properties of the material.

Kania, D.R.

1997-05-16

208

Diamond cutting element in a rotating bit  

SciTech Connect

An improved tooth for use in rotating diamond bits incorporating a generally triangular prismatic polycrystalline diamond element is devised by integrally forming an oval shaped base about the tooth or element extending from the face of the rotating bit, thereby providing a lateral reinforcing collar. The diamond element is also reinforced by a tapered trailing support having a leading surface contiguous and substantially congruous with the trailing surface of the diamond element. In one embodiment, a prepad provides reinforcement or support for the leading surface of the diamond element.

Grappendorf, R. H.

1985-01-01

209

Electron Microscopy of Natural and Epitaxial Diamond  

NASA Technical Reports Server (NTRS)

Semiconducting diamond films have the potential for use as a material in which to build active electronic devices capable of operating at high temperatures or in high radiation environments. Ultimately, it is preferable to use low-defect-density single crystal diamond for device fabrication. We have previously investigated polycrystalline diamond films with transmission electron microscopy (TEM) and scanning electron microscopy (SEM), and homoepitaxial films with SEM-based techniques. This contribution describes some of our most recent observations of the microstructure of natural diamond single crystals and homoepitaxial diamond thin films using TEM.

Posthill, J. B.; George, T.; Malta, D. P.; Humphreys, T. P.; Rudder, R. A.; Hudson, G. C.; Thomas, R. E.; Markunas, R. J.

1993-01-01

210

Microinclusions in polycrystalline diamonds: insights into processes of diamond formation  

NASA Astrophysics Data System (ADS)

Polycrystalline diamond aggregates (framesites) contain silicates of eclogitic and peridotitic affinity (e.g. Kurat and Dobosi, 2000). The minerals occur mostly in interstices and are intimately intergrown with the diamonds, indicating contemporaneous crystallization within the diamond stability field in the Earth's mantle. In addition to silicates, rarer phases such as Fe-carbide can sometimes be found in framesites that record unusually low local oxygen fugacity at the time of their formation (Jacob et al., 2004). Furthermore, while most gem-sized diamonds have old, often Archaean formation ages, some polycrystalline diamond aggregates have been shown to form directly preceding the kimberlite eruption (Jacob et al., 2000). Thus, these samples may provide a unique source of information on the nature and timing of small scale processes that lead to diamond formation and complement evidence from gem-sized diamonds. Here, we present a study of micro- and nano-inclusions in diamonds from a polycrystalline diamond aggregate (framesite) from the Orapa Mine (Botswana) and combine results from TEM/FIB analyses with high-resolution computerized micro-tomography (HR-µCT) and electron microprobe analyses to further constrain the formation of diamond in the Earth's mantle. Results In total, 14 microinclusions from fifteen FIB foils were investigated. Micro- and nano-inclusions identified by TEM were smaller than 1µm down to ca. 50nm in size, and are both monomineralic and multi-phase. The cavities are often lath-shaped and oriented parallel to each other; many show lattice dislocations in the surrounding diamond. In addition, inclusions are found along open cracks within the diamond single crystals. Mineral phases in the microinclusions comprise rutile, omphacite and a FeS phase (pyrrhotite). The multiphase inclusions most often consist of cavities that are only partly occupied (less than 50% of the total space), suggesting that the empty space was originally filled by a fluid. One multiphase inclusion was found to be still fluid-bearing, showing characteristic continuous changes in diffraction contrast due to density fluctuations caused by the electron beam. No other elements than carbon were detected during AEM of this area which suggests that the fluid consists of relatively pure C-H-O species. In addition to the fluid, this inclusion contained fine-grained FeS, a silicate phase rich in Fe, P, Mg, Al, Ca and K and a quench phase, rich in Fe, P and Si. Macroinclusions (>5µm) are magnetite, often surrounded by hematite, FeS, low-Cr garnet (Py50Alm39Grs11) and omphacite (Jd23). Garnet and cpx were found as non-touching inclusions and yield 1256°C at 5 GPa. Most of the magnetite inclusions are single crystals and some are strongly deformed with signs of recrystallization. Hematite occurs as porous aggregates of nano-granules of ca. 5-7 nm sizes. High Resolution µ-Computer Tomography (HR-µCT) shows pores in the sample and the included mineral phases as areas of differing grey-values. These are a direct function of the specific x-ray density of the specific phase and can be used to differentiate oxides and silicates. Based on the 3D tomogram, the amount of pores per total volume of the diamond plus inclusion matrix is calculated to be 0.65 vol%, while magnetite inclusions amount to 3.16 vol%. The average equivalent radius of the magnetite grains (radius of a sphere with the same volume as the grain) is 17.8 µm, while that of the pores is 12.6µm. Discussion The occurrence of omphacite, rutile and FeS as microinclusions within the diamond crystals clearly shows that these phases are cogenetic to the diamonds. However, magnetite and hematite were only encountered as large inclusions in cavities that appear to be interstitial porosity. Moreover, analysis of the equivalent radius distribution of the pores and the magnetite inclusions derived from HR-µCT shows a complete overlap of the mode, indicating that magnetite preferentially fills the porosity in the sample. Furthermore, hematite occurs exclusively along the outer rim of

Jacob, D. E.; Wirth, R.; Enzmann, F.; Schwarz, J. O.; Kronz, A.

2009-04-01

211

Valleytronics: Electrons dance in diamond  

NASA Astrophysics Data System (ADS)

In addition to manipulating the charge or spin of electrons, another way to control electric current is by using the 'valley' degree-of-freedom of electrons. The first demonstration of the generation, transport and detection of valley-polarized electrons in bulk diamond now opens up new opportunities for quantum control in electronic devices.

Nebel, Christoph E.

2013-08-01

212

OH and H2O of garnets in diamond-bearing and diamond-free garnet-clinopyroxene rocks from the Kumdy-kol area, Kokchetav Massif  

NASA Astrophysics Data System (ADS)

Garnet-clinopyroxene (Grt-Cpx) rocks consisting mainly of Grt + Na-poor Cpx + calcite with various proportions, occur in the Kumdy-kol area. Diamond-bearing Grt-Cpx rock was first reported by Sobolev and Shatsky (1990) and has been well-known as one of the Kokchetav diamond-bearing rocks. UHP evidence, e.g., coesite exsolution from supersilicic titanite, was discovered also in the diamond-free Grt-Cpx rock (Inoue and Ogasawara, 2003). Presence/lack of diamond in Grt-Cpx rocks is one of important features to understand the stability of diamond in the Kokchetav UHP calcsilicate and carbonate rocks. We focused on OH and H2O in garnets in two types of Grt-Cpx rock to clarify fluid conditions during UHP metamorphism. One of the samples, the diamond-bearing Grt-Cpx rock (sample no. 25018; provided by Prof. H.-P. Schertl) is composed of two monomineralic layers, Grt-layer and Cpx-layer, with minor amounts of rutile and calcite. Coarse-grained diamond (up to 0.15 mm across) is included in garnet. Another Grt-Cpx rock, diamond-free one (sample no. XX16) shows a glanoblastic texture, and consists of Grt (30 %) + Cpx (30 %) + calcite (30 %) × titanite (5 %) with exsolved coesite-needles and plates. The precursor supersilicic compositions of titanite indicate six-coordinated Si at UHP conditions (Ogasawara et al, 2002; Sakamaki and Ogasawara, IGR in press). To understand the fluid environments during the formation of these two calcsilicate rocks, we chose garnets and conducted micro FT-IR spectroscopy. IR spectra of garnets in the diamond-bearing Grt-Cpx rock showed OH bands at 3430 and 3570 cm-1, sometimes with a week band at 3675 cm-1. The absorption band at 3570 cm-1 is the strongest and is sharp, whereas the band at 3430 cm-1 is broad. IR spectra of garnets in diamond-free one show strong OH bands at 3400 and 3555 cm-1, sometimes with week bands at 3590 and 3640 cm-1. The OH band at 3555 cm-1 is the strongest and is sharp, whereas the band at 3400 cm-1 is broad. IR analyses of garnets in the Grt-Cpx rocks show bimodal spectra; the relatively sharp band at ~3550 cm-1 and the broad band at ~3400 cm-1. The former band is attributed to OH in garnet structure and the latter one molecular H2O. The similar bimodal spectra were obtained from garnet in diamond-bearing dolomite marble. When we regard the total absorption at the range of 3100-3750 cm-1 as structural OH, the garnets in diamond-bearing Grt-Cpx rock contain 797 to 2506 ppm wt. H2O, and those in the diamond-free Grt-Cpx rock contain 679 to 2169 ppm wt. H2O. To evaluate the absorption spectra of the garnets in the Grt-Cpx rocks, we analyzed the garnet of different origin, Cr- and pyrope-rich garnet in mantle peridotite from the Garnet Ridge, northern Arizona. This peridotitic garnet shows a single-modal absorption band of OH at 3575 cm-1. No molecular H2O band was detected. Such results suggest that the environment during Kokchetav UHP metamorphism of calcsilicate may be saturated in H2O in contrast with the peridotitic garnet from the Garnet Ridge. The molecular H2O in the garnets of the Kokchetav Grt-Cpx rocks probably is submicron fluid inclusions trapped during UHP metamorphism. We thank Prof. H.-P. Schertl for providing us a very precious sample, diamond-bearing garnet-clinopyroxene rock.

Sakamaki, K.; Ogasawara, Y.

2013-12-01

213

High-temperature optical scatter characteristics of CVD diamond and natural type IIa diamond  

NASA Astrophysics Data System (ADS)

In support of Strategic Defense Initiative Organization objectives to develop optical quality chemical vapor deposition (CVD) diamond windows, the infrared optical scatter characteristics of thin, polished, free-standing CVD and natural type IIa diamond films were measured at room temperature and 500 degree(s)C. The CVD diamond scatter characteristics are compared with those of the natural type IIa diamond of similar thickness at identical temperature. The diamond samples were about 10 to 30 mm in size and 250 to 500 micrometers in thickness. The diamond samples were provided by various manufacturers and laboratories both in the United States and abroad.

McIntosh, Malcolm B.; McNeely, Joseph R.; Clausing, Robert E.; Snyder, William B., Jr.

1993-12-01

214

Microstructure and tribological performance of self-lubricating diamond/tetrahedral amorphous carbon composite film  

NASA Astrophysics Data System (ADS)

In order to smooth the rough surface and further improve the wear-resistance of coarse chemical vapor deposition diamond films, diamond/tetrahedral amorphous carbon composite films were synthesized by a two-step preparation technique including hot-filament chemical vapor deposition for polycrystalline diamond (PCD) and subsequent filtered cathodic vacuum arc growth for tetrahedral amorphous carbon (ta-C). The microstructure and tribological performance of the composite films were investigated by means of various characterization techniques. The results indicated that the composite films consisted of a thick well-grained diamond base layer with a thickness up to 150 ?m and a thin covering ta-C layer with a thickness of about 0.3 ?m, and sp3-C fraction up to 73.93%. Deposition of a smooth ta-C film on coarse polycrystalline diamond films was proved to be an effective tool to lower the surface roughness of the polycrystalline diamond film. The wear-resistance of the diamond film was also enhanced by the self-lubricating effect of the covering ta-C film due to graphitic phase transformation. Under dry pin-on-disk wear test against Si3N4 ball, the friction coefficients of the composite films were much lower than that of the single PCD film. An extremely low friction coefficient (?0.05) was achieved for the PCD/ta-C composite film. Moreover, the addition of Ti interlayer between the ta-C and the PCD layers can further reduce the surface roughness of the composite film. The main wear mechanism of the composite films was abrasive wear.

Chen, Xinchun; Peng, Zhijian; Yu, Xiang; Fu, Zhiqiang; Yue, Wen; Wang, Chengbiao

2011-02-01

215

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

NASA Astrophysics Data System (ADS)

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.

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

2011-12-01

216

Large area graphene layer synthesis  

Microsoft Academic Search

The large area graphene layer is synthesized by a conventional metal melting method (MMM). And we use the mechanism of diamond synthesis in liquid phase and produced graphene of about 5 ?? 7 cm2. This promising process appears scalable for making device-sized graphene in the near future. This paper also presented many intriguing aspects related to the growth of large

Kuen-Liang Chang; Kai-Hung Hsu; Chien-Min Sung; Ting-Ying Wu

2010-01-01

217

Laser diagnostics of CVD diamond film growth  

SciTech Connect

Diamond has one of hte most exciting combinations of properties known.{sup 1} It is the hardest material known, has extremely high thermal conductivity, wide optical transparency, and a durability that is unmatched by other substances. The scarcity and high cost of natural diamond has precluded its use in many potential applications that would benefit from this unique combination of properties. Over the last two decades, the technique of chemical vapor deposition (CVD) of diamond at low pressure has been developed, providing the technology to produce thin and thick film coatings on a variety of materials as well as freestanding films and plates of diamond. High optical clarity diamond plates grown by the CVD method are now available in diameters that exceed that of the largest natural diamond ever found. Products spanning from diamond coated machine t{sq_bullet}oling to semiconducting diamond-based electronics have been developed using this technology. Recent estimates suggest that the global market for chemical vapor deposited diamond and diamond-like carbon films will reach {dollar_sign}1 billion by 2000.

Feigerle, C.S.; Shaw, R.W.

1996-05-01

218

Medical applications of diamond particles and surfaces.  

SciTech Connect

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).

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

2011-04-01

219

Diamond and Related Materials, 3 (1994) 939-941 939 CVD diamond growth on germanium for IR window applications  

E-print Network

of a means to produce thin films of Diamond deposition was performed in a hot-filament diamond by chemical and optical components [3, 4]. CVD diamond standard cm3 min 1 and a pressure of 30 Torr. A Ta can be usedDiamond and Related Materials, 3 (1994) 939-941 939 CVD diamond growth on germanium for IR window

Bristol, University of

220

Strains and cracks in undoped and phosphorus-doped {111} homoepitaxial diamond films  

NASA Astrophysics Data System (ADS)

Undoped and phosphorus-doped diamond thin films grown by Microwave Plasma-enhanced Chemical Vapour Deposition (MPCVD) on Ib {111}-oriented diamond substrates have been studied by confocal micro-Raman spectroscopy and confocal Raman imaging. A distinct Raman peak, broader and 6 cm-1 lower than the zone-centre optical phonon line of the substrate, was nearly systematically detected showing that in most cases the homoepitaxial layers were under an intense tensile strain. The magnitude of this strain increased with deposited thickness. In the thicker films, it was further observed that a network of oriented cracks could relieve the internal stress. These results suggest that tensile strain is a general feature of defective {111}-oriented CVD diamond homoepitaxial layers. (

Tajani, A.; Mermoux, M.; Marcus, B.; Bustarret, E.; Gheeraert, E.; Koizumi, S.

2003-09-01

221

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

SciTech Connect

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.

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

222

A novel method of fabricating ZnO\\/diamond\\/Si multilayers for surface acoustic wave (SAW) device applications  

Microsoft Academic Search

A novel process for fabricating ZnO\\/diamond\\/Si for a surface acoustic wave device is as follows: to form a trench of 10 ?m in depth, the Si wafer is chemically etched by employing the SiO2 layer as a mask. Selective growth of polycrystalline diamond film is carried out by a microwave plasma CVD using nominal conditions of 700 W microwave power,

Soo-Hyung Seo; Wan-Chul Shin; Jin-Seok Park

2002-01-01

223

Nanodiamonds in the Younger Dryas boundary sediment layer.  

PubMed

We report abundant nanodiamonds in sediments dating to 12.9 +/- 0.1 thousand calendar years before the present at multiple locations across North America. Selected area electron diffraction patterns reveal two diamond allotropes in this boundary layer but not above or below that interval. Cubic diamonds form under high temperature-pressure regimes, and n-diamonds also require extraordinary conditions, well outside the range of Earth's typical surficial processes but common to cosmic impacts. N-diamond concentrations range from approximately 10 to 3700 parts per billion by weight, comparable to amounts found in known impact layers. These diamonds provide strong evidence for Earth's collision with a rare swarm of carbonaceous chondrites or comets at the onset of the Younger Dryas cool interval, producing multiple airbursts and possible surface impacts, with severe repercussions for plants, animals, and humans in North America. PMID:19119227

Kennett, D J; Kennett, J P; West, A; Mercer, C; Hee, S S Que; Bement, L; Bunch, T E; Sellers, M; Wolbach, W S

2009-01-01

224

Characterization of hypervelocity impact craters on chemical vapour-deposited diamond and diamond- like carbon films  

Microsoft Academic Search

Microwave plasma chemical vapour-deposited (CVD) process has been used to grow polycrystalline diamond films over silicon substrates. Diamond-like carbon (DLC) thin films were grown over silicon substrates using a microwave plasma disc reactor. Reactant gases of CH4 and H2 were used in both CVD processes. Some preliminary feasibility tests were performed on the possible applicability of diamond and diamond-like carbon

R. R AMESHAM; S. BEST; M. F. R OSE; M. CRUMPLER

225

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

Microsoft Academic Search

Densifying non-mined diamond powder precursors with diamond produced by chemical vapor infiltration (CVI) is an attractive approach for forming thick diamond deposits that avoids many potential manufacturability problems associated with predominantly chemical vapor deposition (CVD) processes. The authors developed techniques for forming diamond powder precursors and densified these precursors in a hot filament-assisted reactor and a microwave plasma-assisted reactor. Densification

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

1995-01-01

226

Cosmogenic 10Be in Zaire alluvial diamonds: implications for 3He contents of diamonds  

Microsoft Academic Search

To determine the amounts of cosmic-ray produced ('cosmogenic') 3He which could be created in diamonds during their post-eruptive residence in near-surface regions, we have measured the concentration of 10Be (half life, 1.6 Myr) in an industrial diamond sample. The motivation to study cosmogenic 3He in diamonds comes from the recent observations1,2 of 3He\\/4He ratios in some diamonds that are even

D. Lal; K. Nishiizumi; J. Klein; R. Middleton; H. Craig

1987-01-01

227

High-temperature optical scatter characteristics of CVD diamond and natural type IIa diamond  

Microsoft Academic Search

In support of Strategic Defense Initiative Organization objectives to develop optical quality chemical vapor deposition (CVD) diamond windows, the infrared optical scatter characteristics of thin, polished, free-standing CVD and natural type IIa diamond films were measured at room temperature and 500 degree(s)C. The CVD diamond scatter characteristics are compared with those of the natural type IIa diamond of similar thickness

Malcolm B. McIntosh; Joseph R. McNeely; Robert E. Clausing; William B. Snyder

1993-01-01

228

Coordinating diamond interchange and arterial street signal control  

E-print Network

In urban areas, diamond interchanges are often located on arterial streets. There are significant functional differences between diamond interchanges and arterial streets, as arterial streets serve mainly through traffic, while diamond interchanges...

Engelbrecht, Roelof Johannes

2012-06-07

229

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

NASA Astrophysics Data System (ADS)

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

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

2013-10-01

230

Diamond turning machine controller implementation  

SciTech Connect

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.

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

1988-12-01

231

TSP diamonds open new potential for bits  

SciTech Connect

The maximum performance potential of a one-piece bit in a given formation is, to a large degree, dependent upon the size, shape and quality of the diamond material used in the bit's cutting structure. The introduction of a thermally stable polycrystalline (TSP) diamond has opened new potential for one-piece bits, and offered fresh challenges in the determination of how this material is to be best employed. This article describes the advantages of the TSP diamond.

King, W.W.

1986-04-01

232

Mineral resource of the month: diamond  

USGS Publications Warehouse

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

Olson, Donald W.

2009-01-01

233

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

Microsoft Academic Search

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

Alison Mainwood; Mark E. Newton; Marshall Stoneham

2009-01-01

234

The carbon isotopic composition of diamonds: relationship to diamond shape, color, occurrence and vapor composition  

Microsoft Academic Search

Three hundred and thirty new 13 C analyses of diamonds are presented, indicating, in conjunction with earlier published work, a range of about 30%. in the carbon isotopic composition of diamonds. The frequency distribution of diamond 13 C analyses shows a very pronounced mode at -5 to -6%.vs PDB, a large negative skewness, and a sharp boundary at about -1%..

Peter Deines

1980-01-01

235

Kankan diamonds (Guinea) III: delta13C and nitrogen characteristics of deep diamonds  

Microsoft Academic Search

Diamonds from the Kankan area in Guinea formed over a large depth profile beginning within the cratonic mantle lithosphere and extending through the asthenosphere and transition zone into the lower mantle. The carbon isotopic composition, the concentration of nitrogen impurities and the nitrogen aggregation level of diamonds representing this entire depth range have been determined. Peridotitic and eclogitic diamonds of

T. Stachel; J. W. Harris; S. Aulbach; P. Deines

2001-01-01

236

Kankan diamonds (Guinea) III: d 13 C and nitrogen characteristics of deep diamonds  

Microsoft Academic Search

Diamonds from the Kankan area in Guinea formed over a large depth profile beginning within the cratonic mantle lithosphere and extending through the asthenosphere and transition zone into the lower mantle. The carbon isotopic composition, the concentration of nitrogen impurities and the nitrogen aggregation level of diamonds representing this entire depth range have been determined. Peridotitic and eclogitic diamonds of

T. Stachel; J. Harris; S. Aulbach; P. Deines

2002-01-01

237

Shock compression of diamond crystal  

Microsoft Academic Search

Two shock wave experiments employing inclined mirrors have been carrried out to determine the Hugoniot elastic limit (HEL), final shock state at 191 and 217 GPa, and the post-shock state of diamond crystal, which is shock-compressed along the intermediate direction between the and crystallographic axes. The HEL wave has a velocity of 19.9+\\/-0.3 mm\\/musec and an amplitude of 63+\\/-28 GPa.

Ken-ichi Kondo; Thomas J. Ahrens

1983-01-01

238

Diamond turning of thermoplastic polymers  

SciTech Connect

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.

