A comparative study of concentration effect of complexing agent on the properties of spray deposited Sb2S3 thin films and precipitated powders

Sb2S3 semiconducting thin films and precipitated powders have been prepared by a spray pyrolysis technique and bulk precipitation method, respectively. The concentration of solution is kept constant at 0.1 M and only the concentration of complexing agent (tartaric acid) is varied from 0.25 M to 1 M. The thickness of the film measured by weight difference method is found to be relatively higher for the film deposited with 0.5 M tartaric acid. The film thickness is of the order of 0.1 mu m. As-deposited films are found to be uniform, dark grey and well adherent to the glass substrates. In contrast, the precipitated powders are orange in colour. X-ray diffraction studies reveal that the precipitated powders are polycrystalline whereas films are amorphous in nature. Also it has been found that the crystallinity of the precipitated powder is higher for 0.25 M concentration and decreases for the further concentrations of complexing agent. The direct bandgap of the thin films is found to be 2.7 eV irrespective of concentration of complexing agent, whereas the direct bandgap of the precipitated powder varies from 1.92 to 2.02 eV and is found to be higher (2.02 eV) for the powder prepared using 0.75 M tartaric acid. Electrical resistivity study reveals that at 0.5 M tartaric acid, the R.T. resistivity of the thin film is relatively lower (similar to 10(6) Ohm cm) than that of precipitated powder (similar to 10(8)-10(9) Ohm cm). (C) 1997 Elsevier Science S.A.