Effect of tin impurity on the photoconductivity kinetics of thin amorphous layers of arsenic selenide

In thermally sputtered As2Se3 and As2Se3 + 0.1 at. % Sn films the tin impurity strongly influences the photoconductivity kinetics under stepped optical excitation. The tin quenches thr ''spike'' on the section of increasing photocurrent, eliminates the dependence of the form of the decrease on the excitation intensity, and leads to a temperature-dependent delay in recombination onset. The effect of the impurity is attributed to an increase in trapping in deep localized states produced by the introduction of tin. (C) 1997 American Institute of Physics.