SEM-CL of high quality polycrystalline CVD and high pressure synthetic diamond

摘要

The free-exciton luminescence spectrum of diamond has been studied in detail using both SEM-CL and a lower spatial resolution cathodoluminescence technique. In polycrystalline CVD diamond the free-exciton luminescence is confined to the crystallites whereas a broad luminescence band believed to be associated with the presence of dislociations, is centred on the grain boundaries. The free-exciton luminescence intensity at constant beam current is found to increase with beam accelerating voltage V in the range 15 to 50 kV with a V~n dependence, where n may vary as 3 <=n<=5.