SYMMETRY DETERMINATION OF THE EL-2 DEFECT BY NUMERICAL FITTING OF CAPACITANCE TRANSIENTS UNDER UNIAXIAL-STRESS

The symmetry of the EL2 center in n-type liquid-encapsulated Czochrals ki GaAs is investigated through numerical fitting of capacitance trans ients measured under uniaxial stress. From experimental data which sup erficially appears compatible with T-d symmetry, we extract reproducib le defect energy-level splitting under uniaxial stress and conclude th at EL2 has C-3v symmetry, supporting the As(G)a-As-i pair model with A s-i wound to As-Ga.