Interrelation of structural and electronic properties of InGaN/GaN quantum dots using an eight-band k.p model

TL;DR

This paper develops an eight-band k.p model to analyze the electronic structure of InGaN/GaN quantum dots, highlighting the impact of built-in fields and structural parameters on their electronic and excitonic properties.

Contribution

The paper introduces a comprehensive eight-band k.p model that includes strain, piezoelectric, pyroelectric, spin-orbit, and crystal field effects for InGaN QDs, and applies it to study their properties.

Findings

Built-in piezoelectric and pyroelectric fields cause spatial separation of charge carriers.

Quantum dot composition and geometry significantly affect electronic and excitonic energies.

Built-in fields induce a redshift in exciton transition energies.

Abstract

We present an eight-band k.p model for the calculation of the electronic structure of wurtzite semiconductor quantum dots (QDs) and its application to indium gallium nitride (InGaN) QDs formed by composition fluctuations in InGaN layers. The eight-band k.p model accounts for strain effects, piezoelectric and pyroelectricity, spin-orbit and crystal field splitting. Exciton binding energies are calculated using the self-consistent Hartree method. Using this model, we studied the electronic properties of InGaN QDs and their dependence on structural properties, i.e., their chemical composition, height, and lateral diameter. We found a dominant influence of the built-in piezoelectric and pyroelectric fields, causing a spatial separation of the bound electron and hole states and a redshift of the exciton transition energies. The single-particle energies as well as the exciton energies depend heavily on the composition and geometry of the QDs.