Enhanced interband tunneling in two-dimensional tunneling transistors through anisotropic energy dispersion

The unsatisfactory transmission probability in tunneling junction is a major challenge that restricts the performance and scaling of next-generation nanodevices, such as the tunnel field-effect transistors (TFETs). Here, we propose a strategy utilizing anisotropic electronic structures to enhance the inter-band tunneling performance. In the tunneling process, the sharp energy dispersion in transport direction ensures a high transmission eigenvalue, and the weak transverse energy state can broaden the transverse tunneling window, thus strengthening the tunneling probability. Furthermore, our quantum transport simulations demonstrate that in two-dimensional (2D) group VA-VA TFETs, the stronger anisotropic band structures make 2D BiAs and arsenene exhibit high on-state current several times higher than other systems, and the relative larger bandgap of arsenene also gives rise to a steep subthreshold slope below 60 mV/dec. This work provides a physical understanding of the tunneling transport performance, and the anisotropic 2D electronic structures can be regarded as a target feature to design tunneling transistors.