Impurity breakdown in GaAs samples grown by molecular beam Epitaxy

Abstract

In this work we present studies for the behavior of impurity breakdown of two GaAs samples grown by Molecular Beam Epitaxy at 200°C and 300°C. We vary the temperature and the illumination intensity. For the sample grown at 200°C, the transport mechanism after the breakdown is of the same type of the main free carriers at low electric fields. Below 100K, a clear dependence of the threshold electric field with temperature was observed. The sample grown at 300°C shows a breakdown due to an acceptor level at 41meV from the valence band. The threshold electric field increases with illumination due to the generation of free electrons by deep levels. A similar behavior was also observed for a Cr doped GaAs sample.