Radiation-induced luminescence of pyrolytic boron nitride

Luminescence spectra of pyrolytic boron nitride are obtained upon photoexci tation at 315, 365, and 403 nm. It is shown that luminescent centers repres ent intrinsic defects which have a quasi-continuous band of levels in the e nergy gap and are localized in the regions near the boundary of grains. The spectra of radiation-induced luminescence (RIL) of pyrolytic boron nitride are obtained upon its irradiation by 8.13 MeV-protons with an intensity of 3.2 x 10(12) cm(-2) s(-1). A linear irreversible decrease in the RIL inten sity with increasing irradiation dose was observed. At a dose of 1.88 x 10( 16) cm(-2), the RIL intensity saturates. The saturation effect is connected with radiation-induced structural changes on the surfaces of the grains ca used by the electron-hole relaxation and a considerable increase in the sel f-diffusion coefficients.