Effect of concentration of cadmium sulfate solution on structural, optical and electric properties of Cd_1–x Zn _x S thin films

Abstract

Cd1– x Zn x S thin films were deposited by chemical bath deposition (CBD) on the glass substrate to study the influence of cadmium sulfate concentration on the structural characteristics of the thin film. The SEM results show that the thin film surfaces under the cadmium sulfate concentration of 0.005 M exhibit better compactness and uniformity. The distribution diagrams of thin film elements illustrate the film growth rate changes on the trend of the increase, decrease, and increase with the increase of cadmium sulfate concentration. XRD studies exhibit the crystal structure of the film is the hexagonal phase, and there are obvious diffraction peaks and better crystallinity when the concentration is 0.005 M. Spectrophotometer test results demonstrate that the relationship between zinc content x and optical band gap value E g can be expressed by the equation E g(x) = 0.59x 2 + 0.69x + 2.43. Increasing the zinc content can increase the optical band gap, and the absorbance of the thin film can be improved by decreasing the cadmium sulfate concentration, however, all of them have good transmittance. At a concentration of 0.005 M, the thin film has good absorbance in the 300–800 nm range, 80% transmittance, and band gap value of 3.24 eV, which is suitable for use as a buffer layer for solar cells.

Optimization of the properties of CdxZn1-xS films prepared by chemical bath deposition

“…In this paper, the effect of low Cd 2+ concentrations (0.001M-0.009M) on the properties of prepared Cd x Zn 1-x S thin films was systematically investigated by optimizing the concentration ratios of all reaction solutions. and the atomic percentage of Cd increased with increasing CdSO 4 solution concentration, contrary to the experimental results performed by Zhang et al [16]. Also, the prepared Cd x Zn 1-x S thin films have better performance at a CdSO 4 concentration of 0.007 M compared with the results of previous studies.…”

“…However, the Cd 2+ concentration used by the above researchers to conduct their experiments was high and still posed a significant environmental hazard. Zhang et al [16] studied the effect of different concentrations of cadmium sulfate (0.003-0.007M) on the structure and optical properties of Cd x Zn 1-x S films, but its atomic percentage of Cd started to decrease with the increase of the concentration of CdSO 4 solution, which was not consistent with reality and is problematic, and also the properties of the prepared films were low. In conclusion, most of the cadmium sources used were cadmium nitrate and cadmium chloride at high concentrations, and systematic studies on the preparation of Cd x Zn 1-x S films at extremely low concentrations of cadmium sulfate were lacking.…”