Formation of Beta-Indium Selenide Layers Grown via Selenium Passivation of InP(111)B Substrate

TL;DR

This paper reports a novel molecular beam epitaxy method for growing high-quality, twin-free single-phase beta-In2Se3 layers on InP substrates, advancing scalable synthesis of this promising 2D material.

Contribution

It introduces a unique growth approach for single-phase beta-In2Se3 layers on InP, with detailed microstructural characterization to understand the growth mechanism.

Findings

Successful synthesis of twin-free single-phase beta-In2Se3 layers.

Microstructural analysis reveals interface features critical for growth.

Potential applicability to other substrates for 2D material fabrication.

Abstract

Indium selenide, In2Se3, has recently attracted growing interest due to its novel properties, including room temperature ferroelectricity, outstanding photoresponsivity, and exotic in-plane ferroelectricity, which open up new regimes for next generation electronics. In2Se3 also provides the important advantage of tuning the electrical properties of ultra-thin layers with an external electrical and magnetic field, making it a potential platform to study novel two-dimensional physics. Yet, In2Se3 has many different polymorphs, and it has been challenging to synthesize single-phase material, especially using scalable growth methods, as needed for technological applications. In this paper, we use aberration-corrected scanning transmission electron microscopy to characterize the microstructure of twin-free single-phase ultra-thin layers of beta-In2Se3, prepared by a unique molecular beam epitaxy approach. We emphasize features of the In2Se3 layer and In2Se3/InP interface which provide evidence for understanding the growth mechanism of the single-phase In2Se3. This novel approach for forming high-quality twin-free single phase two-dimensional crystals on InP substrates is likely to be applicable to other technologically important substrates.