Irradiated monocrystals were investigated by using positron lifetime measurements. The samples were irradiated with thermal neutrons to various fluences; thus producing transmuted Sn atom concentrations of between 2 x 1015 and 2 x 1018/cm3. The lifetime spectra were analyzed in terms of a single exponential decay component. The mean lifetimes exhibited a monotonic increase, with irradiation dose, of from 246 to 282ps. This increase in lifetime was attributed to a defect that contained an In vacancy. Thermal annealing at 550C reduced the lifetime to values that were close to those obtained for as-grown and conventionally doped InP crystals.

F.J.Navarro, L.C.Damonte, B.Mari, J.L.Ferrero: Journal of Applied Physics, 1996, 79[12], 9043-6