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

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.