Tin Oxide Thin Films: Synthesis and Room Temperature Gas Sensing Properties

Dense tin oxide films were solvothermally grown from the tin oxide seed films fabricated on glass substrates by sol-gel technique. The morphology and crystal structure of the tin oxide films were characterized by using scanning electron microscopy and X-ray diffraction techniques. The results reveal that the films are composed of cassiterite-type tin oxide crystals with size of 7 similar to 10 nm. The film quality can be improved significantly when the sodium dodecylbenzenesulfonate is used as the surfactant during the solvothermal reaction. The gas sensor, which is directly connected tin oxide films to the test circuits by using tweezers with special gripping surfaces, exhibits good sensing performance to nitrogen dioxide gas under mild testing conditions, i.e. room temperature, ambient pressure, and dry air background. The sensor can achieve a detection limit of 0.5 mu L.L-1.