Peer Reviewed Gems & Gemology, Fall 2011, Volume 47, No. 3

Exploring the Origin and Nature of Luminescent Regions in CVD Synthetic Diamond

In the DiamondView instrument, blue to blue-green luminescent zones may be seen in CVD synthetic diamond when the growth run has been interrupted and resumed, a well-known practice in the production of gem-quality CVD synthetics. DiamondView, photoluminescence (PL), and cathodoluminescence (CL) imaging were applied to study the origin and nature of these luminescent regions in two samples of high-purity single-crystal CVD synthetic diamond. DiamondView and PL measurements showed a correlation with silicon-related centers. In addition, CL analysis confirmed the presence of boron. Both silicon and boron showed preferential incorporation at the interface between CVD layers, where a higher uptake of impurities lead to the observed luminescence. Although the growth interruptions cannot be detected with the naked eye, the growth history can be determined accurately using luminescence imaging and spectroscopy techniques.