▎ 摘　　要

We have succeeded in enhancing the gas sensitivity of graphene field-effect transistor (FET)-based gas sensors using surface-treated SiO2/Si substrates. Graphene FETs on SiO2 treated with three types of treatment, namely, H-2 annealing, Al2O3 coating, and CF4 reactive ion etching (CF4-RIE), were prepared. Enhanced sensitivities were obtained for graphene FETs on surface-treated SiO2 substrates compared with those on bare SiO2 substrates. Moreover, a distinct O-2 concentration dependence in O-2 sensing was observed for graphene FETs with different treatments. These results will lead to highly sensitive and concentration-optimized graphene-FET-based gas sensors. (C) 2015 The Japan Society of Applied Physics