GAS SENSITIVITY OF SNO2 CUO HETEROCONTACTS

Gas sensors have been fabricated by a mixture of SnO2, CuO powder, and tetraethylorthosilicate. Their response to H2S gas has been investiga ted. A five ppm H2S gas concentration changes their resistivity to a v alue lower than that in air, even in the presence of other gases. By p rotecting the sensor surface with organic material, sensitivity and se lectivity for H2S gas has been achieved. The observed change in conduc tivity of these films upon exposure to H2S gas in air has been explain ed on the basis of band theory of solids supported by our x-ray diffra ction data and I-V characteristics.