Investigation on electrical properties and irradiation-induced defects of neutron-transmutation-doped germanium in different neutron spectra

摘要

This study aims to investigate the annealing behavior of neutron irradiation-induced defects and transmuted impurities in neutron transmutation doped germanium (NTD-Ge). Different irradiation sites at THOR with a variety of neutron spectra were selected to conduct the neutron irradiation of Ge specimens. Also the approach of Cd-shielding was adopted to cut off the influence of thermal neutrons. The results revealed that the neutron flux is an important factor in determining the amount of lattice defects as well as transmuted impurities. Neutron irradiation-induced defects act as acceptors and dominate the electrical properties in the as-irradiated and low-temperature-annealed specimens. Increasing annealing temperature enhances the defect recovery and the activation of transmuted impurities in NTD-Ge. As evidenced by the results of this study, some residual defects could still remain in NTD-Ge and take effect on its electrical conduction even though the annealing temperature is raised to 500 °C.