Electron Capture on EL2 in GaAs

Abstract

There have been few determinations of the capture cross-section for electrons of the EL2 midgap level in GaAs. The reported values exhibit different temperature dependences. We present here new measurements in the temperature range where the cross-section is expected to become temperature independent, as reported once. We do not reproduce this observation which was used as evidence for an electron capture via a multiphonon emission process. This implies that the understanding of the EL2 defect based on the existence of a large electron–phonon interaction has to be revised.