Size Dependent Sensitivity of Raman Line-Shape Parameters in Silicon Quantum Wire

TL;DR

This study compares experimental and theoretical Raman spectra of silicon quantum wires to analyze how size confinement affects spectral parameters, revealing their potential as tools to probe external perturbations.

Contribution

It provides a detailed analysis of size-dependent variations in Raman line-shape parameters across different confinement regimes, validated by experimental data on silicon nanostructures.

Findings

FWHM, peak position, and asymmetry ratio vary with confinement size.

Moderately confined Si nanostructures show significant spectral shifts.

Sensitivity of Raman parameters can probe external influences on materials.

Abstract

A comparison of experimentally observed Raman scattering data with Raman line-shapes, generated theoretically using phonon confinement model, has been carried out to understand the sensitivity of different Raman spectral parameters on quantum confinement effect. Size dependent variations of full width at half maximum (FWHM), Raman peak position and asymmetry ratio have been analyzed to establish the sensitivity of their corresponding physical counterparts (phonon life time and dispersion) in confined systems. The comparison has been done in three different confinement regimes namely, weakly, moderately and strongly. Proper reasoning has been assigned for such a variation after validation of the theoretical analysis with the experimental observations. A moderately confined system was created by preparing 6 nm sized Si NSs using metal induced etching. An asymmetrically broadened and red-shifted Raman line-shape was observed which established that all the parameters get affected in moderately confined system. Sensitivity of a given Raman spectral parameters has been shown to be used as a tool to understand the role of external perturbations in a material.