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.