Optical Properties of In2S3 Thin Films

Laser deposition on substrates at temperatures of 480, 610, and 720 K has been used to produce films of the compound In2S3. Single crystals of this compound grown by the Bridgeman-Stockbarger method are used as targets. The composition is determined by x-ray spectral analysis and the structure of the resulting crystals and films is determined by x-ray methods. Both the crystals and the films crystallize into a tetragonal spinel structure. Transmission spectra in the region of the intrinsic absorption edge are used to determine the width of the band gap and the refractive index of the In2S3 films. The band gap width is found to increase as the substrate temperature is raised.