Valence band offset, strain and shape effects on confined states in self-assembled InAs/InP and InAs/GaAs quantum dots

TL;DR

This study systematically investigates how valence band offset, strain, and shape influence the electronic and many-body properties of self-assembled InAs/InP and InAs/GaAs quantum dots using atomistic tight-binding calculations.

Contribution

It provides a detailed analysis of the interplay between strain and valence band offset on quantum dot confined states and many-body properties, highlighting effects on hole state structure and excitonic features.

Findings

Strain effects determine hole state structure and shell-like configurations.

Strain induces single band-like behavior in certain quantum dots.

Valence band offset and strain significantly influence excitonic properties.

Abstract

I present a systematic study of self-assembled InAs/InP and InAs/GaAs quantum dots single particle and many body properties as a function of quantum dot-surrounding matrix valence band offset. I use an atomistic, empirical tight-binding approach and perform numerically demanding calculations for half-million atom nanosystems. I demonstrate that the overall confinement in quantum dots is a nontrivial interplay of two key factors: strain effects and the valence band offset. I show that strain effects determine both the peculiar structure of confined hole states of lens type InAs/GaAs quantum dots and the characteristic ,,shell-like" structure of confined holes states in commonly considered "low-strain" lens type InAs/InP quantum dot. I also demonstrate that strain leads to single band-like behavior of hole states of disc type (,,indium flushed") InAs/GaAs and InAs/InP quantum dots. I show how strain and valence band offset affect quantum dot many-body properties: the excitonic fine structure, an important factor for efficient entangled photon pair generation, and the biexciton and charged excitons binding energies