Charge Transfer as an Alternative to Metastability of Defects in Semi-Insulating GaAs?

Abstract
We have compared the variations of different paramagnetic signals, including that of the AsGa -related antisite, as revealed during 1.2 eV light exposures at 4.2 K, with those observed during a subsequent warming up in several semi-insulating GaAs samples. In addition to a confirmation of the sequence of acceptor levels regarding their energy depth, these experiments suggest a possibility of a mere charge transfer mechanism instead of a metastability for the photoquenchable AsGa-related deep donors.