High Current\nGain MoS<sub>2</sub> Bipolar Junction\nTransistor Based on Metal–Semiconductor Schottky Contacts

Bipolar junction transistors (BJTs) are crucial components\nin high-power\nelectronic applications. However, while two-dimensional (2D) semiconductors\nwith exceptional electrical properties have been extensively studied\nin field-effect transistors, their application in BJTs has received\nfar less attention. In this study, we demonstrate high-gain MoS<sub>2</sub> BJTs based on metal–semiconductor Schottky contacts.\nThe emitter-base junction uses the thermal ionization properties of\na Schottky diode to emit electrons, while the collector-base junction\nleverages the Schottky barrier to collect electrons. This design enables\nthermal ionization of electrons into the base region, where they are\nsubsequently accelerated and transferred to the collector region under\nthe influence of the collector-base junction voltage. Our MoS<sub>2</sub> BJTs achieves a common-base current gain 0.99 and a remarkable\ncommon-emitter current gain of 1967, representing the highest performance\nreported for BJTs based on 2D semiconductors to date, which is comparable\nto traditional silicon-based BJTs.