Fabrication and characterizations of large homoepitaxial single crystal diamond grown by DC arc plasma jet CVD

Subsurface cleavage of diamond after high-speed three-dimensional dynamic friction polishing

“…Four identical 3.5 mm × 3.5 mm high quality (100) SCD samples were cut from a large CVD diamond (to ensure the surface morphology and quality uniformity) mother-crystal (initial dimensions 7 mm × 7 mm). Homoepitaxial growth was applied on a high-pressure high-temperature (HPHT) diamond substrate at 1000 °C for 20 h by a home-build direct current arc-jet plasma CVD system [26][27][28]. In order to guarantee the uniformity of each sample and the precise repeatability of 3DM-DFP, three samples were pre-polished with nano-diamond powder slurry and deionized water on a sacrificial diamond composite plate (diameter of 20 mm) at an extremely slow rotational velocity of 40 rpm to 60 rpm, by a precision lapping/polishing machine (UNIPOL-802), until a mirror surface was realized.…”

Doomed Couple of Diamond with Terahertz Frequency: Hyperfine Quality Discrimination and Complex Dielectric Responses of Diamond in the Terahertz Waveband

“…Four identical 3.5 × 3.5 × 0.24 mm high quality SCD (100) samples were cut from a large grinded CVD diamond mother-crystal, of initial dimensions 7 mm × 7 mm. Homoepitaxial growth was applied on the high-pressure high-temperature diamond substrate at 1000 °C for 20 h in a home-built 100 kW dc arc-jet plasma CVD system. , After prepolish the mother-crystal using a lapping/polishing machine (UNIPOL-802), three of the dissected SCD samples were further precisely polished using the high-speed 3-dimensional dynamic friction polishing (3D-DFP, Helix) system at a linear speed of 12, 35.8, and 60 m s –1 , respectively, corresponding to moderate speed (MS), high speed (HS), and super high speed (SHS). Although the surface of samples was achieved to ultrasmooth [roughness <1 nm in root-mean-square (rms)], some specific subsurface artificial defects were created purposely, which has been thoroughly investigated in our previous work .…”

Synthesis of multiple single crystal diamonds by DC-GD-CVD

“…The high growth rate could be mainly attributed to the introduction of Ar gas during the CVD process [15]. Owing to the much lower thermal diffusivity coefficient of Ar than that of H 2 , the energy loss of the formed plasma during deposition is reduced and the gas plasma temperature is increased after the Ar addition in reasonable content, which lead to the formation of more confined and hotter plasma cores, promoting the active group concentration of C 2 and therefore improving the growth rate of SCDs efficiently [6,15,16]. In addition, the SCD located at the centre of deposition area (No.…”

“…Recently, microwave plasma CVD (MPCVD) [3], hot filament CVD [4] and direct current arc plasma jet CVD (DC arc plasma jet CVD) [5] have been gradually developed for SCD fabrication, and the SCD products with large size and high quality had been successfully synthesised [6]. Many researches on the SCD synthesised by above methods have been carried out, such as the optimisation of deposition parameters [3], the growth mechanism [6] and rate [7], and the quality [8], mechanical [9] and optical performance of as-synthesised SCD [10]. However, to date, it is still a challenge to fabricate CVD SCD with high growth rate, good growth uniformity, high quality and large size [11,12].…”