Bipolar junction transistors (BJTs) are crucial components in high-power electronic applications. However, while two-dimensional (2D) semiconductors with exceptional electrical properties have been extensively studied in field-effect transistors, their application in BJTs has received far less attention. In this study, we demonstrate high-gain MoS2 BJTs based on metal-semiconductor Schottky contacts. The emitter-base junction uses the thermal ionization properties of a Schottky diode to emit electrons, while the collector-base junction leverages the Schottky barrier to collect electrons. This design enables thermal ionization of electrons into the base region, where they are subsequently accelerated and transferred to the collector region under the influence of the collector-base junction voltage. Our MoS2 BJTs achieves a common-base current gain 0.99 and a remarkable common-emitter current gain of 1967, representing the highest performance reported for BJTs based on 2D semiconductors to date, which is comparable to traditional silicon-based BJTs.
Keywords: Schottky contacts; bipolar junction transistors; current gain; two-dimensional semiconductors.