An ultra-sensitive gas nanosensor based on asymmetric dual-gate graphene nanoribbon field-effect transistor: proposal and investigation

In this paper, a new ultra-sensitive gas nanosensor based on an asymmetric dual-gate graphene nanoribbon field-effect transistor (ADG GNRFET) is proposed. The performance of the proposed gas nanosensor is examined using an atomistic quantum simulation based on the mode space non-equilibrium Green's function approach, self-consistently coupled to a two-dimensional Poisson's equation in the ballistic limit. The gas-induced change in work function of sensitive gates is considered as a sensing mechanism, where the threshold voltage shift is taken as a sensing metric. The sensitivity analysis has shown that the gas-induced shift in threshold voltage can be significantly increased by decreasing the ratio of top-oxide capacitance to that of back-oxide, to less than unity. Moreover, the length and width of graphene nanoribbon are found independent of sensor sensitivity. The possibility of reaching ultra-high sensitivities at the nanoscale domain using the proposed ADG GNRFET-based gas sensor makes it an exciting alternative to the conventional FET-based gas sensors.