Effect of Temperature and Humidity on $\hbox{NO}_{2}$ and $\hbox{NH}_{3}$ Gas Sensitivity of Bottom-Gate Graphene FETs Prepared by ICP-CVD

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 (<i>T</i>) 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 <i>ID</i> with increasing <i>T</i> and also increasing <i>ID</i> with increasing humidity. However, the FET shows an opposite trend with the <i>T</i> and humidity for NH₃ gas.