The influence of CdS quantum dots incorporation on the properties of CdO thin films

¹ Department of Energy Systems Engineering, Faculty of Engineering, Karamanoğlu Mehmetbey University, 70100 Karaman, Turkey
² Department of Chemical Engineering, Selçuk University, Advanced Technology Research and Application Center, 42075 Konya, Turkey
³ Department of Chemistry, Faculty of Science, Anadolu University, 26470 Eskişehir, Turkey
⁴ Department of Materials Science and Engineering, Faculty of Engineering, Karamanoğlu Mehmetbey University, 70100 Karaman, Turkey

^a e-mail: aysari@yahoo.com

Received: 6 September 2013
Revised: 30 October 2013
Accepted: 6 November 2013
Published online: 9 December 2013

Abstract

The aim of our work is to obtain nano-structured cadmium oxide (CdO) thin films by sol-gel spin coating method and to investigate the effects of cadmium sulfide quantum dots (CdS QDs) doping on the structural modification and surface morphology evolution. X-ray diffraction (XRD) results show that the intensities of the peaks of the crystalline phase increase with the increase in CdS QDs concentrations. From scanning electron microscopy (SEM) images, the distinct variations in the morphology of the thin films were also observed. In addition, the evolution of surface morphology, roughness and granularity has been characterized by atomic force microscopy (AFM). Moreover, we have performed the optical characteristics of the thin films such as transparency, energy band gap and Urbach tail. The optical band gap of the thin films increases from 2.23 to 2.51 eV with the increase in CdS QDs concentrations due to the Moss–Burstein effect. The enhanced values of the transparency, energy band gap and crystallity indicate that addition of CdS QDs can be used to modify the optical, structural and morphological properties of CdO thin films.