The transient photodecay process and its interpretation in the case of disordered single crystals of arsenic triselenide

Abstract

Measurements of the decay of the photocurrent, following excitation by a short flash of light, are reported for arsenic triselenide crystals in which disorder has been induced by intense irradiation with high-energy electrons. The decay characteristics exhibit considerable structure, in contrast to the featureless power-law decays observed in the case of some amorphous solids. The results are employed in the computation of the energy distribution of localized gap states, using both previously-suggested techniques and a new procedure which evolved during the present study. The differences between the energy distributions computed by the various techniques are identified and accounted for, and it is established that a careful assessment of the validity of the assumptions inherent in such procedures is vital if meaningful results are to be obtained.