Polarization Response in InAs Quantum Dots: Theoretical Correlation between Composition and Electronic Properties

TL;DR

This study uses large-scale simulations to explore how the chemical composition of InAs quantum dots influences their polarization response, providing a model that aligns well with experimental data and aids in engineering optical properties.

Contribution

The paper introduces a two-layer composition model for InAs quantum dots that accurately predicts polarization properties and matches experimental photoluminescence spectra.

Findings

A two-layer composition model explains polarization behavior.

Structural parameters can be tuned to control polarization response.

Simulations match experimental optical spectra.

Abstract

III-V growth and surface conditions strongly influence the physical structure and resulting optical properties of self-assembled quantum dots (QDs). Beyond the design of a desired active optical wavelength, the polarization response of QDs is of particular interest for optical communications and quantum information science. Previous theoretical studies based on a pure InAs QD model failed to reproduce experimentally observed polarization properties. In this work, multi-million atom simulations are performed to understand the correlation between chemical composition and polarization properties of QDs. A systematic analysis of QD structural parameters leads us to propose a two layer composition model, mimicking In segregation and In-Ga intermixing effects. This model, consistent with mostly accepted compositional findings, allows to accurately fit the experimental PL spectra. The detailed study of QD morphology parameters presented here serves as a tool for using growth dynamics to engineer the strain field inside and around the QD structures, allowing tuning of the polarization response.