Nanostructured Diamond Research Articles

Target Detection of Diamond Nanostructures Based on Improved YOLOv8 Modeling.

Boron-doped diamond thin films exhibit extensive applications in chemical sensing, in which the performance could be further enhanced by nano-structuring of the surfaces. In order to discover the relationship between diamond nanostructures and properties, this paper is dedicated to deep learning target detection methods. However, great challenges, such as noise, unclear target boundaries, and mutual occlusion between targets, are inevitable during the target detection of nanostructures. To tackle these challenges, DWS-YOLOv8 (DCN + WIoU + SA + YOLOv8n) is introduced to optimize the YOLOv8n model for the detection of diamond nanostructures. A deformable convolutional C2f (DCN_C2f) module is integrated into the backbone network, as is a shuffling attention (SA) mechanism, for adaptively tuning the perceptual field of the network and reducing the effect of noise. Finally, Wise-IoU (WIoU)v3 is utilized as a bounding box regression loss to enhance the model's ability to localize diamond nanostructures. Compared to YOLOv8n, a 9.4% higher detection accuracy is achieved for the present model with reduced computational complexity. Additionally, the enhancement of precision (P), recall (R), mAP@0.5, and mAP@0.5:0.95 is demonstrated, which validates the effectiveness of the present DWS-YOLOv8 method. These methods provide effective support for the subsequent understanding and customization of the properties of surface nanostructures.

Low-Cost Preparation of Diamond Nanopillar Arrays Based on Polystyrene Spheres.

Diamond nanopillar arrays can enhance the fluorescence collection of diamond color centers, playing a crucial role in quantum communication and quantum sensing. In this paper, the preparation of diamond nanopillar arrays was realized by the processes of polystyrene (PS) sphere array film preparation, PS sphere etching shrinkage control, tilted magnetron sputtering of copper film, and oxygen plasma etching. Closely aligned PS sphere array films were prepared on the diamond surface by the gas-liquid interfacial method, and the effects of ethanol and dodecamethylacrylic acid solutions on the formation of the array films were discussed. Controllable reduction of PS sphere diameter is realized by the oxygen plasma etching process, and the changes of the PS sphere array film under the influence of etching power, bias power, and etching time are discussed. Copper antietching films were prepared at the top of arrayed PS spheres by the tilted magnetron sputtering method, and the antietching effect of copper films with different thicknesses was explored. Diamond nanopillar arrays were prepared by oxygen plasma etching, and the effects of etching under different process parameters were discussed. The prepared diamond nanopillars were in hexagonal close-rowed arrays with a spacing of 800 nm and an average diameter of 404 nm, and the spacing, diameter, and height could be parametrically regulated. Raman spectroscopy and photoluminescence spectroscopy detection revealed that the prepared diamond nanopillar array still maintains polycrystalline diamond properties, with only a small amount of the graphite phase appearing. Moreover, the prepared diamond nanopillar array can enhance the photoluminescence of diamond color centers by approximately 2 times. The fabrication method of diamond nanopillar array structures described in this article lays the foundation for quantum sensing technology based on diamond nanostructures.

Core-shell diamond-graphene needles with silicon-vacancy color centers

Color centers in diamond nanostructures open new horizons in biomedicine, offering a biocompatible material platform for sensing temperature, pH, and magnetic field. Covering of the color centers enriched diamonds with graphene shell can essentially extend their application potential. Specifically, under irradiation with ultrashort laser pulses, the highly absorptive graphene shell can be used for excitation of a shock acoustic wave which can be used for cancer cell destruction or drug photoactivation through the Joule heating. In this study, we present a novel method for creating diamond-graphite core-shell structures. Through precise control of the growth of the graphitic layer on Single Crystal Diamond Needles (SCDNs) via vacuum annealing at 900°C for 30 minutes, we preserved 57% of the light emission from silicon-vacancy (SiV-) centers while maintaining their spectral peaks. Contrary to our expectations of reduced SiV- luminescence due to the presence of the graphitic shell, we observed that the initial high brightness of SiV- in the diamond needles persisted. This enabled us to detect SiV- luminescence spectrally, even within the core-shell structures. Our results underscore the tunability of these structures’ properties through temperature and duration control, suggesting promising prospects for their application in advanced biomedical tools with sensing capabilities.

