Bi2Se3 Growth on (001) GaAs Substrates for Terahertz Integrated Systems

TL;DR

This paper investigates the growth of Bi2Se3 topological insulator films on GaAs (001) substrates, highlighting surface treatment importance and interface properties to enable on-chip terahertz integrated systems.

Contribution

It demonstrates the growth process and interface characteristics of Bi2Se3 on GaAs, providing insights for integrating van der Waals materials with semiconductor substrates for THz applications.

Findings

Atomically smooth GaAs surface is critical for high-quality Bi2Se3 growth.

The Bi2Se3/GaAs interface is selenium-terminated with no chemical bonding.

Results guide the integration of van der Waals materials with conventional semiconductors.

Abstract

Terahertz (THz) technologies have been of interest for many years due to the variety of applications including gas sensing, nonionizing imaging of biological systems, security and defense, etc. To date, scientists have used different classes of materials to perform different THz functions. However, to assemble an on-chip THz integrated system, we must understand how to integrate these different materials. Here, we explore the growth of Bi2Se3, a topological insulator (TI) material that could serve as a plasmonic waveguide in THz integrated devices, on technologically-important GaAs (001) substrates. We explore surface treatments and find that atomically smooth GaAs surface is critical to achieving high-quality Bi2Se3 films despite the relatively weak film/substrate interaction. Calculations indicate that the Bi2Se3/GaAs interface is likely selenium-terminated and shows no evidence of chemical bonding between the Bi2Se3 and the substrate. These results are a guide for integrating van der Waals materials with conventional semiconductor substrates and serve as the first steps toward achieving an on-chip THz integrated system.