We have studied the annealing of vacancy defects in neutron and proton irradiated germanium. After neutron irradiation the Sb-doped samples were annealed at 473, 673 and 773 K for 30 min. The positron lifetime was measured as a function of temperature (30 - 295 K). A lifetime component of 330 ps with no temperature dependence is observed in as irradiated samples, identified as the positron lifetime in a neutral divacancy. The average positron lifetime in the samples annealed at 473 K has a definite temperature dependence, suggesting that the divacancies become negative as the crystal recovers and the Fermi level moves upward in the band gap. Proton irradiation of germanium at 37 K with subsequent room temperature annealing also resulted in a similar lifetime component 315 ps, in good agreement with the neutron irradiation experiment. © 2009 Elsevier B.V. All rights reserved.
Slotte, J., Kuitunen, K., Kilpeläinen, S., Tuomisto, F., & Capan, I. (2010). Divacancies at room temperature in germanium. Thin Solid Films, 518(9), 2314–2316. https://doi.org/10.1007/s00109-013-1089-y