Infrared absorption of electron irradiation induced deep defects in semi-insulating GaAs

Electron irradiation induced defects in semi-insulating GaAs grown by the liquid-encapsulated Czochralski technique were studied using infrared absorption spectroscopy. A broad peak (P1) and a shoulder (P2) were observed in the infrared absorption spectra of the irradiated materials at 0.98 and 0.78 eV, respectively. The electron-phonon coupling strength as well as the Franck–Condon shift of P1 was estimated from the temperature dependence of the linewidth. The annealing kinetics between 375 and 450 °C show that the P1 defect vanishes by a long-range migration process with an enthalpy of 0.78±0.02 eV. A speculation for the atomic structure of P1 is presented.