Enhanced interband tunneling in two-dimensional tunneling transistors through anisotropic energy dispersion
Hengze Qu, Shiying Guo, Wenhan Zhou, Zhenhua Wu, Jiang Cao, Zhi Li, Haibo Zeng, Shengli Zhang
Abstract
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.