Probing Phonons in Nonpolar Semiconducting Nanowires with Raman Spectroscopy
Figure 7
(a) Raman spectra showing the first-order Raman band peaks in four ensembles of Si nanowires. The bulk Si (001) spectrum is also shown. Experimental data: red open circles, least-square fit: black solid lines. is the attenuation factor of the phonon (the width of the Gaussian phonon quantum confinement function) at the real boundary , is the most probable diameter. (b) Comparison of experimental Raman shift of TO phonon in Si [47] and Ge nanowires [80] for different diameters. Top: absolute shift Si (diamond), Ge (circles); bottom: nanowire Raman shift relative to bulk. Note that the Ge diameter range is twice that of Si.
