Stage-II Recovery in Electron-Irradiated InSb

Isochronal and isothermal recovery studies have been carried out in electron-irradiated samples of InSb following irradiation with high-energy electrons, using Hall coefficient and electrical conductivity as measures of the damage. The emphasis in this work has been on the recovery in stage II, and the results show that the recovery depends strongly on the carrier concentration of the sample. The temperature of the center of the recovery stage was observed to vary from 91°K in some $p$-type samples to 203°K in a highly degenerate $n$-type sample. The activation energy for recovery changed from 0.24 to 0.71 eV over this same range of carrier concentrations. These changes have been explained by assuming that the two acceptor levels associated with the radiation-produced defects must be empty in order for annihilation of the defects to occur. The details of the analysis relating these recovery parameters to the sample carrier concentration are presented. In order to fit the observed recovery kinetics, it is assumed that two close interstitial-vacancy pairs produced by the irradiation are involved, and that they annihilate by basically first-order processes with different rate constants. A model for the defects and their mode of annihilation, assuming vacancies to be the mobile species, is suggested.