ENHANCEMENT THE OPTICAL PROPERTIES OF ZINC SULFIDE THIN FILMS FOR SOLAR CELL APPLICATIONS

In this work, semi-conducting ZnS compound was prepared as thin films onto glass substrates at two different substrates temperature (673, 723) K using chemical spray pyrolysis technique. X-ray diffraction was studied for the prepared films, the results shows that the films was polycrystalline with a wurtzite (hexagonal) structure. The optical properties of the films were studied by using VIS-UV spectrophotometer, the absorbance and transmittance spectrum have been recorded at wavelength within the range (300-900) nm. The optical characteristics were studied as a function of the photon energy at the mentioned wavelength. The results appear that the transparency of the films at visible region is rise from 70% to 90% at high substrates temperature. The refractive index was estimated within the visible wavelength at 500 nm, it was 2.45 at substrate temperature 673 K and its value will decrease at the highest substrate temperature. The direct optical band gap of the allow transitions for the deposits films prepared at both substrate temperatures (673, 723) K were varied from 3.2-3.4 eV respectively.