Site symmetry of theEL2center in GaAs

Abstract
A study has been made of the effects of uniaxial stress on the photocapacitance quenching phenomenon associated with the EL2 center in GaAs. The results show directly that the defect is a complex with C3v (trigonal) site symmetry. The internal optical excitation assigned to the EL2 center is shown not to be directly related to the photoquenching transition. The implications of these results with respect to models of EL2 and its photoquenching mechanism are discussed.