Luminescence of CdS crystals due to near-surface potential fluctuations

The nature of the wide emission band observed in the low-temperature (T ≤ 60 K) near-edge photoluminescence spectra of CdS crystals placed in water and irradiated by a He-Cd laser has been investigated. The spectral and temporal characteristics of the band and its dependence on temperature, excitation intensity, and transverse electric field are considered. The relationship between the band and the radiative recombination of carriers localized on near-surface potential fluctuations, which are due to the defect-forming character of the joint effect of laser irradiation and water on near-surface layer of semiconductor is grounded.