Smith, E.; Scattergood, R.O.

1988-12-01

239

Direct Coating of Nanocrystalline Diamond on Steel  

NASA Astrophysics Data System (ADS)

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

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

2012-09-01

240

Electromagnetic Radiation Hardness of Diamond Detectors  

E-print Network

The behavior of artificially grown CVD diamond films under intense electromagnetic radiation has been studied. The properties of irradiated diamond samples have been investigated using the method of thermally stimulated current and by studying their charge collection properties. Diamonds have been found to remain unaffected after doses of 6.8 MGy of 10 keV photons and 10 MGy of MeV-range photons. This observation makes diamond an attractive detector material for a calorimeter in the very forward region of the proposed TESLA detector.

T. Behnke; M. Doucet; N. Ghodbane; A. Imhof; C. Martinez; W. Zeuner

2001-08-22

241

Electromagnetic Radiation Hardness of Diamond Detectors  

E-print Network

The behavior of artificially grown CVD diamond films under intense electromagnetic radiation has been studied. The properties of irradiated diamond samples have been investigated using the method of thermally stimulated current and by studying their charge collection properties. Diamonds have been found to remain unaffected after doses of 6.8 MGy of 10 keV photons and 10 MGy of MeV-range photons. This observation makes diamond an attractive detector material for a calorimeter in the very forward region of the proposed TESLA detector.

Behnke, T; Ghodbane, N; Imhof, A; Martínez, C; Zeuner, W

2002-01-01

242

Negative Electron Affinity Mechanism for Diamond Surfaces  

NASA Technical Reports Server (NTRS)

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

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

1998-01-01

243

(Chemically vapor deposited diamond films)  

SciTech Connect

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.

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

1990-09-22

244

Diamonds and their mineral inclusions from the A154 South pipe, Diavik Diamond Mine, Northwest territories, Canada  

Microsoft Academic Search

Mineral inclusions recovered from 100 diamonds from the A154 South kimberlite (Diavik Diamond Mines, Central Slave Craton, Canada) indicate largely peridotitic diamond sources (83%), with a minor (12%) eclogitic component. Inclusions of ferropericlase (4%) and diamond in diamond (1%) represent “undetermined” parageneses.Compared to inclusions in diamonds from the Kaapvaal Craton, overall higher CaO contents (2.6 to 6.0 wt.%) of harzburgitic garnets

Cara L. Donnelly; Thomas Stachel; Steven Creighton; Karlis Muehlenbachs; Sean Whiteford

2007-01-01

245

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

Microsoft Academic Search

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

Masanori Yoshikawa; Fuminori Okuzumi

1997-01-01

246

High crystalline quality single crystal chemical vapour deposition diamond.  

PubMed

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. ?111? sectors contain the highest concentration of both stacking faults and dislocations but ?100? 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. PMID:21832311

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

247

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

NASA Astrophysics Data System (ADS)

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

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

2009-09-01

248

Growth of diamond on diamond substrates in presence of an alkali and metal under hydrothermal conditions  

SciTech Connect

Evidence of diamond growth was observed on a type II-A single crystal diamond in the hydrothermal pressure-temperature regime (1.4 kbars at 800 C) in which both NaOH and Ni were added. The features seen in the SEM appear to be randomly oriented overgrowths ranging in size from 2--5 {micro}m on the surface of a single crystal diamond. The Raman spectrum with the beam focused on these overgrown crystallites showed a sharp band at 1331 cm{sup {minus}1}, providing further evidence of diamond growth on a single crystal diamond under pressure-temperature hydrothermal conditions.

Ravichandran, D.; Roy, R. [Pennsylvania State Univ., University Park, PA (United States). Materials Research Lab.] [Pennsylvania State Univ., University Park, PA (United States). Materials Research Lab.

1996-09-01

249

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

SciTech Connect

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

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

1993-12-31

250

Formation of diamond in the Earth's mantle.  

PubMed

The principal sources of natural diamonds are peridotitic (about 2/3 of diamonds) and eclogitic (1/3) domains located at 140-200 km depth in the subcratonic lithospheric mantle. There, diamonds probably form during redox reactions in the presence of melt (likely for eclogitic and lherzolitic diamonds) or under subsolidus conditions in the presence of CHO fluids (likely for harzburgitic diamonds). Co-variations of ?(13)C and the nitrogen content of diamonds suggest that two modes of formation may have been operational in peridotitic sources: (1) reduction of carbonates, that during closed system fractionation drives diamond compositions to higher ?(13)C values and lower nitrogen concentrations and (2) oxidation of methane, that in a closed system leads to a trend of decreasing ?(13)C with decreasing nitrogen. The present day redox state of subcratonic lithospheric mantle is generally too reduced to allow for methane oxidation to be a widespread process. Therefore, reduction of carbonate dissolved in melts and fluids is likely the dominant mode of diamond formation for the Phanerozoic (545 Ma-present) and Proterozoic (2.5 Ga-545 Ma). Model calculations indicate, however, that for predominantly Paleoarchean (3.6-3.2 Ga) to Mesoarchean (3.2-2.8 Ga) harzburgitic diamonds, methane reduction is the principal mode of precipitation. This suggests that the reduced present day character (oxygen fugacity below carbonate stability) of peridotitic diamond sources may be a secondary feature, possibly acquired during reducing Archean (>2.5 Ga) metasomatism. Recycling of biogenic carbonates back into the mantle through subduction only became an important process in the Paleoproterozoic (2.5-1.6 Ga) and diamonds forming during carbonate reduction, therefore, may predominantly be post-Archean in age. For eclogitic diamonds, open system fractionation processes involving separation of a CO(2) fluid appear to dominate, but in principal the same two modes of formation (methane oxidation, carbonate reduction) may have operated. Direct conversion of graphitized subducted organic matter is not considered to be an important process for the formation of eclogitic diamonds. The possible derivation of (12)C enriched carbon in eclogitic diamonds from remobilized former organic matter is, however, feasible in some cases and seems likely involved, for example, in the formation of sublithospheric eclogitic diamonds from the former Jagersfontein Mine (South Africa). PMID:21832312

Stachel, Thomas; Harris, Jeff W

2009-09-01

251

Formation of diamond in the Earth's mantle  

NASA Astrophysics Data System (ADS)

The principal sources of natural diamonds are peridotitic (about 2/3 of diamonds) and eclogitic (1/3) domains located at 140-200 km depth in the subcratonic lithospheric mantle. There, diamonds probably form during redox reactions in the presence of melt (likely for eclogitic and lherzolitic diamonds) or under subsolidus conditions in the presence of CHO fluids (likely for harzburgitic diamonds). Co-variations of ?13C and the nitrogen content of diamonds suggest that two modes of formation may have been operational in peridotitic sources: (1) reduction of carbonates, that during closed system fractionation drives diamond compositions to higher ?13C values and lower nitrogen concentrations and (2) oxidation of methane, that in a closed system leads to a trend of decreasing ?13C with decreasing nitrogen. The present day redox state of subcratonic lithospheric mantle is generally too reduced to allow for methane oxidation to be a widespread process. Therefore, reduction of carbonate dissolved in melts and fluids is likely the dominant mode of diamond formation for the Phanerozoic (545 Ma-present) and Proterozoic (2.5 Ga-545 Ma). Model calculations indicate, however, that for predominantly Paleoarchean (3.6-3.2 Ga) to Mesoarchean (3.2-2.8 Ga) harzburgitic diamonds, methane reduction is the principal mode of precipitation. This suggests that the reduced present day character (oxygen fugacity below carbonate stability) of peridotitic diamond sources may be a secondary feature, possibly acquired during reducing Archean (>2.5 Ga) metasomatism. Recycling of biogenic carbonates back into the mantle through subduction only became an important process in the Paleoproterozoic (2.5-1.6 Ga) and diamonds forming during carbonate reduction, therefore, may predominantly be post-Archean in age. For eclogitic diamonds, open system fractionation processes involving separation of a CO2 fluid appear to dominate, but in principal the same two modes of formation (methane oxidation, carbonate reduction) may have operated. Direct conversion of graphitized subducted organic matter is not considered to be an important process for the formation of eclogitic diamonds. The possible derivation of 12C enriched carbon in eclogitic diamonds from remobilized former organic matter is, however, feasible in some cases and seems likely involved, for example, in the formation of sublithospheric eclogitic diamonds from the former Jagersfontein Mine (South Africa).

Stachel, Thomas; Harris, Jeff W.

2009-09-01

252

Method and apparatus for making diamond-like carbon films  

DOEpatents

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.

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

2008-12-02

253

Fluorinated diamond bonded in fluorocarbon resin  

SciTech Connect

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.

Taylor, Gene W. (Los Alamos, NM)

1982-01-01

254

Fluorinated diamond bonded in fluorocarbon resin  

SciTech Connect

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.

Taylor, G.W.

1982-08-10

255

Double bevel construction of a diamond anvil  

DOEpatents

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

Moss, W.C.

1988-10-11

256

Fracture of synthetic diamond M. D. Droty  

E-print Network

Fracture of synthetic diamond M. D. Droty Ctystallume, 3506 Bassett Street, Santa Clara, California 1995) The fracture behavior of synthetic diamond has been investigated using indentation methods and by the tensile testing of pre-notched fracture-mechanics type samples. Specifically, the fracture toughness

Ritchie, Robert

257

Recent Results on Diamond Radiation Tolerance  

E-print Network

of the FLUKA DPA model to diamond in the radiation regime relevant to the LHC § Measurement of the response #12;The CERN RD42 Collaboration is studying the ability of FLUKA DPA to describe damage in diamond for a range of beam types and energies. FLUKA* is a MC package that provides a general tool for calculations

Seidel, Sally

258

Mining Frequent Diamond Episodes from Event Sequences  

Microsoft Academic Search

In this paper, we introduce a diamond episode of the form s1 ?? E ?? s2 ,w heres1 and s2 are events and E is a set of events. The diamond episode s1 ?? E ?? s2 means that every event of E follows an event s1 and is followed by an event s2. Then, by formulating the support of

Takashi Katoh; Kouichi Hirata; Masateru Harao

2007-01-01

259

Energy Harvesting Diamond Channel with Energy Cooperation  

E-print Network

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

Ulukus, Sennur

260

GEOMETRIC MEASUREMENT COMPARISONS FOR ROCKWELL DIAMOND INDENTERS  

Microsoft Academic Search

In the uncertainty budget of Rockwell C hardness (HRC) tests, geometric error of the Rockwell diamond indenter is a major contributor. The geometric calibration of Rockwell diamond indenters has been a key issue for Rockwell hardness standardization. The National Institute of Standards and Technology (NIST) developed a microform calibration system based on a stylus instrument for the geometric calibration of

John Song; Samuel Low; Alan Zheng

261

Tolerancing Form Deviations for Rockwell Diamond Indenters  

Microsoft Academic Search

The form deviations of Rockwell diamond indenters can cause significant differences in Rockwell hardness readings. In order to control that effect, tolerances for form error deviations of Rockwell diamond indenters have been specified in both the American Society of Testing and Materials (ASTM) and the International Organization for Standardization (ISO) standards. In this paper, experimental data on the effects of

J. F. Song; L. Ma

2002-01-01

262

Laser diagnostics of CVD diamond film growth  

Microsoft Academic Search

Diamond has one of hte most exciting combinations of properties known.¹ It is the hardest material known, has extremely high thermal conductivity, wide optical transparency, and a durability that is unmatched by other substances. The scarcity and high cost of natural diamond has precluded its use in many potential applications that would benefit from this unique combination of properties. Over

Charles S. Feigerle; Robert W. Shaw

1996-01-01

263

Spectroscopic Mode Gruneisen Parameters for Diamond  

Microsoft Academic Search

Room temperature measurements are reported of the first and second order Raman spectra of diamond in the hydrostatic pressure range 0-2.4 GPa. Values calculated from the data for the optic mode Gruneisen parameters have been fitted in terms of a simple lattice dynamical model for diamond involving volume dependent interatomic forces. The interpolated set of mode Gruneisen parameters are shown

B. J. Parsons

1977-01-01

264

The microstructural design of diamond cutting tools  

Microsoft Academic Search

The use of diamond tools has, over recent years, become widely accepted as the most economical method of processing natural stone. The ever-increasing pressure for higher production rates and better surface textures in finished stone products has resulted in diamond cutting becoming one of the major growth areas in the stone industry of Turkey. In this study, a general defect

?adi Karagöz; Muzaffer Zeren

2001-01-01

265

High-voltage diamond Schottky rectifiers  

Microsoft Academic Search

In this paper, we simulate and fabricate diamond Schottky rectifiers. The growth rate of pure diamond single crystal epitaxial is from 0.5 up to 100?m\\/hr with boron doping concentration around 1×1014 cm-3 to 1×1016 cm-3. A \\

W. Huang; T. P. Chow; J. Yang; J. E. Butler

2004-01-01

266

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

PubMed Central

Detailed analysis of a band diagram of a photonic crystal (PhC) slab prepared on a nano-diamond layer is presented. Even though the PhC is structurally imperfect, the existence of leaky modes, determined both theoretically and experimentally in the broad spectral region, implies that an efficient light interaction with a material periodicity occurs in the sample. It is shown that the luminescence emission spectrum of a light source placed directly on the PhC surface can be modified by employing the optical modes of the studied structure. We stress also the impact of intrinsic optical losses of the nano-diamond on this modification. PMID:23209874

Ondic, Lukas; Babchenko, Oleg; Varga, Marian; Kromka, Alexander; Ctyroky, Jiri; Pelant, Ivan

2012-01-01

267

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

NASA Astrophysics Data System (ADS)

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

Ondi?, Lukáš; Babchenko, Oleg; Varga, Marián; Kromka, Alexander; ?tyroký, Ji?í; Pelant, Ivan

2012-12-01

268

Hot-filament chemical vapor deposition of amorphous carbon film on diamond grits and induction brazing of the diamond grits  

NASA Astrophysics Data System (ADS)

The production of a high-quality brazed diamond tool has gradually drawn the attention of the tool industry. Hot-filament chemical vapor deposition (CVD) of amorphous carbon film on diamond grits was conducted. The deposited diamond grits were used to make brazed diamond tools by induction heating. Amorphous carbon film (1-2 ?m thick) was deposited onto the diamond surface. The diamond grits protruding from the filler alloy maintain their sharpness after induction brazing of the deposited diamond grits. Discontinuous irregular carbides are distributed evenly on the brazed diamond surface in the filler alloy. This considerably enhances the bonding strength between the filler alloy and diamond grits. Grinding tests of the brazed diamond wheels show a low percentage of pullouts from the matrix and whole grain fracture for the deposited diamond grits brazed by induction heating.

Ma, Bojiang; Yu, Qingxian

2012-03-01

269

Diamond\\/CdTe: a new inverted heterojunction CdTe thin film solar cell  

Microsoft Academic Search

Recently the concept of the inverted photovoltaic cell has become more attainable as a practical cell. This thin film cell consists of a p–n heterojunction in which the window layer is p-type and the absorber layer is n-type. The feasibility of a new inverted p–n heterojunction p-diamond\\/n-CdTe solar cell has been demonstrated. The non-optimized solar cell structure grown on semi-transparent

Palle von Huth; James E. Butler; Reshef Tenne

2001-01-01

270

Hypervelocity impact tests on polycrystalline diamond deposited over silicon substrates  

Microsoft Academic Search

The microwave plasma-assisted chemical vapor deposition (CVD) technique has been used to grow a polycrystalline diamond thin film over silicon substrate. Reactant gases of methane and hydrogen were used in the diamond CVD process. We have performed a feasibility test on the possible applicability of diamond and diamond-like carbon thin films for space protective applications against artificially simulated hypervelocity impact

R. Ramesham; D. C. Hill; S. R. Best; M. F. Rose; R. F. Askew; V. M. Ayres

1995-01-01

271

Fracture toughness and thermal resistance of polycrystalline diamond compacts  

Microsoft Academic Search

Polycrystalline diamond compacts (PCD) are being used increasingly for oil and gas drilling and in machining of ceramics and hard non-ferrous materials. Average diamond grain size and its distribution are used as one of the means to tailor properties of PCD compacts. The diamond sintering process requires use of a tungsten carbide cobalt disc placed onto diamond powder followed by

D. Miess; G. Rai

1996-01-01

272

COMPUTER SIMULATION OF THE NUCLEATION OF DIAMOND FROM  

E-print Network

of symbols 2 1 Introduction 4 2 Diamond and other allotropes of carbon 6 2.1 The structure of diamondCOMPUTER SIMULATION OF THE NUCLEATION OF DIAMOND FROM LIQUID CARBON UNDER EXTREME PRESSURES ANASTASSIA SORKIN #12;COMPUTER SIMULATION OF THE NUCLEATION OF DIAMOND FROM LIQUID CARBON UNDER EXTREME

Adler, Joan

273

Grade-tonnage and other models for diamond kimberlite pipes  

Microsoft Academic Search

Grade-tonnage and other quantitative models help give reasonable answers to questions about diamond kimberlite pipes. Diamond kimberlite pipes are those diamondiferous kimberlite pipes that either have been worked or are expected to be worked for diamonds. These models are not applicable to kimberlite dikes and sills or to lamproite pipes. Diamond kimberlite pipes contain a median 26 million metric tons

James D. Bliss

1992-01-01

274

Diamond Provenance Through Shape, Colour, Surface Features and Value  

Microsoft Academic Search

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

J. Harris

2002-01-01

275

Two-step process for improved diamond deposition on titanium alloys at moderate temperature  

NASA Astrophysics Data System (ADS)

A simple two-step process is reported here to deposit diamond coatings on titanium alloys at temperatures equal to or lower than 600 °C. The first step allows us to increase the carbon nucleation rate and to deposit a sacrificial layer which contains more than about 25% sp2 carbon. Its thickness is selected both to limit the interaction of titanium element with the plasmas used for diamond growth during all the second step, even when an oxygen-containing mixture is used, and to diffuse completely at the end of the process. After the first step, the formation of titanium carbide is observed by x-ray diffraction and x-ray photoelectron spectroscopy, which does not reveal any oxygen incorporation in the coating-substrate interfacial region. These results are related to the final strong diamond adherence.

Vandenbulcke, L.; Rats, D.; De Barros, M. I.; Beno?t, R.; Erre, R.; Andreazza, P.

1998-01-01

276

Alpha-Voltaic Sources Using Diamond as Conversion Medium  

NASA Technical Reports Server (NTRS)

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).

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

2006-01-01

277

Diamond Detectors for Compton Polarimetry  

NASA Astrophysics Data System (ADS)

Parity-violating electron scattering experiments aim to test the standard model of particle physics through precise low-energy determinations of the weak mixing angle. These experiments require determination of the polarization of the incident electron beam to the 1% level or better. An example of this type of experiment is the Q-weak experiment, which will be conducted in Hall C at Jefferson Lab in 2010 and beyond. We are constructing a Compton polarimeter in Hall C to provide continuous monitoring of the polarization with the goal of 1% absolute polarization determination. In our Compton polarimeter, circularly polarized laser light will impinge upon the electron beam. Electrons scattered by the Compton process will be momentum-analyzed in a dipole magnet downstream of the interaction point. A diamond strip tracker will be placed further downstream of the dipole to sense the Compton-scattered electrons and determine their momenta. The design of the polarimeter, focusing on electron detection, and our progress in prototyping and constructing the diamond strip tracker, are discussed.

Martin, J. W.; Dutta, D.; Narayan, A.; Wang, P.

2009-12-01

278

Diamond Detectors for Compton Polarimetry  

SciTech Connect

Parity-violating electron scattering experiments aim to test the standard model of particle physics through precise low-energy determinations of the weak mixing angle. These experiments require determination of the polarization of the incident electron beam to the 1% level or better. An example of this type of experiment is the Q-weak experiment, which will be conducted in Hall C at Jefferson Lab in 2010 and beyond. We are constructing a Compton polarimeter in Hall C to provide continuous monitoring of the polarization with the goal of 1% absolute polarization determination. In our Compton polarimeter, circularly polarized laser light will impinge upon the electron beam. Electrons scattered by the Compton process will be momentum-analyzed in a dipole magnet downstream of the interaction point. A diamond strip tracker will be placed further downstream of the dipole to sense the Compton-scattered electrons and determine their momenta. The design of the polarimeter, focusing on electron detection, and our progress in prototyping and constructing the diamond strip tracker, are discussed.

