Comparative studies of CdS, CdS:Al, CdS:Na and CdS:(Al-Na) thin films prepared by spray pyrolysis


YILMAZ S., Atasoy Y., Tomakin M. , BACAKSIZ E.

SUPERLATTICES AND MICROSTRUCTURES, vol.88, pp.299-307, 2015 (Journal Indexed in SCI) identifier identifier

  • Publication Type: Article / Article
  • Volume: 88
  • Publication Date: 2015
  • Doi Number: 10.1016/j.spmi.2015.09.021
  • Title of Journal : SUPERLATTICES AND MICROSTRUCTURES
  • Page Numbers: pp.299-307

Abstract

In the present study, the spray pyrolysis technique was used to prepare pure CdS, 4 at.% Al-doped CdS, 4 at.% Na-doped CdS and (4 at.% Al, 4 at.% Na)-co-doped CdS thin films. It was found from X-ray diffraction data that all the specimens showed hexagonal wurtzite structure with the preferred orientation of (101). Scanning electron microscopy results indicated that 4 at.% Al-doping caused a grain growth in the morphology of CdS thin films whereas the 4 at.% Na-doping and (4 at.% Al, 4 at.% Na)-co-doping led to porous structure with small grains. The band gap value of CdS thin films increased to 2.42 eV after 4 at.% Al-doping. However, it reduced to 2.30 eV and 2.08 eV for 4 at.% Na-doping and (4 at.% Al, 4 at.% Na)-co-doping, respectively. The room temperature photoluminescence measurements illustrated that the peak intensity of CdS thin films enhanced with 4 at.% Al-doping while 4 at.% Na-doping and (4 at.% Al, 4 at.% Na)-co-doping caused a decline in the intensity. The maximum carrier concentration and minimum resistivity were obtained for 4 at.% Al-doped CdS thin films, which is associated with the grain growth. Furthermore, (4 at.% Al, 4 at.% Na)-co-doping gave rise to a slight reduction in the carrier concentration and a slight increment in the resistivity. As a result, it can be said that 4 at.% Al-doped CdS thin films exhibited the best electrical and optical properties, which is important for the optoelectronic applications. (C) 2015 Elsevier Ltd. All rights reserved.