A new type carbon nanotube-based gas sensor: palladium nanoparticles decorated single walled carbon nanotube film/SiO2/Si (Pd-SWCNT film/SiO2/Si) heterostructures were fabricated by a simple and practical filtration method. When used for hydrogen (H2) sensing, the Pd-SWCNT film/SiO2/p-Si heterostructure shows very high H2 response, which is tens of times higher than that of Pd-SWCNT film resistance-type H2 sensor in this paper and is superior to those of carbon nanotube-based resistance-type H2 sensors reported previously. The mechanism of the enhanced H2 response can be explained by thermionic emission theory and interfacial effect.