Martin, J. W. [Physics Department, University of Winnipeg, Winnipeg, MB, R3B 2E9 (Canada); Dutta, D.; Narayan, A. [Dept. of Physics and Astronomy, Mississippi State University, Mississippi State, MS 39762-5167 (United States); Wang, P. [Department of Physics and Astronomy, University of Manitoba, Winnipeg, MB, R3T 2N2 (Canada)

2009-12-17

279

In-situ analysis of diamonds and their inclusions from the Diavik Mine, Northwest Territories, Canada: Mapping diamond growth  

Microsoft Academic Search

Results are presented here of an in-situ study of diamonds from the A154 South kimberlite pipe at the Diavik diamond mine, Northwest Territories, Canada. One hundred and ten diamonds were selected from run of mine production on the basis of morphology and visible inclusions. Diamonds that crystallized as cubes have a higher incidence of fluorescence in response to UV light

A. D. Van Rythoven; D. J. Schulze

2009-01-01

280

Diamonds and eclogites of the Jericho kimberlite (Northern Canada)  

Microsoft Academic Search

We studied diamonds and barren and diamondiferous eclogite xenoliths from the Jericho kimberlite (Northern Slave craton).\\u000a The majority of the diamonds are non-resorbed octahedral crystals, with moderately aggregated N (IaB N 13C = ?5 to ?41‰. The diamonds belong to “eclogitic” (90% of the studied samples), “websteritic” (7%) and “peridotitic” (3%)\\u000a assemblages. The Jericho diamonds differ from the majority of “eclogitic” diamonds worldwide in

Andrea De Stefano; M. G. Kopylova; P. Cartigny; V. Afanasiev

2009-01-01

281

Melting temperature of diamond at ultrahigh pressure  

NASA Astrophysics Data System (ADS)

Since Ross proposed that there might be `diamonds in the sky' in 1981 (ref. 1), the idea of significant quantities of pure carbon existing in giant planets such as Uranus and Neptune has gained both experimental and theoretical support. It is now accepted that the high-pressure, high-temperature behaviour of carbon is essential to predicting the evolution and structure of such planets. Still, one of the most defining of thermal properties for diamond, the melting temperature, has never been directly measured. This is perhaps understandable, given that diamond is thermodynamically unstable, converting to graphite before melting at ambient pressure, and tightly bonded, being the strongest bulk material known. Shock-compression experiments on diamond reported here reveal the melting temperature of carbon at pressures of 0.6-1.1TPa (6-11Mbar), and show that crystalline diamond can be stable deep inside giant planets such as Uranus and Neptune. The data indicate that diamond melts to a denser, metallic fluid-with the melting curve showing a negative Clapeyron slope-between 0.60 and 1.05TPa, in good agreement with predictions of first-principles calculations. Temperature data at still higher pressures suggest diamond melts to a complex fluid state, which dissociates at shock pressures between 1.1 and 2.5TPa (11-25Mbar) as the temperatures increase above 50,000K.

Eggert, J. H.; Hicks, D. G.; Celliers, P. M.; Bradley, D. K.; McWilliams, R. S.; Jeanloz, R.; Miller, J. E.; Boehly, T. R.; Collins, G. W.

2010-01-01

282

Cathodoluminescence of natural, plastically deformed pink diamonds.  

PubMed

The 49 type I natural pink diamonds examined exhibit color restricted to lamellae or bands oriented along {111} that are created by plastic deformation. Pink diamonds fall into two groups: (1) diamonds from Argyle in Australia and Santa Elena in Venezuela are heavily strained throughout and exhibit pink bands alternating with colorless areas, and (2) diamonds from other localities have strain localized near the discrete pink lamellae. Growth zones are highlighted by a blue cathodoluminescence (CL) and crosscut by the pink lamellae that emit yellowish-green CL that originates from the H3 center. This center probably forms by the recombination of nitrogen-related centers (A-aggregates) and vacancies mobilized by natural annealing in the Earth's mantle. Twinning is the most likely mechanism through which plastic deformation is accommodated for the two groups of diamonds. The plastic deformation creates new centers visible through spectroscopic methods, including the one responsible for the pink color, which remains unidentified. The differences in the plastic deformation features, and resulting CL properties, for the two groups might correlate to the particular geologic conditions under which the diamonds formed; those from Argyle and Santa Elena are deposits located within Proterozoic cratons, whereas most diamonds originate from Archean cratons. PMID:23217341

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

2012-12-01

283

Adhesion between CVD diamond films and tungsten  

SciTech Connect

Adhesion between diamond films synthesized by a CVD method and tungsten has been investigated by a scratch and pull testing methods. Diamond films have been deposited at temperatures from 1173 to 1323 K with a growth rate ranging from 0.2 to 0.45 {mu}m/hour. The films are highly crystalline and are dominated by (100) faces at low temperatures, changing to (111) at higher temperatures. Grain size and residual stress in the films increases with increasing deposition temperature. X-ray diffraction shows the expected diamond diffraction peaks plus peaks attributed to WC and W{sub 2}C. Raman spectroscopy shows a sharp diamond band for all of the films, with a small broad peak, attributed to amorphous carbon. There is no distinct correlation between diamond/amorphous carbon intensity with deposition temperature. Scratch adhesion testing shows the expected failure mode for brittle coatings, but can not be quantified because of severe degradation of the diamond stylus tip. Sebastion pull testing shows that the failure mode of the films correlates with deposition temperature, but specific adhesion strength values do not. Efforts are continuing to correlate adhesion strength with deposition and structural parameters of the diamond films. 7 refs., 6 figs., 2 tabs.

Alam, M. (New Mexico Inst. of Mining and Technology, Socorro, NM (USA)); Peebles, D.E.; Tallant, D.R. (Sandia National Labs., Albuquerque, NM (USA))

1991-01-01

284

Phosphorylated nano-diamond/ Polyimide Nanocomposites  

NASA Astrophysics Data System (ADS)

In this study, a novel route to synthesize polyimide (PI)/phosphorylated nanodiamond films with improved thermal and mechanical properties was developed. Surface phosphorylation of nano-diamond was performed in dichloromethane. Phosphorylation dramatically enhanced the thermal stability of nano-diamond. Poly(amic acid) (PAA), which is the precursor of PI, was successfully synthesized with 3,3',4,4'-Benzophenonetetracarboxylic dianhydride (BTDA) and 4,4'-oxydianiline (4,4'-ODA) in the solution of N,N- dimethylformamide (DMF). Pure BTDA-ODA polyimide films and phosphorylated nanodiamond containing BTDA-ODA PI films were prepared. The PAA displayed good compatibility with phosphorylated nano-diamond. The morphology of the polyimide (PI)/phosphorylated nano-diamond was characterized by scanning electron microscopy (SEM). Chemical structure of polyimide and polyimide (PI)/phosphorylated nano-diamond was characterized by FTIR. SEM and FTIR results showed that the phosphorylated nano-diamond was successfully prepared. Thermal properties of the polyimide (PI)/phosphorylated nanodiamond was characterized by thermogravimetric analysis (TGA). TGA results showed that the thermal stability of (PI)/phosphorylated nano-diamond film was increased.

Beyler-Çi?il, Asli; Çakmakçi, Emrah; Vezir Kahraman, Memet

2014-08-01

285

Progress on diamond amplified photo-cathode  

SciTech Connect

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.

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

2011-03-28

286

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

NASA Astrophysics Data System (ADS)

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.

Caccia, Mario; Rodríguez, Alejandro; Narciso, Javier

2014-06-01

287

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

Microsoft Academic Search

Gem-quality diamond contains such low abundances of parent-daughter radionuclides that dating the diamond lattice directly by isotopic measurements has been and will be impossible. Absolute ages on diamonds typically are obtained through measurements of their syngenetic mineral inclusions: Rb-Sr in garnet; Sm-Nd in garnet and pyroxene; Re-Os and U-Th-Pb in sulfide; K-Ar in pyroxene; and U-Pb in zircon. The application

S. B. Shirey

2002-01-01

288

Amorphous Diamond MEMS and Sensors  

SciTech Connect

This report describes a new microsystems technology for the creation of microsensors and microelectromechanical systems (MEMS) using stress-free amorphous diamond (aD) films. Stress-free aD is a new material that has mechanical properties close to that of crystalline diamond, and the material is particularly promising for the development of high sensitivity microsensors and rugged and reliable MEMS. Some of the unique properties of aD include the ability to easily tailor film stress from compressive to slightly tensile, hardness and stiffness 80-90% that of crystalline diamond, very high wear resistance, a hydrophobic surface, extreme chemical inertness, chemical compatibility with silicon, controllable electrical conductivity from insulating to conducting, and biocompatibility. A variety of MEMS structures were fabricated from this material and evaluated. These structures included electrostatically-actuated comb drives, micro-tensile test structures, singly- and doubly-clamped beams, and friction and wear test structures. It was found that surface micromachined MEMS could be fabricated in this material easily and that the hydrophobic surface of the film enabled the release of structures without the need for special drying procedures or the use of applied hydrophobic coatings. Measurements using these structures revealed that aD has a Young's modulus of {approx}650 GPa, a tensile fracture strength of 8 GPa, and a fracture toughness of 8 MPa{center_dot}m {sup 1/2}. These results suggest that this material may be suitable in applications where stiction or wear is an issue. Flexural plate wave (FPW) microsensors were also fabricated from aD. These devices use membranes of aD as thin as {approx}100 nm. The performance of the aD FPW sensors was evaluated for the detection of volatile organic compounds using ethyl cellulose as the sensor coating. For comparable membrane thicknesses, the aD sensors showed better performance than silicon nitride based sensors. Greater than one order of magnitude increase in chemical sensitivity is expected through the use of ultra-thin aD membranes in the FPW sensor. The discoveries and development of the aD microsystems technology that were made in this project have led to new research projects in the areas of aD bioMEMS and aD radio frequency MEMS.

SULLIVAN, JOHN P.; FRIEDMANN, THOMAS A.; ASHBY, CAROL I.; DE BOER, MAARTEN P.; SCHUBERT, W. KENT; SHUL, RANDY J.; HOHLFELDER, ROBERT J.; LAVAN, D.A.

2002-06-01

289

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

NASA Astrophysics Data System (ADS)

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.

Xu, Jishou

2000-10-01

290

Compositional and structural analysis of nitrogen incorporated and ion implanted diamond thin films  

NASA Astrophysics Data System (ADS)

Significant progress in area of nano-structured thin film systems has taken place in recent decades. In particular, diamond thin film systems are being widely studied for their wear resistant, optical and electronic properties. Of the various methods researchers use to modify the structure of such films, three techniques in particular are of interest due to their versatility: modification of the growth atmosphere, growth on metalized substrates, providing an interfacial layer, and modification through post-growth ion implantation. The aim of this study is to investigate the effects each has to the structure and composition of elements. Different techniques are applied in each section; nitrogen gas dilution in a microwave plasma CVD system, diamond deposition on a metal interfacial layer and ion implantation in thin nanocrystalline diamond film. The forms of nanocrystalline diamond film resulting from such modifications are investigated using advanced spectroscopic and spectrometric techniques, as well as mechanical testing and surface mapping. The impact of these characterizations will provide valuable perspective to researchers in materials science. Understanding the changes to the structure and properties of this class of thin films, which can be induced through various mechanisms, will allow future researchers to refine these films towards technological applications in areas of hard coatings, electronics and photonics.

Garratt, Elias James

291

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

PubMed

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

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

2014-09-01

292

Tantalum deposition on and reaction with the hydrogen terminated diamond (100) surface studied by Auger electron and electron energy loss spectroscopy  

NASA Astrophysics Data System (ADS)

The evolution of the tantalum/diamond interface upon room-temperature Ta deposition on the (100) surface of a boron doped, synthetically grown diamond single crystal was monitored by Auger electron spectroscopy (AES), ionization loss spectroscopy (ILS), and electron energy loss spectroscopy (ELS). Characteristic loss peaks indicate carbide formation at the interface from very low coverages on, reflecting the strong interaction between tantalum and carbon. Thicker layers of TaC are formed during subsequent thermal annealing by diffusion of carbon into the tantalum film, at the same time the topmost diamond region is transformed into poorly ordered graphitic carbon.

Pitter, M.; Hugenschmidt, M. B.; Behm, R. J.

1996-04-01

293

Quantum information processing in diamond  

E-print Network

Quantum computing is an attractive and multidisciplinary field, which became a focus for experimental and theoretical research during last decade. Among other systems, like ions in traps or superconducting circuits, solid-states based qubits are considered to be promising candidates for first experimental tests of quantum hardware. Here we report recent progress in quantum information processing with point defect in diamond. Qubits are defined as single spin states (electron or nuclear). This allows exploring long coherence time (up to seconds for nuclear spins at cryogenic temperatures). In addition, the optical transition between ground and excited electronic states allows coupling of spin degrees of freedom to the state of the electromagnetic field. Such coupling gives access to the spin state readout via spin-selective scattering of photon. This also allows using of spin state as robust memory for flying qubits (photons).

F. Jelezko; J. Wrachtrup

2005-10-19

294

Quantum information processing in diamond  

E-print Network

Quantum computing is an attractive and multidisciplinary field, which became a focus for experimental and theoretical research during last decade. Among other systems, like ions in traps or superconducting circuits, solid-states based qubits are considered to be promising candidates for first experimental tests of quantum hardware. Here we report recent progress in quantum information processing with point defect in diamond. Qubits are defined as single spin states (electron or nuclear). This allows exploring long coherence time (up to seconds for nuclear spins at cryogenic temperatures). In addition, the optical transition between ground and excited electronic states allows coupling of spin degrees of freedom to the state of the electromagnetic field. Such coupling gives access to the spin state readout via spin-selective scattering of photon. This also allows using of spin state as robust memory for flying qubits (photons).

Jelezko, F

2005-01-01

295

Highly efficient diamond Raman laser.  

PubMed

We report an efficient 532 nm pumped external cavity diamond Raman laser generating output chiefly at the 573 nm first Stokes. At a pulse repetition rate of 5 kHz, the Raman laser generated 1.2 W output with a conversion efficiency of 63.5%, a slope efficiency of 75%, a pulse peak instantaneous conversion efficiency of 85%, and a peak photon conversion efficiency of 91%. The laser generated a maximum output energy of 0.67 mJ by increasing the pump beam size and the pulse energy. The efficiency is commensurate with the highest previously reported for other Raman materials pumped by Q-switched lasers. PMID:19756113

Mildren, R P; Sabella, A

2009-09-15

296

Characteristics of excitonic emission in diamond  

NASA Astrophysics Data System (ADS)

The Editor's Choice [1] is a theoretical study of the excitonic emission properties in diamond, in particular with regard to possible Bose-Einstein condensation (BEC). The cover picture shows a simple phase diagram for electron-hole pairs in dependence on their density and temperature. It is predicted that exciton BEC does occur for highly excited exciton densities, e.g. on the order of 1018-1019 cm-3, at low temperatures.The first author, Hideyo Okushi, started to study homoepitaxial CVD diamond films for electronic devices in 1995, now at AIST. Since 2001, he has been the leader of the CREST project Ultraviolet nanodevices using high-density exciton in diamond.This issue contains papers presented at SBDD X. This year saw the 10th anniversary of the series of International Workshops on Surface and Bulk Defects in CVD Diamond Films, which are traditionally held in Diepenbeek-Hasselt, Belgium.

Okushi, Hideyo; Watanabe, Hideyuki; Kanno, Shokichi

2005-09-01

297

Raman features of CVD diamond films  

SciTech Connect

There is considerable interest in the use of chemically vapor deposited (CVD) polycrystalline diamond films in advanced materials technology. However, most of the potential applications of CVD diamond films require well-controlled properties which depend on the film structure, and in turn, on the conditions under which the films are synthesized. The structure of the vapor-deposited diamond films is frequently characterized by Raman spectroscopy. Despite extensive research, much work still needs to be completed to understand the various features of the Raman spectra and to understand how the processing variables affect the spectral features. This paper examines the Raman spectra of diamond films prepared by a hot-filament-assisted CVD process as a function of substrate processing and deposition parameters.

Alam, M. (New Mexico Inst. of Mining and Technology, Socorro, NM (United States)); Tallant, D.R.; Peebles, D.E. (Sandia National Labs., Albuquerque, NM (United States))

1992-01-01

298

Raman features of CVD diamond films  

SciTech Connect

There is considerable interest in the use of chemically vapor deposited (CVD) polycrystalline diamond films in advanced materials technology. However, most of the potential applications of CVD diamond films require well-controlled properties which depend on the film structure, and in turn, on the conditions under which the films are synthesized. The structure of the vapor-deposited diamond films is frequently characterized by Raman spectroscopy. Despite extensive research, much work still needs to be completed to understand the various features of the Raman spectra and to understand how the processing variables affect the spectral features. This paper examines the Raman spectra of diamond films prepared by a hot-filament-assisted CVD process as a function of substrate processing and deposition parameters.

Alam, M. [New Mexico Inst. of Mining and Technology, Socorro, NM (United States); Tallant, D.R.; Peebles, D.E. [Sandia National Labs., Albuquerque, NM (United States)

1992-05-01

299

Hydrogen chemisorption on diamond surfaces. Final report  

SciTech Connect

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.

Daley, R.; Musket, R.

1994-09-01

300

Diamond coated silicon field emitter array  

SciTech Connect

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.

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

1999-07-01

301

Corticosteroid Therapy for Diamond Blackfan Anemia  

MedlinePLUS

... DBA-NURSE DBA Fact Sheet CortiCosteroid t herapy (prednisone , p rednisolone ) Information for people with Diamond Blackfan ... help the body make more red blood cells. Steroids are also used to stop allergic reactions and ...

302

Magnesium interlayered diamond coating on silicon  

Microsoft Academic Search

Diamond thin films have been deposited using hot filament chemical vapour deposition technique on manually scratched p-Si(100) substrate, with and without magnesium interlayer. In spite of magnesium melting point being lower (Tm=649°C) than the growth temperature of the substrate (Ts?750°C) used in these experiments, it was found that high quality diamond films could be grown on Mg covered substrate. A

M. A. Dar; S. G. Ansari; Z. A. Ansari; Hironobu Umemoto; Young-Soon Kim; Hyung-Kee Seo; Gil-Sung Kim; Eun-Kyung Suh; Hyung-Shik Shin

2006-01-01

303

Diamond film growth from fullerene precursors  

DOEpatents

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.

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

1997-04-15

304

Diamond film growth argon-carbon plasmas  

DOEpatents

A method and system are disclosed 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. 29 figs.

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

1998-12-15

305

Nanophase diamond films produced by laser deposition  

NASA Astrophysics Data System (ADS)

Films of nanophase diamond can be prepared in vacuum by the laser ablation of graphite at intensities in excess of 1011 W cm-2. A variety of structural morphologies can result that depend upon the kinetic energies and charge states employed. The most promising is a nanophase diamond that we originally termed `amorphic diamond.' It is composed of nanometer scale nodules of sp3 bonded carbon. The high energy of condensation from the laser plasma source provides both for the chemical bonding of such films to a wide variety of substrates and for low values of residual compressive stress, 0.6 - 0.8 GPa. This paper reports the solution of a lingering problem with the hardness of nanophase diamond. The packing density of nodules in the finished ceramic depends upon process variables and so hardness can fluctuate. With critical control at the point of ablation, films are produced that are too hard to measure. In this work, raw data produced with an advanced nanoindentation technique was analyzed with the conventional procedure and a hardness value of 125 GPa was obtained. Exceeding the hardness of natural diamond this value was so large as to raise concern for the validity of the conventional model used to interpret data. To avoid model dependent interpretation, a differential loading pressure, independent of depth, was used to give a lower limit on the hardness directly from the raw data. Comparable values of this lower limit, near 75 GPa have been measured on crystalline diamond prepared by CVD and on nanophase diamond deposited by our laser plasma method. The combination of hardness and resiliency together with a coefficient of friction near 0.1, seems to make nanophase diamond an attractive coating for use in current industrial applications.

Collins, Carl B., Jr.; Davanloo, Farzin; You, J. H.; Park, H.

1994-08-01

306

Diamond switches for high temperature electronics  

SciTech Connect

This paper presents the results of switching voltages of 500 V and currents of 10 A using chemical vapor deposited (CVD) diamond as a switching material. The switching is performed by using an electron beam that penetrates the diamond, creates electron hole pairs, and lowers its resistivity to about 20 {Omega}-cm and its resistance to about 4 {Omega}. Tests were performed at room temperature but in a configuration that allows for 250 C.

Loubriel, G.M.; Zutavern, F.J.; Ruebush, M.H. [and others

1997-06-01

307

UV detector based on polycrystalline diamond films  

NASA Astrophysics Data System (ADS)

Unlike other conventional photoconductive detectors, diamond-based devices provide high discrimination between UV and visible radiation. In this work we present the optical and electrical properties of devices based on randomly oriented diamond films, synthesized by microwave plasma enhanced chemical vapor deposition. It was observed that the UV detectors displayed low dark currents, high discrimination for wavelengths longer than 230 nm, high sensitivity and speed.

Girija, K. G.; Nuwad, J.

2013-02-01

308

Internal stresses in {111} homoepitaxial CVD diamond  

Microsoft Academic Search

Undoped and phosphorus-doped diamond thin films grown by microwave plasma-enhanced chemical vapour deposition (MPCVD) on Ib {111}-oriented diamond substrates have been studied by confocal micro-Raman spectroscopy. Thanks to the confocal optics, the Raman signal arising from the epilayer could be discriminated from that arising from the substrate. In this study, a distinct Raman peak, broader and approximately 6 cm?1 lower

M Mermoux; B Marcus; A Crisci; A Tajani; E Gheeraert; E Bustarret

2004-01-01

309

Single crystal diamond detector for radiotherapy  

NASA Astrophysics Data System (ADS)

The new generation of synthetic diamonds grown as a CVD single crystal on a high pressure high temperature substrate offers a wide range of applications. In particular, because of the near tissue equivalence and its small size (good spatial resolution), CVD single crystal diamond finds applicability in radiotherapy as a dosemeter of ionizing radiation. In this paper we report the electrical and dosimetric properties of a new diamond detector which was fabricated at IFJ based on a single crystal detector-grade CVD diamond provided with a novel contact metallization. Diamond properties were assessed at IFJ using a Theratron 680E therapeutic 60Co gamma rays unit and at COOK with 6 and 18 MV x-rays Varian Clinac CL2300 C/D accelerator. The new dosemeter showed high electric and dosimetric performances: low value of dark current, high current at the level of some nanoamperes during irradiation, very fast dynamic response with a rise time amounting to parts of a second, good stability and repeatability of the current and linearity of the detector signal at different dose and dose rate levels typically applied in radiotherapy. The results confirm the potential applicability of diamond material as a dosemeter for applications in radiotherapy.

Schirru, F.; Kisielewicz, K.; Nowak, T.; Marczewska, B.

2010-07-01

310

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

NASA Astrophysics Data System (ADS)

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.

