ANNEALED In2S3 THIN FILMS PREPARED BY SPRAY TECHNIQUE: REPORT ON THE STRUCTURAL, OPTICAL AND DISPERSION ENERGY PARAMETERS

Abstract

In2S3 thin films with different S/In molar ratios (from 1.5 to 3.5) were deposited via a spray pyrolysis technique on glass substrates at 340∘C. Then, the obtained films were annealed at the same temperature 400∘C for 2[Formula: see text]h. X-ray diffraction study reveals the formation of cubic [Formula: see text]-In2S3 phase with (400) as preferred orientation. The crystallite size varies in the range 64–97[Formula: see text]nm. Optical analysis exhibits that transmittance in visible and near infrared regions is higher than 65% for all films. The optical band gap varied from 2.58[Formula: see text]eV to 2.67[Formula: see text]eV. The optical parameters (refractive index, extinction coefficient, dielectric constants) were calculated through the transmittance ([Formula: see text]) and reflectance ([Formula: see text]). Dispersion parameters ([Formula: see text], [Formula: see text]), high frequency dielectric constant ([Formula: see text]), refractive index ([Formula: see text]), oscillator length strength ([Formula: see text]), average oscillator wavelength ([Formula: see text]) and optical moments ([Formula: see text]) were determined by Wemple–DiDomenico model. The surface and volume energy losses with photon energy were also calculated. The optical and electrical conductivities were estimated. These properties of In2S3 films are important for photovoltaic applications.