A study of the deep carrier traps in a Te-Se-Cd rectifying structure

Publisher Website
Google Scholar
Abstract
Deep level transient spectroscopy, by means of capacitance transients, is applied to characterize deep carrier traps located in the depleted zone of a rectifying Te‐Se‐Cd structure. Preliminary observations, such as electron beam induced current and secondary electron and x‐ray emission, show that the depleted region is situated in the p‐type epitaxially grown Se film. Measurements of the thermal emission rate of trapped carriers are made in the 80–340 °K temperature range. From these, the existence of three deep hole traps in Se is demonstrated with the following values of the thermal activation energy ET, capture cross section σe, and volume density NT: 290 meV, 1.2×10−16 cm2, 7.0×1013 cm−3; 400 meV, 2.5×10−15 cm2, 3.0×1013 cm−3; 700 meV, 1.5×10−14 cm2, 3.0×1014 cm−3. The frequency dependence of the differential capacitance is measured between 100 Hz and 1 MHz and is attributed to a shallow hole trap (ET∼100 meV), with a high volume density in the 1019–1020 cm−3 range. This last result agrees with the conclusions deduced from thermally stimulated currents (TSC) experiments on the same type of material.