Arsenic antisite defectAsGaandEL2 in GaAs

The microscopic structure of the paramagnetic anion antisite defect in semi-insulating GaAs was determined by optically detected electron-nuclear double resonance (ODENDOR). It is an arsenic-antisite–arsenic-interstitial (${\mathrm{As}}_{\mathrm{Ga}}$-${\mathrm{As}}_{\mathrm{i}}$) pair. It is shown, by optically detected ESR and ODENDOR experiments, that its energy levels and optical properties in the diamagnetic state are those of the EL2 defect.