HIGHLY SENSITIVE AND SELECTIVE H2S GAS SENSOR FROM RF-SPUTTERED SNO2 THIN-FILM

A highly sensitive and selective H2S gas sensor has been developed. An SnO2 thin film is deposited on an alumina substrate by the r.f. react ive sputtering method. The influence of the preparation conditions, su ch as the calcination temperature and the film thickness, has been exa mined. The sensitivity and the selectivity to H2S are improved by incr easing the calcination temperature from 500 to 600 degrees C and by de creasing the him thickness. The optimized sensor shows high sensitivit y and good selectivity to H2S, a short response time and long-term sta bility over 90 days. The relationship between the preparation conditio ns and the morphologies of SnO2 thin films is also discussed.