Impact of Edge States on Device Performance of Phosphorene Heterojunction Tunneling Field Effect Transistors

TL;DR

This study uses atomistic quantum transport simulations to analyze how edge states influence the performance of black phosphorus heterojunction TFETs, revealing methods to enhance current and suppress unwanted effects for low-power applications.

Contribution

It demonstrates that edge states significantly affect BP heterojunction TFETs and proposes strategies like hydrogen passivation and layer modulation to optimize device performance.

Findings

Edge states cause potential pinning and reduce gate control.

Hydrogen saturation quenches edge states and increases on-state current.

Optimized BP heterojunction TFETs meet low-power application requirements.

Abstract

Black phosphorus (BP) tunneling transistors (TFETs) using heterojunction (He) are investigated by atomistic quantum transport simulations. It is observed that edge states have a great impact on transport characteristics of BP He-TFETs, which result in the potential pinning effect and deteriorate the gate control. While, on-state current can be effectively enhanced by using hydrogen to saturate the edge dangling bonds in BP He-TFETs, in which edge states are quenched. By extending layered BP with a smaller band gap to the channel region and modulating the BP thickness, device performance of BP He-TFETs can be further optimized and fulfill the requirements of the international technology road-map for semiconductors (ITRS) 2013 for low power applications. In 15 nm 3L-1L and 4L-1L BP He-TFETs along armchair direction on-state current can reach above 10$^3$ $\mu$A/$\mu$m with the fixed off-state current of 10 $pA/\mu$m. It is also found that ambipolar effect can be effectively suppressed in BP He-TFETs.