Change in cathodoluminescence spectra and images of type II high-pressure synthetic diamond produced with high pressure and temperature treatment

Type II high-pressure synthetic diamond crystals were examined with cathodoluminescence (CL) spectroscopy and topography before and after high pressure and temperature (HPHT) treatment around 6 GPa and 1600 °C. We found that the HPHT treatment produced mosaic patterns in the CL image and the 2BD(F) bands in the CL spectra, which are commonly seen in type II natural diamond. Polarized optical microscopic observation revealed that a birefringence pattern similar to that of natural diamond is formed with the HPHT treatment, indicating that plastic deformation was produced by the treatment. The present study, therefore, confirmed that the mosaic patterns in the CL image and 2BD bands were formed by plastic deformation.