Experimental studies were made of the effect of irradiation with 230keV electrons and with X-ray photons with energies of 8.06 or 17.5keV, and of the effect of quenching upon the formation and reconstruction of centers of slow recombination of non-equilibrium charge carriers (so-called r-centers) in undoped and Cu-doped (~1018/cm3) single crystals. It is shown that defects in the cadmium sub-lattice of the crystal (such as VCd vacancies and CuCd defects with parameters close to those of the above vacancies) were responsible for the r-centers. In the case of the X-ray irradiation of both undoped and Cu-doped CdS single crystals, sub-threshold defect formation of cadmium vacancies and CuCd defects took place at sites with distorted and weakened interatomic bonds. Starting with a quenching temperature of 170C, the spectrum of slow-recombination centers was considerably affected by thermally formed vacancies VCd and secondary defects CuCd. At quenching temperatures higher than 250C, a significant contribution to the spectrum of optical quenching of photoconductivity was made by thermally introduced free (away from structural imperfections) r-centers. That is, the VCd and CuCd defects.

Features of Subthreshold Defect Formation in CdS and CdS:Cu Single Crystals Subjected to Irradiation with X-Ray Photons. G.L.Mironchuk, H.Y.Davidyuk, V.V.Bozhko, V.Kažukauskas: Semiconductors, 2010, 44[5], 667-71