Acoustoelectric current fluctuations in CdS

Abstract

An extended set of measuring data on current saturation, on current fluctuations associated with the acoustoelectric effect in CdS and on the impedance of acoustoelectrically active CdS single-crystals is presented. These experimental results are discussed and compared with experimental and theoretical results from the literature and with the theoretical calculations we have published before. There is good agreement between the results of our previously published theoretical calculations and our experimental data, particularly as far as nonpolished crystals are concerned. In the case of a plane-parallel polished crystal the measured current noise spectra deviate from the spectra obtained with our model in those frequency ranges where acoustic activity occurred. However, with this crystal too, most of the observed current noise is due to trapping and detrapping of bunches of conduction electrons in potential troughs associated with amplified acoustic waves.