The nature of the dominant γ-induced defects in high-purity germanium

For relatively low Co-60 γ-irradiation doses (3 x 1015 γ cm-2) and dose rates (2.0 x 1010 γ cm-2 sec-1), two hole traps Esub(v) + 0.23 eV, Esub(v) + 0.38 eV) are the dominant defects introduced in high-purity p-type germanium. A comprehensive study involving crystals grown under a wide variety of conditions supports the hypothesis that these centers are most likely due to complexes between oxygen and lattice vacancies. Injection-enhanced annealing was observed for both these hole-trapping states, and a discussion is given of the seemingly dose-dependent nature of the defects produced in γ-irradiated high-purity p-type germanium. (author)