Ab initio simulation of band-to-band tunneling FETs with single- and few-layer 2-D materials as channels

TL;DR

This study uses first-principles quantum transport simulations to evaluate 2-D material-based TFETs, identifying promising candidates like SnTe, As, TiNBr, and Bi for high-performance applications, and exploring multilayer and heterojunction configurations.

Contribution

The paper identifies new 2-D materials suitable for TFETs and analyzes multilayer and heterojunction structures to enhance device performance.

Findings

Single-layer transition metal dichalcogenides are unsuitable for TFETs.

Certain 2-D materials like SnTe, As, TiNBr, and Bi achieve high ON-currents (>100 μA/μm) at 0.5 V.

Multilayer configurations can improve performance if bandgap narrowing outweighs gate control loss.

Abstract

Full-band atomistic quantum transport simulations based on first principles are employed to assess the potential of band-to-band tunneling FETs (TFETs) with a 2-D channel material as future electronic circuit components. We demonstrate that single-layer (SL) transition metal dichalcogenides are not well suited for TFET applications. There might, however, exist a great variety of 2-D semiconductors that have not even been exfoliated yet; this paper pinpoints some of the most promising candidates among them to realize highly efficient TFETs. SL SnTe, As, TiNBr, and Bi are all found to ideally deliver ON-currents larger than 100{\mu}A/{\mu}m at 0.5-V supply voltage and 0.1 nA/{\mu}m OFF-current value. We show that going from single to multiple layers can boost the TFET performance as long as the gain from a narrowing bandgap exceeds the loss from the deteriorating gate control. Finally, a 2-D van der Waals heterojunction TFET is revealed to perform almost as well as the best SL homojunction, paving the way for research in optimal 2-D material combinations.