Modulated photoconductivity study of electron drift mobility in amorphous silicon

The modulated photoconductivity technique, a convenient means of measuring the drift mobility of photocarriers, has been applied to investigate carrier transport in hydrogenated amorphous silicon. The frequency resolved spectra of drift mobility that can be obtained from the measurements were analyzed in accordance with a generalized transport model that included possible carrier interactions between localized states through tunneling transitions. Theory suggests that a tunneling-assisted thermalization of nonequilibrium carriers appreciably affects the transport process. The experimental results are reasonably accounted for by the introduced model, leading to quantitative assessments for transport mechanisms. (C) 2000 American Institute of Physics. [S0021-8979(00)08006-3].