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The dislocation identification method using X-ray topography by reflection mode geometry was applied to characterize IIa, Ib and highly B doped high pressure high temperature (HPHT) grown crystals. In both IIa and Ib crystals, dislocations are found to propagate in the <111> grown direction, with dominant vectors of [110] and [1-10], neither of which has no c-axis segment. For Ib crystal, many dislocations are also generated in the <112> and <121> directions, which are slightly tilted to <111>. It was confirmed that the dislocations in the same direction have the same Burgers vectors, but the dislocations are spread in broad area. A total of up to 20 HPHT crystals were measured and found to exhibit different dislocation distributions. This indicates an immature growth technique in terms of dislocation. Measurements of four chemical vapor deposition (CVD) substrates showed numerous dislocation bundles, making individual dislocation directions analysis impossible. CVD substrates suffer from an increase in dislocations due to CVD growth, resulting in poor diamond quality in terms of dislocation. XRT analysis on dislocations of epitaxial growth will be very important prior to CVD substrates analysis.

Diamond and graphene are considered to be one of the most promising thermal interface materials (TIMs) for electronic devices benefited from their highest thermal conductivity in the natural world. However, orientated fabrication of high thermal conductivity diamond and graphene hybrid arrays with three dimensions (3 D) thermal conductive networks are still problematic. Here, we used a unique one-step microwave plasma chemical vapor deposition, n-butylamine, as the liquid source to prepare a novel high thermal conductivity 3 D vertical diamond/graphene (VDG) hybrid arrays films. The orientated 3 D thermal conduction path of the VDG is regulated by the growth temperature, and the through-plane thermal conductivity value of the VDG700 films up to 97 W m−1 K−1. In the actual TIM performance measurement, the system cooling efficiency with our VDG as TIM is higher than the state-of-the-art commercial TIM, demonstrating the superior ability to solve the inter-facial heat transfer issues in electronic systems.

Diamond/aluminum composite material has the advantages of high thermal conductivity, low expansion, and lightweight, which has a wide range of application prospects in the field of electronic packaging thermal management. However, the serious interface problems between diamond and aluminum limit the full play of the thermal conductivity of composite materials. A reasonable interface design can maximize the thermal conductivity of composite materials. This article focuses on the interface modification of diamond/aluminum composites, briefly describing the theoretical basis of interface design, the research status of interface modification, interface reaction and composite stability, and prospects for diamond/aluminum composites material development.

The high frequency H-diamond metal-oxide-semiconductor field effect transistors (MOSFETs) were fabricated on single diamond substrate using 300°C ALD grown Al₂O₃ as gate dielectric and passivation layer. The devices gate length, gate/drain spacing and dielectric thickness are 100 nm, 2 μm, and 10 nm, respectively. The direct-current and frequency characteristics were investigated. The device shows a maximum saturation drain current of −492.6 mA/mm and g_m of 135.2 mS/mm. The device shows good high temperature working performance, and the maximum saturation drain current only has a little decreasing of 7.6%. at 200°C. In addition, the device exhibits a maximum cut-off frequency of 36.2 GHz and maximum oscillation frequency of 70.5 GHz. The transient drain current response measurement indicates that the drain current can follow the changing of gate voltage at the frequency of 1 MHz. These results indicate that the Al₂O₃ dielectric is suitable for using in high frequency or the high-speed switching devices.

As one of the representatives of carbon-based semiconductors, diamond is called the “Mount Everest” of electronic materials. To maximize its properties and realize its industrial applications, the fabrication of wafer-scale high-quality diamonds is critical. To date, heteroepitaxy is considered as a promising method for the growth of diamond wafers with considerable development. In this review, fundamentals of diamond heteroepitaxy is firstly introduced from several perspectives including nucleation thermodynamics and kinetic, nucleation process at the atomic level, as well as the interplay between the epitaxial film and substrate. Second, the bias enhanced nucleation (BEN) method is reviewed, including BEN setup, BEN process window, nucleation phenomenology (mainly on Iridium), nucleation mechanism by ion bombardment, and large-scale nucleation realization. Third, the following textured growth process is presented, as well as grain boundary annihilation, and dislocation and stress reduction technologies. Fourth, the applications of diamonds in electronic devices are studied, showing its excellent performances in the future power and electronic devices. Finally, prospects in this field are proposed from several aspects.

Combining diamond with GaN can significantly improve the heat dissipation performance of GaN-based devices. However, how to avoid the destructive damage to the GaN epi-layer caused by high-temperature hydrogen plasma during the diamond growth is still a problem. This study employed a Si transition layer and double-substrate structure microwave plasma chemical vapor deposition (MPCVD) to prepare diamond film on GaN epi-layer. The effects of double-substrate structure on the diamond growth were studied. The microwave plasma parameters of both single-substrate structure and double-substrate structure MPCVD diagnosed by emission spectra were comparatively investigated. It has been found that the microwave plasma energy of double-substrate structure MPCVD is relatively more concentrated and has higher radicals activity, which is beneficial to the diamond growth. The impacts of the Si transition layer on the diamond growth were also investigated. It demonstrates that the Si transition layer can effectively protect the GaN epi-layer from being etched by hydrogen plasma and improve the diamond growth. The relationship between the thickness of the Si transition layer and the diamond growth and the relationship between diamond film thickness and adhesion has been studied in detail.

Sub-monolayers of titanium were deposited onto oxidised (100) single-crystal diamond surfaces and annealed in vacuo at temperatures up to 1000 °C to find a temperature-stable termination procedure that produces a surface with Negative Electron Affinity (NEA). The samples were analysed by X-ray Photoelectron Spectroscopy, Ultraviolet Photoelectron Spectroscopy and Energy-Filtered Photoemission Electron Microscopy to determine their electron affinity and work function values. NEA values were observed on samples following annealing above 400 °C, with the largest NEA value being –0.9 eV for a sample coated with a half-monolayer of Ti annealed at 400 °C. Work function values were ∼4.5 eV for all samples annealed at temperatures between 400 and 600 °C, then rose at higher temperatures due to the loss of substantial amounts of O from the surface. Work-function maps indicated that the surface was uniform over areas 5700 μm2, suggesting that the deposition and annealing steps used are reliable methods to produce films with homogeneous surface properties.

This article describes key material science/technology issues to implement polycrystalline diamond scaffolds to enable processes for biological cells growth relevant for using cells grown in the laboratory for the treatment of human biological conditions. Issues investigated include

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.

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.