Pulsed UV-irradiated Graphene Sensors for Ethanol Detection at Room Temperature

Abstract

A graphene-based gas sensor fabricated in a FET (GFET) configuration and its sensitivity towards ethanol and methane is reported. Detection of ethanol at the level of 100 ppm was observed under pulsed UV irradiation and after cleaning by UV light in the N2 ambient. Reduction of the frequency of UV irradiation pulses resulted in increased changes in sensor resistance in the presence of ethanol. Improved sensing behavior was ascribed to more effective diffusion and adsorption processes at the graphene surface during low-frequency UV light pulses. Additionally, modulation of charge carrier density allowed more pronounced sensor responses at higher gate voltages (~30 V). GFET was insensitive to methane (200 ppm) at room temperature, regardless of irradiation frequency used, suggesting the potential application of selective gas sensing capability of graphene-based devices.