Wavelength-Resolved Optical Attenuation in ZnO-Based Transparent Oxide Thin Films and Nanostructures for Optoelectronic Interfaces

Abstract

Transparent oxide thin films and nanostructures are often evaluated using average transmittance, optical bandgap, Urbach energy, electrical conductivity, and transparent-conductor figure of merit. However, optoelectronic interfaces require wavelength-specific optical access rather than broadband transparency alone. Here, discrete wavelength–transmittance coordinates from prior ZnO-based datasets are converted into a dopant- and morphology-resolved attenuation atlas. Undoped ZnO nanorod layers are compared with Mg-doped ZnO (MZO), Al-doped ZnO (AZO), and Sn-doped ZnO films. Transmittance is converted into total optical attenuation, or transmission-derived insertion loss, at 405 nm, 450 nm, 532 nm, and 637 nm and across the 650–800-nm red/near-infrared (NIR) band. This attenuation includes absorption, reflection, scattering, substrate effects, and interference rather than absorption alone. MZO 8 at.% gives the lowest extracted attenuation at 405 nm, AZO 2 at.% gives the lowest at 532 nm, and AZO 4 at.% gives the lowest at 637 nm and across 650–800 nm. The results are positioned against contemporary dopant-free and doped ZnO technologies produced by sputtering, chemical vapor deposition, pulsed laser deposition, spray pyrolysis, spatial atomic layer deposition, and solution processing. The framework converts conventional spectra into device-level attenuation metrics while retaining the thickness, morphology, and processing context required for realistic optoelectronic material selection.