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Materials Science â€ș Materials Chemistry

Diamond and Carbon-based Materials Research

Works Count: 86898

Description

This cluster of papers covers a wide range of topics related to diamond nanotechnology, including quantum sensing using nitrogen-vacancy centers, applications in biomedical and quantum computing, Raman spectroscopy of diamond-like materials, and the synthesis and characterization of nanodiamonds. The research also explores the potential for nanoscale imaging, magnetometry, thermometry, and photonics using diamond-based materials.

Keywords

Nanodiamonds; Quantum Sensing; Raman Spectroscopy; Quantum Computing; Biomedical Applications; Spin Qubits; Fluorescent Nanodiamonds; Magnetic Sensing; Room-Temperature Quantum Memory; Diamond Thin Films

Optical Properties of Diamond

2001-01-01
A.M. Zaitsev

Structural properties and electronic structure of low-compressibility materials: ÎČ-<mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" display="inline"><mml:mrow><mml:msub><mml:mrow><mml:mi mathvariant="normal">Si</mml:mi></mml:mrow><mml:mrow><mml:mn>3</mml:mn></mml:mrow></mml:msub></mml:mrow></mml:math><mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" display="inline"><mml:mrow><mml:msub><mml:mrow><mml:mi mathvariant="normal">N</mml:mi></mml:mrow><mml:mrow><mml:mn>4</mml:mn></mml:


1990-05-15
Amy Liu , Marvin L. Cohen
We present a first-principles pseudopotential study of the structural and electronic properties of \ensuremath{\beta}-${\mathrm{Si}}_{3}$${\mathrm{N}}_{4}$ and the hypothetical compound \ensuremath{\beta}-${\mathrm{C}}_{3}$${\mathrm{N}}_{4}$. \ensuremath{\beta}-${\mathrm{C}}_{3}$${\mathrm{N}}_{4}$, which is ${\mathrm{C}}_{3}$${\mathrm{N}}_{4}$ in the \ensuremath{\beta}-${\mathrm{Si}}_{3}$${\mathrm{N}}_{4}$ structure, with C substituted 
 We present a first-principles pseudopotential study of the structural and electronic properties of \ensuremath{\beta}-${\mathrm{Si}}_{3}$${\mathrm{N}}_{4}$ and the hypothetical compound \ensuremath{\beta}-${\mathrm{C}}_{3}$${\mathrm{N}}_{4}$. \ensuremath{\beta}-${\mathrm{C}}_{3}$${\mathrm{N}}_{4}$, which is ${\mathrm{C}}_{3}$${\mathrm{N}}_{4}$ in the \ensuremath{\beta}-${\mathrm{Si}}_{3}$${\mathrm{N}}_{4}$ structure, with C substituted for Si, is used as a prototype for investigating the properties of possible covalent C-N solids. The calculated lattice constant, bulk modulus, and electronic band structure of \ensuremath{\beta}-${\mathrm{Si}}_{3}$${\mathrm{N}}_{4}$ are in good agreement with experimental results. This gives support for the predicted properties of \ensuremath{\beta}-${\mathrm{C}}_{3}$${\mathrm{N}}_{4}$. The bulk modulus of \ensuremath{\beta}-${\mathrm{C}}_{3}$${\mathrm{N}}_{4}$ is found to be comparable to diamond, and its moderately large cohesive energy suggests that the prototype structure may be metastable. Although the crystal structure and the valencies of the constituent atoms are similar in \ensuremath{\beta}-${\mathrm{Si}}_{3}$${\mathrm{N}}_{4}$ and \ensuremath{\beta}-${\mathrm{C}}_{3}$${\mathrm{N}}_{4}$, the electronic bonding properties in these two solids are found to differ. The large core size and repulsive p pseudopotential of the second-row element, Si, results in a more ionic Si-N bond compared with a covalent C-N bond.

Raman spectroscopy on amorphous carbon films

1996-07-01
J. Schwan , S. Ulrich , V. Batori +2 more
The origin and interpretation of the Raman features of amorphous (hydrogenated) carbon films deposited at room temperature in the region of 1000–1700 cm−1 is discussed in this paper. Possible interpretations 
 The origin and interpretation of the Raman features of amorphous (hydrogenated) carbon films deposited at room temperature in the region of 1000–1700 cm−1 is discussed in this paper. Possible interpretations of the linewidths, positions of the ‘‘G’’ graphite peak and ‘‘D’’ disordered peak, and their intensity ratios are examined using results obtained from magnetron sputtered and magnetic field enhanced plasma deposited films. It is shown that even small ‘‘clusters’’ of condensed benzene rings (cluster size below 20 Å) in carbon films can explain the observed Raman scattering. Besides the care that should be taken in the correct interpretation of Raman results, the utility of Raman scattering in obtaining an estimate of cluster sizes in amorphous (hydrogenated) carbon films is discussed. Carbon films prepared by magnetron sputtering show two additional Raman features at 1180 and 1490 cm−1 in addition to the G and D peaks. It is shown that a correlation exists between the 1180 cm−1 peak and the sp3 content in the films.
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Use of Raman scattering to investigate disorder and crystallite formation in as-deposited and annealed carbon films

1984-03-15
R. O. Dillon , John A. Woollam , V. Katkanant
Carbon films were prepared by ion-beam as well as rf-discharge deposition, and annealed at temperatures up to 950\ifmmode^\circ\else\textdegree\fi{}C. Raman spectra of these films, in the range 1000-1800 ${\mathrm{cm}}^{\ensuremath{-}1}$, were analyzed 
 Carbon films were prepared by ion-beam as well as rf-discharge deposition, and annealed at temperatures up to 950\ifmmode^\circ\else\textdegree\fi{}C. Raman spectra of these films, in the range 1000-1800 ${\mathrm{cm}}^{\ensuremath{-}1}$, were analyzed via a best fit to computer-generated line shapes, used to simulate the $D$ and $G$ lines. Our results are given in terms of the $\frac{I(D)}{I(G)}$ intensity ratio, line position, and linewidth as a function of anneal temperature. The $\frac{I(D)}{I(G)}$ ratio for the rf-discharge-deposited films shows a maximum, and there is a suggestion of similar behavior for the ion-beam-deposited films. This maximum indicates that crystallite growth is promoted by higher anneal temperatures. As suggested by comparison with theory, the down-shifted $G$ line position of 1536 ${\mathrm{cm}}^{\ensuremath{-}1}$ in the as-deposited films indicates the presence of bond-angle disorder. The similarly, down-shifted $D$ line position of \ensuremath{\sim}1283 ${\mathrm{cm}}^{\ensuremath{-}1}$ indicates that the as-deposited films may contain some fourfold-coordinated bonds as well as disorder. The shift of the $D$ and $G$ lines to asymptotes of 1353 and 1598 ${\mathrm{cm}}^{\ensuremath{-}1}$, respectively, as anneal temperature increases, indicates that the crystallites are dominated by threefold over fourfold coordination. The linewidths of both lines decrease in width with increasing anneal temperature. This is also consistent with the removal of bond-angle disorder and the increasing dominance of crystallites as annealing proceeds to higher temperatures.

High Carrier Mobility in Single-Crystal Plasma-Deposited Diamond

2002-09-05
Jan Isberg , J. Hammersberg , Erik M. J. Johansson +5 more
Room-temperature drift mobilities of 4500 square centimeters per volt second for electrons and 3800 square centimeters per volt second for holes have been measured in high-purity single-crystal diamond grown using 
 Room-temperature drift mobilities of 4500 square centimeters per volt second for electrons and 3800 square centimeters per volt second for holes have been measured in high-purity single-crystal diamond grown using a chemical vapor deposition process. The low-field drift mobility values were determined by using the time-of-flight technique on thick, intrinsic, freestanding diamond plates and were verified by current-voltage measurements on p-i junction diodes. The improvement of the electronic properties of single-crystal diamond and the reproducibility of those properties are encouraging for research on, and development of, high-performance diamond electronics.

Electronic and atomic structure of amorphous carbon

1987-02-15
J. David Robertson , Eoin P. O’Reilly
The electronic structure of amorphous carbon and hydrogenated amorphous carbon (a-C:H) has been investigated through calculations on a number of model structures containing different configurations of ${\mathrm{sp}}^{2}$ and ${\mathrm{sp}}^{3}$ sites. 
 The electronic structure of amorphous carbon and hydrogenated amorphous carbon (a-C:H) has been investigated through calculations on a number of model structures containing different configurations of ${\mathrm{sp}}^{2}$ and ${\mathrm{sp}}^{3}$ sites. We find that the most stable arrangement of ${\mathrm{sp}}^{2}$ sites is in compact clusters of fused sixfold rings, i.e., graphitic layers. The width of the optical gap is found to vary inversely with the ${\mathrm{sp}}^{2}$ cluster size, and the \ensuremath{\sim}0.5-eV optical gap of evaporated amorphous carbon is found to be consistent with a model of disordered graphitic layers of about 15 A\r{} in diameter, bounded by ${\mathrm{sp}}^{3}$ sites. It is argued that a-C forms such finite clusters in order to relieve strain. It is then shown that the 1.5--2.5-eV optical gap of a-C:H is unusually small and requires that both its valence and conduction band consist of \ensuremath{\pi} states on ${\mathrm{sp}}^{2}$ sites and that these sites must also be significantly clustered, such as in graphitic clusters containing four or more rings. In other words, the optical gap of both a-C and a-C:H depends on their degree of medium-range order, rather than just on their short-range order as is the case in most amorphous semiconductors. We have also studied the nature of states away from the gap in order to interpret the photoemission data and the carbon 1s core-level absorption spectra. The nature of defects and midgap states is discussed, and it is predicted that the defect density decreases with increasing band gap. Finally it is argued that the doping of a-C:H by group-III and -V elements proceeds via a substitution mechanism, as in a-Si:H, in spite of the coordination disorder present in a-C:H. Doping is also expected to be accompanied by an increase in gap states, as in a-Si:H.

