A systematic study was made of irradiation-induced defects. The irradiation was performed at 4K, using an incident energy of 2MeV. Both defect formation and annealing effects were studied, as a function of fluences ranging from 1015 to 1019/cm2, in undoped, n-type and p-type material. Temperature-dependent positron lifetime measurements were performed at temperatures between 20 and 600K. The thermal stability of defects was studied by annealing at temperatures ranging from 90 to 600K. A defect complex, which annealed in a main stage at 300K, was found in all samples after irradiation. It was suggested that this defect was a complex which involved a vacancy that was connected with an intrinsic defect. A second vacancy-like defect was observed in n-type material after annealing at 550K. This defect was assumed to exist in the As sub-lattice.

A.Polity, F.Rudolf, C.Nagel, S.Eichler, R.Krause-Rehberg: Physical Review B, 1997, 55[16], 10467-79