One-dimensional diamond nanostructures: Fabrication, properties and applications

Diamonds exhibit a unique combination of numerous excellent physical and chemical properties, such as the highest hardness, high Young's modulus, wide bandgap, high carrier mobility, negative electron affinity, and high thermal conductivity. Especially, diamond has attracted significant attention in recent years for its outstanding performance in high-frequency and high-power electronic devices and thermal management. Inheriting the intrinsic physical and chemical properties of diamonds, one-dimensional (1D) diamond nanostructures exhibit many additional properties that are unavailable for bulk diamond or thin films, e.g., large specific surface area, ultrahigh elasticity, and some plasticity, tip effect as well as direct transport for photon or photo-induced carriers. These properties make 1D diamond nanostructures an ideal candidate for applications ranging from micro/nano-electromechanical systems (MEMS/NEMS) to field electron emission, optical, electrochemical, and biological areas. This review will first introduce the development of controlled synthesis methods of 1D diamond nanostructure, including bottom-up chemical vapor deposition growth and top-down selective etching of bulk diamond. Subsequently, we will summarize recent advances in the mechanical, electron field emission, optical, and biological properties of 1D diamond nanostructures and their applications in electron and photon emitter, MEMS, sensing, intracellular delivery, etc.

Bio-inspired transparent and antibiofouling diamond films via layer-by-layer self-assembly seeding

Bio-inspired diamond nanostructures featuring high transparency and anti-bacterial adhesion were constructed via layer-by-layer (LbL) self-assembly seeding and chemical vapor deposition growth. The topography of the diamond nanofilms was determined by initial nanodiamond seeds distribution, which was adjusted by nanodiamond colloidal stability. With increasing number of LbL bilayers, the bulge size and roughness of the deposited films increased. With increasing number of bilayers from 1 to 5, UV–Vis transmittance slightly decreased from max. 90 %–83 %, while the contact angle increased from 90° to 130°. All the nanostructured diamond films possess very high IR transmittance between 85% and 90%, which is close to the bare quartz (95%). Compared with conventional flat diamond films, nanostructured diamond films repelled most of the bacteria, suggesting excellent anti-biofouling property. With increasing seeding bilayer number, more bacteria were repelled. The highest bacterial reduction was achieved to 99% by diamond film seeded with 5 bilayers. The bio-mimicking nanostructured diamond film represent a potent solution for achieving highly transparent, anti-biofouling and highly durable optical coatings for biomedical and marine optical instrument.

Diamond Nanostructures at Different Dimensions: Synthesis and Applications

AbstractDiamond materials at different nanoscales provide them various characteristics such as elastic mechanical properties in needle‐like nanotips, flexibility of 2D films having atomic thicknesses and constant hardness under high pressures, superior field electron emission properties of vertically wall‐like composites, unprecedented hardness and improved toughness of nanotwin diamond (nt‐diamond), while the inherent excellent properties of bulk diamond (e.g., high Young's modulus, robustness, biocompatibility) can be maintained. In this paper, the newly born 1D diamond nanothreads, 2D diamanes, as well as 3D nt‐diamond are briefly reviewed. The innovations, progresses and achievements of different dimensional diamond nanostructures, covering lines, planes and volumes are overviewed. The topical problems and future outlooks of diamond nanostructures are outlined and discussed.

Nanoelectromechanical Control of Spin-Photon Interfaces in a Hybrid Quantum System on Chip.

Color centers (CCs) in nanostructured diamond are promising for optically linked quantum technologies. Scaling to useful applications motivates architectures meeting the following criteria: C1 individual optical addressing of spin qubits; C2 frequency tuning of spin-dependent optical transitions; C3 coherent spin control; C4 active photon routing; C5 scalable manufacturability; and C6 low on-chip power dissipation for cryogenic operations. Here, we introduce an architecture that simultaneously achieves C1-C6. We realize piezoelectric strain control of diamond waveguide-coupled tin vacancy centers with ultralow power dissipation necessary. The DC response of our device allows emitter transition tuning by over 20 GHz, combined with low-power AC control. We show acoustic spin resonance of integrated tin vacancy spins and estimate single-phonon coupling rates over 1 kHz in the resolved sideband regime. Combined with high-speed optical routing, our work opens a path to scalable single-qubit control with optically mediated entangling gates.

Nitrogen-Vacancy Magnetic Relaxometry of Nanoclustered Cytochrome C Proteins.

