A Quasi-Static Electrical Measurement Scheme for Probing Gas Reactions on Graphene Surface

This work marks the first use of a quasi-static electrical measurement method on graphene field effect transistors (FET) to characterize sub-ppm level of toxic gases in air at room temperature. Compared with the state-of-art technology, three distinctive advances have been achieved: (1) a quasi-static electrical measurement scheme on graphene FETs without sweeping a large range gate voltage to avoid the dipole flipping or charge trapping problem; (2) the real-time estimation of the charge neutral point (VCNP) and carrier mobility (μ) of graphene during the exposure to sub-ppm toxic gases in air; and (3) the demonstration of differentiable characteristics of NO
₂
and formaldehyde by the extractions of their intrinsic charge transfer and Coulomb scattering characteristics. As such, the proposed quasi-static monitoring method can be used to sense and differentiate sub-ppm level toxic gases on graphene FETs without using an array of devices with different surface functionalization materials.