Computational Study of Tunneling Transistor Based on Graphene Nanoribbon

TL;DR

This paper investigates the physics of graphene nanoribbon tunneling FETs using atomistic simulations, highlighting the impact of edge relaxation and proposing design modifications to improve device performance.

Contribution

It provides a detailed atomistic analysis of GNR tunneling FETs and suggests design strategies to suppress ambipolar behavior and enhance subthreshold slope.

Findings

Edge bond relaxation significantly affects device characteristics.

Asymmetric doping or gate underlap suppresses ambipolar I-V.

Achieved subthreshold slope of 14mV/dec and improved on-off ratio.

Abstract

Tunneling field-effect transistors (FETs) have been intensely explored recently due to its potential to address power concerns in nanoelectronics. The recently discovered graphene nanoribbon (GNR) is ideal for tunneling FETs due to its symmetric bandstructure, light effective mass, and monolayer-thin body. In this work, we examine the device physics of p-i-n GNR tunneling FETs using atomistic quantum transport simulations. The important role of the edge bond relaxation in the device characteristics is identified. The device, however, has ambipolar I-V characteristics, which are not preferred for digital electronics applications. We suggest that using either an asymmetric source-drain doping or a properly designed gate underlap can effectively suppress the ambipolar I-V. A subthreshold slope of 14mV/dec and a significantly improved on-off ratio can be obtained by the p-i-n GNR tunneling FETs.