Polarized Raman scattering from single GaP nanowires

Abstract

We report the systematic investigation of polarized Raman scattering on individual crystalline GaP nanowires (NWs) with diameters $40<d<600\text{ }\text{nm}$. At small diameter, $d<70\text{ }\text{nm}$, the NWs are found to act like a nearly perfect dipole antenna that leads to a polarized scattering intensity function $I(\ensuremath{\theta})\ensuremath{\sim}{\text{cos}}^{4}\text{ }\ensuremath{\theta}$ where $\ensuremath{\theta}$ is the angle between NW axis and the incident laser polarization. For larger diameter $(70<d<600\text{ }\text{nm})$ NWs, some other different polar patterns were found. A simple theoretical approach which takes into account the Raman tensor and photon confinement in NWs was used to understand the experimental data.