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

2014-06-01

311

Physicochemical formation conditions of natural diamond deduced from experimental study of the eclogite-carbonatite-sulfide-diamond system  

NASA Astrophysics Data System (ADS)

A diagram of the syngenesis of diamond, silicate, carbonate, and sulfide minerals and melts is compiled based on experimental data on phase relations in the heterogeneous eclogite-carbonate-sulfidediamond system at P = 7 GPa. Evidence is provided that silicate and carbonate minerals are paragenetic, whereas sulfides are xenogenic with respect to diamond. Diamond and paragenetic phases are formed in completely miscible carbonate-silicate growth melts with dissolved elemental carbon. Coherent data of physicochemical experiment and mineralogy of primary inclusions in natural diamonds allows us to prove the mantle-carbonatite theory of diamond origin. The genetic classification of primary inclusions in natural diamonds is based on this theory. The phase diagrams of syngenesis are applicable to interpretation of diamond and syngenetic minerals formation in natural magma sources. They ascertain physicochemical mechanism of natural diamond formation and conditions of entrapment of paragenetic and xenogenic mineral phases by growing diamonds.

Litvin, Yu. A.

2012-11-01

312

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

NASA Astrophysics Data System (ADS)

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.

Laikhtman, A.; Hoffman, A.

2002-02-01

313

Metal films on the surfaces and within diamond crystals from Arkhangelskaya and Yakutian diamond provinces  

NASA Astrophysics Data System (ADS)

Representative samples of diamonds from five kimberlite pipes (Lomonosovskaya, Archangel'sk, Snegurochka, XXIII Congress of the Communist Party of the Soviet Union (CPSU), and Internationalnaya) of the Arkhangelskaya and Yakutian diamond provinces in Russia have been studied. Thirty-three varieties of metal films have been identified as syngenetic associated minerals. The films consist of 15 chemical elements that occur in the form of native metals and their natural alloys. Remnants of metal films were detected within diamond crystals. The metal films coating diamonds are a worldwide phenomenon. To date, these films have been described from Europe, Asia, South America, and Africa. Native metals, their alloys, and intermetallides are actual companion minerals of diamond.

Makeev, A. B.; Kriulina, G. Yu.

2012-12-01

314

Status and applications of diamond and diamond-like materials: An emerging technology  

NASA Technical Reports Server (NTRS)

Recent discoveries that make possible the growth of crystalline diamond by chemical vapor deposition offer the potential for a wide variety of new applications. This report takes a broad look at the state of the technology following from these discoveries in relation to other allied materials, such as high-pressure diamond and cubic boron nitride. Most of the potential defense, space, and commercial applications are related to diamond's hardness, but some utilize other aspects such as optical or electronic properties. The growth processes are reviewed, and techniques for characterizing the resulting materials' properties are discussed. Crystalline diamond is emphasized, but other diamond-like materials (silicon carbide, amorphous carbon containing hydrogen) are also examined. Scientific, technical, and economic problem areas that could impede the rapid exploitation of these materials are identified. Recommendations are presented covering broad areas of research and development.

1990-01-01

315

Superconducting YBa{sub 2}Cu{sub 3}O{sub 7} bolometer on polycrystalline diamond  

SciTech Connect

The authors have deposited superconducting YBCO (YBa{sub 2}Cu{sub 3}O{sub 7}) thin films on polycrystalline diamond using a composite Si/YSZ (yttria stabilized zirconia) diffusion barrier. 10--20 micron thick, free standing diamond films were coated with a micron thick layer of amorphous Si by plasma CVD. This was vacuum annealed at 700 C to crystallize Si prior to the in-situ deposition of YSZ and YBCO by laser ablation. A primary layer of Si was found essential to avoid the peeling of the multilayer structure during the cooling of the substrates. A T{sub c{minus}zero} = 50K was observed for the best films. A bolometer fabricated from this film exhibited a 18V/W responsivity and NEP = 6.3 {times} 10{sup {minus}9}W/{radical}Hz at 60K. Both the buffer layers and YBCO were polycrystalline. They believe single crystal Si backing CVD grown diamond can be used instead of a polycrystalline Si layer to further improve the quality of the YBCO deposited on polycrystalline diamond.

Ganapathi, L.; Zheng, J.P.; Giles, S.; Rao, R.; Kwok, H.S. [Excel Superconductor, Inc., Bohemia, NY (United States)

1994-12-31

316

Enhanced photoluminescence extraction efficiency from a diamond photonic crystal via leaky modes  

NASA Astrophysics Data System (ADS)

Two-dimensional photonic crystal can be exploited as the top part of a light source in order to increase its extraction efficiency. Here, we report on the room-temperature intrinsic photoluminescence (PL) behavior of a nanocrystalline diamond (NCD) layer with diamond columns prepared on the top and periodically ordered into the lattice with square symmetry. Angle-resolved far-field measurements in the ?-X crystal direction of broadband visible PL revealed up to six-fold enhancement of extraction efficiency as compared to a smooth NCD layer. A photonic band diagram above the lightcone derived from these measurements is in agreement with the diagram obtained from transmission measurements and simulation, suggesting that the enhancement is primarily due to light's coupling to leaky modes.

Ondi?, L.; K?sová, K.; Cibulka, O.; Pelant, I.; Dohnalová, K.; Rezek, B.; Babchenko, O.; Kromka, A.; Ganesh, N.

2011-06-01

317

Spectrally dependent photovoltages in Schottky photodiode based on (100) B-doped diamond  

NASA Astrophysics Data System (ADS)

Spectrally and spatially resolved photovoltages were measured by Kelvin probe force microscopy (KPFM) on a Schottky photo-diode made of a 4 nm thin tungsten-carbide (WC) layer on a 500 nm oxygen-terminated boron-doped diamond epitaxial layer (O-BDD) that was grown on a Ib (100) diamond substrate. The diode was grounded by the sideways ohmic contact (Ti/WC), and the semitransparent Schottky contact was let unconnected. The electrical potentials across the device were measured in dark (only 650 nm LED of KPFM being on), under broad-band white light (halogen lamp), UV (365 nm diode), and deep ultraviolet (deuterium lamp) illumination. Illumination induced shift of the electrical potential remains within 210 mV. We propose that the photovoltage actually corresponds to a shift of Fermi level inside the BDD channel and thereby explains orders of magnitude changes in photocurrent.

?ermák, Jan; Koide, Yasuo; Takeuchi, Daisuke; Rezek, Bohuslav

2014-02-01

318

Abrasion resistant active braze alloys for metal single layer technology  

Microsoft Academic Search

The technology of brazing a single layer of abrasive on to the surface of a grinding tool, metal single layer (MSL) technology, provides an alternative way to make use of the superabrasives diamond and cubic boron nitride in machining ceramic materials or super- alloys, cutting of construction materials, etc. For cer- tain applications of MSL bonded wheels, the grinding or

319

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 ...

320

21 CFR 872.4535 - Dental diamond instrument.  

Code of Federal Regulations, 2010 CFR

... (a) Identification. A dental diamond instrument is an abrasive device intended to smooth tooth surfaces during the fitting...imbedded into it. Rotation of the diamond instrument provides an abrasive action when it contacts a tooth. (b)...

2010-04-01

321

Yield Optimization of Nitrogen Vacancy Centers in Diamond  

E-print Network

Nanodiamond ODMR Optical Detected Magnetic Resonance TEM Transmission Electron Microscopy T1 Spin-Lattice Relaxation Time T2 Spin... Properties .................................................................. 3 1. Synthesized Diamonds and Classification ............................. 4 2. NV Centers in Diamond ......................................................... 5 B...

Chen, Jeson

2012-10-19

322

Sparkling Diamonds – Reducing High Energy in the Frozen North  

E-print Network

De Beers, the undisputed world leader in diamond mining, in a typically proactive approach, completed an energy review at the Snap Lake Diamond Mine in the Northwest Territories. What makes the approach unique is that the mine is still under...

Feldman, J.

2007-01-01

323

Oxidation state of the lithospheric mantle beneath Diavik diamond mine, central Slave craton, NWT, Canada  

Microsoft Academic Search

Oxygen fugacity (fO2) conditions were determined for 29 peridotite xenoliths from the A154-North and A154-South kimberlites of the Diavik diamond\\u000a mine using the newly developed flank method modified specifically for measuring Fe3+ in mantle-derived pyropic garnets. The results indicate that the garnet-bearing lithospheric mantle beneath the central Slave\\u000a craton is vertically layered with respect to oxidation state. The shallow (<140 km),

Steven Creighton; Thomas Stachel; Dave Eichenberg; Robert W. Luth

2010-01-01

324

Synthesis of diamond thin films for applications in high temperature electronics  

NASA Astrophysics Data System (ADS)

High-temperature electronics and MEMS (Micro-Electro-Mechanical Systems) based on polycrystalline diamond (PCD) are promising because of its wide band gap, high thermal conductivity, and large carrier mobility. To take advantage of this opportunity, research was undertaken to develop techniques for the synthesis of both undoped and doped high quality PCD films with good surface flatness suitable for the fabrication of high temperature electronics and MEMS devices. One way to fabricate smooth films is to decrease the grain size because diamond films with large grain size bring forth problems in contact formation and device fabrication due to the large surface roughness. Consequently, there is a need to fabricate nanocrystalline films with small grain size and good smoothness. In addition, the electrical properties and conduction mechanisms in nanocrystalline diamond (NCD) films have not been sufficiently analyzed. This study also aims at achieving high resistivity nanocrystalline diamond films and to study the electrical conduction mechanism. Several approaches have been used in our research to achieve these goals. Initially microcrystalline diamond (MCD) films were grown on silicon (100) substrates by the microwave plasma enhanced chemical vapor deposition (MPCVD) method using methane in a hydrogen plasma environment. Introduction of small amounts of argon into the Argon/Hydrogen plasma was used to deposit diamond films with a range of microstructures from microcrystalline to nanocrystalline grains. A detailed quantitative study of the sp3, sp 2 content in the films grown with varying amounts of argon in the plasma was done using Raman spectroscopy. Electrical properties of the microcrystalline and nanocrystalline diamond films were measured over a range of temperatures by fabricating capacitors using a metal-insulator-metal (MIM) configuration that could withstand temperatures up to 600°C. Typical electrical resistivities of MCD were ˜10 12 O.cm while the dielectric constant was near 5.6, which was representative of natural diamond. For NCD, the electrical resistivities were of ˜1011 O.cm was obtained, which was eight orders of magnitude higher than values reported by other researchers. A lower dielectric constant of 5.2 was obtained for the NCD. The electrical conduction mechanisms in undoped MCD, NCD, and nitrogen-doped films were studied. The Hill's conduction mechanism was dominant in MCD and NCD films due to the deep-level traps present, which contributed to grain-boundary conduction. The average distances between the trap sites were found to be 11 nm for the MCD, and 5 nm for the NCD were estimated. These related to the hopping conduction across impurities present in the grain boundaries. These impurities were attributed to graphite in the PCD films. The nitrogen-doped diamond films were processed to fabricate a metal-insulator-semiconductor (MIS) structure. The resistivity of a 1% nitrogen-doped diamond was 2.8x107 O.cm. The space-charge-limited-conduction mechanism was suggested for the nitrogen-doped diamond films due to holes injected from the p-type silicon into the n-type diamond layer, and the injected holes played a role of the current carriers. (Abstract shortened by UMI.)

Ramamurti, Rahul

325

Water-related absorption in fibrous diamonds  

NASA Astrophysics Data System (ADS)

Cubic and coated diamonds from several localities (Brasil, Canada, Yakutia) were investigated using spectroscopic techniques. Special emphasis was put on investigation of water-related features of transmission Infra-red and Raman spectra. Presence of molecular water is inferred from broad absorption bands in IR at 3420 and 1640 cm-1. These bands were observed in many of the investigated samples. It is likely that molecular water is present in microinclusions in liquid state, since no clear indications of solid H_2O (ice VI-VII, Kagi et al., 2000) were found. Comparison of absorption by HOH and OH vibrations shows that diamonds can be separated into two principal groups: those containing liquid water (direct proportionality of OH and HOH absorption) and those with stronger absorption by OH group. Fraction of diamonds in every group depends on their provenance. There might be positive correlation between internal pressure in microinclusions (determined using quartz barometer, Navon et al., 1988) and affiliation with diamonds containing liquid water. In many cases absorption by HOH vibration is considerably lower than absorption by hydroxyl (OH) group. This may be explained if OH groups are partially present in mineral and/or melt inclusions. This hypothesis is supported by following fact: in diamonds with strong absorption by silicates and other minerals shape and position of the OH band differs from that in diamonds with low absorption by minerals. Moreover, in Raman spectra of individual inclusions sometimes the broad band at 3100 cm-1 is observed. This band is OH-related. In some samples water distribution is not homogeneous. Central part of the diamond usually contains more water than outer parts, but this is not a general rule for all the samples. Water absorption usually correlated with absorption of other components (carbonates, silicates and others). At that fibrous diamonds with relatively high content of silicates are characterized by molecular water. OH-enriched diamonds contain more carbonatitic material. This was supported by JSPS and grant of University of Russia (No. 09.01.054).

Zedgenizov, D. A.; Shiryaev, A. A.; Kagi, H.; Navon, O.

2003-04-01

326

Diamond heat sinks for electronic circuits  

NASA Astrophysics Data System (ADS)

During the interim stage of this Phase 1 R and D, a useful metallizing procedure for bulk diamond has been developed, with natural diamond chips, granules, and polished wafers from two vendors. Small-scale statistical experiments were designed and executed by systematically varying several material and processing variables including: metallizing and brazing compositions, processing temperature and time, ambient control, and other procedural changes. Under selected combinations of these variables, metallizing of these diamond samples was achieved. Surface wetting appears to be excellent. The metallized surfaces were brazed or soldered to metal for future heat sink uses in high-power electronic circuits. These results clearly demonstrate the proof of the principle that is our main objective in Phase 1. The remainder of the Phase 1 work will be directed to metallizing and brazing polished diamond wafers to metal (copper and/or Kovar) substrates; detailed sample characterization including scanning electron microscopy (SEM), microstructural and microprobing analyses; thermal conductance measurements of mounted diamond wafers; and analyzing all results for the final report.

Li, Chou H.

327

Lubrication by Diamond and Diamondlike Carbon Coatings  

NASA Technical Reports Server (NTRS)

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.

Miyoshi, Kazuhisa

1997-01-01

328

Bias-enhanced nucleation of diamond on silicon dioxide  

Microsoft Academic Search

Characterization of amorphous SiO2 surfaces after biasing pretreatments, which induce nucleation of diamond, has been carried out using x-ray photoelectron spectroscopy and Raman spectroscopy. A mixture of silicon carbide, silicon oxycarbide, and diamond are formed upon exposure of biased SiO2 surfaces to a CH4+H2 plasma used for diamond deposition. It is concluded that nucleation of diamond on amorphous SiO2 surfaces

M. D. Irwin; C. G. Pantano; P. Gluche; E. Kohn

1997-01-01

329

Silicon-on-diamond material by pulsed laser technique  

Microsoft Academic Search

We present a method to bond directly silicon and diamond plates to obtain a single silicon-on-diamond material, with a carbon-silicon interface of unprecedented quality. The bonding is performed at room temperature, via picosecond 355 nm pulsed laser irradiation of the silicon-diamond interface, through the transparent diamond. The obtained material exhibits excellent mechanical strength and uniformity of the bonding, as shown

S. Lagomarsino; G. Parrini; S. Sciortino; M. Santoro; M. Citroni; M. Vannoni; A. Fossati; F. Gorelli; G. Molesini; A. Scorzoni

2010-01-01

330

The diamond-tungsten carbide polycrystalline composite material  

Microsoft Academic Search

The sintering of a diamond composite from diamond and tungsten powders of submicron and nanosizes at high pressure and temperature\\u000a has been discussed. It has been shown that as a result of the diamond and tungsten interaction tungsten carbide particles,\\u000a which are chemically bonded to diamond particles, form in spaces between them. Over the whole volume of the composite the

S. N. Nazarchuk; A. A. Bochechka; V. S. Gavrilova; L. A. Romanko; N. N. Belyavina; L. I. Aleksandrova; V. N. Tkach; E. F. Kuz’menko; S. D. Zabolotnyi

2011-01-01

331

The Mysteries of Diamonds: Bizarre History, Amazing Properties, Unique Applications  

SciTech Connect

Diamonds have been a prized material throughout history. They are scarce and beautiful, wars have been fought over them, and they remain today a symbol of wealth and power. Diamonds also have exceptional physical properties which can lead to unique applications in science. There are now techniques to artificially synthesize diamonds of extraordinarily high quality. In this talk, Professor Kagan will discuss the history of diamonds, their bizarre properties, and their manufacture and use for 21st century science.

Kagan, Harris (Ohio State University) [Ohio State University

2008-06-24

332

Chemical vapor deposition diamond based multilayered radiation detector: Physical analysis of detection properties  

SciTech Connect

Recently, solid state photovoltaic Schottky diodes, able to detect ionizing radiation, in particular, x-ray and ultraviolet radiation, have been developed at the University of Rome 'Tor Vergata'. We report on a physical and electrical properties analysis of the device and a detailed study of its detection capabilities as determined by its electrical properties. The design of the device is based on a metal/nominally intrinsic/p-type diamond layered structure obtained by microwave plasma chemical vapor deposition of homoepitaxial single crystal diamond followed by thermal evaporation of a metallic contact. The device can operate in an unbiased mode by using the built-in potential arising from the electrode-diamond junction. We compare the expected response of the device to photons of various energies calculated through Monte Carlo simulation with experimental data collected in a well controlled experimental setup i.e., monochromatic high flux x-ray beams from 6 to 20 keV, available at the Diamond Light Source synchrotron in Harwell (U.K.).

Almaviva, S.; Marinelli, Marco; Milani, E.; Prestopino, G.; Tucciarone, A.; Verona, C.; Verona-Rinati, G. [Dip. di Ing. Meccanica, Universita di Roma 'Tor Vergata', Roma 00133 (Italy); Angelone, M.; Pillon, M. [Associazione EURATOM-ENEA sulla Fusione, Frascati, Roma 00044 (Italy); Dolbnya, I.; Sawhney, K.; Tartoni, N. [Diamond Light Source, Harwell Science and Innovation Campus, Chilton-Didcot, OX11 0DE Oxfordshire (United Kingdom)

2010-01-15

333

In situ observation of quasimelting of diamond and reversible graphite-diamond phase transformations.  

PubMed

Because of technique difficulties in achieving the extreme high-pressure and high-temperature (HPHT) simultaneously, direct observation of the structures of carbon at extreme HPHT conditions has not been possible. Banhart and Ajayan discovered remarkably that carbon onions can act as nanoscopic pressure cells to generate high pressures. By heating carbon onions to approximately 700 degrees C and under electron beam irradiation, the graphite-to-diamond transformation was observed in situ by transmission electron microscopy (TEM). However, the highest achievable temperature in a TEM heating holder is less than 1000 degrees C. Here we report that, by using carbon nanotubes as heaters and carbon onions as high-pressure cells, temperatures higher than 2000 degrees C and pressures higher than 40 GPa were achieved simultaneously in carbon onions. At such HPHT conditions and facilitated by electron beam irradiation, the diamond formed in the carbon onion cores frequently changed its shape, size, orientation, and internal structure and moved like a fluid, implying that it was in a quasimelting state. The fluctuation between the solid phase of diamond and the fluid/amorphous phase of diamond-like carbon, and the changes of the shape, size, and orientation of the solid diamond, were attributed to the dynamic crystallization of diamond crystal from the quasimolten state and the dynamic graphite-diamond phase transformations. Our discovery offers unprecedented opportunities to studying the nanostructures of carbon at extreme conditions in situ and at an atomic scale. PMID:17628113

Huang, J Y

2007-08-01

334

Neutron detection at jet using artificial diamond detectors  

Microsoft Academic Search

Artificial diamond neutron detectors recently proved to be promising devices to measure the neutron production on large experimental fusion machines. Diamond detectors are very promising detectors to be used in fusion environment due to their radiation hardness, low sensitivity to gamma rays, fast response and high energy resolution. High quality “electronic grade” diamond films are produced through microwave chemical vapour

M. Pillon; M. Angelone; D. Lattanzi; M. Marinelli; E. Milani; A. Tucciarone; G. Verona-Rinati; S. Popovichev; R. M. Montereali; M. A. Vincenti; A. Murari

2007-01-01

335

Adhesion at diamond-metal interfaces: a chemical composition perspective  

Microsoft Academic Search

Diamond films were chemically vapor deposited (CVD) on titanium, tungsten, molybdenum, copper and aluminum oxide substrates. In these studies, the interface formed between diamond and the substrate was exposed by mechanically deforming the metal substrate or diamond film to cause film delamination. The observed degree of adhesion for these interfaces can be ranked in the order: Ti » Al2O3 (thin

Scott S. Perry; Sean P. McGinnis; Gabor A. Somorjai

1995-01-01

336

In situ analysis of carbon isotopes in North American diamonds  

Microsoft Academic Search

Diamonds from three North American kimberlite occurrences were investigated with cathodoluminescence (CL) and secondary ion mass spectrometry (SIMS) to determine their growth history and carbon isotope composition. Diamonds analyzed include fourteen from Lynx (Quebec), twelve from Kelsey Lake (Colorado) and eleven from A154 South (Diavik mine, Northwest Territories). Growth histories for the diamonds vary from simple to highly complex based

A. D. van Rythoven; E. H. Hauri; J. Wang; T. McCandless; S. B. Shirey; D. J. Schulze

2010-01-01

337

Thermal aspects of high performance packaging with synthetic diamond  

SciTech Connect

The extraordinary thermal conductivity and dielectric properties of diamond translate into performance and reliability advantages for electronic packaging of high performance semiconductors. Demonstrated diamond substrate Pin Grid Array (PGA) packages and Multi Chip-Modules (MCM) have changed the whole approach to high performance computing. Subnanosecond computer performance is made possible for the first time by a diamond substrate 3-D architecture.

