Gas sensing characteristics of the FET-type gas sensor having inkjet-printed WS2 sensing layer

Abstract This paper investigates the gas sensing characteristics of the MOSFET-type sensor having an inkjet-printed WS 2 sensing layer. The drain current of the gas sensor increases when NO 2 gas is injected into the test chamber since NO 2 gas is an oxidizing gas that extracts electrons from the sensing layer. On the contrary, the drain current decreases when H 2 S gas is injected into the test chamber since H 2 S gas is a reducing gas that donates electrons to the sensing layer. In both cases, the change of the drain current increases as the gas concentration increases. However, for other gases (NH 3 and CO 2 ), the gas sensor has a small change of the drain current. The responses of the gas sensor to 10 ppm NO 2 , H 2 S, NH 3 , and CO 2 gases are 15.20%, 7.18%, 1.66%, and 3.02%, respectively. Therefore, the WS 2 sensor has a high selectivity for NO 2 gas among the four target gases.