Surface-Enhanced Raman Scattering from GaP Nanowires with a Gallium Droplet

In this paper, the results of studying the structural and optical properties of individual GaP(111) nanowires (NWs) and their arrays by Raman spectroscopy and atomic force microscopy (AFM) were presented. The GaP NW arrays were grown on a Si(111) substrate by self-catalytic growth via the vapor–liquid–crystal mechanism. Individual NWs were mechanically transferred onto a gold surface. In the Raman spectra of GaP nanowires, the modes of transversal (TO), longitudinal (LO), and surface (SO) optical phonons were observed. Surface-enhanced Raman scattering by optical modes was revealed in GaP nanowires near the gallium droplet due to the localized surface plasmon resonance in the droplet. The Raman maps of GaP NWs were recorded in different scattering geometries. The Raman enhancement factor for GaP NWs of 104 and 60 nm in diameter attained \(\sim\) 11 and 6, respectively.