Microphotoluminescence spectra of cadmium telluride grown under nonequilibrium conditions

Abstract

Microphotoluminescence spectroscopy and imaging were used to study impurities and defects in CdTe crystals grown by nonequilibrium techniques. The growth procedure includes low-temperature synthesis and purification of the material via congruent sublimation, with subsequent deposition under the conditions of gas-dynamic vapor flow and high-rate low-temperature condensation. Although the growth conditions are highly nonequilibrium, the obtained polycrystalline material with a grain size of 1–2 mm exhibits strong low-temperature exciton luminescence, whose intensity is nearly uniform over the bulk of the ingots. At the same time, it is found that residual impurities and defects have a tendency to accumulate to form clusters within certain areas which are a hundred micrometers in size; the density of some impurities in these clusters is sufficiently high.