Study of a paramagnetic center on an SiO-treated GaAs surface

Abstract We have observed enhanced photoluminescence and an isotropic, singlet electron paramagnetic resonance (EPR) signal from samples of SI c-GaAs as a result of a thermal annealing treatment with SiO under vacuum. The treated samples showed a tenfold increase in photoluminescence. The EPR signal was detected at room temperature and was found to have a g value of 2.0017 and a linewidth of 0.1 mT. The enhanced photoluminescence and the EPR signal were both quenched by a 10 min exposure to hydrogen plasma with the sample near room temperature. Chemical and spectroscopic evidence indicates that the resonance is due to a silicon-related center near the GaAs surface.