FREQUENCY-RESOLVED PHOTOCONDUCTIVITY OF BULK CDS SINGLE-CRYSTALS

Photoconductivity measurements in CdS single crystal showed that a.c. photoconductivity decays as omega(-s), with s value = {1 + alpha} for omega > 1/tau and = {1 - alpha} for omega < 1/tau. At low frequency va lues, recombination might be controlled by monomolecular behaviour. As the frequency increases bimolecular behaviour, in shallow states, dom inates. Direct recombination is found to be weak dependent on both the intensity and applied voltage. However when band tail recombination i s dominant (at higher frequencies), strong dependence is observed.