Graphene FET-Based Zero-Bias RF to Millimeter-Wave Detection

We report direct radio-frequency (RF) and millimeter-wave detection of epitaxial graphene field-effect transistors (FETs) up to 110 GHz with no dc biases applied, leveraging the nonlinearity of the channel resistance. A linear dynamic range of$>$40 dB was measured, providing at least 20-dB greater linear dynamic range compared to conventional CMOS detectors at transistor level. The measured noise power of the graphene FETs was~\!7.5 × 10⁻¹⁸\ V²/Hzat zero bias and without1/fnoise. At a 50-Ωload, measured detection responsivity was 71 V/W at 2 GHz to 33 V/W at 110 GHz. The noise-equivalent power at 110 GHz was estimated to be~\!80\ pW/Hz0.5. For the first time, we demonstrated graphene FETs as zero-bias ultrawideband direct RF detectors with comparable or better performance than state-of-the-art FET-based detectors without dc biases applied.