Optical properties of arrays of quantum dots with internal disorder

TL;DR

This paper presents a theoretical analysis of the optical properties of large arrays of quantum dots with internal disorder, explaining experimental photoluminescence data through energy level fluctuations and shape variations.

Contribution

It introduces a model that accounts for alloy composition fluctuations and shape disorder to explain spectral shifts and lineshapes in quantum dot arrays.

Findings

The theory explains the large shift between emission and absorption energies.

Calculated lineshapes match experimental photoluminescence spectra.

Shape fluctuations influence the spectral lineshape significantly.

Abstract

Optical properties of large arrays of isolated quantum dots are discussed in order to interpret the existent photoluminescence data. The presented theory explains the large observed shift between the lowest emission and absorption energies as the average distance between the ground and first excited states of the dots. The lineshape of the spectra is calculated for the case when the fluctuations of the energy levels in quantum dots are due to the alloy composition fluctuations. The calculated lineshape is in good agreement with the experimental data. The influence of fluctuations of the shape of quantum dots on the photoluminescence spectra is also discussed.