Influence of annealing temperature on structural and optical properties of CdS thin films prepared by sol-gel spin coating method

Abstract

Cadmium Sulphide (CdS) thin films were deposited on glass substrates by sol -gel spin coating method taking cadmium nitrate and thiourea as the precursor solutions. The influence of annealing temperature on the structural, optical and surface morphological properties of the films was studied. The crystallographic structure and crystallite size were determined from the X -Ray Diffraction study. It reveals that the films have a predominant hexagonal crystal phase with a preferential (0 0 2) plane. Transmittance of the deposited films was significantly higher in the visible region. The calculated optical band gap of the films decreases with increase in annealing temperature. The photoluminescence spectra show that the intensity ofPL emission peaks found to decrease in intensity, with increase in annealing temperature. SEM studies reveal that the grains are spherically shaped and distributed uniformly over the entire surface of the substrate. These examined properties of the films show its feasibility for application in optoelectronic devices, especially for solar cells.

Study of the Optical properties for CdS before and after irradiated by CO2 laser for different exposure times

“…The plots of (αhν) 2 versus hν are shown in figures (5)(6)(7)(8)(9) for CdS thin films before and after irradiation with CO 2 laser respectively. Variation of (αhν) 2 with hν for CdS films is a straight line, indicating the presence of a direct transition.…”

“…Cadmium sulfide (CdS) is an important metal chalcogenides .CdS thin films are regarded as one of the most promising materials for heterojunction thin film solar cells. CdS is one of the important II -VI group semiconductor with a direct band gap of 2.42 eV [1,2],and used as the window material together with several semiconductors such as CdTe, Cu 2 S, InP and CuInSe 2 with 14 -16% efficiency [3,4]. Many techniques have been reported for the deposition of CdS thin films.…”