Abstract:SnO2 film is widely used as a gas sensor, whereas, its gas sensitivity at low temperature is not satisfactory. Surface modification is an effective way to enhance sensitivity of SnO2 which is closely related to the surface morphology and microstructure of SnO2. In this paper, nickel nanoparticles surface-modified SnO2 films were prepared by D. C. magnetron sputtering. The effects of distribution and morphology of Ni particles on the surface of SnO2 on hydrogen sensitivity were studied. The results show that the sputtering time of Ni influences gas sensitivity of SnO2. With increasing the annealing temperature, Ni particles separate from SnO2 particles and gradually aggregate into spherical particles distributing uniformly on the surface of SnO2 film. The particle size, porosity, and specific surface area of Ni influence the gas sensitivity of SnO2 directly. Gas sensitivity examination indicates that the spherical Ni particles in a diameter of 100nm lead to the best modification. After heat treated at 800℃ for 3 hours, SnO2 film with 30s sputtering of Ni shows a gas sensitivity of 112， for 4000 ppm H2 at a operating temperature of 60℃.
