Growth and characterization of vacuum deposited cadmium telluride thin films

Abstract

Semiconducting thin films of cadmium telluride, both <i>p</i>-type and <i>n</i>-type, have been prepared by conventional thermal evaporation technique. The influence of various growth parameters such as the rate of deposition, deposition temperature, post-deposition heat treatment, and source material composition has been investigated. The films deposited at high deposition rates and low substrate temperatures exhibited an excess of tellurium and showed a <i>p</i>-type conductivity, whereas those deposited at high substrate temperature and low deposition rates contained excess cadmium and are <i>n</i>-type in nature. An intrinsic bandgap of 1.49 eV for stoichiometric films obtained by both electrical and optical characterization is reported.