OPTICALLY DETECTED MAGNETIC-RESONANCE INVESTIGATION OF A GALLIUM VACANCY-RELATED DEFECT IN ELECTRON-IRRADIATED GALLIUM-ARSENIDE

In different types of GaAs (p-type ai-id semi-insulating) electron-irradiated at 4.2 K and kept below 80 K, a dominant defect with a quartet hyperfine split spectrum was observed with optically detected electron paramagnetic resonance. The defect is attributed to a Gallium vacancy-related defect. It decays at about room temperature while an As antisite-related defect, identified previously as an anti-structure pair, As-Ga with Ga-As as a second nearest neighbour (nnn), is formed. The spectrum of the magnetic circular dichroism of the Ga vacancy-related defect is interpreted to originate from photo-ionisation transitions to the valence band.