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  • Hydrogen-terminated diamond MOSFETs on (0 0 1) single crystal diamond with state of the art high RF power density

    Cui Yu,
    Chuangjie Zhou,
    Jianchao Guo,
    Zezhao He,
    Mengyu Ma,
    Hao Yu,
    Xubo Song,
    Aimin Bu,
    Zhihong Feng

    Diamond field-effect transistor (FET) has great application potential for high frequency and high power electronic devices. In this work, diamond FETs were fabricated on (0 0 1) single crystal diamond with homoepitaxial layer. The nitrogen impurity content in the homoepitaxial layer is greatly decreased as measured by the Raman and photoluminescence spectra. The diamond field effect transistor with 100 nm Al2O3 as gate dielectric shows ohomic contact resistance of 35 Ω . mm, maximum drain saturation current density of 500 mA/mm, and maximum transconductance of 20.1 mS/mm. Due to the high quality of Al2O3 gate dielectric and single crystal diamond substrate, the drain work voltage of −58 V is achieved for the diamond FETs. A continuous wave output power density of 4.2 W/mm at 2 GHz is obtained. The output power densities at 4 and 10 GHz are also improved and achieve 3.1 and 1.7 W/mm, respectively. This work shows the application potential of single crystal diamond for high frequency and high power electronic devices.

    关键词:
    Diamond;
    field effect transistor;
    frequency;
    power density
    Functional Diamond
    2022年 第2卷 第1期
  • Composite-pulse enhanced room-temperature diamond magnetometry

    Yang Dong,
    Jing-Yan Xu,
    Shao-Chun Zhang,
    Yu Zheng,
    Xiang-Dong Chen,
    Wei Zhu,
    Guan-Zhong Wang,
    Guang-Can Guo,
    Fang-Wen Sun

    The sensitivity of practical solid quantum sensing can be boosted up by increasing the number of probes. However, the effects of spin dephasing caused by inhomogeneous broadening and imperfect quantum control can reduce the fidelity of quantum control and the sensitivity of quantum sensing with the dense ensemble of probes, such as nitrogen-vacancy (NV) centers in diamond. Here, we present a robust and effective composite-pulse for high fidelity operation against inhomogeneous broadening and control errors via optimized modulation of the control field. Such a composite-pulse was verified on NV center to keep high fidelity quantum control up to a spectrum detuning as large as 110% of Rabi frequency. The sensitivity of the magnetometer with NV center ensemble was experimentally improved by a factor of 4, comparing to dynamical decoupling with a normal rectangular pulse. Our work marks an important step towards high trustworthy ultra-sensitive quantum sensing with imperfect quantum control in practical applications. The used principle is universal and not restricted to NV center ensemble magnetometer.

    关键词:
    Quantum sensing;
    inhomogeneous broadening;
    nitrogen-vacancy centers;
    composite-pulse method
    Functional Diamond
    2021年 第1卷 第1期
  • Emerging applications of nanodiamonds in photocatalysis

    Li-Xia Su,
    Yu Cao,
    Hao-Shan Hao,
    Qi Zhao,
    Jinfang Zhi

    As a fascinating nanocarbon photocatalytic material, nanodiamonds (NDs) have attracted more and more attention recently due to their high chemical stability, high carrier mobility, narrowing band gap, easy surface modification, and mass production. This review summarizes the latest progress related to elaborated construction of NDs and NDs-based nanocomposite, including microstructure regulation of pristine NDs, elemental doping and formation a heterojunction by coupled with another semiconductor. The construction and properties of each category of NDs-based material are reviewed on their structure, preparation methods, texture control, and photocatalytic performance. Photocatalytic applications of NDs-based nanomaterials for hydrogen evolution from water splitting, organic pollution degradation, CO2 reduction, N2 reduction, graphene oxide reduction, and the latest advances in photocatalytic reaction mechanism have been also systematically reviewed. Finally, the challenges and prospects of the photocatalytic application of NDs are also briefly analyzed.

    关键词:
    nanocarbon;
    nanodiamond;
    photocatalysis;
    H2 evolution;
    pollution degradation;
    CO2 reduction
    Functional Diamond
    2021年 第1卷 第1期
  • Application of high-thermal-conductivity diamond for space phased array antenna

    Wei Lu,
    Jin Li,
    Jianyin Miao,
    Liangxian Chen,
    Junjun Wei,
    Jinlong Liu,
    Chengming Li

    Active phased array antenna typically featured high performance, high device integration, and high heat flux, making it difficult to dissipate heat. Diamond, the substance with the closest arrangement of atoms in nature, has the advantages of a high thermal conductivity and strong adaptability to the space environment. The batch applications of high-thermal-conductivity diamonds for the thermal management of the phased array antennas of the inter-satellite links were introduced in this paper. The diamond was developed by the direct-current arc-plasma chemical vapor deposition method. The product size, thermal conductivity, precision, and application scale all met the engineering requirements. The high-precision assembly of the diamond and the structural frame enabled the efficient heat collection and transfer from the distributed point heat sources of multiple transmit/receive (T/R) modules. Verified on the ground, the thermal matching design between the diamond and the metal frame exhibited an outstanding heat dissipation performance. After four satellites using the diamonds were launched, the flight data showed good antenna thermal control, with temperature gradients of the T/R modules less than 2.2 °C, further verifying the rationality and effectiveness of using high-thermal-conductivity diamonds in the thermal design and implementation of antennas.

