Photoconductive properties of cadmium sulphide

Measurements have been made of the spectral response of the photoconductivity and the infrared quenching of a number of crystals of CdS grown in sealed tubes with a range of different stoichiometries. The thermally stimulated current (TSC) curves have also been investigated, and parameters of eight different traps have been calculated. The concentrations of these traps have been measured in the different crystals, and the effects of illumination at high temperature have also been studied. It is shown that very few of the properties measured vary dramatically with stoichiometry. The reasons for this are discussed in terms of the coulombic interaction between oppositely charged defects.