Author(s): Jijoy P Mathew

Abstract: In this paper we report the synthesis of Co doped ZnO thin films by a low cost sol-gel dip coating method and the effect of Co dopant concentration on the structural and optical properties of the prepared films. In the structural studies, using XRD measurements, no secondary phases or impurity phases were detected suggests that dopant atoms substitutes for host atoms without altering the crystal structure. The surface morphological studies reveal that morphology of the films was greatly influenced by dopant concentration. The band gap of the films decreases with increase in dopant concentration. The red shift in band gap with increase in dopant concentration is due to the p-d exchange interaction. The PL spectrum of the films shows emission peaks in UV, violet and blue regions. The mechanism behind these PL emission peaks were also explained in detail.