Gem-Quality Synthetic Diamonds Grown by a Chemical Vapor Deposition (CVD) Method

Identification of Synthetic Diamond Grown Using Chemical Vapor Deposition (CVD)

“…Table 2 lists features that we have observed in the optical absorption spectra of samples grown with added nitrogen. Many of these lines have been reported previously for samples produced by Apollo Diamond (Butler et al, 2002;Wang et al, 2003). However, we observed an additional absorption feature at 3323 cm −1 in the spectra of dark brown samples that was not reported by either of the above studies.…”

“…In addition, the post-treatment spectrum contains a series of lines in the 451-459 nm region that we have only observed for HPHTtreated CVD synthetic diamond. In all cases where the starting material showed the 737 nm luminescence feature with 633 nm excitation, this was still readily detectable after HPHT treatment, as noted by Wang et al (2003). We never observed the pair of lines at 596 and 597 nm for HPHT-treated samples.…”

“…It also shows a pair of sharp lines at 596 and 597 nm that we have observed only for nitrogen-doped samples. Samples grown early in our research program showed a line at 737 nm (also reported for Apollo Diamond's CVD synthetic material [Wang et al, 2003]), but this feature was absent from the spectra of samples grown more recently.…”

“…More recently, Linares and Doering (1999) and Yan et al (2002) described the properties of layers of single-crystal CVD synthetic diamond, and-as noted above-both Butler et al (2002) and Wang et al (2003) presented results of investigations of faceted material produced by Apollo Diamond. Isberg et al (2002) reported measurements on single-crystal CVD synthetic diamond produced by Element Six that indicated dramatic improvements in the electronic properties, suggesting that this material may have a future in electronic devices.…”

“…Although it often will be impossible to observe birefringence with this viewing direction, it may be feasible for particularly flat cuts or when the culet is large. CVD synthetic diamond will generally have low birefringence compared to type IIa natural diamond, which is usually highly strained, as commented by Wang et al (2003).…”