Tunneling field effect transistors based on in-plane and vertical layered phosphorus heterostructures**Project supported by the National Natural Science Foundation of China (Grant Nos. 11604019, 61574020, and 61376018), the Ministry of Science and Technology of China (Grant No. 2016YFA0301300), the Fund of State Key Laboratory of Information Photonics and Optical Communications (Beijing University of Posts and Telecommunications), China, and the Fundamental

Abstract

Tunneling field effect transistors (TFETs) based on two-dimensional materials are promising contenders to the traditional metal oxide semiconductor field effect transistor, mainly due to potential applications in low power devices. Here, we investigate the TFETs based on two different integration types: in-plane and vertical heterostructures composed of two kinds of layered phosphorous (β-P and δ-P) by ab initio quantum transport simulations. NDR effects have been observed in both in-plane and vertical heterostructures, and the effects become significant with the highest peak-to-valley ratio (PVR) when the intrinsic region length is near zero. Compared with the in-plane TFET based on β-P and δ-P, better performance with a higher on/off current ratio of ~ 106 and a steeper subthreshold swing (SS) of ~ 23 mV/dec is achieved in the vertical TFET. Such differences in the NDR effects, on/off current ratio and SS are attributed to the distinct interaction nature of the β-P and δ-P layers in the in-plane and vertical heterostructures.