Nitrogen-vacancy (NV) magnetometry offers an alternative tool to detect paramagnetic centers in cells with a favorable combination of magnetic sensitivity and spatial resolution. Here, we employ NV magnetic relaxometry to detect cytochrome C (Cyt-C) nanoclusters. Cyt-C is a water-soluble protein that plays a vital role in the electron transport chain of mitochondria. Under ambient conditions, the heme group in Cyt-C remains in the Fe3+ state, which is paramagnetic. We vary the concentration of Cyt-C from 6 to 54 μM and observe a reduction of the NV spin-lattice relaxation time (T1) from 1.2 ms to 150 μs, which is attributed to the spin noise originating from the Fe3+ spins. NV T1 imaging of Cyt-C drop-casted on a nanostructured diamond chip allows us to detect the relaxation rates from the adsorbed Fe3+ within Cyt-C.

Correction: Vertically aligned boron-doped diamond nanostructures as highly efficient electrodes for electrochemical supercapacitors

Correction for ‘Vertically aligned boron-doped diamond nanostructures as highly efficient electrodes for electrochemical supercapacitors' by Shradha Suman et al., J. Mater. Chem. A, 2024, https://doi.org/10.1039/D3TA07728D.

Vertically aligned boron-doped diamond nanostructures as highly efficient electrodes for electrochemical supercapacitors

Nanostructured boron-doped diamond (BDD) offers a sizeable ion-accessible area, high mechanical robustness, and high electrical conductivity, which could be a suitable electrode for high-performance electrochemical (EC) supercapacitors. Herein, two morphological...

Determining the Dependence of Single Nitrogen-Vacancy Center Light Extraction in Diamond Nanostructures on Emitter Positions with Finite-Difference Time-Domain Simulations.

In this study, we obtained a diamond nanocone structure using the thermal annealing method, which was proposed in our previous work. Using finite-difference time-domain (FDTD) simulations, we demonstrate that the extraction efficiencies of nitrogen-vacancy (NV) center emitters in nanostructures are dependent on the geometries of the nanocone/nanopillar, emitter polarizations and axis depths. Our results show that nanocones and nanopillars have advantages in extraction from emitter dipoles with s- and p-polarizations, respectively. In our simulations, the best results of collection efficiency were achieved from the emitter in a nanocone with s-polarization (57.96%) and the emitter in a nanopillar with p-polarization (38.40%). Compared with the nanopillar, the photon extraction efficiency of the emitters in the nanocone is more sensitive to the depth and polarization angle. The coupling differences between emitters and the nanocone/nanopillar are explained by the evolution of photon propagation modes and the internal reflection effects in diamond nanostructures. Our results could have positive impacts on the design and fabrication of NV center-based micro- and nano-optics in the future.

Effect of the nanopillar diameter on diamond silicon vacancy center spin lifetime

Color centers in diamond micro and nano-structures play an important role in a wide range of quantum technologies. However, obtaining high-quality color centers in small structures is challenging, as properties such as spin population lifetimes can be affected by the transition from a bulk to nanostructured crystal host. In this manuscript, we measure how population lifetimes of silicon vacancy center orbital states change when they are created in nanopillars whose diameters vary from 1 μm to 120 nm. We also discuss the influence of annealing methods on the silicon vacancy inhomogeneous linewidth. After selecting a sample with low inhomogeneous broadening and patterning it with nanopillars, we expected that restricted vibrational modes in the smallest structures could extend spin population lifetimes. However, we found that this effect was masked by other effects that reduced population lifetimes, suggesting that imperfections in the crystal lattice or surface damage caused by etching can influence SiV spins.

Deterministic creation of strained color centers in nanostructures via high-stress thin films

Color centers have emerged as a leading qubit candidate for realizing hybrid spin-photon quantum information technology. One major limitation of the platform, however, is that the characteristics of individual color centers are often strain dependent. As an illustrative case, the silicon-vacancy center in diamond typically requires millikelvin temperatures in order to achieve long coherence properties, but strained silicon-vacancy centers have been shown to operate at temperatures beyond 1 K without phonon-mediated decoherence. In this work, we combine high-stress silicon-nitride thin films with diamond nanostructures to reproducibly create statically strained silicon-vacancy color centers (mean ground state splitting of 608 GHz) with strain magnitudes of ∼4×10−4. Based on modeling, this strain should be sufficient to allow for operation of a majority silicon-vacancy centers within the measured sample at elevated temperatures (1.5 K) without any degradation of their spin properties. This method offers a scalable approach to fabricate high-temperature operation quantum memories. Beyond silicon-vacancy centers, this method is sufficiently general that it can be easily extended to other platforms as well.

