Deep Defect Levels in Plastically Deformed GaAs

Defect states in plastically deformed GaAs are investigated by means of the Hall effect, photo-ESR and photoluminescence. A high concentration of acceptors is generated in GaAs as a result of plastic deformation. ESR-active centers giving rise to a signal consisting of four isotropic absorption lines are introduced by both plastic deformation and electron-irradiation. The energy of photo-activation of unpaired electrons from such centers to the conduction band is about 0.8 eV. Defects related to such centers induced by deformation or electron-irradiation are different from grown-in ESR-active centers and are concluded to be As atoms on tetrahedral interstitial sites each surrounded by four Ga atoms. A broad photoluminescence line is developed at 1.13 eV in plastically deformed GaAs but not in electron-irradiated GaAs. This line is thought to be related to the radiative recombination occurring at β dislocations.