Large area graphene electromagnetic devices

Abstract

Large area graphene growth provides a facile route to the development of microwave devices based on the interaction of electromagnetic waves with the two dimensional gas of electrons in a graphene sheet. The strength of microwave scattering with graphene is determined by an impedance mismatch Zσ whose natural scale is itself determined by the fine structure constant α = e2/(4πε0hc). Scattering measurements of graphene monolayer loaded waveguides from 17 Hz to 110 GHz reveal a constant sheet conductance with negligible skin effect owing to monolayer atomic thickness. A Drude conductivity tensor can be used to describe the microwave scattering of a graphene sheet under a static magnetic field bias. Measurement of longitudinal conductivity in a Corbino disk geometry can be used to estimate mobility. Transverse conductivity leads to Faraday rotation, which can be used in hollow waveguide structures to implement a gate voltage tunable isolator. As graphene mobility improves, there is potential to exploit both classical and quantum effects in non-reciprocal devices.