Optical properties of wurtzite GaN/AlN quantum dots grown on non-polar planes: the effect of stacking faults in the reduction of the internal electric field

TL;DR

This study investigates the optical properties of non-polar GaN/AlN quantum dots, highlighting how stacking faults reduce internal electric fields and influence optical behavior, with a theoretical model supporting experimental observations.

Contribution

It presents a realistic shape-based theoretical model for non-polar quantum dots, demonstrating how stacking faults further decrease internal electric fields and affect optical properties.

Findings

Stacking faults cause a 30% reduction in internal electric field.

Theoretical predictions align with observed optical features.

Quantum confined Stark effect persists despite reduced electric fields.

Abstract

The optical emission of non-polar GaN/AlN quantum dots has been investigated. The presence of stacking faults inside these quantum dots is evidenced in the dependence of the photoluminescence with temperature and excitation power. A theoretical model for the electronic structure and optical properties of non-polar quantum dots, taking into account their realistic shapes, is presented which predicts a substantial reduction of the internal electric field but a persisting quantum confined Stark effect, comparable to that of polar GaN/AlN quantum dots. Modeling the effect of a 3 monolayer stacking fault inside the quantum dot, which acts as zinc-blende inclusion into the wurtzite matrix, results in an additional 30 % reduction of the internal electric field and gives a better account of the observed optical features.