Synthesis of copper sulphide thin film on Indium Tin Oxide glass plate by SILAR method and its characterization

Abstract

Thin film of copper sulphide has been deposited on Indium Tin Oxide (ITO) glass plate. This film has been characterized by UV-Visible reflectance spectroscopy, FTIR spectroscopy, EDAX, and SEM. The film has been subjected to polarization study by immersing in sea water. The above studies on the thin film has been compared with copper sulphide prepared by chemical method; that is by mixing a solution of copper sulphate and sodium sulphide solution. For comparison study methods such as UV-Visible reflectance and FTIR have been employed. The UV-Visible reflectance spectrum reveals that the band gap of the copper sulphide film is 1.823eV. This indicates that the film functions as semi conductor. The UV-Visible absorption study of the film indicates that the lmax appears at 310 nm. The FTIR study of the copper sulphide film confirms the presence of CuS. The polarization study reveals that the linear polarization resistance (LPR) value decreases, when compared to ITO plate immersed in sea water. This indicates that the current flowing through the thin film increases. Such a finding can be used in solar cells. This is supported by the fact that the current flowing through the thin film, when it is immersed in sea water increases, when compared to the current flowing through the empty glass plate (without black coating) is immersed in sea water. This is further supported by the fact that for black thin film, the band gap decreases after coating. The EDAX study confirms the presence of elements Cu and S. The SEM study reveals the presence of thin film of copper sulphide on the ITO glass plate. The particle size of the copper sulphide is in the range of 101.1nm, 107.8nm and 114.5nm. Thus it is encouraging to note that copper sulphide nano particles have been prepared by SILAR method.