ABSTRACT
Microelectromechanical systems technology has allowed for the integration of the gas sensor, heating element and temperature sensor on a standard Si wafer with easy integration into standard complementary metal oxide semiconductor circuitry. One of the disadvantages of traditional semiconducting metal oxide gas sensors has been low gas sensitivity due to the limited surface-to-volume ratio. A single semiconducting nanowire gas sensor is excellent for its high sensing performance; still the use is restricted due to its complicated device construction, high cost and non-repeatability. The idea of using semiconductors as gas-sensitive devices leads back to 1952 when Brattain and Bardeen first reported the gas-sensitive effect on germanium. Later Seiyama found the gas sensing effect of metal oxides. Screen printing technique has the advantage that thick films of metal oxide semiconductor sensors are deposited in batch processing thus lowering the production cost.
