Radiation-activated development of defective structure in type Ia diamond

Abstract

A type Ia diamond crystal having nitrogen impurity in the form A, B1 and B2 centers was irradiated with 3.5 MeV electrons at successively increasing doses of 5×10 16 , 2×10 17 , 4×10 17 and 2×10 18 e cm −2 and examined before and after each dose using a series of methods, including positron annihilation, EPR and optical spectroscopy in IR and visible regions. After irradiation with the highest dose, a development of the visible structure of the crystal was revealed. A detailed description of the phenomenon as well as EPR and optic studies for different irradiation doses are given. The first results of CL studies of the as-developed structure are presented. These results include CL-topograms for different regions of the crystal as well as their appropriate CL-spectra. Possible known models of defects responsible for main lines in CL-spectra are considered.