Recombination and Trapping in Tellurium

Photoconductive decay in nearly perfect Te crystals shows a lifetime of up to 50 μsec at 300°K. The temperature dependence does not support previous suggestions of radiative recombination; at temperatures below 150°K marked trapping of excess minority electrons occurs, and at higher temperatures also the results suggest the activity of levels within the gap. Probably chemical impurities behave as recombination centers, and dislocations certainly act in this capacity (lifetime is reduced to ∼1 μsec when ${10}^6$ dislocations/${\mathrm{cm}}^2$ are introduced).