Boudreaux, P.J. [Lab. for Physical Sciences, College Park, MD (United States)

1995-12-31

338

ON A CONJECTURE OF CONRAD, DIAMOND, AND TAYLOR DAVID SAVITT  

E-print Network

ON A CONJECTURE OF CONRAD, DIAMOND, AND TAYLOR DAVID SAVITT Abstract. We prove a conjecture of Conrad, Diamond, and Taylor on the size of certain deformation rings parametrizing potentially Barsotti of potentially Barsotti-Tate representations. 1. Introduction In their paper [CDT99], Conrad, Diamond, and Taylor

Savitt, David

339

27 CFR 9.166 - Diamond Mountain District.  

Code of Federal Regulations, 2010 CFR

...2010-04-01 2010-04-01 false Diamond Mountain District. 9.166 Section 9.166...Viticultural Areas § 9.166 Diamond Mountain District. (a) Name. The name...described in this section is “Diamond Mountain District.” (b) Approved...

2010-04-01

340

Microwave Plasma Enhanced Synthesis of Nanocrystalline Diamond Films  

Microsoft Academic Search

Synthesis of diamond films using fullerene (C_60) precursors in an argon (Ar) microwave plasma without the addition of hydrogen has now been accomplished and strongly suggests that the diamond phase grows by a new and hitherto unexplored mechanism. Diamond films produced in this way are nanocrystalline, smooth (20-30 nm rms surface roughness) and highly reflective. They maintain their nanocrystallinity to

Dieter Gruen

1996-01-01

341

78 FR 25363 - Airworthiness Directives; Diamond Aircraft Industries Airplanes  

Federal Register 2010, 2011, 2012, 2013

...installation of improved design tubing. You may...Information Diamond Aircraft Industries GmbH...with the improved design parts as specified...section of Diamond Aircraft Industries GmbH...with the improved design parts. Follow the...sections Diamond Aircraft Industries...

2013-05-01

342

Aboriginal partnerships in Canada: focus on the Diavik Diamond Mine  

Microsoft Academic Search

Purpose – In negotiation with diamond enterprises, Aboriginal communities have provided their consent for the diamond mines and have ensured their participation in all diamond projects within their traditional territories. The purpose of this study is to evaluate partnership strategies. Design\\/methodology\\/approach – Interviews. Findings – Natural resource enterprises support more than 650 Canadian communities and according to industry Canada this

Richard Missens; Leo Paul Dana; Robert Anderson

2007-01-01

343

The origin of cratonic diamonds — Constraints from mineral inclusions  

Microsoft Academic Search

The origin of cratonic diamonds is reviewed on the basis of nearly 5000 analyses of silicate, oxide and sulphide inclusions in diamonds. Compositional fields are defined for common minerals of the peridotitic, eclogitic and websteritic inclusion suites and used to establish the characteristics of diamond source rocks in the subcratonic lithospheric mantle. Peridotitic inclusion compositions overlap with the record established

T. Stachel; J. W. Harris

2008-01-01

344

Mapping the mantle lithosphere for diamond potential using teleseismic methods  

E-print Network

to be mined. The diamond exploration industry needs discriminating tools to reduce risks at all of these fourMapping the mantle lithosphere for diamond potential using teleseismic methods $ D.B. Snydera,*, S-Billiton Diamonds Inc., Kelowna, BC, Canada V1X 4L1 Received 27 June 2003; accepted 9 January 2004 Available online

Rondenay, Stephane

345

Interview with John and Marcia Diamond by Mike Hastings  

Microsoft Academic Search

Biographical NoteJohn Nathan Diamond was born on November 12, 1954, in Bangor, Maine. His father, Nathan Diamond, was a musician and a teacher, and his mother, Eleanor Diamond, was active in the community and in local politics. John followed politics with his parents, who were registered Republicans until 1978 when they changed their party affiliation and became Democrats. As a

John N Diamond; Marcia L Diamond

2008-01-01

346

Brown diamonds and high pressure high temperature treatment  

Microsoft Academic Search

Much progress has been made in recent years towards greater understanding of the various point and extended defects that give rise to colour in diamond and how such defects can be modified via treatment to change a diamond's colour. Such fundamental understanding has been vital in providing reliable means for gemmological laboratories to identify treated diamonds and ensure maintenance of

David Fisher

2009-01-01

347

Nanodiamond Seeding for Nucleation and Growth of CVD Diamond Films  

Microsoft Academic Search

Detonation nanodiamonds are shown to be effective seeds for growth of CVD diamond films as they provide high nucleation density on a substrate and can be placed on shaped surfaces and even into porous materials. XPS, AES and TEM analyses give useful information on the early stage of diamond growth. The transfer molding technique for manufacturing various diamond shapes is

V. Ralchenko; A. Saveliev; S. Voronina; A. Dementjev; K. Maslakov; M. Salerno; A. Podesta; P. Milani

348

Thermal and Optical Applications of Thin Film Diamond  

Microsoft Academic Search

Virtually all recent reviews of the market potential for chemical vapour deposited (CVD) diamond have featured the thermal management of electronic semiconductor devices as an imminent application for this new material. There is an existing market for natural diamond substrates (`heat sinks') in sub-millimetre sizes, and their thermal performance has been extensively studied. CVD diamond heat sinks in millimetre and

M. Seal

1993-01-01

349

Growth of diamond particles from methane-hydrogen gas  

Microsoft Academic Search

Microcrystals of diamond were grown on non-diamond substrates including silicon, molybdenum and silica, as well as on diamond by chemical vapour deposition. Deposition was carried out by passing a mixture of hydrocarbon and hydrogen gases through a heated reaction chamber in which a hot tungsten filament was held near the substrates. The deposit was identified by reflection electron diffraction and

Seiichiro Matsumoto; Yoichiro Sato; Masayuki Tsutsumi; Nobuo Setaka

1982-01-01

350

Fast bolometer built in an artificial HPHT diamond matrix  

SciTech Connect

A fast bolometer built in a plate of diamond grown at high pressure by the gradient growth method is developed and fabricated. The parameters of this structure are compared with these of the structures investigated earlier, which were fabricated based on chemical vapour deposited (CVD) diamond and natural type IIa diamond.

Klokov, A Yu; Sharkov, A I; Galkina, T I; Khmelnitskii, R A; Dravin, V A; Gippius, Aleksei A [P N Lebedev Physical Institute, Russian Academy of Sciences, Moscow (Russian Federation)

2010-05-26

351

Characterization of hypervelocity impact craters on chemical vapour-deposited diamond and diamond-like carbon films  

Microsoft Academic Search

Microwave plasma chemical vapour-deposited (CVD) process has been used to grow polycrystalline diamond films over silicon\\u000a substrates. Diamond-like carbon (DLC) thin films were grown over silicon substrates using a microwave plasma disc reactor.\\u000a Reactant gases of CH4 and H2 were used in both CVD processes. Some preliminary feasibility tests were performed on the possible\\u000a applicability of diamond and diamond-like carbon

R RAMESHAM; S. BEST; M. F ROSE; M CRUMPLER

1997-01-01

352

Outstanding Problems of Presolar Diamond in Meteorites  

SciTech Connect

Diamond is the first mineral type of presolar grains that were isolated from meteorites, yet it is one of the least understood presolar grain types. An isotopically anomalous component Xe-HL is carried by diamond and is characterized by excesses in both the light, p-process only isotopes (124 and 126) and the heavy, r-process only isotopes (134 and 136). These excesses are always correlated although physical settings of these two processes are quite different and there is little reason to always correlate each other. Furthermore, the r-process Xe and the p-process Xe in diamond inferred from Xe-HL are quite different from what is derived from the solar system abundance as well as stellar models. Further studies are needed to investigate these outstanding problems for over three decades.

Amari, Sachiko [Laboratory for Space Sciences and the Physics Department, Washington University, One Brookings Dr., St. Louis, MO 63130 (United States)

2008-05-21

353

Down-hole replaceable diamond core bit  

SciTech Connect

A one-piece diamond core drill bit of unique geometric shape has been designed, fabricated and field tested. The bit can be withdrawn (or replaced) from the bottom of the well-bore without removing the drill rods from the hole, saving a significant amount of non-productive drilling time. The geometric configuration of the bit is that of a one-piece diamond studded cutting element created by slicing off two parallel sides of a conventional diamond core bit. This geometric configuration, along with some minor modifications to the outer core barrel, allows the bit to be rotated in two planes and, with the retraction-insertion tools, raised or lowered through the interior of the drill rods using a conventional wireline system.

Not Available

1981-10-01

354

Diamond shines in high-power devices  

NASA Astrophysics Data System (ADS)

The 20-W S-band power amplifiers aboard the GOES E and F spacecraft exemplify the problems that type-IIa diamond heat sinks have been developed to solve, including the requirement for junction temperatures to be kept below 125 C. Diamond heat sinks allow high power S-band semiconductors to operate at a flange temperature of 70 C without exceeding the stipulated maximum junction temperature. Type-IIA diamond, which is an excellent electrical insulator, possesses a thermal conductivity four times better than pure copper at 100 C, and outperforms BeO by an even greater margin. Higher costs are offset by high reliability. Attention is presently given to the results of tests conducted by the NASA Goddard Space Flight Center.

Line, L.

1984-07-01

355

The failure strengths of perfect diamond crystals  

NASA Technical Reports Server (NTRS)

Finite elasticity analysis is extended to the 110 direction, where off axis strain symmetry is not present, and the third order elastic data are obtained for diamond. The compressive yield strengths of perfect diamond crystals loaded in the 100, 110, and 111 directions are predicted to be 2.2, 5.6, and 2.8 Mbars, respectively, while the corresponding tensile fracture strengths are 1.0, 0.5, and 0.5 Mbars. From these results and from Hertz theory it is predicted that ring fracture of spherically tipped diamonds pressed against a flat will occur at pressures of 1.8-1.9 Mbars, substantially below the yield pressure (above 3 Mbars). Modification of the tip shape leads to a predicted increase in the pressure at which fracture occurs.

Whitlock, J.; Ruoff, A. L.

1981-01-01

356

Porous boron-doped diamond/carbon nanotube electrodes.  

PubMed

Nanostructuring boron-doped diamond (BDD) films increases their sensitivity and performance when used as electrodes in electrochemical environments. We have developed a method to produce such nanostructured, porous electrodes by depositing BDD thin film onto a densely packed "forest" of vertically aligned multiwalled carbon nanotubes (CNTs). The CNTs had previously been exposed to a suspension of nanodiamond in methanol causing them to clump together into "teepee" or "honeycomb" structures. These nanostructured CNT/BDD composite electrodes have been extensively characterized by scanning electron microscopy, Raman spectroscopy, cyclic voltammetry, and electrochemical impedance spectroscopy. Not only do these electrodes possess the excellent, well-known characteristics associated with BDD (large potential window, chemical inertness, low background levels), but also they have electroactive areas and double-layer capacitance values ?450 times greater than those for the equivalent flat BDD electrodes. PMID:24392640

Zanin, H; May, P W; Fermin, D J; Plana, D; Vieira, S M C; Milne, W I; Corat, E J

2014-01-22

357

Methane-related diamond crystallization in the Earth's mantle: Stable isotope evidences from a single diamond-bearing xenolith  

E-print Network

(formerly called the Premier mine) in South Africa. Diamond sizes range from 0.0005 to 0.169 carats (0Methane-related diamond crystallization in the Earth's mantle: Stable isotope evidences from a single diamond-bearing xenolith E. Thomassot a,b,, P. Cartigny a , J.W. Harris c , K.S. (Fanus) Viljoen d

Cartigny, Pierre

358

Biocompatibility and Surface Studies of Microwave CVD Diamond Films  

NASA Astrophysics Data System (ADS)

The structure and surface properties of a variety of diamond and diamond like carbon films were studied at the nano-scale, in an attempt to assess the biocompatibility of these surfaces. The process of microwave chemical vapor deposition was used to deposit undoped diamond, nitrogen doped diamond, diamond with a titanium monolayer, and diamond-like carbon samples. The contact angles of de-ionized water droplets on the surface of the samples were measured to analyze the surface energy of each film. The rms roughness values of the diamond films measured by atomic force microscopy were also used in determining surface characteristics. Surface treatments of hydrogen passivation, and oxidization were applied to the surface of each film. Hydrogen passivation of the undoped diamond, and nitrogen doped diamond surfaces increases the contact angle on average 30 degrees. Oxidation of the surface decreases the contact angle on average 20 degrees. The surface treatments did not significantly change the contact angle of the diamond like carbon films. Protein adsorption is the first event to take place at a tissue/material interface of an implant into the body, and fibrinogen is the major surface protein, which initiates coagulation and inflammation in the body. The adsorption of fibrinogen was used as an indicator of the biocompatibility of these diamond materials. Fibrinogen was applied to the diamond, and diamond like carbon films. A correlation between contact angle/surface energy, roughness, and the fibrinogen adsorption of these diamond surfaces is reported. There was no significant change in the contact angles following the application of fibrinogen to the surface of the films. This could indicate the biocompatibility of the diamond films. This work supported by the NSF REU program at NCSU and a Physical Sciences Student Research grant from MSU.

Davis, Brian; Garguilo, J. M.; Koeck, F. A. M.; Nemanich, R. J.; Price, K. J.

2002-03-01

359

Manufacturing diamond films using copper vapour lasers  

SciTech Connect

Fifty nanosecond pulses of visible light have been used to produce hard, hydrogen-free diamond-like-carbon (DLC) films at irradiances between 5 x 10{sup 8} and 5 x 10{sup 10} W/cm{sup 2} The films were characterized by a number of techniques including: Raman spectroscopy, Electron Energy Loss Spectroscopy (EELS), atomic force microscopy, and spectroscopic ellipsometry. The cost for manufacturing DLC with high average power, high-pulse repetition frequency, visible light is low enough to compete with other diamond thin film production methods.

McLean, M., LLNL

1996-01-08

360

Field electron emission based on resonant tunneling in diamond/CoSi2/Si quantum well nanostructures  

PubMed Central

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

Gu, Changzhi; Jiang, Xin; Lu, Wengang; Li, Junjie; Mantl, Siegfried

2012-01-01

361

Low on-resistance diamond field effect transistor with high-k ZrO2 as dielectric  

NASA Astrophysics Data System (ADS)

Although several high-k insulators have been deposited on the diamond for metal-insulator-semiconductor field effect transistors (MISFETs) fabrication, the k values and current output are still not fully satisfactory. Here, we present a high-k ZrO2 layer on the diamond for the MISFETs. The k value for ZrO2 is determined by capacitance-voltage characteristic to be 15.4. The leakage current density is smaller than 4.8 × 10-5 A.cm-2 for the gate voltage ranging from -4.0 to 2.0 V. The low on-resistance MISFET is obtained by eliminating source/drain-channel interspaces, which shows a large current output and a high extrinsic transconductance. The high-performance diamond MISFET fabrication will push forward the development of power devices.

Liu, Jiangwei; Liao, Meiyong; Imura, Masataka; Tanaka, Akihiro; Iwai, Hideo; Koide, Yasuo

2014-09-01

362

X-ray topographic study of diamonds: implications for the genetic nature of inclusions in diamond  

NASA Astrophysics Data System (ADS)

In recent years, several studies have focused on the growth conditions of the diamonds through the analysis of the mineral inclusions trapped in them (Howell, 2012 and references therein). Nevertheless, to obtain rigorous information about chemical and physical conditions of diamond formation, it is crucial to determine if the crystallization of the inclusions occurred before (protogenetic nature), during (syngenetic nature) or after (epigenetic nature) the growth of diamond (Wiggers de Vries et al., 2011). X-ray topography (XRDT) can be a helpful tool to verify the genetic nature of inclusions in diamond. This technique characterizes the extended defects and reconstructs the growth history of the samples (Agrosì et al., 2013 and references therein) and, consequently contributes to elucidation of the relationship between the inclusions and the host-diamond. With this aim a diamond from the Udachnaya kimberlite, Siberia, was investigated. The diamond crystal was the one previously studied by Nestola et al. (2011) who performed in-situ crystal structure refinement of the inclusions to obtain data about the formation pressure. The inclusions were iso-oriented olivines that did not show evident cracks and subsequently could not be considered epigenetic. Optical observations revealed an anomalous birefringence in the adjacent diamond and the inclusions had typical "diamond-imposed cubo-octahedral" shape for the largest olivine. The diffraction contrast study shows that the diamond exhibits significant deformation fields related to plastic post growth deformation. The crystallographic direction of strains was established applying the extinction criterion. Section topographs were taken to minimize the overlapping of the strain field associate with the different defects and revealed that no dislocations nucleated from the olivine inclusions. Generally, when a solid inclusion has been incorporated in the growing crystal, the associated volume distortion can be minimized by means the nucleation of dislocations and/or twinning (Agrosì et al., 2013). In our case, the specific and significant features - the olivine inclusions showing a "diamond imposed cubo-octahedral shape" and no dislocation nucleation - that characterize this sample will be discussed in detail. References: F Nestola, P Nimis, L Ziberna, M Longo, A Marzoli, JW Harris, MH Manghnani (2011): Earth and Planetary Science Letters 305 (1), 249-255. Howell, D. (2012): Eur. J. Mineral., 24, 575-585. Wiggers de Vries D.F., Drury M.R., de Winter D.A. M., Bulanova G P., Pearson D. G., Davies G. R. (2011): Contrib. Mineral. Petrol. 161, 565-579. Agrosì G., Tempesta G., Scandale E., Harris J.W. (2013): Eur. J. Mineral, 25 (4), 551-559.

Agrosì, Giovanna; Nestola, Fabrizio; Tempesta, Gioacchino; Bruno, Marco; Scandale, Eugenio; Harris, Jeff W.

2014-05-01

363

Device Design of Diamond Schottky-pn Diode for Low-Loss Power Electronics  

NASA Astrophysics Data System (ADS)

The device parameters of a novel diamond diode, namely, a Schottky-pn diode (SPND), are analyzed to realize a fast switching time, a low on-resistance, and a high blocking voltage simultaneously. The SPND is composed of an n-type active layer sandwiched between a highly doped p+-type layer and a Schottky metal. The key structure is the fully depleted n-type layer. From the simulations of the energy band diagram based on the key structure of the SPND using Poisson's equations, it is concluded that the low donor density in the n-type layer and the high acceptor density in the p+-type layer are key points for the high-performance SPND.

Makino, Toshiharu; Kato, Hiromitsu; Takeuchi, Daisuke; Ogura, Masahiko; Okushi, Hideyo; Yamasaki, Satoshi

2012-09-01

364

Chemical Vapor Deposition of Diamond Coatings onto Dental Burrs  

NASA Astrophysics Data System (ADS)

Chemical vapor deposition (CVD) is an elegant and promising technology for coating dental tools such as burrs and microdrills with a hard diamond coating in order to improve their performance and lifespan. The diamond coatings are formed by decomposing a mixture of methane and hydrogen on the surface of the heated components in a reactor under vacuum conditions. The CVD diamond-coated burrs give a superior performance compared to the conventional diamond burrs made by binding diamond particles onto the metal surface. In addition, the risks of contamination of oral tissues are reduced. Interestingly, the thermal characteristics of diamond are similar to those of dentine and therefore the drilling operation is more comfortable for the patient. These properties of the CVD diamond dental burr make it a highly desirable alternative to the conventional dental burr for odontological applications. If the process can be scaled up to coat multiple substrates, the CVD coated dental burr may replace the conventional dental burr.

Ahmed, Waqar; Sein, Htet; Rajab, Hussam; Jackson, Mark

2003-06-01

365

Development of chemical vapor deposition diamond burrs using hot filament  

NASA Astrophysics Data System (ADS)

The fabrication of boring tools (burrs) for dentistry with the use of a hot-filament chemical vapor deposition (CVD) system, to form the diamond abrading structure, is reported here. The diamond was synthesized from a methane/freon gas mixture diluted in hydrogen. Comparative drilling tests with conventional diamond burrs and the CVD diamond burrs in borosilicate glasses demonstrated a lifetime more than 20 times larger for the CVD diamond burrs. Also, heat flow experiments in dentine showed that the CVD diamond burrs induce temperature gradients of the same order as the conventional ones. These characteristics of the CVD diamond burrs are highly desirable for odontological applications where the burrs' lifetime and the low temperature processing are essential to the quality and comfort of the treatment.

Trava-Airoldi, V. J.; Corat, E. J.; Peña, A. F. V.; Leite, N. F.; Valera, M. C.; Freitas, J. R.; Baranauskas, V.

1996-05-01

366

Diamond technology for Endo-KEW seeker windows  

NASA Astrophysics Data System (ADS)

The attractions of low pressure synthesized diamond films and thick diamond slabs for Endo-KEW seeker window applications are presented. The use of diamond in two forms, as thin films in combination with silicon windows and as thick, free standing windows are discussed. A novel concept of internally cooled silicon/diamond windows that can withstand the rigors of high velocity, endo-atmospheric flight, that do not suffer from window irradiation resulting from aero-optic effects and have the potential for application as multispectral windows is discussed. The synthesis and processing aspects of thin diamond films and free standing diamond windows are presented with an analysis of the significant advantages of silicon and diamond for the fabrication of Endo-KEW seeker windows.

Ravi, K. V.

1992-05-01

367

Influence of environment and temperature on tribological behavior of diamond and diamond-like coatings  

Microsoft Academic Search

The paper presents an analysis of publications dealing with the study of the effect of the environment (vacuum and gaseous\\u000a or liquid medium), the counterbody material, and the temperature on the tribological behavior of diamond and diamond-like\\u000a coatings. The high antifriction properties of the coatings are explained by their graphitizing during friction and the specific\\u000a role of hydrogen.

