Gigahertz Cutoff Frequencies and High Gain in Graphene-Based Hot-Electron Transistor Enabled by Material Engineering

High Resolution Image Download MS PowerPoint Slide Graphene (Gr)-based hot-electron transistors (GHETs) offer high potential for high-frequency applications due to the extremely thin nature of graphene as a base material. For the first time we present GHETs with excellent DC device characteristics and gigahertz operation achieved by an optimization of the emitter-base (E/B) composition. The optimized E/B composition enables more efficient injection of hot electrons into the base, thereby improving charge transport and reducing scattering losses. As a result, a record-high measured common-emitter current gain beta of 42 was achieved using a SiO 2 /Gr E/B structure. Moreover, when using a MoS 2 /Gr E/B junction the maximum output current is increased to record values of approximately 2000 A/cm 2, representing a significant improvement in performance over previous devices. Furthermore, cutoff frequencies of close to 1 GHz are determined for nonoptimized SiO 2 /Gr-based devices. The experimentally observed device characteristics are very promising for future high-speed nanoelectronics.