Dual-parameter gas sensing with functional graphene field-effect transistors

Graphene's physical and chemical properties have garnered significant attention for its use in detecting hazardous gases through electrical detection methods such as conductance or resistance measurements. Despite the development of multi-functionalized sensor arrays, the challenge of limited selectivity in detecting multiple gases persists. To address this issue, we employ a lock-in technique to measure both conductance and dielectric modulations in graphene chips, resulting in valuable enhanced selectivity and uncompromised sensing response compared with conventional charge detection methods based on mere conductance measurements. We also demonstrate the practicality of our dual-parameter sensing scheme through selective detection of multiple gases at (sub) ppm concentrations using metal oxide functionalized graphene sensor arrays, serving as a proof of concept for its broader application in gas sensing.