Novel optical properties of Ag films deposited by plasma enhanced atomic layer deposition (PEALD)

We have deposited Ag metal via plasma enhanced atomic layer deposition (PEALD) and we investigated the novel optical behavior of this material. We have found that as-deposited flat PEALD Ag films exhibit unexpected plasmonic properties and the plasmonic enhancement can differ markedly, depending on the microstructure of the Ag film. Electromagnetic field simulations indicate that this plasmonic behavior is due to air gaps that are an inherent property of the mosaiclike microstructure of the PEALD-grown Ag film. We show that this material is plasmonic by itself, and when combined with previously developed dielectric core nanowires, it can produce enhancements which are two orders of magnitude greater than those reported using electroless Ag or Ag produced by e-beam deposition. We have also investigated the effect of substrate on the plasmonic enhancement, as well deposition on fabric, which results in a flexible plasmonic material.