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Issue articles

Volume 1, Issue 1 (2021)

Properties, mechanism and applications of diamond as an antibacterial material

Aude Cumont,
Andrew R. Pitt,
Peter A. Lambert,
Marco R. Oggioni,
Haitao Ye

Antibiotic resistance in bacteria is a current threat causing an increasing number of infections of difficult clinical management. While the overuse and misuse of antibiotics are investigated to reduce them, the need for alternatives to approaches is rising. Carbon-based materials shown recent moderate to high antibacterial properties and diamond, thanks to its superior mechanical, tribological, electrical, chemical and biological quality is a choice material to investigate for safe antibacterial films, coatings and particles. Here, the antibacterial properties of diamond films, nanodiamonds, DLC films and a comprehensive list of the composites developed from them are discussed along with a summary of the bacterial strains used and the most efficient composition and/or concentration discovered. In a later stage, the mechanisms of action and the parameters that are believed to influence them are discussed and finally, an overview of the biomedical and food industry applications is given.

surface functionalisation;
Functional Diamond
Volume 1, Issue 1 (2021)

Progress in semiconductor diamond photodetectors and MEMS sensors

Meiyong Liao

Diamond with an ultra-wide bandgap shows intrinsic performance that is extraordinarily superior to those of the currently available wide-bandgap semiconductors for deep-ultraviolet (DUV) photoelectronics and microelectromechanical systems (MEMS). The wide-bandgap energy of diamond offers the intrinsic advantage for solar-blind detection of DUV light. The recent progress in high-quality single-crystal diamond growth, doping, and devices design have led to the development of solar-blind DUV detectors satisfying the requirement of high Sensitivity, high Signal-to-Noise ratio, high spectral Selectivity, high Speed, and high Stability. On the other hand, the outstanding mechanical hardness, chemical inertness, and intrinsic low mechanical loss of diamond enable the development of MEMS sensors with boosted sensitivity and robustness. The micromachining technologies for diamond developed in these years have opened the avenue for the fabrication of high-quality single-crystal diamond mechanical resonators. In this review, we report on the recent progress in diamond DUV detectors and MEMS sensors, which includes the device principles, design, fabrication, micromachining of diamond, and devices physics. The potential applications of these sensors and a perspective are also described.

Single-crystal diamond;
Functional Diamond
Volume 1, Issue 1 (2021)

Coessential-connection by microwave plasma chemical vapor deposition: a common process towards wafer scale single crystal diamond

Guoyang Shu,
Bing Dai,
Andrey Bolshakov,
Weihua Wang,
Yang Wang,
Kang Liu,
Jiwen Zhao,
Jiecai Han,
Jiaqi Zhu

Large size single crystal diamond (SCD) wafer has been strongly desired for various of advanced applications, while two major potential approaches, including mosaic growth and heteroepitaxy based on chemical vapor deposition method, are both stuck with respective technical barriers. This paper reveals and summarizes the essential commonality of the two schemes, and denominates the concept of “coessential-connection” (CC) growth. Such generalized concept involved the nature of the single crystal and polycrystalline diamond film deposition with similar mechanism and processes. The principle of CC growth process with detailed classification was elaborated, and influence of nucleus size and orientation mismatch was clarified, which is regarded as the core problem of large area SCD film growth via coessential-connection process.

Single crystal diamond;
crystal growth;
Functional Diamond
Volume 1, Issue 1 (2021)

Diamond with nitrogen: states, control, and applications

Yuting Zheng,
Chengming Li,
Jinlong Liu,
Junjun Wei,
Haitao Ye

The burgeoning multi-field applications of diamond concurrently bring up a foremost consideration associated with nitrogen. Ubiquitous nitrogen in both natural and artificial diamond in most cases as disruptive impurity is undesirable for diamond material properties, eg deterioration in electrical performance. However, the feat of this most common element-nitrogen, can change diamond growth evolution, endow diamond fancy colors and even give quantum technology a solid boost. This perspective reviews the understanding and progress of nitrogen in diamond including natural occurring gemstones and their synthetic counterparts formed by high temperature high pressure (HPHT) and chemical vapor deposition (CVD) methods. The review paper covers a variety of topics ranging from the basis of physical state of nitrogen and its related defects as well as the resulting effects in diamond (including nitrogen termination on diamond surface), to precise control of nitrogen incorporation associated with selective post-treatments and finally to the practical utilization. Among the multitudinous potential nitrogen related centers, the nitrogen-vacancy (NV) defects in diamond have attracted particular interest and are still ceaselessly drawing extensive attentions for quantum frontiers advance.

nitrogen-related defect;
post treatment;
Functional Diamond
Volume 1, Issue 1 (2021)

