Confined phonons in Si nanowires.
Raman microprobe studies of long crystalline Si nanowires reveal for the first time the evolution of phonon confinement with wire diameter. The Raman band at approximately 520 cm-1 in bulk Si is found to downshift and asymmetrically broaden to lower frequency with decreasing wire diameter D, in good agreement with a phenomenological model first proposed by Richter et al. An adjustable parameter (alpha) is added to the theory that defines the width of the Gaussian phonon confinement function. We find that this parameter is not sensitive to diameter over the range 4-25 nm.
Adu
K W
KW
Department of Physics, The Pennsylvania State University, University Park, Pennsylvania 16802, USA.
Gutiérrez
H R
HR
Kim
U J
UJ
Sumanasekera
G U
GU
Eklund
P C
PC
D003198:Computer Simulation; D003460:Crystallization / Q000379:methods*; D008422:Materials Testing; D008956:Models, Chemical; D008958:Models, Molecular; D008968:Molecular Conformation; D036103:Nanotechnology / Q000379:methods*; D043942:Nanotubes / Q000032:analysis / Q000737:chemistry* / Q000648:ultrastructure; D010316:Particle Size; D012825:Silicon / Q000032:analysis / Q000737:chemistry*; D013059:Spectrum Analysis, Raman / Q000379:methods*; D013329:Structure-Activity Relationship; D014732:Vibration
D012825:Silicon