Carbon-doped Sb2S3 thin films: Structural, optical and electrical properties

We report the modification of electrical properties of chemical-bath-deposited antimony sulphide (Sb₂S₃) thin films by thermal diffusion of carbon. Sb₂S₃ thin films were obtained from a chemical bath containing SbCl₃ and Na₂S₂O₃ salts at room temperature (27 °C) on glass substrates. A carbon thin film was deposited on Sb₂S₃ film by arc vacuum evaporation and the Sb₂S₃-C layer was subjected to heating at 300 °C in nitrogen atmosphere or in low vacuum for 30 min. The value of resistivity of Sb₂S₃ thin films was substantially reduced from 10⁸ Ω cm for undoped condition to 10² Ω cm for doped thin films. The doped films, Sb₂S₃:C, retained the orthogonal stibnite structure and the optical band gap energy in comparison with that of undoped Sb₂S₃ thin films. By varying the carbon content (wt%) the electrical resistivity of Sb₂S₃ can be controlled in order to make it suitable for various opto-electronic applications.