Showing papers on "Diamond published in 2006"
TL;DR: In this paper, the physics of the nitrogen vacancy and other defect centers from the perspective of single defect center spectroscopy were discussed, where the electron spin wave function hyperfine coupling to close nuclei leads to a splitting in the spectrum which allows for optically detected electron nuclear double resonance.
Abstract: The nitrogen vacancy and some nickel related defects in diamond can be observed as single quantum systems in diamond by their fluorescence. The fabrication of single colour centres occurs via generation of vacancies or via controlled nitrogen implantation in the case of the nitrogen vacancy (NV) centre. The NV centre shows an electron paramagnetic ground and optically excited state. As a result electron and nuclear magnetic resonance can be carried out on single defects. Due to the localized nature of the electron spin wavefunction hyperfine coupling to nuclei more than one lattice constant away from the defect as dominated by dipolar interaction. As a consequence the coupling to close nuclei leads to a splitting in the spectrum which allows for optically detected electron nuclear double resonance. The contribution discusses the physics of the NV and other defect centre from the perspective of single defect centre spectroscopy.
837 citations
TL;DR: The air oxidation process does not require the use of toxic or aggressive chemicals, catalysts, or inhibitors and opens avenues for numerous new applications of nanodiamond.
Abstract: The presence of large amounts of nondiamond carbon in detonation-synthesized nanodiamond (ND) severely limits applications of this exciting nanomaterial. We report on a simple and environmentally friendly route involving oxidation in air to selectively remove sp2-bonded carbon from ND. Thermogravimetric analysis and in situ Raman spectroscopy shows that sp2 and sp3 carbon species oxidize with different rates at 375−450 °C and reveals a narrow temperature range of 400−430 °C in which the oxidation of sp2-bonded carbon occurs with no or minimal loss of diamond. X-ray absorption near-edge structure spectroscopy detects an increase of up to 2 orders of magnitude in the sp3/sp2 ratio after oxidation. The content of up to 96% of sp3-bonded carbon in the oxidized samples is comparable to that found in microcrystalline diamond and is unprecedented for ND powders. Transmission electron microscopy and Fourier transform infrared spectroscopy studies show high purity 5-nm ND particles covered by oxygen-containing sur...
811 citations
TL;DR: In this article, a model of the electronic structure and the associated dynamics of the nitrogen-vacancy center in diamond was presented for the occurrence of optically induced spin polarization, for the change of emission level with spin polarization and for new experimental measurements of transient emission.
Abstract: Symmetry considerations are used in presenting a model of the electronic structure and the associated dynamics of the nitrogen-vacancy center in diamond. The model accounts for the occurrence of optically induced spin polarization, for the change of emission level with spin polarization and for new experimental measurements of transient emission. The rate constants given are in variance to those reported previously.
601 citations
TL;DR: Two new transition metal nitrides, IrN2 and OsN2, were synthesized at high pressures and temperatures using laser-heated diamond-anvil cell techniques and have bulk moduli comparable with those of the traditional superhard materials.
Abstract: Two new transition metal nitrides, IrN2 and OsN2, were synthesized at high pressures and temperatures using laser-heated diamond-anvil cell techniques. Synchrotron x-ray diffraction was used to determine the structures of novel nitrides and the equations of states of both the parent metals as well as the newly synthesized materials. The compounds have bulk moduli comparable with those of the traditional superhard materials. For IrN2, the measured bulk modulus [K0 = 428(12) GPa] is second only to that of diamond (K0 = 440 GPa). Ab initio calculations indicate that both compounds have a metal:nitrogen stoichiometry of 1:2 and that nitrogen intercalates in the lattice of the parent metal in the form of single-bonded N-N units.
453 citations
TL;DR: The observation of the normal mode splitting indicates that the dipole optical interaction between the relevant nitrogen vacancy center and whispering gallery mode has reached the strong coupling regime of cavity QED.
Abstract: Normal mode splitting is observed in a cavity QED system in which nitrogen vacancy centers in diamond nanocrystals are coupled to whispering gallery modes in a silica microsphere. The composite nanocrystal-microsphere system takes advantage of the exceptional spin properties of nitrogen vacancy centers as well as the ultrahigh quality factor of silica microspheres. The observation of the normal mode splitting indicates that the dipole optical interaction between the relevant nitrogen vacancy center and whispering gallery mode has reached the strong coupling regime of cavity QED.
