Defects Produced in Germanium by Quenching and Electron Irradiation

Irradiation with 1.5 MeV electrons slightly below room temperature induced the transformation of about half (≃1.7×1014 cm-3) of quenched-in shallow acceptors (SA2) at E v+13 meV into more shallow acceptors at E v+9 meV. These new acceptors returned to the SA2 acceptors after annealing around 300°C. The irradiation also caused a decrease (≃4×1014 cm-3) in substitutional-copper density. Part of the annihilated copper atoms reappeared after annealing around 300°C, suggesting that various defect complexes involving copper were formed by the irradiation.