| 摘要 |
A chemical species sensor (10) for detection one or more chemical species present in a gas, liquid or vapour phases comprises a layer of semiconducting material (12A) forming a conductive channel (C1;C2), a layer of gate material (52,54) overlying the semiconducting layer and acting as an ion collection layer, at least first and second spaced apart electrodes (S1, D1; S2,D2) at respective ends of the channel, a supply of alternating voltage connected to the electrodes, a circuit for varying the frequency of the alternating voltage, and an analyser (102) for determining whether a chemical species is present at the gate material from the frequency response of the sensor. The sensor may further comprise an ionisation source (34, 40, 42) e.g. a heated filament (platinum). Also shown is a method for detecting one or more chemical species present in a gas, liquid or vapour phase using the sensor. |
