Highly sensitive hydrogen sulphide sensors operable at room temperature

Tellurium thin films have been investigated for use as hydrogen sulphide gas sensors. The films were prepared by thermal evaporation on alumina substrates at a temperature of 373 K and were found to be sensitive towards 0.1 ppm of H2S at room temperature. The response was reproducible and the films were stable for operation over 3 months. Detection mechanism of the sensors was investigated and it was found that hydrogen sulphide reduced the amount of adsorbed oxygen on the Te film surface leading to increase in resistance.