Low-Pressure, Metastable Growth of Diamond and "Diamondlike" Phases

1988-08-19
John C. Angus , C. Hayman
Diamond may be grown at low pressures where it is the metastable form of carbon. Recent advances in a wide variety of plasma and electrical discharge methods have led to 
 Diamond may be grown at low pressures where it is the metastable form of carbon. Recent advances in a wide variety of plasma and electrical discharge methods have led to dramatic increases in growth rates. All of these methods have certain aspects in common, namely, the presence of atomic hydrogen and the production of energetic carbon-containing fragments under conditions that support high mobilities on the diamond surface. Some understanding of the processes taking place during nucleation and growth of diamond has been achieved, but detailed molecular mechanisms are not yet known. Related research has led to the discovery of a new class of materials, the "diamondlike" phases. Vapor-grown diamond and diamondlike materials may have eventual applications in abrasives, tool coatings, bearing surfaces, electronics, optics, tribological surfaces, and corrosion protection.

Nanoscale magnetic sensing with an individual electronic spin in diamond

2008-10-01
J. R. Maze , Paul L. Stanwix , J. S. Hodges +7 more

Diamond-like carbon: state of the art

1999-03-01
A. Grill

Origin of the<mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" display="inline"><mml:mn>1</mml:mn><mml:mn>1</mml:mn><mml:mn>5</mml:mn><mml:mn>0</mml:mn><mml:mo>−</mml:mo><mml:mrow><mml:msup><mml:mrow><mml:mi mathvariant="normal">cm</mml:mi></mml:mrow><mml:mrow><mml:mi>−</mml:mi><mml:mn>1</mml:mn></mml:mrow></mml:msup></mml:mrow></mml:math>Raman mode in nanocrystalline diamond

2001-03-13
Andrea C. Ferrari , John Robertson
The peak near 1150 ${\mathrm{cm}}^{\mathrm{\ensuremath{-}}1}$ in the visible Raman spectra of poor quality chemical-vapor-deposited diamond is often used as the signature of nanocrystalline diamond. We argue that this peak should 
 The peak near 1150 ${\mathrm{cm}}^{\mathrm{\ensuremath{-}}1}$ in the visible Raman spectra of poor quality chemical-vapor-deposited diamond is often used as the signature of nanocrystalline diamond. We argue that this peak should not be assigned to nanocrystalline diamond or other ${\mathrm{sp}}^{3}$-bonded phases. Its wave number disperses with excitation energy, its intensity decreases with increasing excitation energy, and it is always accompanied by another peak near 1450 ${\mathrm{cm}}^{\mathrm{\ensuremath{-}}1}$, which acts similarly. This behavior is that expected for ${\mathrm{sp}}^{2}$-bonded configurations, with their smaller band gap. The peaks are assigned to transpolyacetylene segments at grain boundaries and surfaces.

Resonant Raman spectroscopy of disordered, amorphous, and diamondlike carbon

2001-07-26
Andrea C. Ferrari , John Robertson
The Raman spectra of a wide range of disordered and amorphous carbons have been measured under excitation from 785 to 229 nm. The dispersion of peak positions and intensities with 
 The Raman spectra of a wide range of disordered and amorphous carbons have been measured under excitation from 785 to 229 nm. The dispersion of peak positions and intensities with excitation wavelength is used to understand the nature of resonant Raman scattering in carbon and how to derive the local bonding and disorder from the Raman spectra. The spectra show three basic features, the D and G around 1600 and 1350 ${\mathrm{cm}}^{\mathrm{\ensuremath{-}}1}$ for visible excitation and an extra T peak, for UV excitation, at \ensuremath{\sim}1060 ${\mathrm{cm}}^{\mathrm{\ensuremath{-}}1}$. The G peak, due to the stretching motion of ${\mathrm{sp}}^{2}$ pairs, is a good indicator of disorder. It shows dispersion only in amorphous networks, with a dispersion rate proportional to the degree of disorder. Its shift well above 1600 ${\mathrm{cm}}^{\mathrm{\ensuremath{-}}1}$ under UV excitation indicates the presence of ${\mathrm{sp}}^{2}$ chains. The dispersion of the D peak is strongest in ordered carbons. It shows little dispersion in amorphous carbon, so that in UV excitation it becomes like a density-of-states feature of vibrations of ${\mathrm{sp}}^{2}$ ringlike structures. The intensity ratio $I(D)/I(G)$ falls with increasing UV excitation in all forms of carbon, with a faster decrease in more ordered carbons, so that it is generally small for UV excitation. The T peak, due to ${\mathrm{sp}}^{3}$ vibrations, only appears in UV Raman, lying around 1060 ${\mathrm{cm}}^{\mathrm{\ensuremath{-}}1}$ for H-free carbons and around 980 ${\mathrm{cm}}^{\mathrm{\ensuremath{-}}1}$ in hydrogenated carbons. In hydrogenated carbons, the ${\mathrm{sp}}^{3}{\mathrm{C}\ensuremath{-}\mathrm{H}}_{x}$ stretching modes around 2920 ${\mathrm{cm}}^{\mathrm{\ensuremath{-}}1}$ can be clearly detected for UV excitation. This assignment is confirmed by deuterium substitution.

Synthesis and characterization of carbide nanorods

1995-06-01
Hongjie Dai , Eric W. M. Wong , Yuan Z. Lu +2 more

Diamond-like amorphous carbon

2002-05-24
John Robertson
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Man-Made Diamonds

1955-07-09
F. P. Bundy , H. Tracy Hall , H. M. Strong +1 more

Empirical Interatomic Potential for Carbon, with Applications to Amorphous Carbon

1988-12-19
J. Tersoff
An empirical interatomic potential is introduced, which gives a convenient and relatively accurate description of the structural properties and energetics of carbon, including elastic properties, phonons, polytypes, and defects and 
 An empirical interatomic potential is introduced, which gives a convenient and relatively accurate description of the structural properties and energetics of carbon, including elastic properties, phonons, polytypes, and defects and migration barriers in diamond and graphite. The potential is applied to study amorphous carbon formed in three different ways. Two resulting structures are similar to experimental $a\ensuremath{-}\mathrm{C}$, but another more diamondlike form has essentially identical energy. The liquid is also found to have unexpected properties.

Ultralong spin coherence time in isotopically engineered diamond

2009-04-06
Gopalakrishnan Balasubramanian , Philipp Neumann , Daniel J. Twitchen +7 more

A second-generation reactive empirical bond order (REBO) potential energy expression for hydrocarbons

2002-01-18
Donald W. Brenner , Olga Shenderova , Judith A. Harrison +3 more
A second-generation potential energy function for solid carbon and hydrocarbon molecules that is based on an empirical bond order formalism is presented. This potential allows for covalent bond breaking and 
 A second-generation potential energy function for solid carbon and hydrocarbon molecules that is based on an empirical bond order formalism is presented. This potential allows for covalent bond breaking and forming with associated changes in atomic hybridization within a classical potential, producing a powerful method for modelling complex chemistry in large many-atom systems. This revised potential contains improved analytic functions and an extended database relative to an earlier version (Brenner D W 1990 Phys. Rev. B 42 9458). These lead to a significantly better description of bond energies, lengths, and force constants for hydrocarbon molecules, as well as elastic properties, interstitial defect energies, and surface energies for diamond.
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Vapor growth of diamond on diamond and other surfaces

1981-04-01
Б. В. ĐĄĐżĐžŃ†Ń‹Đœ , L.L. Bouilov , B.V. Derjaguin

The properties and applications of nanodiamonds

2011-12-18
Vadym N. Mochalin , Olga Shenderova , Dean Ho +1 more

Raman spectroscopic characterization of some commercially available carbon black materials

1995-01-01
T. Jawhari , A. Roid , Juan Casado

Empirical potential for hydrocarbons for use in simulating the chemical vapor deposition of diamond films

1990-11-15
Donald W. Brenner
An empirical many-body potential-energy expression is developed for hydrocarbons that can model intramolecular chemical bonding in a variety of small hydrocarbon molecules as well as graphite and diamond lattices. The 
 An empirical many-body potential-energy expression is developed for hydrocarbons that can model intramolecular chemical bonding in a variety of small hydrocarbon molecules as well as graphite and diamond lattices. The potential function is based on Tersoff's covalent-bonding formalism with additional terms that correct for an inherent overbinding of radicals and that include nonlocal effects. Atomization energies for a wide range of hydrocarbon molecules predicted by the potential compare well to experimental values. The potential correctly predicts that the \ensuremath{\pi}-bonded chain reconstruction is the most stable reconstruction on the diamond {111} surface, and that hydrogen adsorption on a bulk-terminated surface is more stable than the reconstruction. Predicted energetics for the dimer reconstructed diamond {100} surface as well as hydrogen abstraction and chemisorption of small molecules on the diamond {111} surface are also given. The potential function is short ranged and quickly evaluated so it should be very useful for large-scale molecular-dynamics simulations of reacting hydrocarbon molecules.

