A nanopore structured high performance toluene gas sensor made by nanoimprinting method

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 (TiO₂) pores with a diameter of 70~80 nm using this method. This thin film had a Pd/TiO₂ nanoporous/SiO₂/Si MIS layered structure with Pd-TiO₂ as the catalytic sensing layer. The nanoimprinting method was useful in expanding the TiO₂ 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/TiO₂ interface work function, resulting in a change in the I-V characteristics.