Electron-irradiation-induced damage production effects in lightly doped n- and p-type α-tin

Irradiations at 4.5 K using 0.675-MeV electrons have been performed on a number of n - and p -type α-tin filaments, with impurity concentrations from 4×1015 to 2×1017 cm−3. Large and reproducible changes with radiation dose have been observed in the electrical resistivity and the thermoelectric power, resulting from changes in carrier concentrations and carrier scattering. It is shown that a model, which requires that the induced defects behave as acceptor sites, accounts satisfactorily for the experimental results. A carrier removal rate of 0.6±0.1 cm−1 is deduced and is compared to the theoretical damage production rate of 1.6±0.3 cm−1; this indicates that only a fraction of the induced defects are active as carrier removal centers. Mobilities (μe and μh) have been calculated as functions of impurity and defect concentrations. It is found that the observed changes in the polarity of the thermoelectric power with dose can be accounted for qualitatively.