Non-monotonic size dependence of the elastic modulus of nanocrystalline ZnO embedded in a nanocrystalline silver matrix

TL;DR

This study investigates how the elastic modulus of nanocrystalline ZnO varies with grain size, revealing a non-monotonic relationship influenced by grain and intergranular properties, using high-pressure Raman spectroscopy.

Contribution

First high-pressure Raman analysis of nanocrystalline ZnO with embedded Ag, demonstrating non-monotonic size dependence of elastic modulus due to grain-intergranular interactions.

Findings

Elastic modulus varies non-monotonically with grain size.

Surface enhancement improves Raman signal detection.

Interplay between grain and intergranular regions affects elasticity.

Abstract

We present the first high pressure Raman study on nanocrystalline ZnO films with different average crystallite sizes. The problem of low Raman signals from nano sized particles was overcome by forming a nanocomposite of Ag and ZnO nanoparticles. The presence of the nanodispersed Ag particles leads to a substantial surface enhancement of the Raman signal from ZnO. We find that the elastic modulus of nanocrystalline ZnO shows a non-monotonic dependence on the crystallite size. We suggest that the non-monotonicity arises from an interplay between the elastic properties of the individual grains and the intergranular region.