Probing exciton localization in non-polar GaN/AlN Quantum Dots by single dot optical spectroscopy

TL;DR

This study uses optical spectroscopy to investigate exciton localization in non-polar GaN/AlN quantum dots, revealing carrier localization on a scale smaller than the quantum dot size through linewidth and decay time analysis.

Contribution

It provides new insights into exciton localization and phonon coupling in non-polar GaN/AlN quantum dots using advanced optical spectroscopy techniques.

Findings

Isolated quantum dots show sharp emission lines with narrow linewidths.

Carriers are laterally localized on a scale much smaller than the quantum dot size.

Decay time analysis supports the localization conclusion.

Abstract

We present an optical spectroscopy study of non-polar GaN/AlN quantum dots by time-resolved photoluminescence and by microphotoluminescence. Isolated quantum dots exhibit sharp emission lines, with linewidths in the 0.5-2 meV range due to spectral diffusion. Such linewidths are narrow enough to probe the inelastic coupling of acoustic phonons to confined carriers as a function of temperature. This study indicates that the carriers are laterally localized on a scale that is much smaller than the quantum dot size. This conclusion is further confirmed by the analysis of the decay time of the luminescence.