Raman spectroscopy for study of interplay between phonon confinement and Fano effect in silicon nanowires

A combined effect of doping (type and species) and size on Raman scattering from silicon (Si) nanowires (NWs) has been presented here to study interplay between quantum confinement and Fano effects. The SiNWs prepared from low doping Si wafers show only confinement effect, as evident from the asymmetry in the Raman line-shape, irrespective of the doping type. On the other hand SiNWs prepared from wafer with high doping shows the presence of electron-phonon interaction in addition to the phonon confinement effect as revealed from the presence of asymmetry and antiresonence in the corresponding Raman spectra. This combined effect induces an extra asymmetry in the lower energy side of Raman peak for n-type SiNWs whereas the asymmetry flips from lower energy side to the higher energy side of the Raman peak in p-type SiNWs. Such an interplay can be represented by considering a general Fano-Raman line-shape equation to take care of the combined effect in SiNWs. Copyright (c) 2015 John Wiley & Sons, Ltd.