PROPERTIES AND MECHANISM STUDY OF AG DOPED SNO2 THIN-FILMS AS H2S SENSORS

Ag doped tin oxide thin films were prepared by evaporating the mixture of SnO2, and Ag powder. The granular film with a high Ag incorporatio n (16 at.%) was found to possess excellent sensitivity, selectivity an d rapid response to the presence of H2S gas at low temperature. X-ray diffraction, scanning electron microscopy and energy-dispersive X-ray analysis were carried out to investigate the sensing mechanism. The fi lm was composed of tin oxide with oxygen deficiency (Sn3O4) and Ag2O c rystals. Direct evidence of H2S adsorption on the Ag2O grain surface w as observed. (C) 1997 Elsevier Science S.A.