Bright Fluorescent Nanodiamonds: No Photobleaching and Low Cytotoxicity

2005-11-25
Amy S. Yu , Ming‐Wei Kang , Huan‐Cheng Chang +2 more
Diamond nanocrystals emit bright fluorescence at 600−800 nm after irradiation by a 3 MeV proton beam (5 × 1015 ions/cm2) and annealing at 800 °C (2 h) in vacuum. The 
 Diamond nanocrystals emit bright fluorescence at 600−800 nm after irradiation by a 3 MeV proton beam (5 × 1015 ions/cm2) and annealing at 800 °C (2 h) in vacuum. The irradiation/annealing process yields high concentrations of nitrogen-vacancy defect centers (∌107 centers/ÎŒm3), making possible visualization of the individual 100 nm diamond crystallites using a fluorescence microscope. The fluorescent nanodiamonds (FND) show no sign of photobleaching and can be taken up by mammalian cells with minimal cytotoxicity. The nanomaterial can have far-reaching biological applications.

Electric-field sensing using single diamond spins

2011-04-17
Florian Dolde , Helmut Fedder , Marcus W. Doherty +7 more
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Nanoscale imaging magnetometry with diamond spins under ambient conditions

2008-10-01
Gopalakrishnan Balasubramanian , I. Y. Chan , Roman Kolesov +7 more
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The aethalometer — An instrument for the real-time measurement of optical absorption by aerosol particles

1984-07-01
A. D. A. Hansen , H. Rosen , T. Novakov
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Extraordinary strain hardening by gradient structure

2014-05-05
Xiaolei Wu , Ping Jiang , Liu Chen +2 more
Significance Nature creates the gradient structure (GS) for a purpose: to make biological systems strong and tough to survive severe natural forces. For the grain-size GS, the deformation physics is 
 Significance Nature creates the gradient structure (GS) for a purpose: to make biological systems strong and tough to survive severe natural forces. For the grain-size GS, the deformation physics is still unclear. One wonders if the grain-size GS in the nanomicroscale would also benefit materials engineered by mankind. In this paper, a universal strain hardening mechanism is revealed in the GS. We discovered a unique extra strain hardening that is intrinsic to the GS. Its mechanism is the presence of strain gradient together with the stress state change. A superior combination of strength and ductility that is not accessible to conventional homogeneous materials is obtained. As a novel mechanism, extra strain hardening renders high ductility in the GS materials.
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Superconductivity in diamond

2004-04-01
Е. А. ЕĐșĐžĐŒĐŸĐČ , V. A. Sidorov , E. D. Bauer +4 more
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Coherent Dynamics of Coupled Electron and Nuclear Spin Qubits in Diamond

2006-09-15
Lilian Childress , Meenakshi Dutt , Jacob M. Taylor +5 more
Understanding and controlling the complex environment of solid-state quantum bits is a central challenge in spintronics and quantum information science. Coherent manipulation of an individual electron spin associated with a 
 Understanding and controlling the complex environment of solid-state quantum bits is a central challenge in spintronics and quantum information science. Coherent manipulation of an individual electron spin associated with a nitrogen-vacancy center in diamond was used to gain insight into its local environment. We show that this environment is effectively separated into a set of individual proximal 13C nuclear spins, which are coupled coherently to the electron spin, and the remainder of the 13C nuclear spins, which cause the loss of coherence. The proximal nuclear spins can be addressed and coupled individually because of quantum back-action from the electron, which modifies their energy levels and magnetic moments, effectively distinguishing them from the rest of the nuclei. These results open the door to coherent manipulation of individual isolated nuclear spins in a solid-state environment even at room temperature.
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Quantum photoyield of diamond(111)—A stable negative-affinity emitter

1979-07-15
F. J. Himpsel , J. A. Knapp , J. A. Vanvechten +1 more
Quantum photoyield and secondary-electron distributions are presented for an unreconstructed diamond (111) surface (type-$\mathrm{II}b$, gem-quality blue-white semiconductor). This chemically inert surface exhibits a negative electron affinity, resulting in a stable 
 Quantum photoyield and secondary-electron distributions are presented for an unreconstructed diamond (111) surface (type-$\mathrm{II}b$, gem-quality blue-white semiconductor). This chemically inert surface exhibits a negative electron affinity, resulting in a stable quantum yield that increases linearly from photothreshold (5.5 eV) to \ensuremath{\sim}20% at 9 eV, with a very large yield of \ensuremath{\sim}40%-70% for $13\ensuremath{\lesssim}h\ensuremath{\nu}\ensuremath{\lesssim}35$ eV. For all photon energies, secondary-electron energy distributions show a dominant \ensuremath{\sim}0.5-eV-wide emission peak at the conduction-band minimum (${\ensuremath{\Delta}}_{1}^{min}=5.50\ifmmode\pm\else\textpm\fi{}0.05$ eV above the valence-band maximum ${{\ensuremath{\Gamma}}_{25}}^{\ensuremath{'}}$). In contrast with recent self-consistent calculations [J. Ihm, S. G. Louie, and M. L. Cohen, Phys. Rev. B 17, 769 (1978)] no occupied intrinsic surface states with ionization energies in the fundamental gap (the Fermi level was 1 eV above ${{\ensuremath{\Gamma}}_{25}}^{\ensuremath{'}}$) were observed. Likewise, the measured photothreshold (${E}_{\mathrm{vac}}\ensuremath{-}{{\ensuremath{\Gamma}}_{25}}^{\ensuremath{'}}$) is significantly smaller than calculated (7.0\ifmmode\pm\else\textpm\fi{}0.7 eV).

Quantum Register Based on Individual Electronic and Nuclear Spin Qubits in Diamond

2007-05-31
Meenakshi Dutt , Lilian Childress , Liang Jiang +6 more
The key challenge in experimental quantum information science is to identify isolated quantum mechanical systems with long coherence times that can be manipulated and coupled together in a scalable fashion. 
 The key challenge in experimental quantum information science is to identify isolated quantum mechanical systems with long coherence times that can be manipulated and coupled together in a scalable fashion. We describe the coherent manipulation of an individual electron spin and nearby individual nuclear spins to create a controllable quantum register. Using optical and microwave radiation to control an electron spin associated with the nitrogen vacancy (NV) color center in diamond, we demonstrated robust initialization of electron and nuclear spin quantum bits (qubits) and transfer of arbitrary quantum states between them at room temperature. Moreover, nuclear spin qubits could be well isolated from the electron spin, even during optical polarization and measurement of the electronic state. Finally, coherent interactions between individual nuclear spin qubits were observed and their excellent coherence properties were demonstrated. These registers can be used as a basis for scalable, optically coupled quantum information systems.

Ion-Beam Deposition of Thin Films of Diamondlike Carbon

1971-06-01
S. Aisenberg , Ronald Chabot
An ion-beam deposition technique has been developed and was used to deposit thin films of insulating carbon on room-temperature substrates. It was established that the carbon films deposited using this 
 An ion-beam deposition technique has been developed and was used to deposit thin films of insulating carbon on room-temperature substrates. It was established that the carbon films deposited using this technique are insulating and have the following characteristics similar to that of carbon in the diamond form: (1) transparency, (2) index of refraction greater than 2.0, (3) highly insulating, (4) able to scratch glass, (5) resistant to hydrofluoric acid for long periods of time, (6) at least partially crystalline and with a lattice constant similar to diamond as demonstrated by x-ray diffraction, (7) dielectric constant between about 8 and 14 (diamond is 16.5). A resistance to sodium ion diffusion has been experimentally demonstrated. Preliminary measurements at a dose of 1 Mrad indicated a radiation resistance from the point of view of stability of leakage resistance and of negligibly small flat band voltage shifts. Several coplanar thin-film transistors using the insulating carbon gate have been fabricated.

Stable Solid-State Source of Single Photons

2000-07-10
Christian Kurtsiefer , Sonja Mayer , P. Zarda +1 more
Fluorescence light observed from a single nitrogen-vacancy center in diamond exhibits strong photon antibunching: The measured pair correlation function ${g}^{(2)}(0)$ shows that only one photon is emitted at a time. 
 Fluorescence light observed from a single nitrogen-vacancy center in diamond exhibits strong photon antibunching: The measured pair correlation function ${g}^{(2)}(0)$ shows that only one photon is emitted at a time. Nitrogen-vacancy centers are well localized, stable against photobleaching even at room temperature, and can be addressed in simple experimental configurations.

