The influence of Deposition Temperature on the Properties of Chemically Sprayed Nanostructured Cu2CdSnS4 Thin Films

Abstract

In this study, Cu2CdSnS4 thin films were deposited on glass substrates at fixed concentrations: 0.02 M of (CuCl2.2H2O), 0.08 M of CS (NH2)2 and 0.01 M of both SnCl2.2H2O and (CdCl2.2H2O) using Chemical Spray Pyrolysis (CSP) technique at different deposition temperatures (300, 350, 400 and 450) °C. The thickness of all samples were (300 ± 10) nm. X-ray diffraction patterns showed that all films have a tetragonal structure with a preferred orientation of (112). The maximum value of the crystallite size was 8.09 nm at 400 °C deposition temperature. Raman spectra analysis confirmed the purity of the film peaks located at (332-333). The FESEM micrographs showed that the nanostructures appeared in the form of cauliflower. The highest average grain size was 62.8 nm for the film deposited at 300 °C substrate temperature. The optical properties of all films were studied by recording the transmittance and absorbance in the wavelength range (400-900) nm. The results showed that absorption occurs in the visible and ultraviolet regions. Through the Tauc’s equation, the optical energy gap was calculated for the allowed direct transition. Its value was in the range (1.59-1.40) eV. Therefore, these films are suitable for use in solar cell applications. Hall effect results showed that Cu2CdSnS4 thin films are p-type and the highest conductivity was 0.288 (Ω.cm)-1 at 400 ˚C corresponding to the maximum mobility value and the highest charge concentration.