Micromachined nanocrystalline silver doped SnO sub(2) H sub(2)S sensor

An ultrahigh sensitive hydrogen sulfide gas sensor was developed utilizing micromachined nanocrystalline SnO sub(2)-Ag on ceramic wafer (alumina). A polymeric sol-gel process has been successfully developed in fabricating thin film SnO sub(2)-Ag nanocomposite, which shows excellent sensing characteristics upon exposure to H sub(2)S as low as 1 ppm at working temperature as low as 70 C. This sensor also shows higher sensitivity to H sub(2)S under various humidity conditions, in comparing to commercialized H sub(2)S sensors as well as published data. The environmental influences on sensor's sensitivity and selectivity have been tested and discussed. The results show that the sensor has a good selectivity due to its less sensitive to common interference gases like Cl sub(2), HCl, SO sub(2), C sub(6)H sub(14), CH sub(4), CO, C sub(3)H sub(8), etc.