Stored-Energy Released in Electron-Irradiated Germanium

Abstract

Stored-energy release measurements have been made on heavily doped $n$- and $p$-type specimens of germanium following irradiation at 15°K by 1.0-MeV electrons. A novel feature of the technique is the use of a portion of the specimen as one element of a germanium-copper thermocouple to detect small tenperature differences arising from stored-energy release. The experimental results indicate that there are several annealing stages in the temperature range from 20 to 80°K in which stored energy is released in $n$-type germanium. This is interpreted to mean that the annealing involves recombination of vacancies and interstitials. No measurable release of energy is observed in $p$-type germanium over the above temperature range. Comparing the energy release to previous measurements of electrical properties indicates that the return of one electron to the conduction band in $n$-type germanium is accompanied by the release of 5.5±1.5 eV in thermal energy for annealing stages between 30 and 60°K, and 3.7±1.8 eV for stages between 60 and 80°K.