Electrical Properties of 1.7-MeV-Electron-Irradiated Sulfur-Doped GaP

The electrical properties of 1.7-MeV-electron-irradiated sulfur (S)-doped GaP were studied by using Hall effect and resistivity measurements. It was found that the concentration of S donors decreased and the deep acceptors were introduced by 1.7-MeV electron irradiation. The decrease of the concentration of S donors could be understood by considering the formation of a complex center of radiation-produced defects with S. A complex center acted as a deep acceptor and recovered in the stage centered at 150°C anneal. The introduction rate of this center was ~2.1 cm-1. From the isothermal annealing experiments, it was found that the recovery for this center approximately obeyed first-order kinetics and its activation energy was ~1.7 eV. Furthermore, another complex center involving S, which was a non-compensating defect in n-type GaP, was introduced. This center was seemed to be a deep donor.