The effect of Te alloying on the electronic gap of a-Se

Abstract

The effect on the electronic density of gap states in a-Se produced by the isoelectronic additive Te has been studied by a combination of drift mobility and xerographic measurements. Drift mobility experiments probe the shallow gap states which control photoinjected carrier transport. Addition of Te to Se in the nominal range 0–18 wt.% progressively decreases both electron and hole drift mobility while simultaneously increasing dispersion. The number and distribution of deep gap states which control injected carrier range have been determined in the same films from analysis of xerographic residual potentials. Taken together these measurements show that progressive addition of Te to a-Se increases the integrated number of deep traps and broadens the distribution of both deep and shallow transport interactive electronic gap states.