On the Importance of Bandgap Formation in Graphene for Analog Device Applications

We present a study that identifies the ideal bandgap value in graphene devices, e.g., through size quantization in graphene nanoribbons (GNRs), to enable graphene-based high-performance RF applications. When considering a ballistic graphene GNR-LNA, including aspects like stability, gain, power dissipation, and load impedance, our calculations predict a finite bandgap of the order of Eg ≈ 100 meV to be ideally suited. GNR-LNAs with this bandgap, biased at the optimum operating point, are ultrafast (THz) low-noise amplifiers exhibiting performance specs that show considerable advantages over state-of-the-art technologies. The optimum operating point and bandgap range are found by simulating the impact of the bandgap on several device and circuit relevant parameters including transconductance, output resistance, bandwidth, gain, noise figure, and temperature fluctuations. Our findings are believed to be of relevance in particular for graphene-based RF applications.