Langmuir Analysis On Hydrogen Gas Response Of Palladium-gate Fet

Field effect transistor with a thin palladium electrode annealed in high hydrogen concentration atmosphere was characterized as a hydrogen gas sensor at the operation temperature of 100/spl deg/C in the flowing dry air mixed with hydrogen gas ranged from I to 10,000ppm. The response of threshold voltage from the base-level to the steady-state was achieved within 1 minute, and the recovery time to the 1ppm level was 2-4 minutes. The base-level drift observed in the continuous operation over 3 months was smaller than 30mV/month. The dipole model adapted to the Langmuir equation well describes the observed hydrogen response of the FET gas sensor, and the one-point calibration in the implementation of the hydrogen detector may be possible by use of the Langmuir relationship.