Microstructural characterization, electrical, and optical study of V2O5-doped Cr2O3 films for photonic applications

Abstract

The performance and optoelectronic properties of the transition metal (TM) oxide thin films can be enhanced by doping with other materials. In this study, V₂O₅ nanoparticles (NPs) were prepared by sol–gel and then used to prepare V₂O₅-doped Cr₂O₃ thin films using the spin-coating technique. The microstructural, morphological characterization, I–V measurements, and optical properties of the films were investigated. The XRD, FE-SEM, EDAX, and FTIR measurements revealed the polycrystalline nature, granular morphology, reduction in particle size (from 43 ± 2.58 nm to 21 ± 1.25 nm), crystallinity deterioration, and the limited stretching vibrations of Cr–O and Cr–O–Cr upon inclusion of V₂O₅. The doping didn’t alter the rhomoboedric corundum structure of Cr₂O₃. The films exhibited linear I–V behavior and their resistance decreased with doping. The films are highly transparent (up to 88%), and their absorption was minimal in the visible region. A new figure of merit was in the range of 0.255–0.270. The refractive index has bell-shaped behavior with the wavelength and increased with increasing V₂O₅. Additionally, the optical band gap (E_g) of the films decreased from 3.0 to 2.5 eV. The influences of 0.5–5.0% V₂O₅ doping ratio on the grain size, dislocation density, microstrain, and charge carrier concentration were investigated. The finding of this study indicates that the optoelectronic features of V₂O₅-doped Cr₂O₃ films were improved and the films can be used for various optoelectronic and photonic devices.