A high performance ethanol sensor based on field-effect transistor using a LaFeO3 nano-crystalline thin-film as a gate electrode

The LaFeO3 nano-crystalline thin-film of perovskite-type composite-oxides is obtained by using a sol–gel coating technique, and the photo-etching technique is employed to etch and pattern the film. Combining this thin-film technology with the NMOS integrated circuit technology, we have developed an ethanol-sensitive field-effect transistor by using a LaFeO3 nano-crystalline thin-film as a gate electrode of an ordinary n-channel MOSFET. The sensor has excellent selectivity, good sensitivity to ethanol, and a good stability. In order to improve the recovery transient of the sensor, the LaFeO3 doped with strontium ions has been investigated.