Preparation and characterization of new window material CdS thin films at low substrate temperature (< 300 K) with vacuum deposition


TOMAKİN M. , Altunbas M., BACAKSIZ E., POLAT İ.

MATERIALS SCIENCE IN SEMICONDUCTOR PROCESSING, vol.14, no.2, pp.120-127, 2011 (Journal Indexed in SCI) identifier identifier

  • Publication Type: Article / Article
  • Volume: 14 Issue: 2
  • Publication Date: 2011
  • Doi Number: 10.1016/j.mssp.2011.01.015
  • Title of Journal : MATERIALS SCIENCE IN SEMICONDUCTOR PROCESSING
  • Page Numbers: pp.120-127

Abstract

Low-temperature vacuum deposition instead of the commonly used vacuum deposition at high substrate temperatures has been applied to prepare new window material CdS thin films. The structural, optical and electrical properties of vacuum-evaporated CdS thin films were investigated as a function of substrate temperature (100-300 K) and the post-deposition annealing temperature (at 473, 573 and 673 K). It was determined that films deposited at all substrate temperatures were polycrystalline in nature with hexagonal structure and a strong (0 0 2) texture. The AFM and SEM studies showed that the microstructures of the as-deposited films agreed with the expectations from structure zone model. X-ray diffraction studies showed that the crystallinity of the CdS films was improved on annealing. Optical spectroscopy results of the films indicated that the optical band gap value increased from 2.40 to 2.42 eV with decreased substrate temperature. Increasing the annealing temperature sharpened the band edge. The dark resistivity increased from 4.5 x 10(3) to 7.3 x 10(3) Omega cm and the carrier concentration decreased from 4.7 x 10(17) to 3.5 x 10(15) cm(-3) as the substrate temperature decreased from 300 to 100 K. (C) 2011 Elsevier Ltd. All rights reserved.