Threshold energy for atomic displacement in electron irradiated germanium

n-type germanium has been irradiated with electrons of various energies in the range 0.5 to 3 MeV. Using transient capacitance measurements we observed four majority carrier traps associated with levels at 0.27 eV (E1), 0.39 eV (E2), 0.35 eV (E4), 0.32 eV (E5) below the conduction band. We have studied the variations of the introduction rates of these traps with the energy of irradiation. These variations are found to correspond to a threshold energy for atomic displacement of 20 ± 5 eV for the E 1 and E2 traps and of 40 ± 10 eV for the E 4 and E5 traps. It is concluded that the E 1 and E2 traps are associated with vacancy-or interstitial-type defects (association of a vacancy or of an interstitial with an impurity) while the E4 and E5 traps are associated with the divacancy.