Nanoplasmonic hybrid hotspot in graphene transistor

Abstract

A field effect transistor based on graphene was introduced to generate a hybrid plasmonic mode. The main reasons to consider graphene in this study are the achievement of high field confinement and the graphene two carrier transport channel near its charge neutrality point. We have observed a nonlinear behavior of the hybrid plasmonic mode near the graphene charge neutrality point because of the existence of the two carrier model. This nonlinear behavior reflects the intrinsic nanoelectronic characteristics of graphene. The proposed nanoelectronic device presents an ultraconfined tunable hybrid hotspot, the mode area of which is ${10}^{5}$ times smaller than the diffraction limited spot area. Moreover, this area is three orders of magnitude smaller than the modal area of the similar metal-based hybrid nanostructure. Such a nanoscale 3D hotspot with plasmonic-photonic character has been reported here. Furthermore, a hybrid structure based on bilayer twisted graphene was numerically investigated which renders ultrahigh confinement and ultralong propagation distance. The proposed nanodevice can be applied to design compact integrated circuits, optical neural networks, and high resolution sensors.