Raman spectroscopy of indium phosphide nanowire networks coated with gold clusters

Enhanced Raman signal of the longitudinal optical phonon mode in indium phosphide nanowire networks with gold coating of up to 5 nm thickness was observed experimentally to further study the phonon spectrum of nanowire networks. Indium phosphide nanowire networks coated with different nominal thicknesses of gold were prepared and optically studied. Scanning electron microscopy, photoluminescence spectroscopy and Raman spectroscopy were used to study the dependence of surface morphology and phonon modes of the nanowire networks on the nominal thickness of the gold coating. The Raman peak of longitudinal optical phonon mode for as grown sample was negligible, while the peak intensity for 1 and 5 nm gold coated sample reached to 1,379 and 792 a.u. respectively. Electromagnetic enhancement and extinction coefficient are discussed to qualitatively assess the role of the gold coating on indium phosphide nanowire networks.