Resonance Raman mapping as an interface phonon probe in Si-SiO2 nanocomposites

TL;DR

This paper demonstrates how resonance Raman mapping can be used to probe interface phonons in Si-SiO2 nanocomposites, revealing size-dependent contributions of core and surface phonons, with implications for photovoltaic device characterization.

Contribution

It introduces a novel application of resonance Raman mapping to distinguish interface phonons in Si-SiO2 nanocomposites based on nanocrystal size.

Findings

Interface phonons are observable via resonance Raman scattering.

Core phonon contribution increases with nanocrystal size.

The method correlates with absorption spectra for characterization.

Abstract

Intermediate frequency range (511 - 514 cm-1) Si phonons in Si-SiO2 nanocomposites are shown to have contribution from both core1 and surface/interface1 Si phonons, where, ratio of contribution of the two depends on the size of a Si nanocrystal. Further, laser heating experiment shows that contribution of the core phonon increases due to increase in size of a nanocrystal. Wavelength dependent Raman mapping reveals that interface phonons are observable due to Resonance Raman scattering. This can well be corroborated with the absorption spectra. This understanding can be gainfully used to manipulate and characterize Si-SiO2 nanocomposite, simultaneously for photovoltaic device applications.