Raman spectroscopy of hydrogenated amorphous carbons

2005-08-01
Cinzia Casiraghi , Andrea C. Ferrari , John Robertson
We present a comprehensive multiwavelength Raman investigation of a variety of hydrogenated amorphous carbons $(a\text{\ensuremath{-}}\mathrm{C}:\mathrm{H})$, ranging from polymeric $a\text{\ensuremath{-}}\mathrm{C}:\mathrm{H}$ to diamond-like $a\text{\ensuremath{-}}\mathrm{C}:\mathrm{H}$ and ta-C:H, which allows us to derive values 
 We present a comprehensive multiwavelength Raman investigation of a variety of hydrogenated amorphous carbons $(a\text{\ensuremath{-}}\mathrm{C}:\mathrm{H})$, ranging from polymeric $a\text{\ensuremath{-}}\mathrm{C}:\mathrm{H}$ to diamond-like $a\text{\ensuremath{-}}\mathrm{C}:\mathrm{H}$ and ta-C:H, which allows us to derive values for their bonding, density, band gap, hydrogen content, and mechanical properties. The Raman spectra of $a\text{\ensuremath{-}}\mathrm{C}:\mathrm{Hs}$ show two different trends. In one case, the $G$ peak width increases with $G$ peak dispersion. In the second case, the opposite trend is found. In the first case, the Raman parameters vary with optical, structural, and mechanical properties in the same way as in hydrogen-free carbon films. In the second case, typical of polymeric $a\text{\ensuremath{-}}\mathrm{C}:\mathrm{H}$, the $G$ peak width correlates with the density, while the $G$ peak dispersion varies with the optical gap and hydrogen content. This allows a unified picture of bonding and disorder of all carbon films. UV Raman is particularly useful for $a\text{\ensuremath{-}}\mathrm{C}:\mathrm{Hs}$, as it gives clear measurements in the $D$ and $G$ peaks spectral region even for highly hydrogenated samples, for which the visible Raman spectra are overshadowed by photoluminescence. On the other hand, the slope of the photoluminescence background in visible Raman spectra can be used to estimate the H content. UV Raman measurements also allow the detection of $\mathrm{C}\mathrm{H}$ stretching vibrations.

Heralded entanglement between solid-state qubits separated by three metres

2013-04-23
Hannes Bernien , Bas Hensen , Wolfgang Pfaff +7 more
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Raman microprobe studies on carbon materials

1994-01-01
Ana Cuesta , P. Dhamelincourt , J. Laureyns +2 more

Tribology of diamond-like carbon films: recent progress and future prospects

2006-09-01
Ali Erdemir , Christophe Donnet
During the past two decades, diamond-like carbon (DLC) films have attracted an overwhelming interest from both industry and the research community. These films offer a wide range of exceptional physical, 
 During the past two decades, diamond-like carbon (DLC) films have attracted an overwhelming interest from both industry and the research community. These films offer a wide range of exceptional physical, mechanical, biomedical and tribological properties that make them scientifically very fascinating and commercially essential for numerous industrial applications. Mechanically, certain DLC films are extremely hard (as hard as 90 GPa) and resilient, while tribologically they provide some of the lowest known friction and wear coefficients. Their optical and electrical properties are also extraordinary and can be tailored to meet the specific requirements of a given application. Because of their excellent chemical inertness, these films are resistant to corrosive and/or oxidative attacks in acidic and saline media. The combination of such a wide range of outstanding properties in one material is rather uncommon, so DLC can be very useful in meeting the multifunctional application needs of advanced mechanical systems. In fact, these films are now used in numerous industrial applications, including razor blades, magnetic hard discs, critical engine parts, mechanical face seals, scratch-resistant glasses, invasive and implantable medical devices and microelectromechanical systems. DLC films are primarily made of carbon atoms that are extracted or derived from carbon-containing sources, such as solid carbon targets and liquid and gaseous forms of hydrocarbons and fullerenes. Depending on the type of carbon source being used during the film deposition, the type of bonds (i.e. sp1, sp2, sp3) that hold carbon atoms together in DLC may vary a great deal and can affect their mechanical, electrical, optical and tribological properties. Recent systematic studies of DLC films have confirmed that the presence or absence of certain elemental species, such as hydrogen, nitrogen, sulfur, silicon, tungsten, titanium and fluorine, in their microstructure can also play significant roles in their properties. The main goal of this review paper is to highlight the most recent developments in the synthesis, characterization and application of DLC films. We will also discuss the progress made in understanding the fundamental mechanisms that control their very unique friction and wear behaviours. Novel design concepts and the principles of superlubricity in DLC films are also presented.

High-sensitivity diamond magnetometer with nanoscale resolution

2008-09-14
Jacob M. Taylor , Paola Cappellaro , Lilian Childress +6 more
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Raman spectroscopy of amorphous, nanostructured, diamond–like carbon, and nanodiamond

2004-09-28
Andrea C. Ferrari , John Robertson
Raman spectroscopy is a standard characterization technique for any carbon system. Here we review the Raman spectra of amorphous, nanostructured, diamond–like carbon and nanodiamond. We show how to use resonant 
 Raman spectroscopy is a standard characterization technique for any carbon system. Here we review the Raman spectra of amorphous, nanostructured, diamond–like carbon and nanodiamond. We show how to use resonant Raman spectroscopy to determine structure and composition of carbon films with and without nitrogen. The measured spectra change with varying excitation energy. By visible and ultraviolet excitation measurements, the G peak dispersion can be derived and correlated with key parameters, such as density, sp3 content, elastic constants and chemical composition. We then discuss the assignment of the peaks at 1150 and 1480 cm−1 often observed in nanodiamond. We review the resonant Raman, isotope substitution and annealing experiments, which lead to the assignment of these peaks to trans–polyacetylene.

Nitrogen-Vacancy Centers in Diamond: Nanoscale Sensors for Physics and Biology

2013-11-26
Romana Schirhagl , K.J. Chang , M. Loretz +1 more
Crystal defects in diamond have emerged as unique objects for a variety of applications, both because they are very stable and because they have interesting optical properties. Embedded in nanocrystals, 
 Crystal defects in diamond have emerged as unique objects for a variety of applications, both because they are very stable and because they have interesting optical properties. Embedded in nanocrystals, they can serve, for example, as robust single-photon sources or as fluorescent biomarkers of unlimited photostability and low cytotoxicity. The most fascinating aspect, however, is the ability of some crystal defects, most prominently the nitrogen-vacancy (NV) center, to locally detect and measure a number of physical quantities, such as magnetic and electric fields. This metrology capacity is based on the quantum mechanical interactions of the defect's spin state. In this review, we introduce the new and rapidly evolving field of nanoscale sensing based on single NV centers in diamond. We give a concise overview of the basic properties of diamond, from synthesis to electronic and magnetic properties of embedded NV centers. We describe in detail how single NV centers can be harnessed for nanoscale sensing, including the physical quantities that may be detected, expected sensitivities, and the most common measurement protocols. We conclude by highlighting a number of the diverse and exciting applications that may be enabled by these novel sensors, ranging from measurements of ion concentrations and membrane potentials to nanoscale thermometry and single-spin nuclear magnetic resonance.

Quantum entanglement between an optical photon and a solid-state spin qubit

2010-08-01
Emre Togan , Yiwen Chu , Alexei Trifonov +7 more

Nanometre-scale thermometry in a living cell

2013-07-30
Georg Kucsko , Peter C. Maurer , Norman Y. Yao +5 more
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Characterization of amorphous and nanocrystalline carbon films

2005-08-23
Paul K. Chu , Liuhe Li

Characterization of diamond films by Raman spectroscopy

1989-04-01
Diane S. Knight , William B. White

Interpretation of Raman spectra of disordered and amorphous carbon

2000-05-15
Andrea C. Ferrari , John Robertson
The model and theoretical understanding of the Raman spectra in disordered and amorphous carbon are given. The nature of the G and D vibration modes in graphite is analyzed in 
 The model and theoretical understanding of the Raman spectra in disordered and amorphous carbon are given. The nature of the G and D vibration modes in graphite is analyzed in terms of the resonant excitation of \ensuremath{\pi} states and the long-range polarizability of \ensuremath{\pi} bonding. Visible Raman data on disordered, amorphous, and diamondlike carbon are classified in a three-stage model to show the factors that control the position, intensity, and widths of the G and D peaks. It is shown that the visible Raman spectra depend formally on the configuration of the ${\mathrm{sp}}^{2}$ sites in ${\mathrm{sp}}^{2}$-bonded clusters. In cases where the ${\mathrm{sp}}^{2}$ clustering is controlled by the ${\mathrm{sp}}^{3}$ fraction, such as in as-deposited tetrahedral amorphous carbon (ta-C) or hydrogenated amorphous carbon (a-C:H) films, the visible Raman parameters can be used to derive the ${\mathrm{sp}}^{3}$ fraction.

The large-scale structure of the Universe

1981-01-01
F. R. Stephenson

Solid-state single-photon emitters

2016-09-29
Igor Aharonovich , Dirk Englund , Milos Toth

The nitrogen-vacancy colour centre in diamond

2013-03-04
Marcus W. Doherty , Neil B. Manson , Paul Delaney +3 more
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Amorphous carbon

1986-01-01
John Robertson
Abstract The properties of various types of amorphous carbon and hydrogenated amorphous carbon are reviewed with particular emphasis on the effect of atomic structure on the electronic structure. It is 
 Abstract The properties of various types of amorphous carbon and hydrogenated amorphous carbon are reviewed with particular emphasis on the effect of atomic structure on the electronic structure. It is shown how the proportion of sp3 and sp2 sites not only defines the short-range order but also a substantial medium-range order. Medium-range order is particularly important in amorphous carbon because it is the source of its optical gap, whereas short-range order is usually sufficient to guarantee a gap in other amorphous semiconductors. The review discusses the following properties: short-range order and the radial distribution function, the infrared and Raman spectra, mechanical strength, the electronic structure, photoemission spectra, optical properties, electron energy-loss spectra, core-level excitation spectra, electrical conductivity, electronic defects and the electronic doping of hydrogenated amorphous carbon.

