Dark and Bright Excitonic States in Nitride Quantum Dots

TL;DR

This paper investigates excitonic states in nitride-based quantum dots, revealing how dark and bright states form and transition depending on size and crystal field splitting in GaN and AlN quantum dots.

Contribution

It provides new insights into the formation and size-dependent transition of dark and bright excitonic states in nitride quantum dots with different crystal structures.

Findings

Dark exciton formation occurs in GaN and AlN quantum dots.

A transition from dark to bright excitons occurs around 40 Å.

The splitting between excitonic states varies with crystal field splitting and size.

Abstract

Formation of excitonic states in quantum dots of nitride based III-V semiconductors GaN and AlN including coulomb and exchange interactions are investigated. Dark exciton formation is found to occur for both GaN quantum dots(QDs) with wurtzite structure having positive crystal field splitting and GaN and AlN QDs with zero crystal field splitting with a transition from dark to bright exciton at about 40{\AA}. In wurtzite AlN QDs with negative crystal field splitting the splitting between the dark and bright excitonic states is very small and vanishes at about 15{\AA}.