Impact of diamond nanothread on the viscosity of asphalt binder: Insights from atomistic simulations

Viscosity stands as a pivotal property within asphalt binder, exerting influence not only over the pavement quality and construction efficiency but also over energy consumption and harmful gas emissions. Lower viscosity at the mixing temperature can reduce the energy consumption and emissions remarkably. As such, extensive efforts have been devoted to tailor the viscosity of asphalt by adding nanomaterials. Through atomistic simulations, this work provides an in-depth assessment on the viscosity of asphalt binder modified by ultrathin diamond nanothread (DNT). It is observed that the addition of DNT can reduce the viscosity of asphalt, a phenomenon traced back to the sp3-bonded nature of DNT that prevents the formation of π - π bonds with asphaltene molecules. Notably, samples endowed with higher count of stacked asphaltene molecules tend to display higher viscosity. Further investigation reveals that the sample with aggregated DNTs exhibits a lower viscosity, as the aggregated DNTs exert a more subdued influence on asphalt molecule mobility. Specifically, DNTs are found to promote the mobility of all molecules, and a remarkable enhancement on the mobility of saturated molecules is observed. This distinct behavior sets them apart from single-walled carbon nanotubes (SWNTs), where viscosity rises with increasing content due to the SWNT-induced aggregation of asphaltene molecules. Overall, this work unveils the intricate mechanisms influencing the viscosity of asphalt binders through diamond nanostructures. These findings could be beneficial for the design of asphalt binders with tailored rheological properties.

ТЕРМОДИНАМИЧЕСКИЙ АНАЛИЗ ПРОЦЕССА ФОРМИРОВАНИЯ НАНОСТРУКТУРНОГО ПОЛИКРИСТАЛЛИЧЕСКОГО МАТЕРИАЛА НА ОСНОВЕ НАНОАЛМАЗОВ, МОДИФИЦИРОВАННЫХ НЕАЛМАЗНЫМ УГЛЕРОДОМ (ЧАСТЬ 2)

The paper presents the results of thermodynamic analysis showing that the use of nanodiamonds with a thin graphite-like coating formed by surface graphitization of nanodiamonds makes it possible to increase the thermodynamic stimulus for the formation of a diamond structure under conditions of high pressures and temperatures. For a thin carbon film with a disordered structure (amorphous carbon, soot), the pressure of transition into diamond will exceed the equilibrium pressure due to the lower surface energy of amorphous carbon compared to the surface energy of graphite. In this case, a decrease in the thickness of the non-diamond carbon film on the surface of a diamond particle leads to an increase in the pressure of the graphite–diamond phase transition. The proposed approach provides the possibility of reducing the synthesis parameters of nanostructured polycrystalline diamond materials without additional use of phase transformation catalysts.

Bending behavior of diamane and twisted bilayer graphene: Insights from four-point bending deformation

The intriguing physical properties of two-dimensional (2D) nanomaterials make them promising building blocks for flexible electronics. Using a four-point bending approach, this work establishes a comprehensive understanding of the bending behavior of diamane – a 2D diamond nanostructure, from elastic deformation to structural failure through atomistic simulations. The four-point bending method accurately reproduces the pure bending of the sample, and the obtained force-displacement curve fit well with the classical Euler beam theory. Structural failure is observed from diamane under bending when its thickness or the number of layers increases. Atomic insights reveal that the crack initiates from the tension side of the sample, resulting in a tension-induced bending failure. Specifically, the bending limit is found to be slightly larger than the fracture strain under tensile deformation. Additionally, the bending behaviour of the diamane analogous – twisted bilayer graphene with interlayer-bonding (TBGIB), has been investigated. Different from diamane, TBGIB bends elastically at the initial stage and then experiences structural failures with increasing bending strain. Higher interlayer bonding density is observed to result in a higher bending stiffness. Meanwhile, significant interlayer shear strain is detected during bending, which leads to interlayer bond breakage, rippling, and buckling of the graphene layer. This work provides a full description of the pure bending behavior of diamane and its analogous structure, which could be beneficial for their applications in flexible electronics.

