Wide spectral range optical characterization of tantalum pentoxide (Ta₂O₅) films by the universal dispersion model

Abstract

This study presents a comprehensive optical characterization of tantalum pentoxide (Ta 2 O 5 ) thin films across a wide spectral range, using a combination of ellipsometric and spectrophotometric data. The films prepared using e-beam evaporation, ranging in thickness from 20 to 250 nm, were analyzed using a complex structural model that integrates inhomogeneous layer profiles with three distinct phases, allowing for a more accurate representation of the material’s optical properties. A universal dispersion model was employed to describe the optical constants, revealing the refractive index and extinction coefficient with exceptional precision. This work stands out due to the extensive spectral range covered–extending from the far infrared (400 µ m, 25 cm −1 ) to the vacuum ultraviolet (116 nm, 10.7 eV)–and the diverse array of instruments used, providing a level of detail and insight into Ta 2 O 5 ’s optical behavior that has not been achieved before. This novel approach offers significant advancements in understanding Ta 2 O 5 ’s optical characteristics, demonstrating its potential for advanced optical coatings and optoelectronic applications.