A. P. Semenov; M. M. Khrushchov

2010-01-01

368

Eclogitic Minerals in Diamond: MORB Reincarnated  

Microsoft Academic Search

Following participation in creation of oceanic lithosphere, MORB and related rocks can be altered, contaminated and eventually subducted. Evidence for these processes survives in Alpine eclogites, subcratonic eclogite xenoliths and especially in some diamonds. One of the key pieces of evidence exists as anomalous oxygen isotope values of silicates in these high-pressure assemblages. Sea floor alteration changes the d18-O VSMOW

D. J. Schulze; B. Harte; J. W. Valley; D. Channer

2003-01-01

369

Ultrasensitive Magnetometry and Imaging with NV Diamond  

E-print Network

nitrogen (14N) electron must be suppressed because it causes linewidth broadening. Magic angle spinning is an accepted technique to push T2 and T2 * down toward the T1 limit. An experiment was performed using the HPHT diamond with a high concentration...

Kim, Changdong

2011-08-08

370

The Geopolitical Setting of Conflict Diamonds  

Microsoft Academic Search

September 11, 2001 will live in infamy. Ideological differences have also led to senseless atrocities in Angola, Congo Republic, Sierra Leone, and Liberia. Hundreds of thousands have died, scores mutilated, and millions displaced. These have gone virtually unnoticed for decades. Unnoticed that is until it became evident that these barbaric acts were fueled by the sale or bartering of diamonds

S. E. Haggerty

2002-01-01

371

The Diamond Eye Image Mining System  

Microsoft Academic Search

Diamond Eye is a new image mining system that enables users (scientists) to locate and catalog objects of interest in large image collections. This system provides a platform-independent interface to novel image mining algorithms, as well as to computational and database resources that allow scientists to browse, annotate and search through images and analyze the resulting object catalogs

Joseph Roden; Michael C. Burl; Charless Fowlkes

1999-01-01

372

wvBLACK DIAMONDS table of contents  

E-print Network

wvBLACK DIAMONDS table of contents CEMR Distinguished Lecture experience in the coal mining industry, 25 with the WVCA. He is responsible for legislative, regulatory, and as co-chair of the Mountaintop Mining Coalition. The former owner of a safety training consulting firm

Mohaghegh, Shahab

373

wvBLACK DIAMONDS Engineering and  

E-print Network

wvBLACK DIAMONDS College of Engineering and Mineral Resources DepartmentofMiningEngineering table in Mining Engineering at WVU. Christopher Bise, the Chair of the Department of Mining Engineering invited. Robert E. Murray is president of Murray Energy Corp., the largest privately owned coal mining company

Mohaghegh, Shahab

374

Quantum Information NV Centers in Diamond  

E-print Network

of testing quantum mechanics · Temporal versus Spatial inequalities · Temporal Bell Inequality (TBI) based to violate TBI ­ Flash green light to put into excited NV- state #12;Set up for the diamond · Electron Spin the resulting TBI graph #12;VBI Conclusion · Violated TBI! ­ Ove

Budker, Dmitry

375

Diamond film by hot filament CVD method  

NASA Technical Reports Server (NTRS)

Diamond synthesis by the hot filament CVD method is discussed. A hot filament decomposes gas mixtures and oxygen containing organic compounds such as alcohols. which are carbon sources. The resulting thin films, growth mechanisms, and characteristics and problems associated with the hot filament CVD method are analyzed and evaluated.

Hirose, Y.

1988-01-01

376

Microform calibration uncertainties of Rockwell diamond indenters  

SciTech Connect

The Rockwell hardness test is a mechanical testing method for evaluating a property of metal products. National and international comparisons in Rockwell hardness tests show significant differences. Uncertainties in the geometry of the Rockwell diamond indenters are largely responsible for these differences. By using a stylus instrument, with a series of calibration and check standards, and calibration and uncertainty calculation procedures, the authors have calibrated the microform geometric parameters of Rockwell diamond indenters. These calibrations are traceable to fundamental standards. The expanded uncertainties are {+-} 0.3 {micro}m for the least-squares radius; {+-} 0.01{degree} for the cone angle; and {+-} 0.025 for the holder axis alignment calibrations. Under ISO and NIST guidelines for expressing measurement uncertainties, the calibration and uncertainty calculation procedure, error sources, and uncertainty components are described, and the expanded uncertainties are calculated. The instrumentation and calibration procedure also allows the measurement of profile deviation from the least-squares radius and cone flank straightness. The surface roughness and the shape of the spherical tip of the diamond indenter can also be explored and quantified. The calibration approach makes it possible to quantify the uncertainty, uniformity, and reproducibility of Rockwell diamond indenter microform geometry, as well as to unify the Rockwell hardness standards, through fundamental measurements rather than performance comparisons.

Song, J.F.; Rudder, F.F. Jr.; Vorburger, T.V.; Smith, J.H. [National Inst. of Standards and Technology, Gaithersburg, MD (United States)

1995-09-01

377

Microform calibration uncertainties of Rockwell diamond indenters  

Microsoft Academic Search

The Rockwell hardness test is a mechanical testing method for evaluating a property of metal products. National and international comparisons in Rockwell hardness tests show significant differences. Uncertainties in the geometry of the Rockwell diamond indenters are largely responsible for these differences. By using a stylus instrument, with a series of calibration and check standards, and calibration and uncertainty calculation

J. F. Song; F. F. Jr. Rudder; T. V. Vorburger; J. H. Smith

1995-01-01

378

Diamond Raman laser in eye safe region  

NASA Astrophysics Data System (ADS)

The goal of this work was the external cavity CVD diamond Raman laser generating at wavelength of 1.63 ?m which belongs to an eye safe region. As the Raman medium a sample of CVD grown single diamond crystal was used. The crystal was grown in the [100] direction and after cutting, the sample sides were formed by {110} planes. The diamond crystal sample dimensions were 5 mm × 5 mm × 2 mm and it had no anti-reflection coatings. As a pumping radiation source the compact Q-switched Nd:YAP laser operating at the wavelength 1.34 ?m was used. The pulse duration was 12 ns. This pumping radiation was focused by the lens (f = 250 mm) perpendicularly on the diamond crystal face. The beam radius inside the crystal was 180 ?m. The 15 mm long Raman laser resonator was formed by a pumping mirror (HR @ 1.63 ?m and T = 97 % @ 1.34 ?m) and an output coupler (R = 95 % @ 1.63 ?m, r = 500 mm). The maximum generated laser output energy was 18 ?J @ 1.63 ?m for the pumping energy of 3.35 mJ corresponding to the conversion efficiency of 0.5 %. The output spatial beam profile corresponds to the fundamental Gaussian beam in both axes.

Jelinková, Helena; Kitzler, Ond?ej; Jelínek, Michal; Šulc, Jan; N?mec, Michal; Kube?ek, Václav

2011-09-01

379

Diamond Raman laser in eye safe region  

NASA Astrophysics Data System (ADS)

The goal of this work was the external cavity CVD diamond Raman laser generating at wavelength of 1.63 ?m which belongs to an eye safe region. As the Raman medium a sample of CVD grown single diamond crystal was used. The crystal was grown in the [100] direction and after cutting, the sample sides were formed by {110} planes. The diamond crystal sample dimensions were 5 mm × 5 mm × 2 mm and it had no anti-reflection coatings. As a pumping radiation source the compact Q-switched Nd:YAP laser operating at the wavelength 1.34 ?m was used. The pulse duration was 12 ns. This pumping radiation was focused by the lens (f = 250 mm) perpendicularly on the diamond crystal face. The beam radius inside the crystal was 180 ?m. The 15 mm long Raman laser resonator was formed by a pumping mirror (HR @ 1.63 ?m and T = 97 % @ 1.34 ?m) and an output coupler (R = 95 % @ 1.63 ?m, r = 500 mm). The maximum generated laser output energy was 18 ?J @ 1.63 ?m for the pumping energy of 3.35 mJ corresponding to the conversion efficiency of 0.5 %. The output spatial beam profile corresponds to the fundamental Gaussian beam in both axes.

Jelinková, Helena; Kitzler, Ond?ej; Jelínek, Michal; Šulc, Jan; N?mec, Michal; Kube?ek, Václav

2012-02-01

380

In-situ analysis of diamonds and their inclusions from the Diavik Mine, Northwest Territories, Canada: Mapping diamond growth  

NASA Astrophysics Data System (ADS)

Results are presented here of an in-situ study of diamonds from the A154 South kimberlite pipe at the Diavik diamond mine, Northwest Territories, Canada. One hundred and ten diamonds were selected from run of mine production on the basis of morphology and visible inclusions. Diamonds that crystallized as cubes have a higher incidence of fluorescence in response to UV light than those that have crystallized in the octahedral primary form. Fifty-one diamonds were cut and polished to expose included mineral grains and to allow for imaging of internal structure. Mineral inclusions were analysed in-situ for major element composition using electron microbeam methods. Internal zonation of the diamonds was imaged using cathodoluminescence in thirteen P-type diamonds, two U-type diamonds, nine E-type diamonds, and two diamonds with only sulfide inclusions of indeterminate paragenesis. Inclusions of Fe ± Cu ± Ni sulfide, magnesian chromite, ferropericlase, chromian diopside, forsteritic olivine, omphacite, and enstatite occur in order from most to least abundant. The chromite inclusions are lower in Mg than the worldwide average. At least six of the sulfide inclusions are significantly heterogeneous. Equilibration temperature and pressure conditions for the diopside inclusions indicate that the diamonds equilibrated in a region of geothermal gradient with an equivalent surface heat flow of 42 mW/m 2 over a range from 51-57 kbar and 1170-1260 °C.

Van Rythoven, A. D.; Schulze, D. J.

2009-11-01

381

Signal transduction and conversion with color centers in diamond and piezo-elements  

E-print Network

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

Jianming Cai; Fedor Jelezko; Martin B. Plenio

2014-04-25

382

The Influence of Volcanological and Sedimentological Processes on Diamond Grade Distribution: Examples From the Ekati Diamond Mine, NWT, Canada  

NASA Astrophysics Data System (ADS)

The study of the diamond distribution within two kimberlite pipes, Fox and Koala, from the Ekati Diamond Mine, NWT, Canada, in conjunction with detailed facies models has shown several distinct relationships of deposit type and grade distribution. In both pipes the lithological facies represent grade units which can be distinguished from each other in terms of relative size and abundance of diamonds. Positive correlation of olivine grain size and abundance with diamond grade is seen, indicating that density sorting of fragmental kimberlites occurs both in pyroclastic and resedimented deposits. Though surface geological processes do not control the diamond potential of the erupting magma, they can be responsible for concentrating diamonds into economically significant proportions. A good understanding of the eruption, transport and depositional processes responsible for the individual lithological units and the diamond distribution within them is important for successful resource estimation and may lead to recognition of areas suitable for selective mining, making a marginal deposit economic.

Porritt, L. A.; Cas, R. A.; Ailleres, L.; Oshust, P.

2009-05-01

383

Diamond films grown from fullerene precursors  

SciTech Connect

Fullerene precursors have been shown to result in the growth of diamond films from argon microwave plasmas. In contradistinction to most diamond films grown using conventional methane-hydrogen mixtures, the fullerene-generated films are nanocrystalline and smooth on the nanometer scale. They have recently been shown to have friction coefficients approaching the values of natural diamond. It is clearly important to understand the development of surface morphology during film growth from fullerene precursors and to elucidate the factors leading to surface roughness when hydrogen is present in the chemical vapor deposition (CVD) gas mixtures. To achieve these goals, we are measuring surface reflectivity of diamond films growing on silicon substrates over a wide range of plasma processing conditions. A model for the interpretation of the laser interferometric data has been developed, which allows one to determine film growth rate, rms surface roughness, and bulk losses due to scattering and absorption. The rms roughness values determined by reflectivity are in good agreement with atomic force microscope (AFM) measurements. A number of techniques, including high-resolution transmission electron microscopy (HRTEM) and near-edge x-ray absorption find structure (NEXAFS) measurements, have been used to characterize the films. A mechanism for diamond-film growth involving the C{sub 2} molecule as a growth species will be presented. The mechanism is based on (1) the observation that the optical emission spectra of the fullerene- containing plasmas are dominated by the Swan bands of C{sub 2} and (2) the ability of C{sub 2} to insert directly into C-H and C-C bonds with low activation barriers, as shown by recent theoretical calculations of reactions of C{sub 2} with carbon clusters.

Gruen, D.M.; Zuiker, C.D.; Krauss, A.R.

1995-07-01

384

CVD diamond thin film for IR optics and X-ray optics  

Microsoft Academic Search

Optical quality diamond thin films have been deposited using a hot filament chemical vapor deposition (HFCVD) system. The diamond films were characterized by Raman shift spectra, X-ray diffraction spectra, scanning electron microscopy. Diamond near infrared antireflective filter window and diamond X-ray window have been fabricated using above technology. The diamond near infrared antireflective filter windows have been successfully used in

Xuantong Ying; Xinmin Xu

2000-01-01

385

Applications of diamond films and related materials; Proceedings of the 1st International Conference, Auburn, AL, Aug. 17-22, 1991  

NASA Astrophysics Data System (ADS)

The present conference discusses the nucleation and growth of diamond from hydrocarbons, the cutting tool performance of CVD thick-film diamond, the characterization of CVD diamond grinding powder, industrial applications of crystalline diamond-coated tools, standardized SEM tribometry of diamond-coated substrates, residual stress in CVD diamond films, the optical properties of CVD diamond films, polycrystalline diamond films for optical applications, and diamond growth on ferrous metals. Also discussed are ion beam-irradiation smoothing of diamond films, electronic circuits on diamond substrates, diamond-laminated surfaces for evaporative spray cooling, electron devices based on the unique properties of diamond, diamond cold cathodes, thin-film diamond microstructure applications, Schottky diodes from flame-grown diamond, diamond films for thermionic applications, methods of diamond nucleation and selective deposition, high-rate/large-area diamond film production, halogen-assisted diamond growth, the economics of diamond technology, and the optical and mechanical properties of diamondlike films.

Tzeng, Yonhua; Yoshikawa, Manasori; Murakawa, Masao; Feldman, Albert

386

Applications of diamond films and related materials; Proceedings of the 1st International Conference, Auburn, AL, Aug. 17-22, 1991  

NASA Technical Reports Server (NTRS)

The present conference discusses the nucleation and growth of diamond from hydrocarbons, the cutting tool performance of CVD thick-film diamond, the characterization of CVD diamond grinding powder, industrial applications of crystalline diamond-coated tools, standardized SEM tribometry of diamond-coated substrates, residual stress in CVD diamond films, the optical properties of CVD diamond films, polycrystalline diamond films for optical applications, and diamond growth on ferrous metals. Also discussed are ion beam-irradiation smoothing of diamond films, electronic circuits on diamond substrates, diamond-laminated surfaces for evaporative spray cooling, electron devices based on the unique properties of diamond, diamond cold cathodes, thin-film diamond microstructure applications, Schottky diodes from flame-grown diamond, diamond films for thermionic applications, methods of diamond nucleation and selective deposition, high-rate/large-area diamond film production, halogen-assisted diamond growth, the economics of diamond technology, and the optical and mechanical properties of diamondlike films.

Tzeng, Yonhua (editor); Yoshikawa, Manasori (editor); Murakawa, Masao (editor); Feldman, Albert (editor)

1991-01-01

387

Synthetic single crystal diamond as a fission reactor neutron flux monitor  

NASA Astrophysics Data System (ADS)

Thermal neutron flux monitors were fabricated using chemical vapor deposited single crystal diamond in a p-type/intrinsic/metal/Li6F layered structure. They were placed 80cm above the core midplane of a 1MW research fission reactor, where the maximum neutron flux is 2.2×109neutrons/cm2s. Good stability and reproducibility of the device response were observed over the whole reactor power range. A 150000counts/s count rate was measured at the maximum reactor power with no degradation of the detector signal. As the multiple pile-up process due to the slow readout electronics is accounted for, an excellent linearity of the diamond response is observed.

Marinelli, Marco; Milani, E.; Prestopino, G.; Tucciarone, A.; Verona, C.; Verona-Rinati, G.; Angelone, M.; Lattanzi, D.; Pillon, M.; Rosa, R.; Santoro, E.

2007-04-01

388

sup 3 He in diamonds: The cosmogenic component  

SciTech Connect

The authors have measured {sup 3}He and {sup 4}He concentrations in a number of diamonds received directly from mines as well as in industrial samples. None of the authors diamonds recovered from underground mining has a {sup 3}He/{sup 4}He ratio, R, exceeding 3 R{sub A}. One of the five diamonds from the Consolidated Diamond mine has a ratio of 142 R{sub A}. Based on a number of facts: (i) the Zaire alluvial diamonds have >29% cosmogenic {sup 3}He; (ii) some documented high {sup 3}He/{sup 4}He ratio diamonds are from alluvial mines, and (iii) the apparent diffusion coefficients of {sup 3}He and {sup 4}He in diamonds are ten orders of magnitude too large to preserve diamond helium ratios in the mantle. They conclude that Ozima's hypothesis of high primordial {sup 3}He/{sup 4}He ratios in diamonds exceeding MORB ratios is not required. The present data are readily explainable as the result of cosmogenic and nucleogenic production of {sup 3}He within the diamonds.

Lal, D.; Craig, H.; Wacker, J.F.; Poreda, R. (Univ. of California, San Diego, La Jolla (USA))

1989-02-01

389

In situ analysis of carbon isotopes in North American diamonds  

NASA Astrophysics Data System (ADS)

Diamonds from three North American kimberlite occurrences were investigated with cathodoluminescence (CL) and secondary ion mass spectrometry (SIMS) to determine their growth history and carbon isotope composition. Diamonds analyzed include fourteen from Lynx (Quebec), twelve from Kelsey Lake (Colorado) and eleven from A154 South (Diavik mine, Northwest Territories). Growth histories for the diamonds vary from simple to highly complex based on their CL images and depending on the individual stone. Deformation laminae are evident in CL images of the Lynx diamonds that typically are brownish in color. Two to five points per diamond were analyzed by SIMS for carbon isotope composition. Sample heterogeneity is minimal in terms of ?13C (vs. PDB) values. Points within single diamond had a maximum range of approximately 1 ‰. The results for the A154 South (-6.4 to -3 ‰) and Kelsey Lake (-11.2 to -2.6 ‰) stones were in accordance with earlier reported values. The Lynx kimberlite stones have anomalously high ratios and range from -3.5 to +0.2 ‰ (average: -1.4 ‰). No previous carbon isotope analyses on diamonds from Lynx or any other eastern Superior craton occurrence have been published. The diamonds possess carbon isotope ratios higher than those for the only other reported analyses of Superior craton diamonds at Wawa, Ontario (-5.5 to -1.1 ‰). In global terms, the only published analyses of diamonds that consistently contain even higher values are those from New South Wales (Australia). However, these diamonds are alluvial and contain eclogitic and/or exotic mineral inclusions. The Lynx diamonds are entirely peridotitic and from a primary deposit. The unusually low (i.e. >-5‰) ?13C values of the Lynx (and Wawa) diamonds may indicate a different carbon reservoir for the Superior craton mantle as compared to other cratons.

van Rythoven, A. D.; Hauri, E. H.; Wang, J.; McCandless, T.; Shirey, S. B.; Schulze, D. J.

2010-12-01

390

Real-Time Spectro-Ellipsometry Study of the Growth of Thin Film Diamond and Hydrogenated Amorphous Carbon.  

NASA Astrophysics Data System (ADS)

Real time spectroscopic ellipsometry (RTSE) has been developed to study the nucleation and growth of vacuum deposited thin films for the first time--specifically, chemical vapor deposition (CVD) diamond and ion beam-deposited hydrogenated amorphous carbon (a-C:H) thin films. A rotating polarizer ellipsometer with an optical multichannel analyzer (OMA) detection system is coupled with a deposition chamber to obtain spectra from 1.5 eV to 4.5 eV during thin film growth typically at a time resolution of 3.2 s and a repetition period of 15 s. Comprehensive optical characterization of the a-C:H thin films by direct ion beam deposition technique has been carried out. The bulk dielectric function of a-C:H and an approximate dielectric function for the interface layer has been deduced. As a result, the optical gap of a-C:H has been determined, representing the first such determination from real-time data. Finally, the time evolution of the bulk and interface layer thicknesses have also been obtained. Quantitative information of optical quality diamond thin films has been deduced from high accuracy ex situ spectroscopic ellipsometry (SE) measurements. The optical functions of CVD diamond film and its sp^2 C bonding defects are determined. RTSE was also applied to monitor surface modification of optical quality diamond films during exposure to low energy Ar and H ion beams, and atomic H. Monolayer sensitivity to optically absorbing sp^2 C bonding at the diamond surface is attained even in the presence of surface roughness. The feasibility of ion beam surface densification and smoothing is also demonstrated. Finally, RTSE is applied to study the processes occurring in the initial nucleation of thin film diamond by heated-filament assisted CVD. These studies reveal that an accurate measurement of the true temperature of the substrate-surface can be obtained from the energy position of critical points in the c-Si band structure. For the diamond nucleation and growth, the evolution of the diamond film mass thickness has been deduced from RTSE analysis. The results of final film mass thickness and film thickness from SE analysis are found to be in good agreement with those from scanning electron microscopy.

