A micro gas sensor using TiO₂ nanotubes to detect volatile organic compounds

To develop a portable gas sensor with low power consumption, we deposited a micro size sensing film (100 × 100 μm2) on a Si substrate with an integrated micro heater and electrodes constructed using micro-electro- mechanical system (MEMS) technology. TiO₂ nanotubes ca. 500nm long with a 50 nm diameter were used to sense and detect volatile organic compounds (VOCs). We demonstrate that the MEMS sensor responded well to ethanol and toluene in air at elevated temperatures, such as 500 °C, which suggests that it is a promising battery-operable micro gas sensor for detecting VOCs.