Acoustoelectrical Relaxation in GaAs by the Formation and the Recovery of Metastable EL2

Abstract

The transformations between the normal and metastable state of EL2 in GaAs are investigated. We apply the internal friction technique as a probe for very small conductivities and discuss the changes in conductivity by the formation and recovery of EL2*. At 40 K both shallow acceptors and EL2 are photoquenched into neutral metastable states. The acceptors are likely to be associated with EL2* forming an electrically inactive state. We identify two damping peaks at 60 and 95 K with the regeneration of the acceptors and EL2 respectively. The latter indicates a regeneration via the charged defect (EL2)+