POSITRON LIFETIMES AT VACANCIES IN ELECTRON-IRRADIATED INDIUM-PHOSPHIDE

We report positron lifetime results on electron-irradiated (2.0 MeV at 20 K) Zn-, Fe- and S-doped indium phosphide. In all samples, the average positron lifetime at 300 K increases after irradiation and annealing at 300 K. In electron-irradiated InP(S) (n = 3.9 x 10(18) cm(-3)), a defect identified as the indium vacancy recovers between 150 and 200 K. After annealing at 300 K, another defect lifetime is detected, interpreted as the upper limit for the positron lifetime at the phosphorus vacancy. The phosphorus vacancies remain intact up to annealing temperatures of 300 K.