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.
@article{arxiv.0708.2229,
title = {Multi-phonon Raman scattering in GaN nanowires},
author = {S. Dhara and Sharat Chandra and G. Mangamma and S. Kalavathi and P. Shankar and K. G. M. Nair and A. K. Tyagi and C. W. Hsu and C. C. Kuo and L. C. Chen and K. H. Chen and K. K. Sriram},
journal= {arXiv preprint arXiv:0708.2229},
year = {2007}
}