We have investigated molecule adsorption phenomena on a chemically active surface of titanium oxide nanosheet by coupling with an electrically sensitive graphene field effect transistor (FET). Super-hydrophilic surface of the titanium oxide nanosheet forms a water-layer in ambient air which exhibits a large hysteresis of drain current in the hybrid FET for sweeping gate-voltage. The large hysteresis disappears in vacuum, which indicates physically adsorbed water molecules on the surface of the titanium oxide nanosheet dominantly contribute to the hysteresis. UV light irradiation in vacuum significantly changes the drain current due to desorption of the adsorbed molecules. Sufficient UV irradiation results in symmetric gate-voltage dependence similar to those of conventional graphene FETs. Exposure to an oxygen gas atmosphere leads to a heavy hole doping in the FET, where the binding of the oxygen molecules is stronger than that of water molecules. In a humidified nitrogen atmosphere, a large shift of charge neutrality point is observed in transfer characteristics crossing between electron doping and hole doping. By contrast, a clear square-shaped hysteresis loop is observed in a humidified oxygen atmosphere, where the hole density in the graphene drastically changed with O₂/H₂O redox couple reaction on the titanium oxide nanosheet.

我们已经通过与电敏感的石墨烯场效应晶体管（FET）耦合研究了氧化钛纳米片的化学活性表面上的分子吸附现象。氧化钛纳米片的超亲水表面在环境空气中形成水层，该水层在混合FET中表现出大的漏电流滞后，以扫除栅极电压。较大的磁滞现象在真空中消失，这表明物理吸附在氧化钛纳米片表面的水分子占主导地位。真空中的紫外线照射会由于吸附分子的解吸而显着改变漏极电流。与常规石墨烯FET相似，足够的紫外线照射会导致对称的栅极电压依赖性。暴露在氧气气氛中会导致FET中出现重空穴掺杂，其中氧分子的结合比水分子的结合更强。在湿润的氮气氛中，在电子掺杂和空穴掺杂之间的传递特性中观察到电荷中性点的大位移。相比之下，在潮湿的氧气气氛中观察到清晰的方形磁滞回线，其中石墨烯中的空穴密度随O急剧变化。在氧化钛纳米片上进行₂ / H ₂ O氧化还原偶联反应。