Cong, Yue

391

Synthesis of growth-type polycrystalline diamond compact (PDC) using the solvent Fe55Ni29Co16 alloy under HPHT  

NASA Astrophysics Data System (ADS)

A growth-type polycrystalline diamond compact (PDC) was synthesized under high temperature and high pressure (HPHT). The infiltration technique was used with an Fe55Ni29Co16 (KOV) alloy as the sintering solvent. The morphology and weight ratio of the PDC were investigated through scanning electron microscopy (SEM) and electron dispersion spectroscopy (EDS). Note that the KOV alloy evenly infiltrated throughout the polycrystalline diamond (PCD) layer and WC-Co substrate in a short sintering time due to its low viscosity and high soakage capability. A transition layer confirmed the presence of the M x C phase near the interface of the PDC, which can make the diamond layer and WC-Co substrate combine as a complex material. X-ray diffraction (XRD) performed on the PCD layer confirmed the presence of cubic diamond, WC, cubic CoC x , the high temperature cubic phase of ?-Co, the alloy phase of FeNi x , and no graphite phase. Besides, a surface residual stress of the PCD layer, measured with reasonable accuracy using micro-Raman spectroscopy, is found to be a homogeneous compressive stress with an average value of 0.16 GPa, much lower than that of the powders-mixing method.

Jia, HongSheng; Jia, XiaoPeng; Ma, HongAn; Li, HaiBo

2012-08-01

392

Effect of Titanium Addition on the Thermal Properties of Diamond/Cu-Ti Composites Fabricated by Pressureless Liquid-Phase Sintering Technique  

PubMed Central

In this study, minor-addition elements such as Si, Co, Cr, W, Mo, and Ti were added to matrix to improve the wettability between the diamonds and Cu matrix. The pressureless liquid-phase sintering technique adopted in this study provides a low-cost method for producing diamond/Cu composites with high potential for industrial mass production. Thermal properties of the diamond/Cu-Ti composites fabricated by pressureless liquid-phase sintering at 1373?K with variation in Ti contents were thoroughly investigated. XRD and TEM analysis show that TiC layer formed in the interface between Cu and diamond. The composites exhibited thermal conductivity as high as 620?W/m·K for 50?vol% diamond/Cu-0.6? at % Ti composite with diamond particle size of 300?µm. This value comes up to 85% of the thermal conductivity calculated by the Hasselman and Johnson (H-J) theoretical analysis. Under these conditions, a suitable coefficient of thermal expansion of 6.9?ppm/K was obtained. PMID:24715816

Chung, Chih-Yu; Chu, Chao-Hung; Lee, Mu-Tse; Lin, Chun-Ming; Lin, Su-Jien

2014-01-01

393

Diamond Shaving of Contaminated Concrete Surfaces  

SciTech Connect

Decommissioning and decontamination of existing facilities presents technological challenges. One major challenge is the removal of surface contamination from concrete floors and walls while eliminating the spread of contamination and volumetric reduction of the waste stream. Numerous methods have been tried with a varying degree of success. Recent technology has made this goal achievable and has been used successfully. This new technology is the Diamond Floor Shaver and Diamond Wall shaver. The Diamond Floor Shaver is a self-propelled, walk behind machine that literally shaves the contaminated concrete surface to specified depths. This is accomplished by using a patented system of 100 dry cutting diamond blades with offset diamond segments that interlock to provide complete shaving of the concrete surface. Grooves are eliminated which allows for a direct frisk reading to analyze results. When attached to an appropriate size vacuum, the dust produced is 100% contained. Dust is collected in drums ready for disposition and disposal. The waste produced in shaving 7,500 square feet at 1/8 inch thickness would fill a single 55 gallon drum. Production is dependent on depth of shaving but averages 100 square feet per hour. The wall shaver uses the same patented diamond drum and blades but is hydraulically driven and is deployed using a robotic arm allowing its operation to be to totally remote. It can reach ceilings as high as 20 feet. Numerous small projects were successfully completed using this technology. Large scale deployment came in 2003. Bluegrass, in conjunction with Bartlett Services, deployed this technology to support decontamination activities for closing of the Rocky Flats nuclear weapons site. Up to six floor shavers and one wall shaver were deployed in buildings B371 and B374. These buildings had up to one half-inch, fixed plutonium and beryllium contamination. Hundred-thousands of square feet of floors and walls were shaved successfully to depths of up to one half inch. Decontamination efforts were so successful the balance of the buildings could be demolished using conventional methods. The shavers helped keep the project on schedule while the vacuum system eliminated the potential for contaminants becoming airborne.

Mullen, Lisa K. [Bluegrass Concrete Cutting Inc., 107 Mildred Street PO Box 427, Greenville, Alabama 36037 (United States)

2008-01-15

394

Polishing is made cheaper by disposable diamond-impregnated abrasive cloth  

NASA Technical Reports Server (NTRS)

Diamond impregnated abrasive cloth eliminated expensive diamond pastes and was economically disposed of to avoid contamination. Cloth was spunbonded nylon, but any napless fabric could be used. Cloth was sprayed with diamond abrasive gel.

Harper, F. J.

1972-01-01

395

Diamond optics V; Proceedings of the Meeting, San Diego, CA, July 20, 21, 1992  

NASA Astrophysics Data System (ADS)

Attention is given to unconventional diamond and DLC deposition processes, deposition characterization; diamond characterization, and structural, thermal, and optical properties. Particular attention is given to diamond CVD growth chemistry; a synthesis technique of diamondlike carbon films by a laser ablation ion source in the atmosphere; mass spectrometry studies of diamond deposition; characterization of electron cyclotron resonance plasmas for diamond deposition; thinning and polishing of diamond films by a diffusional reaction with metals; twin quituplets in a CVD diamond; characterization of diamond films deposited by hot-filament CVD using CF4 as a doping gas by Raman spectroscopy, FTIR spectroscopy, and atomic force microscopy; properties of optically smooth diamond thin films produced by ECR-PACVD; calculations of energy barriers to CVD diamon growth; thermal properties of optical-quality diamond films; attenuated total reflectance infrared absorption in CVD diamond films; and optical properties of boron-doped diamond films. (No individual items are abstracted in this volume)

Feldman, Albert; Sandor, Holly

396

Processing of Photonic Crystal Nanocavity for Quantum Information in Diamond  

E-print Network

The realization of photonic crystals (PC) in diamond is of major importance for the entire field of spintronics based on fluorescent centers in diamond. The processing steps for the case of diamond differ from those commonly used, due to the extreme chemical and mechanical properties of this material. The present work summarizes the state of the art in the realization of PC's in diamond. It is based on the creation of a free standing diamond membrane into which the desired nano-sized patterns are milled by the use of Focused-Ion-Beam (FIB). The optimal fabrication-oriented structure parameters are predicted by simulations. The milling strategies, the method of formation the diamond membrane, recipes for dielectric material-manipulation in FIB and optical characterization constraints are discussed in conjunction with their implication on PC cavity design. The thus produced structures are characterized via confocal photoluminescence.

Bayn, Igal; Lahav, Alex; Salzman, Joseph; Kalish, Rafi; Fairchild, Barbara A; Prawer, Steven; Barth, Michael; Benson, Oliver; Wolf, Thomas; Siyushev, Petr; Jelezko, Fedor; Wrachtrup, Jorg

2010-01-01

397

On the Fabrication and Behavior of Diamond Microelectromechanical Sensors (DMEMS)  

NASA Technical Reports Server (NTRS)

CVD (chemically vapor deposited) diamond films can be processed similar to "conventional" semiconductor device fabrication and as such can be used to achieve microelectromechanical structures (MEMS) also similar to, for example, silicon technology. Very small cantilever beams, membranes, stripes, tips, etc. can be constructed in doped and undoped diamond films and offer an array of choices in diamond with its known superior properties such as elastic modulus, high temperature semiconduction, high thermal conductivity, very low coefficient of expansion and numerous other diamond parameters. This paper will review the construction and behavior of the second generation DMEMS devices comprised as an accelerometer with a diamond diaphragm for use in very high G applications and a diamond pressure sensor for very high temperature and frequency response.

Holmes, K.; Davidson, J. L.; Kang, W. P.; Howell, M.

2001-01-01

398

Electronic and physico-chemical properties of nanometric boron delta-doped diamond structures  

NASA Astrophysics Data System (ADS)

Heavily boron doped diamond epilayers with thicknesses ranging from 40 to less than 2 nm and buried between nominally undoped thicker layers have been grown in two different reactors. Two types of [100]-oriented single crystal diamond substrates were used after being characterized by X-ray white beam topography. The chemical composition and thickness of these so-called delta-doped structures have been studied by secondary ion mass spectrometry, transmission electron microscopy, and spectroscopic ellipsometry. Temperature-dependent Hall effect and four probe resistivity measurements have been performed on mesa-patterned Hall bars. The temperature dependence of the hole sheet carrier density and mobility has been investigated over a broad temperature range (6 K < T < 450 K). Depending on the sample, metallic or non-metallic behavior was observed. A hopping conduction mechanism with an anomalous hopping exponent was detected in the non-metallic samples. All metallic delta-doped layers exhibited the same mobility value, around 3.6 ± 0.8 cm2/Vs, independently of the layer thickness and the substrate type. Comparison with previously published data and theoretical calculations showed that scattering by ionized impurities explained only partially this low common value. None of the delta-layers showed any sign of confinement-induced mobility enhancement, even for thicknesses lower than 2 nm.

Chicot, G.; Fiori, A.; Volpe, P. N.; Tran Thi, T. N.; Gerbedoen, J. C.; Bousquet, J.; Alegre, M. P.; Piñero, J. C.; Araújo, D.; Jomard, F.; Soltani, A.; De Jaeger, J. C.; Morse, J.; Härtwig, J.; Tranchant, N.; Mer-Calfati, C.; Arnault, J. C.; Delahaye, J.; Grenet, T.; Eon, D.; Omnès, F.; Pernot, J.; Bustarret, E.

2014-08-01

399

An infrared investigation of inclusion-bearing diamonds from the Venetia kimberlite, Northern Province, South Africa : implications for diamonds from craton-margin settings  

Microsoft Academic Search

The Venetia kimberlites in the Northern Province of South Africa sampled diamonds from the lithosphere underlying the Central Zone of the Limpopo Belt. Given the general correlation of diamond-bearing kimberlites with old stable cratons, this tectonic setting is somewhat anomalous and, therefore, it is desirable to characterise the diamonds in terms of their infrared characteristics. A suite of diamonds of

2002-01-01

400

Two photon excited fluorescence from diamond nanoparticles  

NASA Astrophysics Data System (ADS)

The possibility of two photon eaxcited fluorescence by diamond nanoparticles is an interesting nonlinear phenomenon. We have grown 20-100 nm diamond nanoparticles by using chemical vapor deposition (CVD) and characterized their properties by using complementary techniques of AFM, SEM, and Raman spectroscopy.footnotetextR. Chakraborty, S. C. Sharma, and J. K. LaRoque, J. Nano Research, 12, 1123 (2010)^,footnotetextR. Chakraborty and S. C. Sharma, Physica B, 406, 4170 (2011) In this work, we have utilized femtosecond laser based two-photon excitation to study the emission of visible light (˜ 530 nm) as functions of the excitation wavelength (750-850 nm), excitation power, and size of the NPs. These results and their potential applications will be discussed.

Singh, Ankit; Ajaeroh, Mathias; Mohanty, Samar; Sharma, Suresh

2012-10-01

401

CVD diamond soft x-ray detectors  

NASA Astrophysics Data System (ADS)

A class of wide band-gap semiconductor offers an attractive alternative to Si and X-ray diode (XRD) detector technologies for x-ray detection in Inertial Confinement Fusion (ICF) experiments. Because diamond presents high thermal conductivity, resistance and breakdown field, fast charge collection, low leakage current, wide band-gap, low dielectric constant, large carrier drift velocity and outstanding radiation hardness. Using chemical vapor deposited (CVD) technology, 1 mm×1 mm×2 mm, 1 mm×1 mm×3 mm diamond was synthesized. And the detectors were fielded with metal-semiconductor-metal structure. Characteristics of the detectors have been studied on a pulse laser equipment. The results indicate that the rise time and FWHM of the detector reach 60 ps and 120 ps respectively.

Hou, Lifei; Yang, Guohong; Liu, Shenye

2010-10-01

402

Carbon stardust: From soot to diamonds  

NASA Technical Reports Server (NTRS)

The formation of carbon dust in the outflow from stars and the subsequent evolution of this so called stardust in the interstellar medium is reviewed. The chemical and physical processes that play a role in carbon stardust formation are very similar to those occurring in sooting flames. Based upon extensive laboratory studies of the latter, the structure and physical and chemical properties of carbon soot are reviewed and possible chemical pathways towards carbon stardust are discussed. Grain-grain collisions behind strong interstellar shocks provide the high pressures required to transform graphite and amorphous carbon grains into diamond. This process is examined and the properties of shock-synthesized diamonds are reviewed. Finally, the interrelationship between carbon stardust and carbonaceous meteorites is briefly discussed.

Tielens, Alexander G. G. M.

1990-01-01

403

Precision diamond grinding of ceramics and glass  

SciTech Connect

A new research initiative will be undertaken to investigate the effect of machine parameters and material properties on precision diamond grinding of ceramics and glass. The critical grinding depth to initiate the plastic flow-to-brittle fracture regime will be directly measured using plunge-grind tests. This information will be correlated with machine parameters such as wheel bonding and diamond grain size. Multiaxis grinding tests will then be made to provide data more closely coupled with production technology. One important aspect of the material property studies involves measuring fracture toughness at the very short crack sizes commensurate with grinding damage. Short crack toughness value`s can be much less than the long-crack toughness values measured in conventional fracture tests.

Smith, S.; Paul, H.; Scattergood, R.O.

1988-12-01

404

Measurement of tool forces in diamond turning  

SciTech Connect

A dynamometer has been designed and built to measure forces in diamond turning. The design includes a 3-component, piezoelectric transducer. Initial experiments with this dynamometer system included verification of its predicted dynamic characteristics as well as a detailed study of cutting parameters. Many cutting experiments have been conducted on OFHC Copper and 6061-T6 Aluminum. Tests have involved investigation of velocity effects, and the effects of depth and feedrate on tool forces. Velocity has been determined to have negligible effects between 4 and 21 m/s. Forces generally increase with increasing depth of cut. Increasing feedrate does not necessarily lead to higher forces. Results suggest that a simple model may not be sufficient to describe the forces produced in the diamond turning process.

Drescher, J.; Dow, T.A.

1988-12-01

405

Analyzing the performance of diamond-coated micro end mills  

Microsoft Academic Search

A method is presented to improve the tool life and cutting performance of 300?m diameter tungsten carbide (WC) micro end mills by applying thin (<300nm) fine-grained diamond (FGD) and nanocrystalline diamond (NCD) coatings using the hot-filament chemical vapor deposition (HF-CVD) process. The performance of the diamond-coated tools has been evaluated by comparing their performance in dry slot milling of 6061-T6

C. D. Torres; P. J. Heaney; A. V. Sumant; M. A. Hamilton; R. W. Carpick; F. E. Pfefferkorn

2009-01-01

406

Science 101: Is it possible to turn coal into diamonds?  

NSDL National Science Digital Library

How cool would it be to be Lois Lane? Anytime she wants a diamond, she just has Superman use his super strength to squeeze a lump of coal. But is this really possible? Using a high enough temperature and enough pressure, can you turn coal into diamonds? To answer this, we have to address the nature and formation of coal and the nature and formation of diamonds.

Robertson, William C.

2006-12-01

407

Pulsed laser surface modifications of diamond thin films  

Microsoft Academic Search

In view of practical applications requiring diamond films, plates and membranes with very smooth surfaces, ArF excimer laser polishing treatments were applied to thin (30?m) diamond films grown by CVD on silicon substrates. The as-prepared diamond surfaces and the laser-treated parts of the samples were characterised by SEM analysis, Raman and micro-Raman spectroscopy. The presence on the laser-treated surface of

E. Cappelli; G. Mattei; S. Orlando; F. Pinzari; P. Ascarelli

1999-01-01

408

Growth and characterization of diamond film on aluminum nitride  

SciTech Connect

Diamond films have been fabricated on aluminum nitride (AlN) ceramics by hot filament (HFCVD) method. High nucleation density of more than 10{sup 9}/cm{sup 2} can be obtained on AlN wafers by the pre-irradiation of high temperature filament in the hydrogen atmosphere. Thermal properties of the composites were measured by using photothermal deflection techniques (PTD). Thermal diffusivity of diamond film/AlN depends on the quality and thickness of coated diamond films.

Cui, J.B.; Ma, Y.R.; Zhang, J.F.; Chen, H.; Fang, R.C. [Univ. of Science and Technology of China, Hefei (China)] [Univ. of Science and Technology of China, Hefei (China)

1996-07-01

409

Conduction mechanisms in undoped polycrystalline diamond films  

Microsoft Academic Search

The unadopted polycrystalline diamond films are deposited on p-type silicon substrates by a microwave plasma chemical vapor deposition (MPCVD) system. The deposition conditions are CH4?\\/H(subscript 2=0.5%, pressure equals 45 torr, power equals 2.2kW, and subtract temperature equals 885 degree(s)C. SEM was used to inspect the surface morphology, Raman Spectroscopy to determine the quality, and XPS to analyze the chemical composition.

Hsueh-Tao Chou; Chia-Chang Lee; Chia-Hsin Sun

2000-01-01

410

Electron emission from a hydrogenated diamond surface  

Microsoft Academic Search

Electron emission from a polycrystalline diamond coated silicon field emitter surface was studied using insitu exposure to various gas species during its operation. Significant enhancement of the electron emission was found after the emitting surface was exposed to hydrogen at pressures in the range 5×10?4 to 10?3 Torr. Introducing other gases such as Ne and He only suppressed the emission

J. Liu; V. V. Zhirnov; W. B. Choi; G. J. Wojak; A. F. Myers; J. J. Cuomo; J. J. Hren

1996-01-01

411

Diamond paste based immunosensor for the determination of azidothymidine.  

PubMed

An amperometric immunosensor, based on diamond paste (diamond powder and paraffin oil), has been constructed for the assay of azidothymidine (AZT). The diamond paste is impregnated with anti-AZT. The immunosensor can be used reliably for the assay of azidothymidine in its pharmaceutical formulations. The potential used for azidothymidine assay was + 240 mV vs. Ag/AgCl electrode. The surface of the immunosensor can be regenerated by simply polishing, thereby obtaining fresh immunocomposite ready to be used in a new assay. The new amperometric immunosensor, based on diamond paste, gives reliable results for the assay of AZT as raw material and from its pharmaceutical formulation. PMID:12953976

Stefan, Raluca-Ioana; Bokretsion, Rahel Girmai

2003-01-01

412

Noble gases in diamonds - Occurrences of solarlike helium and neon  

NASA Technical Reports Server (NTRS)

Seventeen diamond samples from diverse locations were analyzed for the contents of He, Ar, Kr, and Xe, and of their isotopes, using a Reynolds (1956) type glass mass spectrometer. The results disclosed a large spread in the He-3/He-4 ratios, ranging from values below atmospheric to close to the solar ratio. In particular, solarlike He-3/He-4 ratios were seen for an Australian colorless diamond composite and an Arkansas diamond, which also displayed solarlike neon isotopic ratios. Wide variation was also observed in the He-4/Ar-40 ratios, suggesting a complex history for the source regions and the diamond crystallization processes.

Honda, M.; Reynolds, J. H.; Roedder, E.; Epstein, S.

1987-01-01

413

Technology assessment for CVD-diamond-coated cutting tool inserts  

SciTech Connect

This study assesses the potential for manufacturing diamond-coated, cutting tool inserts by plasma-enhanced chemical vapor deposition (PA-CVD), an emerging technology expected to compete with the static, high-pressure sintering method presently used for the commercial production of polycrystalline diamond composite (PDC) coatings on tool inserts. Using a 4-step manufacturing model based upon microwave PA-CVD for diamond growth, insert manufacturing costs were estimated for three technology scenarios, representing the present (1988, 1st generation) near-term (1990-1999, 2nd generation), and possible long-term (2,000+, 3rd generation) development of diamond PA-CVD technology. Model calculations were then analyzed to provide research guidance on insert manufacturing characteristics, insert performance, and insert life required for the development of markets for thin (1-25 micron) and thick (500-1,000 micron) CVD-diamond-coated inserts. Analysis shows that present technology requires a prohibitively large investment in multiple reactors to grow thin-diamond-coated inserts in commercial quantities. However, technology now under development shows promise for the economical manufacture of thin-diamond-coated inserts, provided tough, adherent coatings can be achieved at high yield. The US market for thin-diamond-coated WC-Co inserts could approach 2M inserts ($25M) by the year 2000. Thick, CVD-diamond-coated inserts (500-1,000 microns), necessary for the most demanding cutting applications, will require development of new technology to be competitive with sintered PDC inserts.

Walton, K.R.; Dismukes, J.P. (Exxon Research and Engineering Co., Annandale, NJ (United States)); Krueger, R.A.; Field, F.R. III; Clark, J.P. (Massachusetts Inst. of Tech., Cambridge (United States))

1989-01-01

414

Radiation Hardness and Linearity Studies of CVD Diamonds  

E-print Network

We report on the behavior of CVD diamonds under intense electromagnetic radiation and on the response of the detector to high density of deposited energy. Diamonds have been found to remain unaffected after doses of 10 MGy of MeV-range photons and the diamond response to energy depositions of up to 250 GeV/cm^3 has been found to be linear to better than 2 %. These observations make diamond an attractive detector material for a calorimeter in the very forward region of the detector proposed for TESLA.

Behnke, T; Ghodbane, N; Imhof, A

2003-01-01

415

Radiation Hardness and Linearity Studies of CVD Diamonds  

E-print Network

We report on the behavior of CVD diamonds under intense electromagnetic radiation and on the response of the detector to high density of deposited energy. Diamonds have been found to remain unaffected after doses of 10 MGy of MeV-range photons and the diamond response to energy depositions of up to 250 GeV/cm^3 has been found to be linear to better than 2 %. These observations make diamond an attractive detector material for a calorimeter in the very forward region of the detector proposed for TESLA.

