Aerosol-chemical vapor deposition method for synthesis of nanostructured metal oxide thin films with controlled morphology

An aerosol-chemical vapor deposition (ACVD) was designed to de-posit nanostructured metal oxide films with controlled morphologies. Characteristic times of the different processes governing deposition of the film were used to establish the relationship of process parameters to the resultant morphology of the film. Titanium dioxide (TiO₂) films were synthesized with different morphologies: dense, columnar, granular, and branched tree-type structures. The developed ACVD process was also used to deposit columnar nickel oxide (NiO) films. The various films with well-controlled characteristics (length, morphology) were used to establish the performance in solar energy applications, such as photosplitting of water to produce hydrogen. Columnar TiO₂ films of 1.6 μm length with a platinum wire counter electrode resulted in 15.58% hydrogen production efficiencies under UV light illumination, which was 2.50 times higher than dense TiO₂ films with a platinum wire counter electrode. On replacing the Pt counter electrode with a columnar NiO film, efficiencies of 10.98% were obtained.