Investigation of fabrication conditions for VO₂ thin films by MOD using carbon thermal reduction

Abstract

Vanadium dioxide (VO2) thin films were fabricated by metal‐organic decomposition (MOD). To utilize a carbon thermal reduction for obtaining a VO2 composition, the precursor films were fabricated at the temperature Tp from 300°C to 380°C in a N2 atmosphere. From the measurement results of XRD, diffraction peaks indicating VO2 phase were observed with a wide range of firing temperatures from Tf = 560°C to 620°C. Furthermore, the peaks indicating VO2 phase were also observed with a wide range of firing time from tf = 15–45 min. Regarding the surface morphology of the films, the nanoparticles of 100–200 nm were densely packed although small spaces existed between the particles. The R‐T characteristics of the films indicated the phase transition with a rapid resistance change of about three orders of magnitude and hysteresis loop. From these experimental results, it was found that wide windows of firing conditions for fabricating VO2 thin film can be obtained in the MOD process using the carbon thermal reduction.

An electron-donating system composed of a CIDS@CFO@F0C0 catalyst for the sustainable generation of free radicals to inactivate pathogens

“…35 In the presence of carbon, the metal oxides may be further reduced into metal elements (eqn (3) and (4)), depending on the reaction conditions where temperature plays a key role. 39 The direction and possibility of a chemical reaction can usually be estimated from the changes in Gibbs free energy (Δ x G θ m ), which can be calculated based on parameters including enthalpy change (Δ r H θ m ), entropy change (Δ r S θ m ), and reaction temperature (eqn (5)). According to the Δ x G θ m formula, the iron reduction reaction can only be triggered when the pyrolysis temperature is above 838.00 K (564.85 °C).…”