Particle growing mechanisms in Ag-ZrO2 and Au-ZrO2 granular films obtained by pulsed laser deposition

TL;DR

This study investigates the growth mechanisms of Ag and Au nanoparticles in ZrO2 thin films prepared by pulsed laser deposition, revealing distinct nucleation and coalescence behaviors affecting particle size and percolation thresholds.

Contribution

It provides new insights into how Ag and Au nanoparticles grow within ZrO2 matrices, highlighting different mechanisms and thresholds for each metal.

Findings

Ag particles grow more abruptly with volume content than Au particles.

Two growth mechanisms identified: nucleation and coalescence.

Different percolation thresholds for Ag (~0.28) and Au (~0.52).

Abstract

Thin films consisting of Ag and Au nanoparticles embedded in amorphous ZrO2 matrix were grown by pulsed laser deposition in a wide range of metal volume concentrations in the dielectric regime (0.08<x(Ag)<0.28 and 0.08<x(Au)<0.52). High resolution transmission electron microscopy (TEM) showed regular distribution of spherical Au and Ag nanoparticles having very sharp interfaces with the amorphous matrix. Mean particle size determined from X-ray diffraction agreed with direct TEM observation. The silver mean diameter increases more abruptly with metal volume content than that corresponding to gold particles prepared under the same conditions. Two mechanisms of particle growing are observed: nucleation and particle coalescence, their relative significance being different in both granular systems, which yields very different values of the percolation threshold (xc(Ag)~0.28 and xc(Au)~0.52).