Semi-Deterministic Quantum Dot Placement in Heteroepitaxy

TL;DR

This paper demonstrates a theoretical approach to achieve semi-deterministic placement of quantum dots during epitaxial growth by engineering boundary geometries, enabling controlled nucleation and improved quantum photonic device fabrication.

Contribution

It introduces a novel boundary engineering method to control quantum dot nucleation during heteroepitaxy, enhancing deterministic placement capabilities.

Findings

Boundary geometry influences adatom movement and QD nucleation.

Primary QDs form along boundaries due to curvature and diffusion anisotropy.

Secondary QDs can be formed within the growth region through many-body interactions.

Abstract

Achieving deterministic placement of self-assembled quantum dots (QDs) during epitaxial growth is essential for the reliable and efficient fabrication of high-quality single-photon sources and solid-state cavity quantum electrodynamics (cQED) systems, yet it remains a significant challenge due to the inherent stochasticity of QD nucleation processes. In this work, we theoretically and numerically demonstrate that deterministic QD nucleation within a pristine growth region, e.g., InAs on a (001)-oriented GaAs substrate, can be achieved by engineering the boundary geometry of that region. During epitaxial growth, adatoms initially move toward the boundary and promote the formation of primary QDs along the boundary, driven by curvature and diffusion anisotropy. The resulting primary QDs distribution will generate many-body interactions that dynamically reshape the chemical potential landscape for subsequently deposited adatoms, enabling the formation of secondary QDs within the pristine growth region. These findings provide a theoretical foundation for reliable patterning of high optical-quality QDs, with potential applications in next-generation quantum photonic devices.