Low-Phase-Noise Graphene FETs in Ambipolar RF Applications

In this letter, we present both the 1/f noise and phase noise performance of top-gated epitaxial graphene field-effect transistors (FETs) in nonlinear circuit applications for the first time. In the case of frequency doublers, the fundamental signal is suppressed by 25 dB below the second harmonic signal. With a phase noise of -110 dBc/Hz measured at a 10-kHz offset, a carrier-to-noise degradation (ΔCNR) of 6 dB was measured for the frequency doubler. This implies noiseless frequency multiplication without additional 1/f noise upconversion during the nonlinear process. The frequency multiplication was demonstrated above the gigahertz range. The 1/f noise of top-gated epitaxial graphene FETs is comparable or lower than that of exfoliated graphene FETs.