Structure, kinetics, and vibrational properties of complexes formed by hydrogen and gallium vacancies in GaAs: A theoretical study

In the last years, complexes formed by atomic H and gallium vacancies (V-Ga ) have been investigated in order to account for donor-acceptor bands obser ved in the photoluminescence spectra of hydrogenated GaAs. New configuratio ns for these complexes are investigated here, together with the kinetic pro perties of the H donors that affect the complex stability critically. In ad dition to the H donor, a peculiar V-Ga-H complex has been shown to behave a s a donor. The electronic levels in the energy gap and several H vibrationa l modes have been studied for the new and the old configurations of the H-V -Ga complexes, as well as for the new donor. The new complexes are more sta ble than those previously studied and can well account for the photolumines cence results. The values of the H vibrational frequencies are quite differ ent for the different types of complexes, which should permit a determinati on of the microstructure of the H-V-Ga complexes by infrared spectroscopy.