Observation of Coherent Folded Acoustic Phonons Propagating in a Hybrid Au- InGaN/GaN Quantum Wells

TL;DR

This study observes and analyzes coherent folded longitudinal acoustic phonons in gold nanoparticle-embedded InGaN/GaN quantum wells, revealing multiple phonon modes and their propagation characteristics using pump-probe spectroscopy.

Contribution

First demonstration of coherent folded acoustic phonons in Au-InGaN/GaN quantum wells with detailed mode analysis and propagation behavior.

Findings

Up to five phonon modes observed

Phonons propagate back and forth within quantum wells

Results align with similar superlattice measurements

Abstract

The coherent folded longitudinal acoustic phonons (FLAPs) in gold nanoparticles (NPs) imbedded InGaN/GaN sample have been studied using degenerate pump-probe technique. When the FLAPs are generated within the multiple quantum wells, the zone-center FLAPs extending from multiple quantum wells is detected in the GaN and sapphire substrate. Up to five phonon modes are clearly observed and they are well explained by the back and forth propagation of the signal phonon wave packet in the InGaN/GaN quantum wells. The results are consistent with similar measurements to GaAs/AlAs superlattices.