Realizing a topological-insulator field-effect transistor using iodostannanane

Monolayer hexagonal tin (stannanane) is a topological insulator and upon functionalization with halogens, such as iodine, a gap exceeding 300 meV is obtained. In a stannanane ribbon the topologically protected edge states lead to very high conductivities and mobilities; moreover the conductivity is strongly dependent on the Fermi level. We show how this property can be exploited to make a topological-insulator field-effect transistor (TIFET). We simulate the input and output characteristics of the TIFET using a drift-diffusion-like approximation and obtain promising transistor characteristics with a high on-current which exceeds the off-current by over three orders of magnitude.

Introduction

As transistor dimensions are decreasing, further scaling is becoming increasingly challenging. The main challenge is to maintain electrostatic control and to reduce power consumption while maintaining or further improving performance. To maintain electrostatic control, a transition to two-dimensional materials will be required at extremely scaled dimensions [1]. To further reduce power consumption, the energy per switching cycle must be reduced and to maintain high performance, a high electron mobility must be retained. Many alternative devices exploiting different switching mechanisms such as BISFETs [2] or TFETs [3] are being investigated. However up to now, none of these devices have proven to be a worthy competitor for Si-based MOSFETs.