Nano-structured oxide semiconductor materials for gas-sensing applications

Several types of nano-structured metal oxide semiconductor materials have been successfully synthesized for the sensing of both ethanol and oxygen gases. Using the high-energy ball milling process, stable nano-particle powders down to a few nanometers can be achieved at room temperature. In the case of ethanol sensing, the α-Fe2O3–SnO2, α-Fe2O3–ZrO2, and α-Fe2O3–TiO2 materials are investigated while for the oxygen sensing, the ZrO2–α-Fe2O3, TiO2–α-Fe2O3, and SrTiO3 types are studied for different applications. All the nano-structured oxide materials are systematically characterized using XRD, TEM, and the fabricated sensor devices characterized for their electrical and sensing properties. The sensing properties are compared and analyzed and the sensing mechanisms are explained for the different type of sensing materials. The effects of the nano-structure on the sensing properties are investigated.