    关键词:
    diamond;
    thermal control;
    phased array;
    high heat flux
    Functional Diamond
    2021年 第1卷 第1期
  • Boron/nitrogen co-doped diamond electrode for highly efficient electrochemistry detection of aniline

    Jiahan Li,
    Qiliang Wang,
    Yaofeng Liu,
    Zhigang Jiang,
    Junsong Liu,
    Hongdong Li,
    Xiaoxi Yuan

    Aniline is a mutagenic and carcinogenic material for human health, and it is desirable to construct high-performance detecting system for the trace detection of aniline. In this work, the boron (B)/nitrogen (N)-doped diamond (BND) films prepared by chemical vapor deposition are proposed as electrochemical electrodes to detect aniline in a wide concentration scale. The BND electrodes have a high sensitivity (detect limitation of 0.29 μmol L−1) and a wide linear detection range (0.5 − 500 μmol L−1). Both the detection limitation and linear range are significantly improved with respect to that from traditional electrodes of boron-doped diamond and various carbonaceous materials, which can be attributed to the synergistic effect of increased electrochemistry reduction and density of reaction sites on the BND electrode surfaces. This work develops a kind of electrochemical electrodes of B/N-doped diamond films with high performances for quantitative detections of aniline in practical applications.Supplemental data for this article is available online at http://dx.doi.org/10.1080/26941112.2021.1939170

    关键词:
    Aniline;
    electrochemical sensor;
    B/N-doped diamond electrode;
    wide detection range
    Functional Diamond
    2021年 第1卷 第1期
  • Correlation of the role of boron concentration on the microstructure and electrochemical properties of diamond electrodes

    Yinhao Chen,
    Xiaolei Gao,
    Guoshuai Liu,
    Ruitong Zhu,
    Wanlin Yang,
    Zhishen Li,
    Fangmu Liu,
    Kechao Zhou,
    Zhiming Yu,
    Qiuping Wei,
    Li Ma

    In this article, a series of highly boron-doped diamond ([B] > 1021 cm−3) electrodes with small gradient variations in boron concentration were prepared by hot filament chemical vapor deposition (HF-CVD). Reactive blue 19 (RB-19) dye solution was used as a prototype wastewater. Interestingly, we found that the electrochemical properties (electrochemically active surface area and oxygen evolution potential) and the electrochemical degradation performance did not deteriorate linearly with increasing boron concentration. Specifically, the electrochemically active surface area of the electrode at [B]/[C] = 50,000 ppm was the highest of 9.366 cm2, the chromaticity removal rate of RB-19 dye wastewater reached 100% after 90 min, and the TOC removal rate reached 74.48% after 180 min with the lowest energy consumption.

    关键词:
    Boron doped diamond;
    boron concentration;
    electrochemical advanced oxidation
    Functional Diamond
    2021年 第1卷 第1期
  • Diamond and carbon nanostructures for biomedical applications

    Yuxiang Xue,
    Xue Feng,
    Samuel C. Roberts,
    Xianfeng Chen

    Diamond and carbon nanostructures possess outstanding advantages, such as chemical inertness, stable fluorescence, tunable surface characteristics and excellent biocompatibility. In particular, diamond has extremely strong mechanical properties, and therefore the nanostructures have been developed for unique applications. Herein, we systematically review the very recent applications of these structures in drug delivery, bioimaging and biosensing, followed by discussion of their advantages, limitations and challenges in translation to potential clinical applications and presentation of our insights of their future development.

