Special features of optical and photoelectric properties of nominally undoped and Cu-doped CdS single crystals

Experimental data on the effect of fast reactor neutrons on the absorption spectra, photoconductivity, and luminescence of nominally undoped and Cu-doped CdS single crystals are reported. It is shown that defect clusters formed as a result of neutron irradiation exhibit the properties of getters for easily migrating optically active impurities in the crystal lattice. In neutron-irradiated samples, the defects can be annealed in two stages. The first stage (100-150 deg. C) involves the annealing of point defects, while the second stage (250-420 deg. C) involves mainly the annealing of defect clusters. The degradation of the defect clusters is accompanied with the enrichment of the lattice with Cd and S vacancies