Low-Compressibility Carbon Nitrides

1996-01-05
David M. Teter , Russell J. Hemley
First-principles calculations of the relative stability, structure, and physical properties of carbon nitride polymorphs predict a cubic form of C 3 N 4 with a zero-pressure bulk modulus exceeding that 
 First-principles calculations of the relative stability, structure, and physical properties of carbon nitride polymorphs predict a cubic form of C 3 N 4 with a zero-pressure bulk modulus exceeding that of diamond. Like diamond, this new phase could potentially be synthesized at high pressure and quenched to ambient pressure for use as a superhard material. The calculations also predict that α-C 3 N 4 and graphite-C 3 N 4 are energetically favored relative to ÎČ-C 3 N 4 and that published diffraction data can be re-indexed as α-C 3 N 4 with lower error.

Highly Sensitive Magnetometer with Continuous Excitation Ramsey Protocol by Utilizing Long Dephasing Time of Millimeter‐Scale Spin Ensembles in (111) Diamond

2025-06-25
Ikuya Fujisaki , æŽæłœæ±‰ Li Zehan , Yuji Hatano +7 more | Advanced Quantum Technologies
Abstract We developed a highly sensitive magnetometer with continuous excitation (CE) Ramsey protocol for (111) diamonds. The distinctive feature of the magnetometer is the magnet array and antenna design to 
 Abstract We developed a highly sensitive magnetometer with continuous excitation (CE) Ramsey protocol for (111) diamonds. The distinctive feature of the magnetometer is the magnet array and antenna design to realize a uniform bias field and efficient application of quantum manipulation techniques of spin bath driving and double quantum Ramsey in millimeter‐scale spin ensembles directed to the surface normal. CE‐ and pulsed‐Ramsey show dephasing times of and , respectively, with an excitation power of 160 mW. Analysis of the compositions of dephasing factors unveils the dephasing channels limiting the dephasing time. Thanks to the long dephasing time, a sensitivity of is achieved in CE‐Ramsey. Furthermore, the comparison of sensitivity between CE‐ and pulsed‐Ramsey indicated that the noise induced by laser pulsing exists. This work paves the way for realizing ultra‐high sensitivity magnetometers with simple implementation.

Lubrication of Graphene Nanoplatelets (GNs) on Rough Gold

2025-06-24
Ruyi Jia , Xuesen Zhao , Tianji Xing +1 more | Langmuir
Lubrication employing graphene nanoplatelets has emerged as a critical topic in nano- and microtribology research, both as additives and as stand-alone solid lubricants. Nevertheless, simulation studies addressing the molecular dynamics 
 Lubrication employing graphene nanoplatelets has emerged as a critical topic in nano- and microtribology research, both as additives and as stand-alone solid lubricants. Nevertheless, simulation studies addressing the molecular dynamics of graphene nanoplatelets (GNs) remain scarce in the literature. This paper primarily investigates the lubrication effects of various graphene morphologies on rough gold substrates using atomistic simulations with a particular focus on elucidating the lubrication and wear mechanisms of graphene nanoplatelets. The frictional properties of monolayer graphene nanoplatelets are found to be intermediate between those of continuous monolayer graphene and those of a bare substrate. A pronounced friction transition─divisible into six distinct phases─is observed when the tip ascends and descends the graphene nanoplatelet. Furthermore, the lubrication performance is influenced by factors such as the arrangement state, sliding speed, applied pressure, and number of friction cycles. Notably, stacks comprising at least two layers of graphene nanoplatelets exhibit an enhanced friction reduction and wear resistance.

Size Effects on the Electronic and Mechanical Properties of Diamond‐XII: A Machine Learning Potential Study

2025-06-24
Zicheng Wang , Zhenqing Li , Chaoyu He | physica status solidi (RRL) - Rapid Research Letters
Ultrahard carbon materials offer great potential for energy storage and advanced devices. Diamond‐XII, a cubic carbon allotrope with twelvefold diamond segments, stands out for its stability and hardness. This study 
 Ultrahard carbon materials offer great potential for energy storage and advanced devices. Diamond‐XII, a cubic carbon allotrope with twelvefold diamond segments, stands out for its stability and hardness. This study refines a deep potential model for Diamond‐XII using potential fine‐tuning and first‐principles calculations. Structures with n = 1–11 are optimized, showing a turning point in energy and density at n = 9. All exhibit Vickers hardness above 50 GPa, with decreasing bandgap from n = 1 to 9. The results highlight the power of deep learning potentials in designing ultrahard carbon materials.

Band-edge Localization of Twisted Bilayer hBN

2025-06-23
Mina Maruyama , Yanlin Gao , Susumu Okada | Journal of the Physical Society of Japan

Humidity‐Resistant Ultralow Friction in Diamond‐Like Carbon Coatings Enabled by Graphitic Nanodiamonds

2025-06-23
Andrea Mescola , Giovanni Bertoni , Gian Carlo Gazzadi +5 more | Small Structures
Hydrogenated diamond‐like carbon (H‐DLC) coatings are extensively employed in high‐performance tribological applications, yet their frictional behavior in humid environments remains a critical limitation. A scalable and industrially viable strategy based 
 Hydrogenated diamond‐like carbon (H‐DLC) coatings are extensively employed in high‐performance tribological applications, yet their frictional behavior in humid environments remains a critical limitation. A scalable and industrially viable strategy based on graphitic nanodiamonds (Gr‐NDs) is here proposed, enabling humidity‐resistant ultralow friction (coefficient of friction &lt;0.1) without requiring controlled atmospheres or complex surface treatments. This approach is distinct from many recent methods involving the deposition of nanoparticles and 2D materials, which often fail under humid conditions. Gr‐NDs leverage their intrinsic core–shell nanostructure to promote the in operando formation of a peculiar graphitic transfer layer (TL), directly enhancing interfacial lubrication. High‐resolution transmission electron microscopy and Raman spectroscopy confirm that these nanostructures are effectively retained within the TL, ensuring superior wear resistance and friction reduction. Furthermore, spectroscopic analysis reveals that moderate tribochemical oxidation stabilizes the TL, extending its durability under realistic operating conditions. This work establishes Gr‐NDs as a disruptive functional additive for H‐DLC coatings, offering a robust, scalable, and environmentally friendly solution for next‐generation tribological systems in demanding mechanical applications.

Lubrication Performance Promotion of GTL Base Oil by BN Nanosheets via Cascade Centrifugation-Assisted Liquid-Phase Exfoliation

2025-06-23
Jiashun Liu , Shuo Xiang , Xiaoyu Zhou +7 more | Lubricants
Broad lateral size and thickness distributions impede the application of hexagonal boron nitride nanosheets (BNNSs) as friction modifiers in base oil, although they possess remarkable potential for lubrication performance promotion. 
 Broad lateral size and thickness distributions impede the application of hexagonal boron nitride nanosheets (BNNSs) as friction modifiers in base oil, although they possess remarkable potential for lubrication performance promotion. In this work, a cascade centrifugation-assisted liquid-phase exfoliation approach was presented to prepare BNNSs from hexagonal boron nitride (h-BN) efficiently and scalably. Subsequently, they were ultrasonically dispersed into gas-to-liquid (GTL) base oil, and their lubrication performance promotion was evaluated by a four-ball tribotester. Tribological tests demonstrated that BNNS possesses excellent friction-reducing and anti-wear properties in GTL. Furthermore, the findings indicate that at a BNNS content of 0.8 wt.%, the system displayed the lowest COF and WSD. Particularly, with an addition of 0.8 wt.% BNNS into GTL, the AFC and WSD are reduced significantly by 40.1% and 35.4% compared to pure base oil, respectively, and the surface roughness, wear depth, and wear volume were effectively reduced by 91.0%, 68.5%, and 76.8% compared to GTL base oil, respectively. Raman, SEM-EDS, and XPS results proved that the outstanding friction-reducing and anti-wear properties of BNNS can mainly be ascribed to the presence of physical adsorption film and tribo-chemical film, which were composed of FeOOH, FeO, Fe3O4, and B2O3.

Room-temperature high-purity single-photon emission from carbon-doped boron nitride thin films

2025-06-20
Arka Chatterjee , Abhijit Biswas , Addis Fuhr +5 more | Science Advances
Hexagonal boron nitride (h-BN) has emerged as a promising platform for generating room temperature single photons exhibiting high brightness and spin-photon entanglement. However, improving emitter purity, stability, and scalability remains 
 Hexagonal boron nitride (h-BN) has emerged as a promising platform for generating room temperature single photons exhibiting high brightness and spin-photon entanglement. However, improving emitter purity, stability, and scalability remains a challenge for quantum technologies. Here, we demonstrate highly pure and stable single-photon emitters (SPEs) in h-BN by directly growing carbon-doped, centimeter-scale h-BN thin films using the pulsed laser deposition (PLD) method. These SPEs exhibit room temperature operation with polarized emission, achieving a g (2) (0) value of 0.015, which is among the lowest reported for room temperature SPEs and the lowest achieved for h-BN SPEs. It also exhibits high brightness (~0.5 million counts per second), remarkable stability during continuous operation (&gt;15 min), and a Debye-Waller factor of 45%. First-principles calculations reveal unique carbon defects responsible for these properties, enabled by PLD’s low-temperature synthesis and in situ doping. Our results demonstrate an effective method for large-scale production of high-purity, stable SPEs in h-BN, enabling robust quantum optical sources for various quantum applications.

