Modified Confinement Model for Size Dependent Raman Shift and Linewidth of Silicon Nanocrystals

TL;DR

This paper introduces a modified phonon confinement model that accurately predicts size-dependent Raman spectra of silicon nanocrystals, including shifts, linewidths, and asymmetries, aligning well with experimental data.

Contribution

The paper presents a novel modified confinement model that incorporates size distribution, improved phonon dispersion, and a new confinement function for better Raman spectrum predictions.

Findings

Accurately predicts size-dependent Raman shift and linewidth.

Reproduces rapid changes in spectra for smaller nanocrystals.

Captures asymmetric Raman spectral features.

Abstract

A modified phonon confinement model considering the size distribution, an improved phonon dispersion curve and a confinement function is developed for the calculation of size dependent Raman spectra of the silicon (Si) nanocrystals. The model is capable in simultaneous calculation of the Raman shift, intensity and linewidth. The calculated size dependent redshift and linewidth of Raman spectra are in good agreement with the available experimental data in literature and better than previously reported theoretical results. The rapid rise in the redshift and linewidth for relatively smaller Si nanocrystals are well reproduced. The asymmetric behavior of Raman spectra is also obtained from the present model.