Deep levels in n-CdTe

Publisher Website
Google Scholar
Abstract
Deep‐level transient spectroscopy (DLTS) was used to study electron traps in n‐CdTe crystals. High‐purity undoped and indium‐doped samples were examined with Au Schottky barriers. Five levels were observed in CdTe:In, three of which are in good agreement with previously observed defect levels. The capture cross sections of these levels were measured. The energy levels relative to the conduction band were measured by isothermal DLTS. A single very deep level was observed in high‐purity undoped CdTe. Modified CdTe surfaces were produced by brief (∼60 s) low‐temperature (400 °C) annealing in air or argon. Schottky barriers made on these surfaces indicate a decrease in the near‐surface carrier concentration. Changes in deep level concentrations were also observed. A very deep level (labeled IR5 in our study) (Ec =0.82 eV) is most changed by this process; annealing increases its concentration. It is suggested that IR5 is a native defect.