Demonstration of low contact resistance in SiC using high-repetition-rate KrF excimer laser irradiation

2025-06-20
Kaname Imokawa , Yohei Tanaka , Keita Katayama +3 more | Applied Physics A

Green Superlubrication achieved on Diamond-like Carbon Film by S-carboxymethyl-L-cysteine Molecules

2025-06-20
Jinyan Chen , Shuang Yi , Shaowen Dong +1 more | Carbon

Effect of oxidizing treatment on surface modification of detonation nanodiamond

2025-06-19
Changjian Geng , Chong Peng , Guangtong Zhou +5 more | Research Square (Research Square)
<title>Abstract</title> Detonation nanodiamond (DND) possesses high hardness, high thermalconductivity, good insulation, and fine grains, offering a wide range of applicationprospects. However, DND particles typically exist in an agglomerated state due 
 <title>Abstract</title> Detonation nanodiamond (DND) possesses high hardness, high thermalconductivity, good insulation, and fine grains, offering a wide range of applicationprospects. However, DND particles typically exist in an agglomerated state due to theirhigh specific surface area and high surface activity caused by the detonation reactionThis often leads to the loss of many of its advantages as a nano-powder during actualuse, preventing the full utilization of its superior properties. In this study, air oxidationwas adopted to investigate the dispersion and purification of DND. DND samples weretreated with air oxidation at different temperatures using a muffle furnace, andcharacterized using X-ray diffraction (XRD), inductively coupled plasma (ICP), Ramanspectroscopy, infrared spectroscopy, and other techniques. The results showed that at 450 ℃, SP<sup>2</sup> amorphous carbon and CH functional groups in DND were effectively removed, improving the purity of DND and reducing impurity content by 30% asdetermined by ICP, The average particle size of DND was approximately 15 nm, with adispersing effect improved by 92.5% compared to unoxidized DND. Air oxidation at 450 ℃ selectively removes non-diamond carbon without losing the diamond phase.

First-Principles Dynamics of the Surface Fluorination of Diamond

2025-06-18
Henry Thake , Stephen J. Jenkins | Langmuir
We present first-principles dynamic simulations of molecular fluorine dissociatively adsorbing on clean C{001} and identify a range of possible outcomes depending upon the interplay of impact site, molecular orientation, and 
 We present first-principles dynamic simulations of molecular fluorine dissociatively adsorbing on clean C{001} and identify a range of possible outcomes depending upon the interplay of impact site, molecular orientation, and surface temperature. These include adsorption of a single fluorine atom with desorption of the other, in which case both the surface and the isolated atom gain radical character. In most scenarios, however, both fluorine atoms adsorb, either at opposite ends of a single surface dimer or on two such dimers. In the former situation the reaction end-point is closed-shell in nature, whereas in the latter the surface acquires singlet diradical character.

Image Transmission Method Based on Quantum Properties of Nitrogen-Vacancy Centers in Diamond

2025-06-18
Kun Jiang , Yu Wang , Y. W. Jin +7 more | Optics Communications

Maskless epitaxial overgrowth of diamond on 3D patterns formed by self-organization in an oxidation process

2025-06-18
Jacqueline Fendt , M. Schreck | Journal of Applied Physics
Reduction of the dislocation density (DD) in heteroepitaxial diamond quasi-substrates by maskless epitaxial overgrowth on 3D-patterned surfaces is reported. To create structures appropriate for maskless overgrowth, three different approaches were 
 Reduction of the dislocation density (DD) in heteroepitaxial diamond quasi-substrates by maskless epitaxial overgrowth on 3D-patterned surfaces is reported. To create structures appropriate for maskless overgrowth, three different approaches were explored. First, CO2/H2 etching in a microwave plasma chemical vapor deposition setup was applied to generate dislocation induced pits. Even for high etch depths of 182 ÎŒm, pits with the shape of inverted pyramids aligned along ⟹110⟩ remained rather small (≈10−6 cm2). In the second approach, dry oxidation in a furnace using synthetic air provided structures of suitable size (&amp;gt;10−5 cm2) but insufficient depth. Finally, moisturizing the feed gas reduced the etch velocity by a factor of ≈7, but also produced ⟹100⟩ oriented pits with both high facet angles of ≈35° and large areas of up to &amp;gt;10−4 cm2. Subsequent maskless overgrowth resulted in a reduction of the initial DD by more than one order of magnitude down to 1.7 × 106 cm−2. Repetition of the etching/overgrowth sequence is expected to facilitate further improvement. The novel technique of self-organized 3D pattern formation is applicable to as-grown surfaces without the need for polishing and lithography. It provides a simple, robust, and scalable concept to improve the structural quality of diamond wafers.

Mechanism of IR assisted charge state conversion of nitrogen vacancy centre in diamond

2025-06-17
N. V. Nguyen , Juil Hwang , Seunghyun Bang +4 more | Journal of the Korean Physical Society

Robust 1-ÎŒm-Resolution Magnetic Probe Enabled by Optical Trapping of Nanodiamonds on a Tapered Fiber

2025-06-17
Die Fang , Yibo Wang , Xin Wang +7 more | Nano Letters
High-resolution magnetic field scanning is critical for investigating nanoscale spin systems and characterizing defects in microelectronic devices. We present a fabrication-free approach to create robust magnetic probes with 1-ÎŒm spatial 
 High-resolution magnetic field scanning is critical for investigating nanoscale spin systems and characterizing defects in microelectronic devices. We present a fabrication-free approach to create robust magnetic probes with 1-ÎŒm spatial resolution by synergizing the quantum magnetic sensitivity of nitrogen-vacancy (NV) centers in nanodiamonds with the enhanced photon efficiency of tapered fibers. Through gradient-force optical trapping, nanodiamonds are precisely positioned at the fiber tip, where van der Waals forces immobilize them without requiring micro-nanoprocessing. In addition to possessing high spatial resolution, the probe exhibits a magnetic sensitivity reaching 80âĄÎŒT/Hz. By demonstrating a magnetic field scan of crossed microwires, this method can be extended to measure tiny magnetic structures or microcircuits, leveraging the integrated photonic enhancement of tapered fibers for robust high signal-to-noise sensing.

Optically Detected Coherent Spin Control of Organic Molecular Color Center Qubits

2025-06-17
Sebastian M. Kopp , Shunta Nakamura , Yong Rui Poh +5 more | Journal of the American Chemical Society
Molecular optical-spin interfaces are emerging as promising alternatives to solid-state defects, such as diamond nitrogen vacancy centers for quantum information science applications. In this work, we report a new organic 
 Molecular optical-spin interfaces are emerging as promising alternatives to solid-state defects, such as diamond nitrogen vacancy centers for quantum information science applications. In this work, we report a new organic molecular color center consisting of two luminescent tris(2,4,6-trichlorophenyl)methyl (TTM) radicals connected at the 2,6-positions of a toluene bridge. Optical polarization of the |T0⟩ sublevel of the triplet ground state is achieved by spin-selective excited-state intersystem crossing from the |T+⟩ and |T-⟩ sublevels of the triplet excited state. Steric hindrance between the toluene methyl group and the phenyls of the TTM radicals results in a structure that increases the excited-state intersystem crossing spin selectivity while reducing the electronic coupling between the TTM subunits. This results in an order of magnitude increase in the optically detected magnetic resonance contrast and longer excited-state lifetimes relative to the sterically unencumbered analogue. We demonstrate coherent microwave manipulation of the spin-polarized ground-state populations and coherences using optical detection of Rabi nutations, Hahn echo formation, and echo decay measurements at 85 K in a nuclear-spin-rich solvent matrix. This marks a crucial step toward leveraging the favorable spin relaxation times of organic molecules for applications as quantum sensors at temperatures that heretofore have been difficult to achieve by molecular color centers.

Chemically Tuning Room Temperature Pulsed Optically Detected Magnetic Resonance

2025-06-17
Sarah K. Mann , Angus Cowley-Semple , Emma Bryan +4 more | Journal of the American Chemical Society
Optical detection of magnetic resonance enables spin-based quantum sensing with high spatial resolution and sensitivity─even at room temperature─as exemplified by solid-state defects. Molecular systems provide a complementary, chemically tunable, platform 
 Optical detection of magnetic resonance enables spin-based quantum sensing with high spatial resolution and sensitivity─even at room temperature─as exemplified by solid-state defects. Molecular systems provide a complementary, chemically tunable, platform for room-temperature optically detected magnetic resonance (ODMR)-based quantum sensing. A critical parameter governing sensing sensitivity is the optical contrast─i.e., the difference in emission between two spin states. In state-of-the-art solid-state defects such as the nitrogen-vacancy center in diamond, this contrast is approximately 30%. Here, capitalizing on chemical tunability, we show that room-temperature ODMR contrasts of 40% can be achieved in molecules. Using a nitrogen-substituted analogue of pentacene (6,13-diazapentacene), we enhance contrast compared to pentacene and, by determining the triplet kinetics through time-dependent pulsed ODMR, show how this arises from accelerated anisotropic intersystem crossing. Furthermore, we translate high-contrast room-temperature pulsed ODMR to self-assembled nanocrystals. Overall, our findings highlight the synthetic handles available to optically readable molecular spins and the opportunities to capitalize on chemical tunability for room-temperature quantum sensing.

