SURFACE-ENHANCED RAMAN SCATTERING FROM GaP NANOWIRES WITH A GALLIUM DROPLET
A. V. Taranenko1,2, L. S. Basalaeva1, V. V. Fedorov3, V. S. Tumashev1, A. G. Milekhin1
1Rzhanov Institute of Semiconductor Physics, Siberian Branch, Russian Academy of Sciences, Novosibirsk, Russia
2Novosibirsk State University, Novosibirsk, Russia
3Alferov University, Saint Petersburg, Russia
Keywords: Raman scattering, atomic-force microscopy, nanowire, nanoparticle, phonons
Abstract
This paper presents the results of a study of the structural and optical properties of arrays of (111)-oriented GaP nanowires (NWs) and single NWs using Raman spectroscopy and atomic force microscopy (AFM). GaP NW arrays are grown on a (111)-Si substrate by self-catalytic growth via the vapor-liquid-crystal mechanism. Single GaP NWs are mechanically transferred onto a gold surface. Transverse (TO), longitudinal (LO), and surface (SO) optical phonon modes are observed in the Raman spectra of GaP NWs. Surface-enhanced Raman scattering by optical phonon modes in GaP NWs near a gallium droplet is detected, due to the localized surface plasmon resonance in the droplet. Raman maps for GaP NWs recorded on various scattering geometries are obtained. The Raman enhancement factor for GaP NWs with a diameter of 104 and 60 nm reaches values of ~11 and 6, respectively.
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