384 citations
TL;DR: Lifetime-limited optical excitation lines of single nitrogen-vacancy defect centers in diamond display unprecedented spectral stability over many seconds and excitation cycles and have potential applications in quantum information processing.
Abstract: Lifetime-limited optical excitation lines of single nitrogen-vacancy (NV) defect centers in diamond have been observed at liquid helium temperature. They display unprecedented spectral stability over many seconds and excitation cycles. Spectral tuning of the spin-selective optical resonances was performed via the application of an external electric field (i.e., the Stark shift). A rich variety of Stark shifts were observed including linear as well as quadratic components. The ability to tune the excitation lines of single NV centers has potential applications in quantum information processing.
331 citations
TL;DR: The organic functionalisation method for small detonation diamond agglomerates is reported, which is potentially useful for the synthesis of surface-bound peptides and for the attachment of biologically active building blocks, which could be used in drug delivery and fluorescence marker applications.
Abstract: Detonation diamond is a promising material for biological applications due to its biocompatibility and fluorescence from lattice defects. Here we report on the organic functionalisation method for small detonation diamond agglomerates. After surface homogenisation by reduction and grafting of a silane linker, amino acids have been coupled to the diamond surface and the formation of a small peptide has been achieved. These novel functionalised diamond materials are potentially useful for the synthesis of surface-bound peptides and for the attachment of biologically active building blocks, which could be used in drug delivery and fluorescence marker applications.
324 citations
TL;DR: In this paper, the authors reported the observation of single photon emission from single SiV (silicon-vacancy) centers in diamond produced by ion implantation and discussed problems that arise from the nonradiaditve transitions which lower the brightness of the source.
Abstract: We report the observation of single photon emission from single SiV (silicon-vacancy) centres in diamond produced by ion implantation. The high photostability and the narrow emission bandwidth of about 5 nm at room temperature make SiV centres interesting as a single photon source in practical quantum cryptography. We discuss problems that arise from the nonradiaditve transitions which lower the brightness of the source.
287 citations
TL;DR: In this paper, the first-order Raman spectra of diamond anvils were investigated at pressures up to 310GPa and the high-frequency edge of the Raman band, which corresponds to Raman shift of the anvil culet due to the normal stress, was calibrated against the sample pressure derived from the equation of state of Pt.
Abstract: In order to develop an optical method for pressure determination in the multimegabar region, the first-order Raman spectra of diamond anvils were investigated at pressures up to 310GPa The high-frequency edge of the Raman band, which corresponds to the Raman shift of the anvil culet due to the normal stress, was calibrated against the sample pressure derived from the equation of state of Pt The obtained pressure dependence of the edge frequency demonstrates the reliability of this diamond anvil Raman gauge Up to the maximum pressure of this study, the relation between Raman frequency and normal stress at the diamond anvil culet is formally similar to the equation of state of a hydrostatically compressed isotropic elastic body having a bulk modulus of K0=547(11)GPa and a pressure derivative of the bulk modulus K0′=375(20)
286 citations
TL;DR: In this paper, an Optically Detected Magnetic Resonance (OMR) was employed to measure the hyperfine coupling of single nitrogen-vacancy (NV−) centers.
Abstract: Nitrogen-vacancy (NV−) color centers in diamond were created by implantation of 7 keV N15(I=1∕2) ions into type IIa diamond. Optically detected magnetic resonance was employed to measure the hyperfine coupling of single NV− centers. The hyperfine spectrum from NV−15 arising from implanted N15 can be distinguished from NV−14 centers created by native N14(I=1) sites. Analysis indicates 1 in 40 implanted N15 atoms give rise to an optically observable NV−15 center. This report ultimately demonstrates a mechanism by which the yield of NV− center formation by nitrogen implantation can be measured.
271 citations
TL;DR: The physical and chemical properties of wide bandgap semiconductors silicon carbide and diamond make these materials an ideal choice for device fabrication for applications in many different areas, e.g. light emitters, high temperature and high power electronics, high power microwave devices, micro-electromechanical system (MEMS) technology, and substrates as mentioned in this paper.
