Carrier transport studies in graphene-base Hot Electron Transistor*

Hot electron transistors (HETs) are promising devices for potential high-frequency operation and hot electron spectroscopy. In HET, carrier transport is due to the injection of hot electrons from an emitter to a collector which is modulated by a base electrode. Monolayer graphene, being the thinnest available conductive membrane in nature, provides us with the opportunity to study the transport properties of HET at the ultimate scaling limit. Previously, we have demonstrated high performance graphene-base HET with GaN/AlN emitter and a graphene/WSe₂ van der Waals heterostructure base-collector stack. In this work, we discuss the effect of material parameters on the transport properties of the heterojunction diodes (i.e. Emitter-Base and Base-Collector) of HETs, and their impact on the HET performance. From the temperature dependent transport measurements, we identify the quantum mechanical tunneling as the major carrier transport mechanism in HETs. Finally, we demonstrate a new generation of graphene-base HET with record current density above kA/cm²_.