Generalization of Phonon Confinement Model for Interpretation of Raman Line-Shape from Nano-Silicon

TL;DR

This paper enhances the phonon confinement model to better interpret Raman spectra from nano-silicon, accounting for phonon momentum and zone center shifts, resulting in more accurate line-shape representations.

Contribution

A modified phonon confinement model incorporating phonon momentum conservation and zone center shifts, providing a more symmetric and accurate Raman line-shape for nano-silicon.

Findings

The modified model produces symmetric Raman line-shapes.

Fitting experimental data validates the model's accuracy.

The model better represents low-dimensional semiconductors.

Abstract

A comparative analysis of two Raman line-shape functions has been carried out to validate the true representation of experimentally observed Raman scattering data for semiconducting nanomaterials. A modified form of already existing phonon confinement model incorporates two basic considerations, phonon momentum conservation and shift in zone centre phonon frequency. After incorporation of the above mentioned two factors, a rather symmetric Raman line-shape is generated which is in contrary to the usual asymmetric Raman line-shapes obtained from nanostructured semiconductor. By fitting an experimentally observed Raman scattering data from silicon nanostructures, prepared by metal induced etching, it can be established that the Raman line-shape obtained within the framework of phonon confinement model is a true representative Raman line-shape of sufficiently low dimensions semiconductors.