Atomic-Layer-Deposited Al2O3 on Bi2Te3 for Topological Insulator Field-Effect Transistors

TL;DR

This paper demonstrates the fabrication and dual-gate modulation of topological insulator FETs using atomic-layer-deposited Al2O3 dielectric on Bi2Te3, achieving significant electrical control and highlighting the importance of surface chemistry.

Contribution

It introduces a method for dual-gate control of Bi2Te3-based TI FETs with ALD Al2O3 dielectric, emphasizing the role of surface chemistry in device performance.

Findings

Uniform ALD Al2O3 growth on Bi2Te3 flakes

Critical influence of surface chemistry on device performance

Achieved 76.1% modulation rate with dual gating

Abstract

We report dual-gate modulation of topological insulator field-effect transistors (TI FETs) made on Bi2Te3 thin flakes with integration of atomic-layer-deposited (ALD) Al2O3 high-k dielectric. Atomic force microscopy study shows that ALD Al2O3 is uniformly grown on this layer-structured channel material. Electrical characterization reveals that the right selection of ALD precursors and the related surface chemistry play a critical role in device performance of Bi2Te3 based TI FETs. We realize both top-gate and bottom-gate control on these devices, and the highest modulation rate of 76.1% is achieved by using simultaneous dual gate control.