Properties and mechanism study of Ag doped SnO2 thin films as H2S sensors

Abstract Ag doped tin oxide thin films were prepared by evaporating the mixture of SnO 2 and Ag powder. The granular film with a high Ag incorporation (16 at.%) was found to possess excellent sensitivity, selectivity and rapid response to the presence of H 2 S 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 film was composed of tin oxide with oxygen deficiency (Sn 3 O 4 ) and Ag 2 O crystals. Direct evidence of H 2 S adsorption on the Ag 2 O grain surface was observed.