Microwave noise in epitaxial graphene on SiC

Abstract

High frequency noise was measured for epitaxial graphene on SiC. The noise measurements were carried out in the frequency range from 200 MHz up to 10 GHz in the direction parallel to the applied electric field in the graphene layer. Nanosecond voltage pulses were applied to minimize the effect of graphene layer self-heating. The measured spectral density of current fluctuations within 200 MHz–2.5 GHz frequency range can be approximated with a generation-recombination noise and a white noise contribution. Shot noise dominates at 10 GHz. Fano factor of suppressed shot noise was estimated. The shot noise was possibly associated with electron jumps across the potential barriers located in the graphene layer. Current-voltage characteristics were measured up to 17 kV/cm electric field and the maximum drift velocity was estimated as ∼5.2×107 cm/s.