A V2+centre in GaAs studied by thermally detected EPR

Abstract
A comprehensive set of thermally detected EPR experiments on several samples of vanadium-doped GaAs crystals is reported. All samples are semi-insulating at liquid-helium temperatures. The resonances are very strong and are either created or enhanced by illumination. From a detailed study of the variation in resonance peaks with both the direction of the magnetic field and with the frequency, it is proposed that the resonances come from a V2+ centre having a 4T1 ground state.