Shallow Silicon Vacancy Centers with Lifetime-Limited Optical Linewidths in Diamond Nanostructures.

The negatively charged silicon vacancy center (SiV-) in diamond is a promising, yet underexplored candidate for single-spin quantum sensing at sub-kelvin temperatures and tesla-range magnetic fields. A key ingredient for such applications is the ability to perform all-optical, coherent addressing of the electronic spin of near-surface SiV- centers. We present a robust and scalable approach for creating individual, ∼50 nm deep SiV- with lifetime-limited optical linewidths in diamond nanopillars through an easy-to-realize and persistent optical charge-stabilization scheme. The latter is based on single, prolonged 445 nm laser illumination that enables continuous photoluminescence excitation spectroscopy without the need for any further charge stabilization or repumping. Our results constitute a key step toward the use of near-surface, optically coherent SiV- for sensing under extreme conditions, and offer a powerful approach for stabilizing the charge-environment of diamond color centers for quantum technology applications.

Resistive Switching in Bigraphene/Diamane Nanostructures Formed on a La3Ga5SiO14 Substrate Using Electron Beam Irradiation.

Memristors, resistive switching memory devices, play a crucial role in the energy-efficient implementation of artificial intelligence. This study investigates resistive switching behavior in a lateral 2D composite structure composed of bilayer graphene and 2D diamond (diamane) nanostructures formed using electron beam irradiation. The resulting bigraphene/diamane structure exhibits nonlinear charge carrier transport behavior and a significant increase in resistance. It is shown that the resistive switching of the nanostructure is well controlled using bias voltage. The impact of an electrical field on the bonding of diamane-stabilizing functional groups is investigated. By subjecting the lateral bigraphene/diamane/bigraphene nanostructure to a sufficiently strong electric field, the migration of hydrogen ions and/or oxygen-related groups located on one or both sides of the nanostructure can occur. This process leads to the disruption of sp3 carbon bonds, restoring the high conductivity of bigraphene.

Self-healing of fractured diamond.

Materials that possess the ability to self-heal cracks at room temperature, akin to living organisms, are highly sought after. However, achieving crack self-healing in inorganic materials, particularly with covalent bonds, presents a great challenge and often necessitates high temperatures and considerable atomic diffusion. Here we conducted a quantitative evaluation of the room-temperature self-healing behaviour of a fractured nanotwinned diamond composite, revealing that the self-healing properties of the composite stem from both the formation of nanoscale diamond osteoblasts comprising sp2- and sp3-hybridized carbon atoms at the fractured surfaces, and the atomic interaction transition from repulsion to attraction when the two fractured surfaces come into close proximity. The self-healing process resulted in a remarkable recovery of approximately 34% in tensile strength for the nanotwinned diamond composite. This discovery sheds light on the self-healing capability of nanostructured diamond, offering valuable insights for future research endeavours aimed at enhancing the toughness and durability of brittle ceramic materials.

Thermoelectric properties of B-doped nanostructured bulk diamond with lowered thermal conductivity

Diamond exhibits high wear resistance and high chemical resistance. If diamond exhibits high thermoelectric performance, the thermoelectric application will be expanded for various situations such as the use of friction heat on turbines. However, bulk diamond exhibits low electrical conductivity and high thermal conductivity, leading to the low thermoelectric performance. In this study, to solve the above problem, we propose a strategy of heavy impurity doping in nanostructured bulk diamond which brings two things: (1) higher thermoelectric power factor, and (2) phonon scattering enhancement at impurities and nanostructure interfaces reducing the thermal conductivity drastically. We investigate the thermoelectric properties of heavily B-doped nanostructured bulk diamonds prepared by direct conversion sintering under ultra-high pressure and temperature using B-doped graphite as a starting material. This nanostructured bulk diamond exhibited high electrical conductivity due to heavy B doping, resulting in high power factor of 4 μWcm−1 K−2 at 1050 K. Furthermore, we found that this nanostructured bulk diamond exhibited drastic thermal conductivity reduction, resulting in quite low thermal conductivity among bulk diamond ever reported. This comes from phonon scattering both at nanostructure interfaces and by substitutional B atoms. From these results, the present study would be informative for expanding thermoelectric application to various situations such as the use of friction heat.