Doping-Dependent Optical Response of a Hybrid Transparent Conductive Oxide/Plasmonic Medium

TL;DR

This study explores how doping levels in aluminum-doped zinc oxide influence the optical response of hybrid gold nanoparticle/oxide media, revealing doping-dependent plasmonic shifts relevant for optoelectronic applications.

Contribution

It provides new insights into the doping-dependent optical interactions in hybrid plasmonic-conductive oxide systems, advancing understanding for device development.

Findings

Doping causes a blueshift in localized surface plasmon resonance.

Charge transfer between gold nanoparticles and AZO varies with doping.

Dielectric properties of AZO are affected by doping levels.

Abstract

Understanding the interaction between plasmonic nanoparticles and transparent conductive oxides is instrumental to the development of next-generation photovoltaic, opto-electronic and energy-efficient solid-state lighting devices. We investigated the optical response of hybrid media composed of gold nanoparticles deposited on aluminum-doped zinc oxide thin films with varying doping concentration by spectroscopic ellipsometry. The dielectric functions of bare AZO were addressed first, revealing doping-induced effects such as the band-gap shift and the appearance of free carriers. In the hybrid media, a blueshift of the localized surface plasmon resonance of Au NPs as a function of increasing Al-doping of the substrate was observed, ascribed to the occurrence of a charge transfer between the two materials and the doping-dependent variation of the polarizability of the substrate.