Effect of Substrate Temperature on the Structural and Electrical Properties of CdTe Thin Films

Abstract

CdTe thin films were prepared at different substrate temperatures (Tsub=473-
623k) on glass by conventional vacuum evaporation method. The films
showed the existence of the face centered cubic CdTe phase with a preferred
orientation of (111) plane parallelto the substrate. The degree of the preferred
orientation as well as the dark conductivity of CdTe films increased with
increasing Tsub.Electrical studies show two conduction mechanisms ,extrinsic
in the low temperature region ,followed by intrinsic conduction in higher temperature region.The calculated values of the activation energies in the
extrinsic and intrinsic conduction region are given. It is found also that the
transformation between the two conduction mechanisms occur very close to
the temperature range of (330 – 345 K). The dependence of the dark and
photoconductivity on the substrate temperature for CdTe thin films showed
that photoconductivity values are one order of magnitude higher than that of
the dark ones.