Highly Sensitive MOSFET Gas Sensors with Porous Platinum Gate Electrode

Novel gas-sensing devices based on a porous platinum (Pt) gate metal-oxide-semiconductor field-effect transistor (MOSFET) have been fabricated. The catalytic properties of the porous Pt surface for hydrogen (H 2 ) enhance the gas detection sensitivity of the MOSFET gas sensor. The threshold voltage decreased rapidly with time when the device was exposed to H 2 gas. It was possible to detect 22 ppm of H 2 gas with a response time of less than 2 min at a device temperature of 27°C. The gas sensitivity could be enhanced to about 10 times higher than that of an unmodified Pt surface. The device detection mechanism presented corresponds well with the experimental data.