Self-assembled Bismuth Selenide (Bi2Se3) quantum dots grown by molecular beam epitaxy

TL;DR

This paper demonstrates a method to grow self-assembled Bi2Se3 quantum dots on GaAs substrates using molecular beam epitaxy and droplet epitaxy, enabling controlled production of topological insulator quantum dots with potential quantum spin applications.

Contribution

The authors introduce a reproducible droplet epitaxy technique for growing crystalline Bi2Se3 quantum dots with specific size and density on GaAs substrates.

Findings

Quantum dots are crystalline with hexagonal shape.

Average dimensions are 12 nm height and 46 nm width.

Density of quantum dots is 8.5 x 10^9 cm^-2.

Abstract

We report the growth of self-assembled Bi2Se3 quantum dots (QDs) by molecular beam epitaxy on GaAs substrates using the droplet epitaxy technique. The QD formation occurs after anneal of Bismuth droplets under Selenium flux. Characterization by atomic force microscopy, scanning electron microscopy, X-ray diffraction, high-resolution transmission electron microscopy and X-ray reflectance spectroscopy is presented. The quantum dots are crystalline, with hexagonal shape, and have average dimensions of 12 nm height (12 quintuple layers) and 46 nm width, and a density of $8.5 \cdot 10^9 cm^{-2}$. This droplet growth technique provides a means to produce topological insulator QDs in a reproducible and controllable way, providing convenient access to a promising quantum material with singular spin properties.