Electron Sextets as Optically Addressable Molecular Qubits: Triplet Carbenes

2025-06-17
Yong Rui Poh , Xiao Chen , Hai‐Ping Cheng +1 more | Journal of the American Chemical Society
There is a growing demand in quantum information science and sensing for electron spin purification and readout via a spin-optical interface. This technique, known as optically detected magnetic resonance (ODMR), 
 There is a growing demand in quantum information science and sensing for electron spin purification and readout via a spin-optical interface. This technique, known as optically detected magnetic resonance (ODMR), has been applied to diamond-NV centers and transition-metal complexes. Metal-free counterparts of these optically addressable spin qubits promise to be cheaper, more sustainable color centers with prolonged polarization lifetimes. However, progress has been hindered by the low ODMR signals of carbon-based π-diradicals, partly due to the lack of a ground singlet-to-triplet intersystem crossing (ISC). In this work, we propose exploring organic systems that are even more electron-deficient: electron sextets. Using triplet carbenes as an example, we illustrate how the ground singlet-triplet gap can be widened beyond thermal energy with the associated singlet-to-triplet ISC made available by vibronic effects. Through careful molecular engineering, this ISC can occur at a rate similar to and with an opposite spin selectivity from the excited-state ISC well-established in π-diradicals, unlocking a new ODMR pathway with potential signal gains. Persistent triplet carbenes are a renascent field, with multiple stable molecules being isolated in the past five years. To motivate further development of its emissive properties, we illustrate our design in three realistic carbene candidates that incorporate existing strategies for carbene stabilization. Ultimately, we believe that a new realm of quantum materials can be uncovered by expanding our scope toward stable electron sextets.

Doping optimization of charge state stability for shallow nitrogen-vacancy center ensembles in HPHT diamonds

2025-06-16
Qin Wu , Die Fang , Yu Ma +7 more | Applied Physics Letters
Since nitrogen-vacancy (NV) centers in diamond have emerged as crucial quantum sensors in physics and biology, the massive preparation of high-quality and high-concentration shallow NV center samples has become urgent 
 Since nitrogen-vacancy (NV) centers in diamond have emerged as crucial quantum sensors in physics and biology, the massive preparation of high-quality and high-concentration shallow NV center samples has become urgent and demanding. As NV centers approach the surface and their concentration increases, charge state instability can degrade coherence and introduce additional noise. This problem is further complicated in high-pressure and high-temperature (HPHT) diamonds due to the presence of unclear impurities and inhomogeneous strain. Through optically detected magnetic resonance testing on various implanted samples, we analyzed the spin and charge state properties of shallow NV center ensembles. Our results reveal that the doping dose significantly influences the quantity of NV−, charge, and charge stability. Our findings indicate that over-implanting nitrogen as electron donors before starting graphitization helps stabilize the charge environment of the shallow NV center ensembles. By controlling the nitrogen ion implantation dose, we optimized charge state stability under photoionization and prepared high-quality NV center ensemble samples in HPHT diamonds at the optimal implantation dose range of 2×1013–8×1013 ions/cm2. This method, which relies solely on nitrogen ion implantation and annealing on HPHT diamond, significantly reduces the cost of sensor samples, greatly benefiting the promotion of quantum sensing.

Combination of Radiofrequency Ablation and Intramedullary Nailing for the Treatment of Femoral Metastases: Single-center, Retrospective Observational Study

2025-06-16
Nokitaka Setsu , Suguru Fukushima , Nobuhiko Yokoyama +6 more | Research Square (Research Square)
<title>Abstract</title> <italic>Background</italic>: Radiofrequency ablation (RFA) has gained attention as a palliative treatment for bone metastases, offering pain relief and local tumor control. While its use in trunk lesions is well 
 <title>Abstract</title> <italic>Background</italic>: Radiofrequency ablation (RFA) has gained attention as a palliative treatment for bone metastases, offering pain relief and local tumor control. While its use in trunk lesions is well documented, its application in long bones remains limited because ofconcerns about postablationfractures. These risks may be mitigated by combining RFA with prophylactic intramedullary nailing (IMN). <italic>Methods</italic>: Five consecutive patients with femoral metastases who underwent combined RFA and IMN, either as a single-stage procedure with intraoperative fluoroscopic guidance or in two stages using CT-guided RFA followed by IMN, were included. Pain relief, function, radiographic response, histology, and complications were retrospectively assessed. <italic>Results</italic>: All patients experienced early pain relief and regained mobility. The average amount of intraoperative blood loss was 48 ml, which was significantly lower than the historical control cases. At the final follow-up, one lesion had slightly progressed, three remained stable, and one decreased in size. The complicationsincluded one nonunion case requiring revision and one case of skin burn from electrode pad placement. While immediate pain relief was notable, the isolated midterm effect of RFA was difficult to evaluate because of concurrent IMN and frequent postoperative radiotherapy. No adverse interactions were observed with combined radiotherapy. <italic>Conclusion</italic>: RFA combined with IMN offers a minimally invasive, effective option for local control and functional recovery in patients with femoral metastases. Ideal candidates include those with impending fractures with preserved continuity of the femoral shaft, lesser trochanter avulsions, hypervascular tumors, or radiotherapy-resistant lesions. This approach may serve as an alternative to extensive resection in selected patients.

Mechanical effects of ion‐implanted gold nanoparticles on the surface properties of silica glass

2025-06-16
JosĂ© RaĂșl PĂ©rez-Higareda , JesĂșs Alejandro Torres , CĂ©sar Leyva‐Porras +4 more | International Journal of Applied Glass Science
Abstract Silica glass (SG) is a highly versatile material used in optics, electronics, construction, and medicine due to its transparency and mechanical properties. However, enhancing its performance poses scientific challenges, 
 Abstract Silica glass (SG) is a highly versatile material used in optics, electronics, construction, and medicine due to its transparency and mechanical properties. However, enhancing its performance poses scientific challenges, especially in reinforcing it while preserving these properties and understanding its deformation under stress. This study investigates the effect of gold nanoparticles (AuNPs) on the mechanical response of SG material. AuNPs were nucleated into high‐purity SG using a 3MV Tandem Accelerator Pelletron, followed by thermal annealing at 600°C in an H 2 + N 2 atmosphere. High‐resolution transmission electron microscopy (HRTEM) revealed a Gaussian distribution of AuNPs at a depth of ∌450 nm. Nanoindentation tests indicated minor variations in hardness (1.5%) and reduced elastic modulus (4.4%) with AuNP incorporation. Scratch tests demonstrated that the mechanical integrity of the AuNPs/SG sample was preserved when deformation remained below the determined fracture load of SG, although it exhibited a slightly higher coefficient of friction. Finite element analysis provided insights into the strain behavior within the AuNP zone, confirming how AuNPs distribute stress within the SG matrix.

Quantum Sensing with Spin Defects Beyond Diamond

2025-06-16
Henry C. Roberts , Hamza Abudayyeh , Xiaoqin Li +1 more | ACS Nano
Spin defects in solid-state materials offer a platform for quantum sensing that combines the properties of atom-like systems with the scalability, versatility, and technological maturity of semiconductor devices. The past 
 Spin defects in solid-state materials offer a platform for quantum sensing that combines the properties of atom-like systems with the scalability, versatility, and technological maturity of semiconductor devices. The past decade has seen increasing interest in host materials beyond diamond which can offer additional functionality and more effectively leverage the advantage of the existing semiconductor ecosystem. This review provides a survey and comparison of spin defects in silicon carbide, hexagonal boron nitride, and gallium nitride with an emphasis on their applications to magnetometry, electrometry, thermometry, and strain sensing. A practical overview of quantum sensing protocols and sensitivity enhancement is provided along with a final discussion of the future direction of the field and remaining challenges.

Oxidation and graphitization of micro‐grained diamond in vacuum and atmosphere

2025-06-16
Qian Li , Wen‐Fei Dong , Duanwei He +4 more | Journal of the American Ceramic Society
Abstract Thermal stability of diamond is crucial for its applications. However, conflicting reports exist regarding the sequence of oxidation and transformation and the temperature range at which non‐diamond phases form. 
 Abstract Thermal stability of diamond is crucial for its applications. However, conflicting reports exist regarding the sequence of oxidation and transformation and the temperature range at which non‐diamond phases form. In addition, systematic and quantitative studies are insufficient. This study systematically investigates the oxidation and graphitization behavior of micro‐grained diamond powder after heat treatment in air and vacuum environments. The temperature ranges and volume fraction for non‐diamond phase formation were estimated, and the oxidation and non‐diamond phase transition temperatures were directly measured using synchronous thermal analysis. The results indicate that: (1) when annealed in air, the diamond powder oxidizes and then graphitizes as the temperature increases, while the graphitized diamond is then oxidized; (2) diamond powder remains stable in air at temperatures below 596°C, with significant oxidation occurring about 669°C; (3) the conversion of diamond to graphite occurs at 728°C in air and approximately 1300°C in vacuum, with oxygen significantly promoting the graphitization of diamond; and (4) increased specific surface area (smaller particle size) and longer heating times exacerbate thermal instability.