Diamane: design, synthesis, properties, and challenges

Guowen Qin,
Lailei Wu,
Huiyang Gou

Diamane, the two-dimensional counterpart of diamond, is achieved from bi-layer graphene (BLG) or few-layer graphene (FLG) through surface chemical adsorption or high-pressure technology. Diamane with interlayer sp3 bonding is found to have excellent heat transfer, ultra-low friction, high natural frequency, and tunable band gap, which shows the potential technological and industrial applications in nano-photonics, ultrasensitive resonator-based sensors, and improved wear resistance. In this review, we summarize the structure character, synthesis strategies, and physical properties of different diamanes, including hydrogenated diamane (HD), fluorinated diamane (FD), and pristine diamane (PD). In addition, we discuss the effect of functional groups, element doping, and stacking order on the physical properties of diamane. Finally, the remaining challenges and future opportunities for the further development of diamane are addressed.

Two dimensional diamond;
Varied stacking and electronic strcture;
Diamane with different functional group;
Chemicaland physical properties
Functional Diamond
Volume 1, Issue 1 (2021)

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.

H2 evolution;
pollution degradation;
CO2 reduction
Functional Diamond
Volume 1, Issue 1 (2021)

Room temperature direct bonding of diamond and InGaP in atmospheric air

Jianbo Liang,
Yuji Nakamura,
Yutaka Ohno,
Yasuo Shimizu,
Yasuyoshi Nagai,
Hongxing Wang,
Naoteru Shigekawa

A new technique of diamond and InGaP room temperature bonding in atmospheric air is reported. Diamond substrate cleaned with H2SO4/H2O2 mixture solution is bonded to InGaP exposed after removing the GaAs layer by the H2SO4/H2O2/H2O mixture solution. The bonding interface is free from interfacial voids and mechanical cracks. An atomic intermixing layer with a thickness of about 8 nm is formed at the bonding interface, which is composed of C, In, Ga, P, and O atoms. After annealing at 400 °C, no exfoliation occurred along the bonding interface. An increase of about 2 nm in the thickness of the atomic intermixing layer is observed, which plays a role in alleviating the thermal stress caused by the difference of the thermal expansion coefficient between diamond and InGaP. The bonding interface demonstrates high thermal stability to device fabrication processes. This bonding method has a large potential for bonding large diameter diamond and semiconductor materials.

Diamond atmospheric air room temperature bonding;
heat dissipation;
atmospheric air;
interfacial microstructure;
thermal boundary conductance
Functional Diamond
Volume 1, Issue 1 (2021)

Design and optimization of diamond mid-infrared phase shifter

Chengke Chen,
Zhi He,
Ancha Xu,
Xiao Li,
Meiyan Jiang,
Tao Xu,
Bo Yan,
Xiaojun Hu

Herein, the mid-infrared (7.7–13.7 μm) diamond-based phase shifter was designed and optimized by finite-element analysis. The ridge-shaped diamond waveguide is designed and doped to form the internal p–n structure, and the internal carrier distribution is changed by applying forward and reverse voltages to change the effective refractive index to achieve the effect of π-phase shift. The results show that when p-doping concentration is 4 × 1017 cm−3 and n doping concentration is 1 × 1018 cm−3, upon the reverse voltage (8 V) is applied, the change of the real part of effective refractive index (ΔR) is 1.6 × 10−5, and the length of the phase shifter (L) required to realize the π-phase shift is 241 mm; upon the forward voltage (–8 V) is applied, ΔR increases to 3.2 × 10−4, and the length of the phase shifter required is shortened to 12.03 mm. Such a short length is relatively easy in industrial production. In order to make the refractive index distribution more uniform, the carrier concentration has been optimized as 1 × 1017 cm−3 for p-type and 4 × 1017 cm−3 for n-type, respectively.

ridge waveguide;
phase shifter;
refractive index
Functional Diamond
Volume 1, Issue 1 (2021)

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.

Quantum sensing;
inhomogeneous broadening;
nitrogen-vacancy centers;
composite-pulse method
Functional Diamond
Volume 1, Issue 1 (2021)

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

electrochemical sensor;
B/N-doped diamond electrode;
wide detection range
Functional Diamond
Volume 1, Issue 1 (2021)

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.

