The optical parameters of CuInS2 thin films deposited by spray pyrolysis method for photovoltaic applications

In this work, CuInS₂ (CIS) thin films were prepared by spray pyrolysis method, and optical properties were investigated. CuInS₂ in the form of films is prepared at different deposition conditions by a simple and economical spray pyrolysis method. Optical constants such as band gap Eg, extinction coefficient k, refractive index n, and dielectric constants e₁ and e₂ were determined from the measured transmittance and absorption spectra in the wavelength range between 550-850 nm. Furthermore, the optical band gap values were calculated by the Tauc model. The absorption spectra of the films showed that this compound is a direct band gap material. The major result of this study is optical properties of CuInS₂.