1 research outputs found
Spectral Anomaly in Raman Scattering from p‑Type Silicon Nanowires
An
anomalous nature of Raman spectral asymmetry has been reported
here from silicon nanowires (SiNWs) prepared from a heavily doped
p-type Si wafer using a metal induced etching technique. Raman spectra
of SiNWs prepared from two p-type Si wafers with different doping
levels show different behaviors in terms of asymmetry as characterized
by the asymmetry ratio. The SiNWs prepared from high doped p-type
wafer show an anomaly in asymmetry in addition to the red shift and
broadening of the Raman line shape due to the presence of the “FAno-quaNTUM”
(FANTUM) effect. The heavy doping in the wafer provides a continuum
of energy states to be available to interact with confined optic phonons
which results in electron–phonon interaction. SiNWs prepared
from low doped p-type wafer show a red shift and asymmetric broadening
due to the quantum confinement effect alone. Careful analysis has
been provided to clearly understand the role of Fano and quantum effects
in p-type SiNWs with high doping and their relative contribution in
Raman line-shape half-widths. A theoretical framework for supporting
the presence of the FANTUM effect has also been proposed to show that
how a system with appropriate Fano and quantum effects’ relative
contribution may result in a near-symmetric Raman line shape