Graphene-based quantum capacitance wireless vapor sensors

TL;DR

This paper demonstrates a wireless vapor sensor utilizing graphene's quantum capacitance effect, showing a linear frequency shift with humidity and confirming the sensing mechanism through capacitance measurements, opening new avenues for chemical and biological sensing.

Contribution

It introduces a novel wireless vapor sensor based on graphene quantum capacitance, establishing a new transduction mechanism for chemical and biological sensing applications.

Findings

Resonant frequency shifts linearly with humidity from 1% to 97%.

Wireless measurements match capacitance-voltage data, confirming quantum capacitance sensing.

Paves the way for graphene quantum capacitance sensors in various sensing fields.

Abstract

A wireless vapor sensor based upon the quantum capacitance effect in graphene is demonstrated. The sensor consists of a metal-oxide-graphene variable capacitor (varactor) coupled to an inductor, creating a resonant oscillator circuit. The resonant frequency is found to shift in proportion to water vapor concentration for relative humidity (RH) values ranging from 1% to 97% with a linear frequency shift of 5.7 +- 0.3 kHz / RH%. The capacitance values extracted from the wireless measurements agree with those determined from capacitance-voltage measurements, providing strong evidence that the sensing arises from the variable quantum capacitance in graphene. These results represent a new sensor transduction mechanism and pave the way for graphene quantum capacitance sensors to be studied for a wide range of chemical and biological sensing applications.