Abstract: The physical and chemical properties of wide bandgap semiconductors silicon carbide and diamond make these materials an ideal choice for device fabrication for applications in many different areas, e.g. light emitters, high temperature and high power electronics, high power microwave devices, micro-electromechanical system (MEMS) technology, and substrates. These semiconductors have been recognized for several decades as being suitable for these applications, but until recently the low material quality has not allowed the fabrication of high quality devices. Silicon carbide and diamond based electronics are at different stages of their development. An overview of the status of silicon carbide's and diamond's application for high temperature electronics is presented.
TL;DR: Coherent population trapping is demonstrated in single nitrogen-vacancy centers in diamond under optical excitation, showing that all-optical control of single spins is possible in diamond.
Abstract: Coherent population trapping is demonstrated in single nitrogen-vacancy centers in diamond under optical excitation. For sufficient excitation power, the fluorescence intensity drops almost to the background level when the laser modulation frequency matches the 2.88 GHz splitting of the ground states. The results are well described theoretically by a four-level model, allowing the relative transition strengths to be determined for individual centers. The results show that all-optical control of single spins is possible in diamond.
Book•
10 Aug 2006
TL;DR: The Ultra-nanocrystalline diamond: Syntheses, properties and applications as mentioned in this paper is a reference handbook that brings together the basic science of nanoscale carbon structures, particularly its diamond phase, with detailed information on nanodiamond synthesis, properties, and applications.
Abstract: "Ultrananocrystalline Diamond: Syntheses, Properties, and Applications" is a unique practical reference handbook that brings together the basic science of nanoscale carbon structures, particularly its diamond phase, with detailed information on nanodiamond synthesis, properties, and applications. Here you will learn about UNCD in its two forms, as a dispersed powder made by detonation techniques and as a chemical vapor deposited film. You will also learn about the superior mechanical, tribological, transport, electrochemical, and electron emission properties of UNCD for a wide range of applications including MEMS, NEMS, surface acoustic wave (SAW) devices, electrochemical sensors, coatings for field emission arrays, photonic and RF switching, biosensors, and neural prostheses, and more.This everything about "Ultra-nanocrystalline Diamond" book with 16 chapters is written by leading experts worldwide. It is for everyone who researches carbon nanostructures, everyone who produces them, everyone who characterizes them, and everyone who builds devices using them.
01 Jan 2006
TL;DR: In this article, the lattice thermal conductivity of various classes of crystalline solids is reviewed, with emphasis on materials with κ > 0.5Wcm−1K−1.
Abstract: The lattice thermal conductivity κ of various classes of crystalline solids is reviewed, with emphasis on materials with κ > 0.5Wcm−1K−1. A simple model for the magnitude of the lattice thermal conductivity at temperatures near the Debye temperature is presented and compared to experimental data on rocksalt, zincblende, diamond, and wurtzite structure compounds, graphite, silicon nitride and related materials, and icosahedral boron compounds. The thermal conductivity of wide-band-gap Group IV and Group III-V semiconductors is discussed, and the enhancement of lattice thermal conductivity by isotopic enrichment is considered.
TL;DR: In this paper, the out-of-plane compressive, transverse shear and longitudinal shear responses of corrugated cores have been measured at three relative densities 0:03 < q 6 0:10 and compared with analytical and finite element (FE) predictions.
TL;DR: In this paper, a theoretical investigation on the phonon spectrum and heat capacity of graphite and boron nitride polymorphs has been conducted with special interests on the variation of Debye temperature and stiffness with temperature.
Abstract: A theoretical investigation has been made on the phonon spectrum and heat capacity of polymorphs of carbon and boron nitride with special interests on the variation of Debye temperature and stiffness with temperature. A part of optical phonon branches of graphite exhibits higher frequencies than those of diamond. As a consequence, graphite shows smaller heat capacity and higher Debye temperature than diamond above a crossover temperature of $1000\phantom{\rule{0.3em}{0ex}}\mathrm{K}$. This supports experimental reports of heat capacity although available experimental data are widely scattered. The higher Debye stiffness of graphite at above $1000\phantom{\rule{0.3em}{0ex}}\mathrm{K}$ is not contradictory to the fact that conventional stiffness of diamond is much larger than that of graphite, since the Debye stiffness is determined by both acoustic and optical phonons, whereas only acoustic phonons contribute to the conventional stiffness. The same trend was found between hexagonal and cubic boron nitrides with a crossover temperature of $600\phantom{\rule{0.3em}{0ex}}\mathrm{K}$.
