Toluene gas was successfully measured at room temperature using a device microfabricated by a nanoimprinting method. A highly uniform nanoporous thin film was produced with a dense array of titania (TiO(2)) pores with a diameter of 70 ≈ 80 nm using this method. This thin film had a Pd/TiO(2) nanoporous/SiO(2)/Si MIS layered structure with Pd-TiO(2) as the catalytic sensing layer. The nanoimprinting method was useful in expanding the TiO(2) surface area by about 30%, as confirmed using AFM and SEM imaging. The measured toluene concentrations ranged from 50 ppm to 200 ppm. The toluene was easily detected by changing the Pd/TiO(2) interface work function, resulting in a change in the I-V characteristics.
Keywords: MIS structure; gas sensor; nanoimprinting method; nanopore; titania; toluene.