  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.