Influence of SiC surface/subsurface state on laser ablation thresholds

2025-06-14
Haixu Liu , Z.-L. Li , Ping Zhang +1 more | Materials Science in Semiconductor Processing

Graphene Tribofilm Formation on Hydrogen-free DLC/B4C Periodical Nano-Multilayer Coatings: Effect of Sputtering in N2 Atmosphere

2025-06-13
Mingfeng Li , Yuzhen Liu , Dae‐Eun Kim +1 more | Carbon

Medusa 84 SiH - A novel high selectivity electron beam resist for diamond quantum technologies

2025-06-13
Oliver Opaluch , Sebastian Westrich , Nimba Oshnik +7 more | MRS Communications

Laser-Induced Liquid-Phase Boron Doping of 4H-SiC

2025-06-12
Gunjan Kulkarni , Yahya Bougdid , Chandraika Sugrim +2 more | Materials
4H-silicon carbide (4H-SiC) is a cornerstone for next-generation optoelectronic and power devices owing to its unparalleled thermal, electrical, and optical properties. However, its chemical inertness and low dopant diffusivity for 
 4H-silicon carbide (4H-SiC) is a cornerstone for next-generation optoelectronic and power devices owing to its unparalleled thermal, electrical, and optical properties. However, its chemical inertness and low dopant diffusivity for most dopants have historically impeded effective doping. This study unveils a transformative laser-assisted boron doping technique for n-type 4H-SiC, employing a pulsed Nd:YAG laser (λ = 1064 nm) with a liquid-phase boron precursor. By leveraging a heat-transfer model to optimize laser process parameters, we achieved dopant incorporation while preserving the crystalline integrity of the substrate. A novel optical characterization framework was developed to probe laser-induced alterations in the optical constants—refraction index (n) and attenuation index (k)—across the MIDIR spectrum (λ = 3–5 ”m). The optical properties pre- and post-laser doping were measured using Fourier-transform infrared spectrometry, and the corresponding complex refraction indices were extracted by solving a coupled system of nonlinear equations derived from single- and multi-layer absorption models. These models accounted for the angular dependence in the incident beam, enabling a more accurate determination of n and k values than conventional normal-incidence methods. Our findings indicate the formation of a boron-acceptor energy level at 0.29 eV above the 4H-SiC valence band, which corresponds to λ = 4.3 ”m. This impurity level modulated the optical response of 4H-SiC, revealing a reduction in the refraction index from 2.857 (as-received) to 2.485 (doped) at λ = 4.3 ”m. Structural characterization using Raman spectroscopy confirmed the retention of crystalline integrity post-doping, while secondary ion mass spectrometry exhibited a peak boron concentration of 1.29 × 1019 cm−3 and a junction depth of 450 nm. The laser-fabricated p–n junction diode demonstrated a reverse-breakdown voltage of 1668 V. These results validate the efficacy of laser doping in enabling MIDIR tunability through optical modulation and functional device fabrication in 4H-SiC. The absorption models and doping methodology together offer a comprehensive platform for paving the way for transformative advances in optoelectronics and infrared materials engineering.

Management of Material Redeposition Below and Above the Sample for Laser Micromachining of Laser Fusion Targets

2025-06-12
N. R. Schott , Matthias Brönner , F. Richard Christ +3 more | Lasers in Manufacturing and Materials Processing
Abstract Ultrashort pulse laser micromachining is a commonly used technique in the field of target fabrication for laser fusion experiments. In this context, material redeposition caused by ultrashort pulse laser 
 Abstract Ultrashort pulse laser micromachining is a commonly used technique in the field of target fabrication for laser fusion experiments. In this context, material redeposition caused by ultrashort pulse laser ablation can greatly reduce the target quality. This work analyzes material redeposition below and above a polymerized Trimethylolpropantriacrylat (TMPTA) film, by applying the Design of Experiments methodology. The mean and interaction effects of four treatment factors on these processes are identified, using a two-level full factorial design. On the one hand, the results indicate that material redeposition below the sample is dominated by the overlap of consecutive pulses, influencing the degree of chipping. On the other hand, the results suggest that redeposition on the sample top is caused by an interaction of successive ablation plumes. Based on these results, we chose machining parameters that reduce redeposition on both sides of the sample. To further reduce the surface roughness on the sample top, we successfully applied the laser polishing technique using MHz and GHz burst pulses to TMPTA. We find that a number of five sub-pulses within one burst is optimal for polishing TMPTA. The work provides valuable insight into the processes of material redeposition below and above the sample, and demonstrates that laser polishing can be applied to TMPTA. The results are essential to meet the stringent cleanness requirements of targets for laser fusion experiments. The methods deployed in this work can be applied to future polymer ablator materials, making it possible to quickly react to changes in the target design.

Heat-induced transformation of nickel-coated polycrystalline diamond film studied in situ by XPS and NEXAFS

2025-06-12
Olga V. Sedelnikova , Yu. V. Fedoseeva , Dmitriy V. Gorodetskiy +6 more | Beilstein Journal of Nanotechnology
Controlling high-temperature graphitization of diamond surfaces is important for many applications, which require the formation of thin conductive electrodes on dielectric substrates. Transition metal catalysts can facilitate the graphitization process, 
 Controlling high-temperature graphitization of diamond surfaces is important for many applications, which require the formation of thin conductive electrodes on dielectric substrates. Transition metal catalysts can facilitate the graphitization process, which depends on the diamond face orientation. In the present work, the role of a nickel coating on the electronic structure and chemical state of graphite layers formed on the surface of a polycrystalline diamond (PCD) film with mixed grain orientation was studied. A synthetic single-crystal diamond (SCD) with a polished (110) face was examined for comparison. The samples were coated with a thin nickel film deposited by thermal evaporation. The graphitization of diamond with and without a nickel coating as a result of high-vacuum annealing at a temperature of about 1100 °C was studied in situ using synchrotron-based X-ray photoelectron spectroscopy (XPS) and near-edge X-ray absorption fine structure (NEXAFS) methods. XPS data revealed the formation of a thin graphite-like film with low-ordered atomic structure on the surface of the nickel-coated PCD film. The chemical state of sp 2 -hybridized carbon atoms was found to be insensitive to the face orientation of the diamond micro-sized crystallites; however, the layer defectiveness increased in areas with fine-dispersed crystallites. According to NEXAFS and Raman spectroscopy data, the most ordered atomic structure of graphitic layers was obtained by annealing nickel-coated SCD. The angular dependence of NEXAFS C K-edge spectra of nickel-coated (110) face after annealing discovered the vertical orientation of sp 2 -hybridized carbon layers relative to the diamond surface. The observed behavior suggests that sp 2 carbon layers were formed on the diamond surface due to its saturation by released carbon atoms as a result of etching by nickel.

Size-responsive antibacterial diamond coatings with self-activation, high durability, and renewability

2025-06-12
Tao Wang , Yuzhi Liu , Hongjin Wang +5 more | Chemical Engineering Journal

Shallow Nitrogen Vacancy Color Centers in Diamond by Ion Implantation

2025-06-11
G. Speranza , Alessandro Cian , B. Perlingeiro CorrĂȘa +7 more | Advanced Quantum Technologies
Abstract Recent advancements in quantum technologies are fueled by the ability to engineer materials with specific quantum properties, enabling various applications. The nitrogen‐vacancy (NV) center in diamond is a key 
 Abstract Recent advancements in quantum technologies are fueled by the ability to engineer materials with specific quantum properties, enabling various applications. The nitrogen‐vacancy (NV) center in diamond is a key system for nanoscale sensors, capable of detecting weak magnetic fields with nanotesla‐range sensitivity. To achieve high spatial resolution and sensitivity, NV centers must be placed near the diamond surface. This study investigates the creation of NV defects in a pure chemical vapor deposition (CVD) diamond single crystal via broad‐beam ion implantation. The implantations are performed through thin (100 nm) SiO 2 layers deposited by plasma‐enhanced CVD (PECVD). Both normal and oblique ion beam incidences are used, with the oblique incidence chosen to reduce the nitrogen ion penetration depth. Simulations show a subsurface NV center distribution, with the highest concentration near the surface; the expected trends are confirmed by angle‐resolved X‐ray photoelectron spectroscopy (ARXPS) and time‐of‐flight secondary ion mass spectrometry (ToF‐SIMS). This distribution extends to a depth of 30 nm. By adjusting the ion beam incidence angle, NV center density can be modulated. This work contributes to optimizing the fabrication process for shallow color centers through ion implantation using a screening layer.

Effective K valley Hamiltonian for TMD bilayers under pressure and application to twisted bilayers with pressure-induced topological phase transitions

2025-06-09
NULL AUTHOR_ID | Physical review. B./Physical review. B

Synthesis and characterization of Diamond Single Crystals with Fe<sub>3</sub>P Doped under High Pressure and High Temperature

2025-06-06
Zhenghao Guo , Shangsheng Li , Yuan Nie +7 more | NANO