A Raman spectroscopy study of individual SiC nanowires

Raman spectroscopy of a single 40 nm 3C-SiC nanowire (NW) has been achieved at room temperature with the use of surface-enhanced Raman scattering (SERS). The structure used to enhance the Raman scattering process is based on a tungsten tip covered by a thin gold layer; a NW is attached to the apex of this tip. The specific dimensions of the Sic NWs (diameters are a few tens of nanometers and lengths are a few micrometers) allow us to study several parts of an individual NW according to the lateral resolution of the Raman microspectrometer. High-resolution transmission electron microscopy (HRTEM) images show both atomic arrangements in the Sic NWs with growth predominantly in the [111] direction and abundant structural defects. Effort has been focused on the correlation between the Raman spectroscopic profiles and the structural deformations. The Fano interference features of the sharp phonon lines have been used to evaluate the free carrier concentration.