T. Behnke; M. Doucet; N. Ghodbane; A. Imhof

2002-12-09

416

An electrical conductivity inspection methodology of polycrystalline diamond cutters  

NASA Astrophysics Data System (ADS)

The polycrystalline diamond cutter (PDC) is widely used in oil and gas drilling operations. It is manufactured by sintering diamond powder onto a tungsten carbide substrate at 6 GPa and 1500 C. During sintering, molten cobalt from the substrate infiltrates the diamond table. The residual metal content correlates with cutter performance. We present an instrument that employs electrical impedance tomography capable of imaging the 3D metal content distribution in the diamond table. These images can be used to predict cutter performance as well as detect flaws.

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

2012-05-01

417

Growth, characterization and device development in monocrystalline diamond films  

NASA Astrophysics Data System (ADS)

Ordered diamond films have been deposited on single crystal Si(100) substrates via in-situ carburization followed by bias-enhanced nucleation. Photoluminescence and Raman spectroscopy have been employed to determine the time evolution of defect formation in these CVD diamond films for stages of growth spanning nucleation to continuous film formation. Analysis of the 1332/cm diamond feature showed two rates of diamond growth with a transition at the thickness where nearly complete coverage was obtained. Investigation of the various defects in the films led to the conclusions that Si atoms most likely caused the 1.68 eV optical centers at the initial stages of growth. Luminescence associated with sp squared bonding defects appeared only after a continuous film was formed. The CVD growth of diamond films on Si(100) have also been studied using scanning tunneling spectroscopy. The surface of the diamond film possessed electronic structure similar to single crystal diamond. By contrast the initial growth surface showed evidence of Beta-SiC and graphite electronic structures. The microwave performance of p-type diamond MESFET's is also under investigation. The surface breakdown model has been further refined and an activation model has been included so that free charge density as a function of temperature could be determined. Research is also underway to simulate the performance of the Kobe p-channel MESFET. A pn junction gate model is also being formulated so that the operation of a diamond JFET can be investigated.

Davis, Robert F.

1992-09-01

418

Imaging and quantum efficiency measurement of chromium emitters in diamond  

E-print Network

We present direct imaging of the emission pattern of individual chromium-based single photon emitters in diamond and measure their quantum efficiency. By imaging the excited state transition dipole intensity distribution in the back focal plane of high numerical aperture objective, we determined that the emission dipole is oriented nearly orthogonal to the diamond-air interface. Employing ion implantation techniques, the emitters were engineered with various proximities from the diamond-air interface. By comparing the decay rates from the single chromium emitters at different depths in the diamond crystal, an average quantum efficiency of 28\\% was measured.

Aharonovich, I; Gibson, B C; Johnson, B C; Prawer, S

2010-01-01

419

Imaging and quantum efficiency measurement of chromium emitters in diamond  

E-print Network

We present direct imaging of the emission pattern of individual chromium-based single photon emitters in diamond and measure their quantum efficiency. By imaging the excited state transition dipole intensity distribution in the back focal plane of high numerical aperture objective, we determined that the emission dipole is oriented nearly orthogonal to the diamond-air interface. Employing ion implantation techniques, the emitters were engineered with various proximities from the diamond-air interface. By comparing the decay rates from the single chromium emitters at different depths in the diamond crystal, an average quantum efficiency of 28% was measured.

I. Aharonovich; S. Castelletto; B. C. Gibson; B. C. Johnson; S. Prawer

2010-08-17

420

Texture formation in polycrystalline diamond films  

NASA Astrophysics Data System (ADS)

Structure and morphology of polycrystalline diamond films prepared by chemical vapor deposition (CVD) have been studied using x-ray texture analysis, angle-resolved optical reflection, and scanning electron microscopy. The films under investigation exhibit a pronounced 110 fiber texture, i.e., a preferential alignment of {110} planes perpendicular to the growth direction. By thinning a 180-?m-thick CVD diamond film in an oxygen discharge the dependence of the degree of 110 texture on the film thickness has been investigated. It was found that the crystals formed at the beginning of the film growth are randomly oriented, and that a preferential orientation of {110} planes develops with increasing film thickness. Computer simulations show that this behavior can be explained by evolutionary selection, i.e., competing growth of differently oriented crystals, which implies that <110> is the direction of fastest growth. In addition, angle-resolved optical reflection and scanning electron micrographs show that the surface of the diamond films consists of {111} faces. Possible explanations for these findings are discussed.

Wild, Ch.; Herres, N.; Koidl, P.

1990-08-01

421

Plasma, photon, and beam synthesis of diamond films and multilayered structures  

SciTech Connect

In the area of nucleation, it was discovered that C{sub 70} thin films are perfect substitutes for diamond seeds in the growth of diamond films. This research, along with a careful study of diamond growth on carbon ion implanted single crystal copper, have clearly demonstrated that structured carbon is the best precursor for nucleation and growth of diamond films on non-diamond surfaces. In addition, by using fluorine chemistry during diamond growth, it has been shown that diamond films can grow on carbide substrates without the pretreatment of diamond seeding. The growth rates are higher and the film adhesion is much improved.

Chang, R.P.H.

1992-09-01

422

Area selection for diamonds using magnetotellurics: Examples from southern Africa Alan G. Jones a,  

E-print Network

Area selection for diamonds using magnetotellurics: Examples from southern Africa Alan G. Jones a conductivity Kaapvaal Craton Zimbabwe Craton Diamond exploration Southern Africa, particularly the Kaapvaal

Jones, Alan G.

423

Microstructure evolution and non-diamond carbon incorporation in CVD diamond thin films grown at low substrate temperatures  

Microsoft Academic Search

We investigated the development of the microstructure and the incorporation of non-diamond carbon close to the low temperature border of the CVD diamond domain. Thin diamond films were deposited at low substrate temperatures (560°C–275°C) by microwave plasma-assisted CVD on silicon, varying only the substrate temperature. At elevated temperatures (560°C–430°C) the film mainly consists of nearly defect free near 112 oriented

J. Michler; J. Stiegler; Y. von Kaenel; P. Moeckli; W. Dorsch; D. Stenkamp; E. Blank

1997-01-01

424

Panel 2 - properties of diamond and diamond-like-carbon films  

SciTech Connect

This panel attempted to identify and prioritize research and development needs in determining the physical, mechanical and chemical properties of diamond and diamond-like-carbon films (D/DLCF). Three specific goals were established. They were: (1) To identify problem areas which produce concern and require a better knowledge of D/DLCF properties. (2) To identify and prioritize key properties of D/DLCF to promote transportation applications. (3) To identify needs for improvement in properties-measurement methods. Each of these goals is addressed subsequently.

Blau, P.J.; Clausing, R.E. [Oak Ridge National Lab., TN (United States); Ajayi, O.O.; Liu, Y.Y.; Purohit, A. [Argonne National Lab., IL (United States); Bartelt, P.F. [Deere & Co., Moline, IL (United States); Baughman, R.H. [Allied Signal, Morristown, NJ (United States); Bhushan, B. [Ohio State Univ., Columbus (United States); Cooper, C.V. [United Technologies Research Center, East Hartford, CT (United States); Dugger, M.T. [Sandia National Laboratories, Albuquerque, NM (United States); Freedman, A. [Aerodyne Research, Inc., Billerica, MA (United States); Larsen-Basse, J. [National Science Foundation, Washington, DC (United States); McGuire, N.R. [Caterpillar, Peoria, IL (United States); Messier, R.F. [Pennsylvania State Univ., University Park (United States); Noble, G.L.; Ostrowki, M.H. [John Crane, Inc., Morton Grove, IL (United States); Sartwell, B.D. [Naval Research Lab., Washington, DC (United States); Wei, R. [Colorado State Univ., Fort Collins (United States)

1993-01-01

425

Diamond nanoelectromechanical resonators: Dissipation and superconductivity  

NASA Astrophysics Data System (ADS)

Nanoelectromechanical systems (NEMS) have become a viable commercial technology and are becoming more and more prevalent in research applications. Through miniaturization, the mechanical response to external sources becomes ever more sensitive. This transduction, coupled to an electrical readout circuit, results in unprecedented sensitivity. This thesis examines dissipation in diamond NEMS resonators in the MHz to GHz range. NCD (Nano-crystalline diamond) has extraordinary properties that make it an intriguing material to study. To begin with, the mechanical hardness allows for a boost in resonance frequency, but beyond that, boron-doped diamond also shows extraordinary electrical behavior. Although scaling benefits speed and sensitivity, dissipation increases dramatically with miniaturization, negating some of the gains in sensitivity. The dissipative mechanisms at play in the MHz range are identified at high temperatures. It is found that extrinsic dissipation mechanisms, mainly circuit and clamping losses, can limit the quality factor (inverse of the dissipation). Furthermore, due to the high surface-to-volume ratio of NEMS, surface defects become significant at the nano-scale. For the first time, quantum dissipation due to assisted phonon tunneling of two level systems is observed in diamond NEMS resonators at millikelvin temperatures. Through scaling, it is shown that the low temperature behavior is universal for a broad range of MHz resonators, including silicon and gallium arsenide, as well as graphene and carbon-nanotubes. Beyond the mechanical response, the superconducting properties of highly boron-doped diamond (BDD) are studied. It is found that the critical temperature of 3.3 K for the thin-film is maintained at the nano-scale. The high critical field, on the order of 3 T for thin-films, is strongly suppressed, already at the micro-scale. The zero resistance state is compromised with fields as low as 0.1 T for submicron wide constrictions. It is known that the superconducting state will couple to the strain field. Here, the piezoresistive detection technique is developed for BDD structures in the MHz range at room as well as cryogenic temperatures. This serves as a framework for future studies of strain-superconductivity coupling.

Imboden, Matthias

426

Application of a single crystal chemical vapor deposition diamond detector for deuteron plasma neutron measurement  

NASA Astrophysics Data System (ADS)

A single crystal chemical vapor deposition (scCVD) diamond detector has been characterized and employed for the neutron measurement at the HL-2A tokamak device. The scCVD diamond detector has been deposited with 5 ?m of lithium fluoride (LiF) layer to enhance the sensitivity to thermal neutrons. Time stability of the detector has been studied with ?-source and good performance has been found for more than 12 h. Neutron irradiations have been performed in four quasi-monoenergetic neutron fields in the energy range from 2.50 MeV to 16.03 MeV. The measured response function of the scCVD diamond detector to 14.13 MeV neutrons shows a narrow 12C (n, ?)9Be reaction peak which is well isolated from other structures by about 1 MeV in energy, indicating the great potential as a fast neutron spectrometer. Neutron measurement of deuterium plasma discharge was established at the HL-2A tokamak device, and good consistence has been revealed among this detector signal and other related signals.

Xie, Xufei; Yuan, Xi; Zhang, Xing; Chen, Zhongjing; Peng, Xingyu; Du, Tengfei; Li, Tao; Hu, Zhimeng; Cui, Zhiqiang; Chen, Jinxiang; Li, Xiangqing; Zhang, Guohui; Fan, Tieshuan; Yuan, Guoliang; Yang, Jinwei; Yang, Qingwei

2014-10-01

427

Amorphous diamond-like carbon films—a hard anti-reflecting coating for silicon solar cells  

Microsoft Academic Search

Amorphous diamond-line carbon (a:DLC) films are suitable for use as a protective layer and\\/or anti-reflecting coating for silicon solar cells. Microhardness tests show a high hardness of about 4700 kg mm?2. Optical measurements in the visible light on a silicon solar cell without anti-reflecting coating where a:DLC was deposited as an anti-reflecting (AR) coating, show a significant reduction in the

M. Alaluf; J. Appelbaum; L. Klibanov; D. Brinker; D. Scheiman; N. Croitoru

1995-01-01

428

Oxidation state of the lithospheric mantle beneath Diavik diamond mine, central Slave craton, NWT, Canada  

NASA Astrophysics Data System (ADS)

Oxygen fugacity ( fO2) conditions were determined for 29 peridotite xenoliths from the A154-North and A154-South kimberlites of the Diavik diamond mine using the newly developed flank method modified specifically for measuring Fe3+ in mantle-derived pyropic garnets. The results indicate that the garnet-bearing lithospheric mantle beneath the central Slave craton is vertically layered with respect to oxidation state. The shallow (<140 km), “ultra-depleted” layer is the most oxidized section of garnet-bearing subcratonic mantle thus far measured, up to one log unit more oxidizing relative to the FMQ buffer [?log fO2 (FMQ) + 1]. The lower, more fertile layer has fO2 conditions that extend down to ?log fO2 (FMQ) - 3.8, consistent with xenolith suites from other localities worldwide. Based on trace element concentrations in garnets, two distinct metasomatic events affected the mantle lithosphere at Diavik. An oxidized fluid imparted sinusoidal chondrite-normalized REE patterns on garnets throughout the entire depth range sampled. In contrast, a reducing melt metasomatic event affected only the lower portion of the lithospheric mantle. The fO2 state of the Diavik mantle sample suggests that diamond formation occurred by reduction of carbonate by fluids arising from beneath the lithosphere.

Creighton, Steven; Stachel, Thomas; Eichenberg, Dave; Luth, Robert W.

2010-05-01

429

Diamond logic inverter with enhancement-mode metal-insulator-semiconductor field effect transistor  

NASA Astrophysics Data System (ADS)

A diamond logic inverter is demonstrated using an enhancement-mode hydrogenated-diamond metal-insulator-semiconductor field effect transistor (MISFET) coupled with a load resistor. The gate insulator has a bilayer structure of a sputtering-deposited LaAlO3 layer and a thin atomic-layer-deposited Al2O3 buffer layer. The source-drain current maximum, extrinsic transconductance, and threshold voltage of the MISFET are measured to be -40.7 mA.mm-1, 13.2 ± 0.1 mS.mm-1, and -3.1 ± 0.1 V, respectively. The logic inverters show distinct inversion (NOT-gate) characteristics for input voltages ranging from 4.0 to -10.0 V. With increasing the load resistance, the gain of the logic inverter increases from 5.6 to as large as 19.4. The pulse response against the high and low input voltages shows the inversion response with the low and high output voltages.

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

2014-08-01

430

Interfacial studies for improving the adhesion of diamond-like carbon films on steel  

NASA Astrophysics Data System (ADS)

The adhesion of diamond-like carbon (DLC) films on steel is usually very poor. Adhesion of DLC on SKD11 steel was improved for tribological purposes in this study by applying chromium (Cr) metal intermediate layers using magnetron sputtering with substrate bias. DLC films were deposited by inductively coupled plasma (ICP) chemical vapor deposition. However, the adhesion was only at medium level. Intermixing at the Cr-steel interface was further achieved by ion bombardment and found to remarkably improve the adhesion. A reliable process was established to improve the adhesion to top level.

Chen, Chun-Chin; Hong, Franklin Chau-Nan

2005-04-01

431

Fabrication of polycrystalline diamond microtool using a Q-switched Nd:YAG laser  

Microsoft Academic Search

A Q-switched Nd:YAG laser (1,064 nm, 100 ns) was used to machine 2?×?1.5?×?0.5-mm rhombus-shaped tool inserts from a 60?×?0.5-mm\\u000a circular disk of polycrystalline diamond. A systematic experimental study was undertaken to examine the effects of pulse repetition\\u000a rate, feed rate, and number of laser passes on kerf, material removal rate, recast layer, surface morphology, and surface\\u000a roughness. The optimal laser parameters for

C. Everson; P. Molian

2009-01-01

432

Epitaxial (100) iridium on A-plane sapphire: A system for wafer-scale diamond heteroepitaxy  

Microsoft Academic Search

Large-scale heteroepitaxial growth of diamond depends critically on the development of a suitable lattice-matched buffer layer and substrate system. Epitaxial (100) iridium films have been grown on terraced, vicinal a-plane (1120) alpha-Al2O3 (sapphire) by electron-beam evaporation. The epitaxial relationship, Ir(100)\\/\\/Al2O3(1120) with Ir[011]\\/\\/Al2O3[1100], was determined by x-ray diffraction and electron backscattering diffraction analysis. For a 300-nm thickness of Ir, a (200)

Z. Dai; C. Bednarski-Meinke; R. Loloee; B. Golding

2003-01-01

433

Impact of a diamond coating on tool wear behaviour during dry machining of a multidirectional composite materials  

NASA Astrophysics Data System (ADS)

High mechanical performances and lightweight are the principal characteristics of composite materials. However, the main problems encountered when machining these materials are their poor machinability and the short timelife of the tools. Hard diamond coatings are attractive for cutting processes due to their high hardness, low friction coefficient, excellent wear resistance and chemical inertness. In the current study, damage mechanisms of the uncoated tungsten carbide are compared to the coated one. Tool wear behaviour was investigated at different cutting conditions when dry machining the multidirectional carbon/epoxy composite T300/914. The purpose is to determine the effect of the cutting parameters (cutting conditions, forces, temperature, etc.) on the tool-workpiece interface (surface integrity, roughness). The experiments have been carried out under orthogonal cutting configuration for both tools: uncoated and coated cemented carbide WC-Co. Different coatings have been tested: diamond coating (thin and thick diamond layer), and Diamond-Like Carbon (DLC coating). Three rake angles of 0circ, 15circ and 30circ, two cutting speeds of 6 and 60 m/min and three feeds rates of 0.05, 0.1, 0.2 mm were tested. The tool surface topography was analyzed using complementary techniques such as white light interferometry, scanning electron microscopy (SEM) and Auger electron spectroscopy (AES).

Iliescu, D.; Géhin, D.; Nouari, M.; Girot, F.

2006-08-01

434

Diamond and Related Materials 7 (1998) 16511656 Influence of phosphine on the diamond growth mechanism  

E-print Network

a persistent obstacle towards the that the experimental doping efficiency (in the range development of diamond-like carbon (DLC) films can cal value calculated by Jin et al. (1Ã?10-4) [6]. These exhibit semiconducting films was found to be very their standard mixture of 0.15% CH 4 in H 2 . Hall effect low [5

Bristol, University of

435

Conditions of diamond growth: a proton microprobe study of inclusions in West Australian diamonds  

Microsoft Academic Search

Crystalline primary inclusions in diamonds from the Argyle and Ellendale lamproites have been analyzed for Mn, Ni, Cu, Zn, Ga, Pb, Rb, Sr, Y, Zr, Nb, Ta, Ba and Mo by proton microprobe. Eclogite-suite inclusions dominate at Argyle and occur in equal proportions with peridotite-suite inclusions at Ellendale. Eclogitic phases present include garnet, omphacitic clinopyroxene, coesite, rutile, kyanite and sulfide.

W. L. Griffin; A. L. Jaques; S. H. Sie; C. G. Ryan; D. R. Cousens; G. F. Suter

1988-01-01

436

Analyzing the performance of diamond-coated micro end mills.  

SciTech Connect

A method is presented to improve the tool life and cutting performance of 300 {micro}m diameter tungsten carbide (WC) micro end mills by applying thin (<300 nm) fine-grained diamond (FGD) and nanocrystalline diamond (NCD) coatings using the hot-filament chemical vapor deposition (HF-CVD) process. The performance of the diamond-coated tools has been evaluated by comparing their performance in dry slot milling of 6061-T6 aluminum against uncoated WC micro end mills. Tool wear, coating integrity, and chip morphology were characterized using SEM and white light interferometry. The initial test results show a dramatic improvement in the tool integrity (i.e., corners not breaking off), a lower wear rate, no observable adhesion of aluminum to the diamond-coated tool, and a significant reduction in the cutting forces (>50%). Reduction of the cutting forces is attributed to the low friction and adhesion of the diamond coating. However, approximately 80% of the tools coated with the larger FGD coatings failed during testing due to delamination. Additional machining benefits were attained for the NCD films, which was obtained by using a higher nucleation density seeding process for diamond growth. This process allowed for thinner, smaller grained diamond coatings to be deposited on the micro end mills, and enabled continued operation of the tool even after the integrity of the diamond coating had been compromised. As opposed to the FGD-coated end mills, only 40% of the NCD-tools experienced delamination issues.

Torres, C. D.; Heaney, P. J.; Sumant, A. V.; Hamilton, M. A.; Carpick, R. W.; Pfefferkorn, F. E.; Univ. of Wisconsin at Madison; Univ. of Pennsylvania

2009-06-01

437

Chemical Vapor Deposition of Diamond Coatings onto Dental Burrs  

Microsoft Academic Search

Chemical vapor deposition (CVD) is an elegant and promising technology for coating dental tools such as burrs and microdrills with a hard diamond coating in order to improve their performance and lifespan. The diamond coatings are formed by decomposing a mixture of methane and hydrogen on the surface of the heated components in a reactor under vacuum conditions. The CVD

Waqar Ahmed; Htet Sein; Hussam Rajab; Mark Jackson

2003-01-01

438

Is It Possible to Turn Coal Into Diamonds?  

NSDL National Science Digital Library

How cool would it be to be Lois Lane? Anytime she wants a diamond, she just has Superman use his super strength to squeeze a lump of coal. But is this really possible?Using a high enough temperature and enough pressure, can you turn coal into diamonds?

Robertson, William C.

2009-09-15

439

Recent Results on Diamond Radiation Tolerance Sally Seidel,  

E-print Network

FLUKA incorporating the number of displacements per atom (DPA) according to the model by Norgert. 2. Investigation of the application of the FLUKA DPA model to diamond The CERN RD42 collaboration is studying the ability of FLUKA DPA to describe damage in diamond for a range of beam types and energies

Seidel, Sally

440

Kimberlite-hosted diamond deposits of southern Africa: A review  

Microsoft Academic Search

Following the discovery of diamonds in river deposits in central South Africa in the mid nineteenth century, it was at Kimberley where the volcanic origin of diamonds was first recognized. These volcanic rocks, that were named “kimberlite”, were to become the corner stone of the economic and industrial development of southern Africa. Following the discoveries at Kimberley, even more valuable

Matthew Field; Johann Stiefenhofer; Jock Robey; Stephan Kurszlaukis

2008-01-01

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