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 pre pared by a spray pyrolysis technique and bulk precipitation method, re spectively. The concentration of solution is kept constant at 0.1 M an d 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 diff erence 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 adh erent to the glass substrates. In contrast, the precipitated powders a re orange in colour. X-ray diffraction studies reveal that the precipi tated powders are polycrystalline whereas films are amorphous in natur e. Also it has been found that the crystallinity of the precipitated p owder is higher for 0.25 M concentration and decreases for the further concentrations of complexing agent. The direct bandgap of the thin fi lms is found to be 2.7 eV irrespective of concentration of complexing agent, whereas the direct bandgap of the precipitated powder varies fr om 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 reve als 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 precipitat ed powder (similar to 10(8)-10(9) Ohm cm). (C) 1997 Elsevier Science S .A.