Effect of Temperature and Humidity on $\hbox {NO}_{2}$ and $\hbox {NH}_{3}$ Gas Sensitivity of

Graphene was used for a sensing part of bottom-gate field-effect transistor (FET)-type gas sensors, and the sensing performance of the sensors was studied. We investigated the effect of temperature (T) and relative humidity on the gas sensitivity of bottom-gate graphene FETs prepared by the inductively coupled plasma chemical vapor deposition method. The conductivity change of graphene exposed to nitrogen oxide (NO₂) and ammonia (NH₃) was increased with increasing temperature and humidity. For NO₂ gas, the graphene FET shows increasing ID with increasing T and also increasing ID with increasing humidity. However, the FET shows an opposite trend with the T and humidity for NH₃ gas.