Semiconductor-like Optical Properties Unveiled by Modeling of Short-Period Aluminum Oxide-Copper Multi-Layered Nanocomposites Deposited by Sputtering Atomic Layer Augmented Deposition (SALAD)

TL;DR

This study models the optical properties of multi-layered AlOx-Cu nanocomposites produced by SALAD, revealing semiconductor-like behavior and demonstrating the potential of this fabrication method to create novel metal-dielectric semiconductors.

Contribution

The paper introduces a computational modeling approach to describe and predict the optical properties of SALAD-fabricated nanocomposites, highlighting their semiconductor-like behavior.

Findings

Models successfully describe Cu's optical properties.

Predicted semiconductor-like behavior of the nanocomposites.

SALAD enables creation of novel metal-dielectric semiconductors.

Abstract

In our previous publication, we discussed the optical properties of multi-layered nanocomposite samples consisting of 300 pairs of an AlOx layer and a Cu layer produced from sputtering atomic layer augmented deposition (SALAD). These samples displayed unusual spectral reflectance that could not be well described via conventional means and could not be explained as an interpolation of the constituent materials. Computational models were then needed to both describe the results that were obtained and to predict the samples' other material properties. This process was approached by using the transfer-matrix method to describe the spectral reflectance based on the constituent materials, and then the dispersion method was used to find the composite index of refraction for the samples. The models successfully described pure Cu but encountered minor difficulties when it came to AlOx, as such, more research is needed to either properly model non-holomorphic materials like AlOx with the current algorithm or to find a better model that can adequately describe both Cu and AlOx. The dispersion model implemented predicts that the samples, composed of many thin film layers of metal and dielectric, would display semiconductor-like behavior. Therefore, this indicates that SALAD's combination of sputtering and ALD permits the generation of novel metal-dielectric based semiconductors.