  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}.
