Outstanding gas-sensing performance of graphene/SnO2 nanowire Schottky junctions

Schottky junctions (SJ) are considered devices for sensing applications due to their unique properties. Herein, we report on the design, facile fabrication, and outstanding NO2 gas sensing properties of monolayer graphene (GP)/SnO2 nanowire (NW) SJ devices. The devices were prepared by directly growing single crystal SnO2 NWs on interdigitated Pt electrodes via thermal evaporation, followed by transferring a GP layer grown by chemical vapor deposition on top of the NW chip. The SJ-based sensor showed a reversible response to NO2 gas at concentrations of ppb levels with detection limits of about 0.024 ppb at a low operating temperature of 150 degrees C and bias voltage (1 V) with a response/recovery time of less than 50 s. The outstanding gas-sensing characteristics of the device were attributed to tuning the Schottky barrier height and barrier width at the tiny area of contact between GP and SnO2 NW through the adsorption/desorption of gas molecules. (C) 2014 AIP Publishing LLC.