TL;DR: In this article, field effect transistors (FETs) with gate lengths of 0.1 /spl mu/m were fabricated using polycrystalline chemical-vapor-deposited diamond films with large grains.
Abstract: Using high-quality polycrystalline chemical-vapor-deposited diamond films with large grains (/spl sim/100 /spl mu/m), field effect transistors (FETs) with gate lengths of 0.1 /spl mu/m were fabricated. From the RF characteristics, the maximum transition frequency f/sub T/ and the maximum frequency of oscillation f/sub max/ were /spl sim/ 45 and /spl sim/ 120 GHz, respectively. The f/sub T/ and f/sub max/ values are much higher than the highest values for single-crystalline diamond FETs. The dc characteristics of the FET showed a drain-current density I/sub DS/ of 550 mA/mm at gate-source voltage V/sub GS/ of -3.5 V and a maximum transconductance g/sub m/ of 143 mS/mm at drain voltage V/sub DS/ of -8 V. These results indicate that the high-quality polycrystalline diamond film, whose maximum size is 4 in at present, is a most promising substrate for diamond electronic devices.
TL;DR: In this paper, metal-matrix composites were produced by reinforcing aluminum and aluminum-silicon with diamond single crystals via two different liquid metal infiltration techniques, gas pressure infiltration and mechanically assisted infiltration (squeeze casting).
TL;DR: A review of recent advances in the science and technology of composites utilizing carbon nanostructures is presented in this article, including experimental results and modelling studies of composite properties and processing.
Abstract: Recent advances in the science and technology of composites utilizing carbon nanostructures are reviewed, including experimental results and modelling studies of composite properties and processing. Carbon nanotubes are emphasized, with other carbon nanostructures such as fullerenes, ultradispersed diamond clusters and diamond nanorods also being discussed.
TL;DR: In this paper, a diamond cell conical diamond anvils with an x-ray aperture of 85° were successfully tested to over 50GPa using helium as a pressure medium.
Abstract: A new design for a high-precision diamond cell is described. Two kinematically mounted steel disks are elastically deflected to generate pressure. This principle provides higher precision in the diamond anvil alignment than most sliding piston-cylinder or guide-pin devices at significantly lower cost. With this new diamond cell conical diamond anvils with an x-ray aperture of 85° were successfully tested to over 50GPa using helium as a pressure medium. Anvil thickness of less than 1.4mm provides high x-ray transmission and low background, a significant improvement compared to beryllium or diamond-disk backing plates. Because the diamond anvils are supported by tungsten carbide seats, samples and pressure media can be annealed by external or laser heating to provide hydrostatic pressure conditions.
TL;DR: The present critical review highlights recent developments that utilise high pressures and high-temperatures for the synthesis of new materials with unique properties, such as high hardness, or interesting magnetic or optoelectronic features.
Abstract: Besides temperature at one atmosphere, the applied pressure is another important parameter for influencing and controlling reaction pathways and final reaction products. This is relevant not only for the genesis of natural minerals, but also for synthetic chemical products and technological materials. The present critical review (316 references) highlights recent developments that utilise high pressures and high-temperatures for the synthesis of new materials with unique properties, such as high hardness, or interesting magnetic or optoelectronic features. Novel metal nitrides, oxonitrides as well as the new class of nitride-diazenide compounds, all formed under high-pressure conditions, are highlighted. Pure oxides and carbides are not considered here. Moreover, syntheses under high-pressure conditions require special equipment and preparation techniques, completely different from those used for conventional synthetic approaches at ambient pressure. Therefore, we also summarize the high-pressure techniques used for the synthesis of new materials on a laboratory scale. In particular, our attention is focused on reactive gas pressure devices with pressures between 1.2 and 600 MPa, multi-anvil apparatus at P < 25 GPa and the diamond anvil cell, which allows work at pressures of 100 GPa and higher. For example, some of these techniques have been successfully upgraded to an industrial scale for the synthesis of diamond and cubic boron nitride.
