A MEMS-Based Ionization Gas Sensor Using Carbon Nanotubes
We demonstrate here the successful operation of an ionization gas sensor with a gap spacing S of 2 or 7plusmn0.4 mum and using carbon nanotubes as the electrode material. The device is chip based and fabricated using a microelectromechanical system process. Application of a bias of 0.6-1.8 V (Sap2 mum) or 12-15 V (Sap7 mum) to the electrodes generates an electric field that is sufficient to field ionize He, CO2, and their mixtures in air with high sensitivity and selectivity. The approach is considered as effective for lowering the operation voltage of ionization gas sensors below 36 V (safety voltage criterion) and is significant for the development of the smart device in this field