High optical quality multicarat single crystal diamond produced by chemical vapor deposition

Abstract

Finding ways to routinely and reliably produce larger nearcolorless and colorless single-crystal diamond needed for a variety of applications in science and technology is a major challenge. Microwave plasma assisted chemical vapor deposition (MPCVD) techniques have been refined to produce large, high-purity single crystal diamond anvils. Specifically multicarat single crystal diamond has been produced at high growth rate without annealing (around 50 mm/h) with low impurities content. UV-visible absorption, Raman/ photoluminescence spectroscopy, cathodoluminescence, and confocal Raman imaging are used to characterize the diamond. The measurements show that the material has high optical quality and clarity without layers. The large intensity ratio of the second-order Raman peak to the fluorescence background is essential for high-pressure optical windows. The origin of the residual color is also examined.The picture on the right shows a 2.4 carat single-crystal CVD diamond compared with 0.25 carat CVD diamond. Left images: Example of the evolution of CVD diamond single crystal starting with crystal 13.5 carat block to the 2.3 carat cut gem anvil.

Synthetic diamond opens windows into the deep Earth

“…The ultraviolet-visible light absorption spectra of the purest CVD diamond are identical to those of high-purity natural single crystal [Meng et al, 2012]. The material can be tuned to have a hardness similar to that of the pure and defect-free diamond.…”

“…These techniques are readily applied in experiments that address major problems in deep-Earth geophysics, geochemistry, and geodynamics. Further developments of the material are expected to lead to new diamond-based high technologies beyond Earth and planetary science, such as developing electronic sensors, lasers, and diamond-based computers Meng et al, 2012].…”

О Возможности Разращивания Алмазов В Среде Углеводородов

“…Следует отметить работу [8], в которой сообщается о получении крупных друз, из которых удалось выделить желтый алмаз весом 2.3 ct. По ходу процесса растущий на затравке сросток алмаза периоди-чески извлекался из реакционной камеры с удалением слоя пиролитического углерода путем отжига в среде водорода. К сожалению, работа [8] пока не получила продолжения и подтверждения.…”

Single-crystal CVD diamonds as small-angle X-ray scattering windows for high-pressure research

“…Recent developments in microwave plasma-assisted chemical vapor deposition (MPCVD) diamond synthesis have enabled unprecedented growth rates of single-crystal diamonds (McCauley & Vohra, 1995;Yan et al, 2002;Williams & Jackman, 2004;Mokuno et al, 2005;Tallaire et al, 2005;Sternschulte et al, 2006;Yamada et al, 2007) of high optical quality (Meng et al, 2012), changing the prospects for the application of single-crystal CVD diamonds as window materials for SAXS. With MPCVD techniques, single-crystal diamonds can be produced to multicarat sizes at very high growth rates ($200 mm h À1 ) (Yan et al, 2002).…”

“…Single crystals above 12 mm thickness (or 10 carats in size) having a variety of optical and mechanical properties have been synthesized (Yan et al, 2002(Yan et al, , 2004Hemley et al, 2005;Ho et al, 2006;Meng et al, 2008;Liang et al, 2009). High-quality optical components have been fabricated from undoped single-crystal MPCVD diamond materials, either as flat plate windows or as three-dimensional shapes such as anvils, with large dimensions that are not easily possible with natural diamonds (Meng et al, 2012). These type IIa single-crystal MPCVD diamonds have been shown to sustain the generation of multimegabar pressures (1 bar = 100 000 Pa) (Mao et al, 2003).…”