Evidence of three DX centers in Al0.28Ga0.72As:Si from Hall experiments

Abstract

In this article, we report the effect of cooling conditions on transport data in Si-doped AlxGa1−xAs. We show that a rapid cooling induces a freezing out of electrons similar to that observed after photoionization of the sample at low temperatures. By diving the sample in liquid nitrogen, we have evidenced a multicomponent structure with three resolved peaks on transport curves for a relatively low aluminum composition x=0.28. These peaks were assigned to the nonresonant 3 Al–, 2 Al—, and 1 Al–DX levels.