Position lifetime measurement for SixGe1-x bulk crystals has been performed. The bulk lifetime of positron in the crystals varied between those for Ge and Si. The dependence of the lifetime on the alloy composition showed an abrupt change at x= 0.17-0.20 which seems to be correlated with that of the band gap energy. After 3 MeV electron-irradiation, vacancy-type defects giving rise to the lifetimes of ∼280 and ∼330 ps were detected for 0.63≤x≤0.82 and 0.20≤x≤0.40, respectively, but not for x≤0.17. The composition-dependent vacancy production was interpreted in terms of the thermal stability of vacancies with the composition.
ASJC Scopus subject areas
- Physics and Astronomy(all)