Microwave plasma;
SCD lateral growth;
high pressure
Functional Diamond
Volume 1, Issue 1 (2021)

Progress of structural and electronic properties of diamond: a mini review

Hongchao Yang,
Yandong Ma,
Ying Dai

Diamond is of great importance for scientific and practical applications. It is the hardest natural material and holds potential applications in mechanics, electronics and photonics. Over the past few decades, great efforts have been paid for exploring its nature both experimentally and theoretically. Most of the recent studies on diamond are focused on their geometry stability and structural properties, while the research on electronic properties is relatively limited. Here, the recent research advances on diamond from a theoretical perspective are presented. In this mini review, we emphasize the recent breakthroughs related to the geometric and electronic properties of diamond, as well as the promising strategies for tuning their electronic properties, such as doping and constructing heterostructure. We then discuss its potential applications in electronic and optoelectronic devices. Finally, the challenges and opportunities in this field are also provided.

Functional Diamond
Volume 1, Issue 1 (2021)

Diamond quantum sensors: from physics to applications on condensed matter research

Kin On Ho,
Yang Shen,
Yiu Yung Pang,
Wai Kuen Leung,
Nan Zhao,
Sen Yang

Single qubit in solid-state materials recently emerges as a versatile platform for quantum information. Among them, the nitrogen vacancy (NV) centre in diamond has become a powerful tool in quantum sensing for detecting various physics parameters, including electric and magnetic fields, temperature, force, strain, with ultimate precision and resolutions. It has been widely used in different conditions, from samples in ambient to samples in ultra-high pressure and low temperature. It can detect quantum phase transitions as well as neuron activities. Here we give a general review on both the physics of the sensing mechanism and protocols and applications.

quantum sensor;
nitrogen vacancy centre;
NV sensing;
material research;
Functional Diamond
Volume 1, Issue 1 (2021)

Diamond as the heat spreader for the thermal dissipation of GaN-based electronic devices

Liwen Sang

With the increasing power density and reduced size of the GaN-based electronic power converters, the heat dissipation in the devices becomes the key issue toward the real applications. Diamond, with the highest thermal conductivity among all the natural materials, is of the interest for integration with GaN to dissipate the generated heat from the channel of the AlGaN/GaN high electron mobility transistors (HEMTs). Current techniques involve three strategies to fabricate the GaN-on-diamond wafers: bonding of GaN with diamond, epitaxial growth of diamond on GaN, and epitaxial growth of GaN on diamond. As a result of the large lattice mismatch and thermal mismatch, the integration of GaN-on-diamond wafer is suffered from stress, bow, crack, rough interfaces, and large thermal boundary resistance. The interfaces with transition or buffer layers impede the heat flow from the device channel and greatly influence the device performance. In this review, we summarize the three different techniques to achieve the GaN-on-diamond wafers for the fabrication of AlGaN/GaN HEMTs. The problems and challenges of each method are discussed. In addition, the effective thermal boundary resistance between GaN and diamond, which characterizes the heat concentration, is analyzed with regard to different integration and measurement methods.

Functional Diamond
Volume 1, Issue 1 (2021)

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.

thermal control;
phased array;
high heat flux
Functional Diamond
Volume 1, Issue 1 (2021)

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.

Boron doped diamond;
boron concentration;
electrochemical advanced oxidation
Functional Diamond
Volume 1, Issue 1 (2021)

Recent progress in diamond radiation detectors

T. Shimaoka,
S. Koizumi,
J. H.,

This paper reviews recent progress in diamond radiation detectors. Diamond is an ultra-wide gap (5.5 eV) semiconducting material which has several ideal properties for radiation detectors, such as solar blindness, high temperature operation, and fast response. Furthermore, diamond has near tissue-equivalence due to its low atomic number (Z = 6) and chemical stability due to its strong covalent bonds. Because of these features, diamond has long been used as a radiation detector in the fields of nuclear engineering, nuclear fusion, high energy physics and medical therapy. Until the 1990s, most of the research was conducted using selected high purity natural diamonds. Since the 2000s, the detector characteristics of synthetic diamond detectors have been greatly improved by achieving high purity diamond by microwave plasma enhanced chemical vapor deposition (CVD). Single-crystal CVD diamonds present best characteristics for spectroscopy in diamond radiation detectors. For applications requiring large sensitive areas, polycrystalline CVD diamond is mostly used. Heteroepitaxial diamond detectors are a promising alternative to increase the area of spectroscopic diamond radiation detectors. For applications in extreme environments, high radiation flux which leads to polarization effects is a crucial issue. Even with diamond, which has excellent radiation hardness, degradation of detector characteristics due to irradiation is inevitable. Detectors designed with small carrier travel distances, such as membrane diamond detectors and three-dimensional diamond radiation detectors, are effective ways to mitigate the degradation.

Radiation hardness;
high temperature operation;
medical application;
high energy physics;
beam monitor
Functional Diamond
Volume 1, Issue 1 (2021)

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.

carbon nanostructures;
drug delivery;
Functional Diamond
Volume 1, Issue 1 (2021)
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