Annealing Effects on the Properties of Chemically Deposited CdS Thin Films at Ambient Condition

Abstract

Chemically-deposited CdS thin films have been investigated using various techniques to discuss annealing effects on the structural, morphological, optical and electrical properties of the films. It has been observed from XRD that the deposited layers are mainly consisting of CdS phase. After annealing, metastable cubic phase was transformed into stable hexagonal phase. The average grain sizes were found to increase and the lattice constant, micro-strain and dislocation density were found to decrease after annealing. Optical absorption measurements show that band gap is observed to be 2.42 eV for as deposited and be 2.27 eV upon heat treatment at 673 K for one hour in air. The conductivity of this film has been determined by I-V measurement and observed to increase with increase of temperature. The activation energy of electrical conductivity of this film is also determined.