Semiconductor Thin-film Gas and Smell Sensors using a Face-to-face Type Adsorption and Desorption Layer

Abstract

Semiconductor gas sensors have the drawback of poor gas selectivity, though they are sensitive to a wide variety of gases. A novel thin-film gas sensor with a gas adsorption and desorption part mounted on a rotation mechanism is developed to improve the gas selectivity. Activated carbon doped with noble metal catalyst is used as the adsorbent. The sensor exhibits different response to each isovaleric acid gas, ethanol gas and hydrogen gas after rotating the activated carbon to the place close to the sensing part and being heated by an implemented heater on it. Thus the sensor is able to discriminate the kind of gas by analyzing the sensitivity along with the adsorption and desorption response.