From Silver Nanoparticles to Thin Films: Evolution of Microstructure and Electrical Conduction

TL;DR

This study explores how the microstructure of silver nanoparticle thin films influences their electrical conduction, revealing three distinct conductivity regimes and the transition from tunneling to metallic conduction as thickness increases.

Contribution

It provides a detailed analysis of the evolution of electrical properties in silver nanoparticle films across different morphological stages, highlighting the percolation transition.

Findings

Three conductivity zones identified: dielectric, transition, and metallic.

Electrical conduction shifts from tunneling to percolation as film thickness increases.

Sharp increase in conductivity observed during the transition zone.

Abstract

Silver nanoparticles embedded in a dielectric matrix are investigated for their potential as broadband-absorbing optical sensor materials. This contribution focuses on the electrical properties of silver nanoparticles at various morphological stages. The electrical current through thin films, consisting of silver nanoparticles, was characterized as a function of film thickness. Three distinct conductivity zones were observed. Two relatively flat zones ("dielectric" for very thin films and "metallic" for films thicker than 300 - 400 {\AA}) are separated by a sharp transition zone where percolation dominates. The dielectric zone is characterized by isolated particle islands with the electrical conduction dominated by a thermally activated tunneling process. The transition zone is dominated by interconnected silver nanoclusters - a small increase of the film thickness results in a large increase of the electrical conductivity. The metallic conductivity zone dominates for thicknesses above 300 - 400 {\AA}.