Acoustically regulated optical emission dynamics from quantum dot-like emission centers in GaN/InGaN nanowire heterostructures

TL;DR

This study demonstrates how surface acoustic waves can dynamically modulate the optical emission of quantum dots in GaN/InGaN nanowires, enabling control over photon emission timing and spectral properties.

Contribution

It provides experimental evidence of acousto-mechanical coupling effects on quantum dot emission dynamics in GaN/InGaN nanowires, highlighting potential for dynamic optical control.

Findings

Acoustic waves modulate quantum dot excitonic transitions.

High acoustic amplitudes distort transmitted acoustic waveforms.

Acoustic piezoelectric fields influence quantum dot charge populations.

Abstract

We report on experimental studies of the effects induced by surface acoustic waves on the optical emission dynamics of GaN/InGaN nanowire quantum dots. We employ stroboscopic optical excitation with either time-integrated or time-resolved photoluminescence detection. In the absence of the acoustic wave, the emission spectra reveal signatures originated from the recombination of neutral exciton and biexciton confined in the probed nanowire quantum dot. When the nanowire is perturbed by the propagating acoustic wave, the embedded quantum dot is periodically strained and its excitonic transitions are modulated by the acousto-mechanical coupling. Depending on the recombination lifetime of the involved optical transitions, we can resolve acoustically driven radiative processes over time scales defined by the acoustic cycle. At high acoustic amplitudes, we also observe distortions in the transmitted acoustic waveform, which are reflected in the time-dependent spectral response of our sensor quantum dot. In addition, the correlated intensity oscillations observed during temporal decay of the exciton and biexciton emission suggest an effect of the acoustic piezoelectric fields on the quantum dot charge population. The present results are relevant for the dynamic spectral and temporal control of photon emission in III-nitride semiconductor heterostructures.