Capacitive NO2 Detection Using CVD Graphene-Based Device

A graphene-based capacitive NO2 sensing device was developed by utilizing the quantum capacitance effect. We have used a graphene field-effect transistor (G-FET) device whose geometrical capacitance is enhanced by incorporating an aluminum back-gate electrode with a naturally oxidized aluminum surface as an insulating layer. When the graphene, the top-side of the device, is exposed to NO2, the quantum capacitance of graphene and, thus, the measured capacitance of the device, changed in accordance with NO2 concentrations ranging from 1-100 parts per million (ppm). The operational principle of the proposed system is also explained with the changes in gate voltage-dependent capacitance of the G-FET exposed to various concentrations of NO2. Further analyses regarding carrier density changes and potential variances under various concentrations of NO2 are also presented to strengthen the argument. The results demonstrate the feasibility of capacitive NO2 sensing using graphene and the operational principle of capacitive NO2 sensing.

Automated summary

A capacitive NO2 sensing device based on graphene was developed using the quantum capacitance effect. The graphene field-effect transistor (G-FET) device had enhanced geometrical capacitance through an aluminum back-gate electrode with a naturally oxidized aluminum surface as an insulating layer. The quantum capacitance and measured capacitance of the device changed with NO2 concentrations, demonstrating the feasibility of capacitive NO2 sensing using graphene and explaining the operational principle.