EDGE EMISSION OBSERVED IN HEAVILY BORON-DOPED DIAMOND FILMS EPITAXIALLY GROWN ON PLATINUM

Cathodoluminescence (CL) spectra of diamond films epitaxially grown on single crystal platinum (111) have been investigated at room temperat ure and 89 K. It was found that the CL spectra of the heavily boron-do ped (>3 x 10(20) cm(-3)) diamond films of more than 16 mu m thickness consist only of a near-edge emission at 248+/-1 nm (5.00+/-0.02 eV), w hile any mid-gap emissions are absent. That result suggests that few d efects are in the films. It was also found that the temperature depend ence of the 248 nm band is very unique, since its intensity increases as temperature increases. The mechanism of the 248 nm band seems to in volve quasi-direct transition. (C) 1998 American Institute of Physics.