Dose-dependency and recovery behaviour of transport properties of electron irradiated tellurium

Pure tellurium single crystals were irradiated with 1 MeV electrons at low temperatures. Two annealing stages appear in the temperature range from 4 to 130 K. In contrast to findings for other materials an increase of the carrier mobility is observed in the orientation where the current j is perpendicular to the crystallographic c axis. A simple phenomenological model is developed which explains quantitatively all experimental data between 4 and 130 K. It is shown that the vacancies are mobile above the second stage and that the first stage (50 K) is caused by a defect rearrangement. The activation energy for vacancy-migration is determined as 170 meV, in accordance with theoretical calculations. (author)