Multi-phonon Raman scattering in GaN nanowires

TL;DR

This study investigates multi-phonon Raman scattering in GaN nanowires, revealing enhanced LO phonon modes up to the 4th order due to electron-phonon interactions influenced by nanowire size and crystalline quality.

Contribution

It provides the first detailed analysis of multi-phonon Raman scattering in GaN nanowires, highlighting size-dependent electron-phonon interactions and their enhancement compared to bulk material.

Findings

Observation of LO mode up to 4th order in GaN nanowires

Size-dependent increase in electron-phonon interaction energy

Enhanced interaction energy below ~3 nm diameter

Abstract

UV Raman scattering studies show longitudinal optical (LO) mode up to 4th order in wurtzite GaN nanowire system. Frohlich interaction of electron with the long range electrostatic field of ionic bonded GaN gives rise to enhancement in LO phonon modes. Good crystalline quality, as indicated by the crystallographic as well as luminescence studies, is thought to be responsible for this significant observation. Calculated size dependence, incorporating size corrected dielectric constants, of electron-phonon interaction energy agrees well with measured values and also predict stronger interaction energy than that of the bulk for diameter below ~3 nm.