Open AccessSi nanorod length dependent surface Raman scattering linewidth broadening and peak shift
Author(s) -
GongRu Lin,
Yung-Hsiang Lin,
YiHao Pai,
Fan-Shuen Meng
Publication year - 2011
Publication title -
optics express
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.394
H-Index - 271
ISSN - 1094-4087
DOI - 10.1364/oe.19.000597
Subject(s) - nanorod , materials science , raman spectroscopy , raman scattering , laser linewidth , dangling bond , optics , x ray raman scattering , scattering , crystal (programming language) , molecular physics , optoelectronics , nanotechnology , silicon , laser , chemistry , physics , computer science , programming language
Enhanced Stoke Raman scattering of large-area vertically aligned Si nanorod surface etched by metal-particle-catalytic is investigated. By enlarging the surface area with lengthening Si nanorods, the linear enhancement on Stoke Raman scattering intensity at 520 cm(-1) is modeled to show well correlation with increasing quantity of surface Si dangling bonds. With Si nanorod length increasing from 0.19 to 2.73 μm, the Raman peaks of the as-etched and oxidized samples gradually shift from -4 cm(-1) and from -4.5 cm(-1) associated with their linewidth broadening from 3 to 9 cm(-1) and from 7 to 18 cm(-1), respectively. The peak intensity of Raman scattering signal from Si nanorod could be enhanced with the increase of interaction area as the number of phonon mode directly corresponds to the tetrahedrally coordinated Si vibrations in the bulk crystal lattice. The asymmetric linewidth broadening and corresponding Raman peak shift is affected by the strained Si nanorod surface caused by etching and the crystal quality. Fourier transform infrared spectroscopy corroborates the dependency between nanorod length and Si-O-Si stretching mode absorption (at 1097 cm(-1)) on oxidized Si nanorod surface, elucidating the increased transformation of surface dangling bonds to Si-O-Si bonds for passivating Si nanorods and attenuating Stoke Raman scattering after oxidation.