Optical and electrical properties of pure and Sn4+-doped n-SnS films deposited by chemical bath deposition

Pure and Sn4+-doped SnS films with different S/Sn molar ratio were fabricated by chemical bath deposition from the solution of tin dichloride, thiacetamide, and triammonium citrate. The deposited films were characterized by X-ray diffraction, scanning electron microscopy, ultraviolet-visible spectrophotometry, photoluminescence spectrophotometry, and electrical conduction measurement: The effect of S/Sn molar ratios and Sn4+-doping on the properties of the films was investigated. When S/Sn molar ratio in bath solution was designed as 0.55-0.85, the S/Sn ratios in the films were similar to 0.54-0.83. The pure films showed electrical resistivity of similar to 26.2-71.3 k Omega cm, decreasing as decreasing S/Sn ratio. The Sn4+-doping further obviously decreased the resistivity of the films to similar to 1.5-9.6 k Omega cm. The films had thicknesses of similar to 470-650 nm and average transmittances of similar to 48.9-71.4% in the wavelength range of 290-1000 nm. The direct and indirect optical band gaps estimated from the transmittance and reflectance spectra equaled to similar to 1.25-1.83 eV and similar to 1.1-1.65 eV, respectively. The average transmittances and band gap values increased as decreasing S/Sn ratio and doping Sn4+-cation. (C) 2014 Elsevier Ltd. All rights reserved.