Inter-dot coupling and excitation transfer mechanisms of telecommunication band InAs quantum dots at elevated temperatures

TL;DR

This study examines the temperature-dependent photoluminescence of individual InAs quantum dots emitting in telecommunication bands, revealing insights into inter-dot coupling, charge transfer, and emission stability at elevated temperatures.

Contribution

It provides a systematic analysis of temperature effects on emission properties and charge transfer mechanisms of InAs quantum dots at the single-dot level.

Findings

Single recombination lines observed up to 150 K

Transition from zero-phonon to phonon sideband with temperature

Insights into inter-dot charge transfer mechanisms

Abstract

We investigate the photoluminescence temperature dependence of individual InAs/InGaAlAs quantum dots emitting in the optical telecommunication bands. The high-density dots are grown on InP substrates and the selection of a smaller dot number is done by the processing of suitable nanometer sized mesas. Using ensembles of only a few dots inside such mesas, their temperature stability, inter-dot charge transfer, as well as, carrier capture and escape mechanisms out of the dots are investigated systematically. This includes the discussion of the dot ensemble and individual dots. Among the single-dot properties, we investigate the transition of emission lines from zero-phonon line to acoustic phonon sideband dominated line shape with temperature. Moreover, the presence of single recombination lines up to temperatures of around 150 K is demonstrated.