Irradiation defects in superhard cubic boron nitride single crystals

Single crystallites of superhard, semiconducting, n-type, amber colored and p-type, blue colored, Be-doped cubic boron nitride have been irradiated either with UV (350 nm) light or with an intense beam of accelerated (1 MeV) electrons. The examination of the irradiated samples at low temperatures by high frequency W (95 GHz)-band electron spin resonance reveals several new, radiation-induced, isotropic paramagnetic centers. The UV irradiation of both types of crystals yields centers involving very likely protons. In the amber c-BN crystals the irradiation with 1 MeV electrons results in the formation of vacancy associated paramagnetic defects and quasi-free electrons in colloidal particles.