Low temperature photoluminescence study of GaAs defect states

Low temperature (77 K) photoluminescence measurements have been performed on different GaAs substrates to evaluate the GaAs crystal quality. Several defect-related luminescence peaks have been observed, including 1.452 eV, 1.476 eV, 1.326 eV peaks deriving from 78 meV Ga_As antisite defects, and 1.372 eV, 1.289 eV peaks resulting from As vacancy related defects. Changes in photoluminescence emission intensity and emission energy as a function of temperature and excitation power lead to the identification of the defect states. The luminescence mechanisms of the defect states were studied by photoluminescence spectroscopy and the growth quality of GaAs crystal was evaluated.