Solution-based synthesis of wafer-scale epitaxial BiVO thin films exhibiting high structural and optoelectronic quality.

We demonstrate a facile approach to solution-based synthesis of wafer-scale epitaxial bismuth vanadate (BiVO) thin films by spin-coating on yttria-stabilized zirconia. Epitaxial growth proceeds solid-state transformation of initially formed polycrystalline films, driven by interface energy minimization. The (010)-oriented BiVO films are smooth and compact, possessing remarkably high structural quality across complete 2'' wafers.

Nanostructured amorphous gallium phosphide on silica for nonlinear and ultrafast nanophotonics.

Nanophotonics based on high refractive index dielectrics relies on appreciable contrast between the indices of designed nanostructures and their immediate surrounding, which can be achieved by the growth of thin films on low-index substrates. Here we propose the use of high index amorphous gallium phosphide (a-GaP), fabricated by radio-frequency sputter deposition, on top of a low refractive index glass substrate and thoroughly examine its nanophotonic properties. Spectral ellipsometry of the amorphous material demonstrates the optical properties to be considerably close to crystalline gallium phosphide (c-GaP), with low-loss transparency for wavelengths longer than 650 nm.

Mechanistic insights into chemical and photochemical transformations of bismuth vanadate photoanodes.

Artificial photosynthesis relies on the availability of semiconductors that are chemically stable and can efficiently capture solar energy. Although metal oxide semiconductors have been investigated for their promise to resist oxidative attack, materials in this class can suffer from chemical and photochemical instability. Here we present a methodology for evaluating corrosion mechanisms and apply it to bismuth vanadate, a state-of-the-art photoanode.