New explanation of Raman peak redshift in nanoparticles

TL;DR

This paper introduces a new parameter-free model that explains the Raman peak redshift in nanoparticles by considering vibrational spectrum discreteness, enabling accurate size estimation without uncertain parameters.

Contribution

A novel, parameter-free model for Raman peak shifts in nanoparticles that improves size estimation accuracy over traditional phonon confinement models.

Findings

Model accurately relates Raman shift to nanoparticle size for cubic crystals.

No uncertain parameters are needed in the proposed model.

Model can be used for unambiguous nanoparticle size estimation.

Abstract

In this letter, we propose a new model that explains the Raman peak downshift observed in nanoparticles with respect to bulk materials. The proposed model takes into account discreteness of the vibrational spectra of nanoparticles. For crystals with a cubic lattice (Diamond, Silicon, Germanium) we give a relation between the displacement of Raman peak position and the size of nanoparticles. The proposed model does not include any uncertain parameters, unlike the conventionally used phonon confinement model (PCM), and can be employed for unambiguous nanoparticles size estimation.