TL;DR: In this article, a single-crystal homoepitaxial diamond has been grown by chemical vapour deposition using a high-density microwave plasma and it has been shown that the growth rate can be increased by factors of up to 2.5 by adding small concentrations (2 to 10 ppm) of nitrogen to the gas phase.
TL;DR: In this article, the growth and properties of ultrananocrystalline (UNCD) and nanocrystaline (NCD) diamond are compared and compared using optical emission spectroscopy and dual wavelength pyrometry.
TL;DR: In this paper, the authors carried out an integrated experimental and simulation study of thermal transport in ultrananocrystalline diamond (UNCD) films and showed that UNCD films with a grain size of 3-5nm have thermal conductivities as high as 12W∕mK at room temperature.
Abstract: Although diamond has the highest known room temperature thermal conductivity, k∼2200W∕mK, highly sp3 amorphous carbon films have k<15W∕mK. We carry out an integrated experimental and simulation study of thermal transport in ultrananocrystalline diamond (UNCD) films. The experiments show that UNCD films with a grain size of 3–5nm have thermal conductivities as high as k=12W∕mK at room temperature, comparable with that of the most conductive amorphous diamond films. This value corresponds to a grain boundary (Kapitza) conductance greater than 3000MW∕m2K, which is ten times larger than that previously seen in any material. Our simulations of both UNCD and individual diamond grain boundaries yield values for the grain boundary conductance consistent with the experimentally obtained value, leading us to conclude that thermal transport in UNCD is controlled by the intrinsic properties of the grain boundaries.
01 Jan 2006
TL;DR: The concept of thermal conductivity was introduced by Eucken and Debye as discussed by the authors, who showed that diamond was a reasonably good conductor for heat at room temperature and established theoretical support for this discovery.
Abstract: Every university student becomes familiar with the concept of thermal conductivity, a fundamental physical property of materials, through his or her textbooks. Initial work on high thermal conductivity was carried out in 1911 by Eucken, who discovered that diamond was a reasonably good conductor for heat at room temperature. Theoretical support for this discovery was established by Debye in 1914.
TL;DR: The results show that hot, compressed diamond is a semiconductor that undergoes metalization upon melting, and in the stability range of BC8, an insulator to metal transition is likely to occur in the solid phase, providing constraints on the carbon equation of state.
Abstract: At high pressure and temperature, the phase diagram of elemental carbon is poorly known. We present predictions of diamond and BC8 melting lines and their phase boundary in the solid phase, as obtained from first-principles calculations. Maxima are found in both melting lines, with a triple point located at ≈850 GPa and ≈7,400 K. Our results show that hot, compressed diamond is a semiconductor that undergoes metalization upon melting. In contrast, in the stability range of BC8, an insulator to metal transition is likely to occur in the solid phase. Close to the diamond/liquid and BC8/liquid boundaries, molten carbon is a low-coordinated metal retaining some covalent character in its bonding up to extreme pressures. Our results provide constraints on the carbon equation of state, which is of critical importance for devising models of Neptune, Uranus, and white dwarf stars, as well as of extrasolar carbon-rich planets.
TL;DR: In this article, Density functional theory (DFT) calculations were performed to investigate the interaction of diamond surface, to represent non-hydrogenated DLC, with N2, H2, and H2O molecules.
TL;DR: In this article, photochromism in single nitrogen-vacancy optical centers in diamond is demonstrated, and it is shown that the defect state relaxes back to the neutral form under dark conditions.
Abstract: Photochromism in single nitrogen-vacancy optical centers in diamond is demonstrated. Time-resolved optical spectroscopy shows that intense irradiation at 514 nm switches the nitrogen-vacancy defects to the negative form. This defect state relaxes back to the neutral form under dark conditions. Temporal anticorrelation of photons emitted by the different charge states of the optical center unambiguously indicates that the nitrogen-vacancy defect accounts for both 575 nm and 638 nm emission bands. Possible mechanism of photochromism involving nitrogen donors is discussed.
TL;DR: Mposkos and Kostopoulos as mentioned in this paper applied Raman micro-spectroscopy on carbon inclusions in garnet porphyroblasts from kyanite-biotite-garnet schists of the Rhodope Metamorphic Province (RMP), NE Greece.