Micromachined nanocrystalline silver doped SnO2 H2S sensor

An ultrahigh sensitive hydrogen sulfide gas sensor was developed utilizing micromachined nanocrystalline SnO2–Ag on ceramic wafer (alumina). A polymeric sol–gel process has been successfully developed in fabricating thin film SnO2–Ag nanocomposite, which shows excellent sensing characteristics upon exposure to H2S as low as 1 ppm at working temperature as low as 70 °C. This sensor also shows higher sensitivity to H2S under various humidity conditions, in comparing to commercialized H2S 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 Cl2, HCl, SO2, C6H14, CH4, CO, C3H8, etc.