We report the results of a Raman scattering study of well-separated core/shell silicon nanowires grown by CVD (Chemical Vapor Deposition) and deposited on an Au surface. The diameters varies from around 100nm to 400nm. The analysis of Raman scattering shows a presence of both crystalline (520cm^-1) and amorphous (470cm^-1) phases of the silicon, forming quite independent fractions. From the growth conditions, nanowires are expected to form a core-shell cone, with the amorphous silicon phase (aSi) outside, and the crystalline silicon phase (cSi) inside.  Raman spectra have been analyzed in three points along the examined nanowire length: base, middle and tip. Based on the Stokes/anti-Stokes (St/aSt) ratios, the position and full width at half maximum of the Raman peaks temperatures of the amorphous shell and the cSi core were determined [1]. Against our expectations, the crystalline silicon (cSi) temperature was found lower than the amorphous silicon temperature (aSi) [Fig. 1]. This suggests that the nanowire cSi core is in a good thermal contact with the metallic substrate, thus improving the heat evacuation of the SiNW, for which the thermal conductivity is known to be low [2].

Fig. 1 Temperature of the silicon core and the amorphous shell obtained from St/aSt ratio for the 632nm laser line.

[1] Balkanski et al. Phys Rev B. 8, (1983) 1928

[2] Piscanec et al. Phys. Rev. B, 68, (2003) 241312

• Legal notice:
  

  Copyright (c) Pielaszek Research, all rights reserved.
  The above materials, including auxiliary resources, are subject to Publisher's copyright and the Author(s) intellectual rights. Without limiting Author(s) rights under respective Copyright Transfer Agreement, no part of the above documents may be reproduced without the express written permission of Pielaszek Research, the Publisher. Express permission from the Author(s) is required to use the above materials for academic purposes, such as lectures or scientific presentations.
  In every case, proper references including Author(s) name(s) and URL of this webpage: https://science24.com/paper/15985 must be provided.

1. Raman spectroscopy studies of metal - carbon nanotubes composite materials.
2. Laser radiation-induced effects in Raman spectra of multiwalled carbon nanotubes
3. Synthesis of gallium nitride nanowires by Sublimation Sandwich Method
4. Light polarized resonant Raman spectra from individual carbon nanotubes
5. Raman Spectroscopy of boron-doped silicon nanowires
6. Influence of manganese doping on transport properties in thin LCMO films