Ultra-high current gain tunneling hot-electron transfer amplifier based on vertical van der Waals heterojunctions

Due to the backscattered parasitic current from the barriers, the current gain of the widely used amplifier is far from ideal. In this work, we demonstrate a vertical Au/Al₂O₃/BP/MoS₂ tunneling hot-electron transfer amplifier with a hot-electron emitter-base junction and a p-n junction as the base-collector barrier. Fairly monoenergetic electrons traverse through the ultrathin Al₂O₃ dielectric via tunneling, which are accelerated and shifted to the collector region. The devices exhibit a high current on-off ratio of > 10⁵ and a high current density (J_C) of ~ 1,000 A/cm² at the same time. Notably, this work demonstrates a common-emitter current gain (β) value of 1,384 with a nanowatt power consumption at room temperature, which is a record high value among the all 2D based hot-electron transistors. Furthermore, the temperature dependent performance is investigated, and the β value of 1,613 is obtained at 150 K. Therefore, this work presents the potential of 2D based transistors for high-performance applications.