Abstract
High pressure synthetic diamond has been heat treated in graphite powder under a high pressure condition of 6 GPa and 1800 C. The heat treatment produces plastic deformation at edge of the diamond. According to cathodoluminescence measurements of the diamond, it was found that the 2BD luminescence bands, which are observed in brown type II natural diamond, are produced with the heat treatment, indicating that the luminescence bands are related to plastic deformation. Another type II diamond subjected to the heat treatment was found to exhibit a sharp line at 260 nm, which is also observed in type II natural diamond after heat treatment, indicating that this line is also related to plastic deformation.