    关键词:
    Nanodiamond;
    diamond;
    graphene;
    carbon nanostructures;
    drug delivery;
    biosensing
    Functional Diamond
    2021年 第1卷 第1期
  • Science and technology of a transformational multifunctional ultrananocrystalline diamond (UNCD) coating

    Orlando Auciello

    This review focuses on describing the fundamental/applied materials science and technological applications of a transformational multifunctional diamond-based material named ultranano­crytalline diamond (UNCDTM) in film form. The UNCDTM films are synthesized using microwave plasma chemical vapor deposition (MPCVD) and hot filament chemical vapor deposition (HFCVD), via patented Ar/CH4 gas flown into air evacuated chambers, using microwave power, or hot filaments’ surface, to crack CH4 molecules to generate C atoms and CHx (x = 1, 2, 3) species, which produce chemical reactions on substrates’ surfaces, producing diamond film with grain sizes in the range 3–5 nm (smallest grain size known today for any polycrystalline diamond film), providing the bases for the name UNCD. UNCD coatings exhibit a unique combination of properties, namely: (1) super high hardness and Young modulus, similar to the crystal gem of diamond; (2) lowest coefficient of friction compared to other diamond or diamond-like coatings; (3) no mechanical surface wear; (4) highest resistance to chemical attach by any corrosive fluid; (5) only diamond film exhibiting electrical conductivity via Nitrogen inserted in grain boundaries, binding to C atoms and providing electrons for electrical conduction, or B atoms substituting C atoms in the diamond lattice, providing electrons to the conduction band; and (6) best biocompatibility, since UNCD coatings are formed by C atoms (element of life in human DNA, cells/molecules). The UNCD films’ properties provide unique multifunctionalities, enabling new generations of industrial, electronic, high-tech, and implantable medical devices/prostheses, enabling substantial improvement in the way and quality of life of people worldwide.

    关键词:
    Diamond;
    coating;
    industrial;
    high-tech;
    medical;
    products
    Functional Diamond
    2022年 第2卷 第1期
  • Luminescent diamond composites

    Vadim Sedov,
    Sergei Kuznetsov,
    Artem Martyanov,
    Victor Ralchenko

    Diamond is valuable material with extraordinary high thermal conductivity and transparency in a wide spectral range from UV to IR and longer wavelengths. Defects and impurities in the diamond lattice can absorb and emit light at wavelengths specific for each of such “color centers.” Particularly, the vacancy-related defects in diamond, such as nitrogen-vacancy (NV) or silicon-vacancy (SiV) centers, are actively investigated due to their potential for biomedicine, quantum optics, local thermometry and magnetometry. Although a great variety of different color centers in diamond are discovered, only a limited number of those point defects can be reliably reproduced in synthetic diamond, obtained either by chemical vapor deposition (CVD) or high-pressure high-temperature (HPHT). An alternative approach to producing luminescent diamond-based materials is to integrate stable non-diamond sources of luminescence in the form of nano- or microparticles of foreign materials into the pristine diamond. The produced diamond composites possess excellent properties of diamond combined with optical emission characteristics, which cannot be provided with intrinsic defects in diamond. The good candidates for the materials of such impurities are well-investigated fluorides and oxides doped by rare-earth elements (RE) or other luminescent chalcogenides such as sulfides, selenides and tellurides. Here we briefly review recent achievements in fabrication and properties of these new luminescent diamond-RE composites, compare them with luminescent properties of doped diamond, and outline prospects for applications of the luminescent diamond composites for photonics, markers, monitors of high-power synchrotron, X-ray beams and X-ray lasers.

    关键词:
    Diamond;
    polycrystalline films;
    composites;
    CVD growth;
    rare earth elements;
    X-ray luminescence
    Functional Diamond
    2022年 第2卷 第1期
  • Epitaxial lateral growth of single-crystal diamond under high pressure by a plate-to-plate MPCVD

    Wei Cao,
    Deng Gao,
    Hongyang Zhao,
    Zhibin Ma

    The epitaxial lateral growth of single-crystal diamond (SCD) using a plate-to-plate microwave plasma chemical vapor deposition (MPCVD) reactor under high pressure is investigated. The radicals’ distribution in H2/CH4 plasma as a function of pressure was locally detected by optical emission spectroscopy (OES). Raman spectroscopy and optical microscope were employed to analyze the properties of SCD deposited in different pressure. The OES results show that radicals’ distribution along the substrate direction is symmetrical under 20 kPa pressure. The symmetrical distribution of radicals at 20 kPa is in favor of epitaxial lateral growth SCD around the seed and without polycrystalline diamond (PCD) rim. When the pressure is increased to 21.5 kPa, the optical emission spectra center of plasma shifts close to the microwave reflector where is far away from the microwave source. The contact state between the diamond seed and the plasma is deteriorated and the PCD rim occurs in the plasma uncovered area. While the epitaxial lateral growth pattern occurs in the plasma covered area and the lateral growth rate of this region improves with the increase of pressure. A higher growth rate does not result in good quality; meanwhile, the diamond growth step spacing and direction become inconsistent in the transition zone as a function of pressure increasing. Finally, the overall effective lateral expansion area does not increase with the improvement of pressure. Therefore, the uniform and symmetrical distributed plasma is more conducive to the epitaxial lateral growth of SCD, and the effective expansion growth SCD can be realized at 20 kPa.

    关键词:
    Microwave plasma;
    OES;
    SCD lateral growth;
    high pressure
    Functional Diamond
    2021年 第1卷 第1期