POSITRON LIFETIME MEASUREMENTS ON NEUTRON-IRRADIATED INP CRYSTALS

Neutron-irradiated InP single crystals have been investigated by posit ron-lifetime measurements. The samples were irradiated with thermal ne utrons at different fluences yielding concentrations for Sn-transmuted atoms between 2X10(15) and 2X10(18) cm(-3). The lifetime spectra have been analyzed into one exponential decay component. The mean lifetime s show a monotonous increase with the irradiation dose from 246 to 282 ps. The increase in the lifetime has been associated to a defect cont aining an Indium vacancy. Thermal annealing at 550 degrees C reduces t he lifetime until values closed to those obtained for the as-grown and conventionally doped InP crystals. (C) 1996 American Institute of Phy sics.