Spin coated titanium–ruthenium oxide thin films

Abstract

Substrates of different roughness spin coated with Ti0.7Ru0.3O2 films have been evaluated as model system for fundamental studies of the industrially and scientifically interesting (Ti,Ru)O2 based electrodes. The approach allowed for much more accurate control over the material synthesis than the traditionally used brush-, dip-, or spray-coating, on titanium-metal substrates. It moreover yielded well-defined samples suitable for basic studies of the surface properties that are of fundamental importance for understanding the electrochemical functionality of the electrode. We have compared the films on silicon substrates to films prepared by spin coating the same material on titanium-metal substrates. Samples have been characterized using atomic force microscopy (AFM), X-ray diffraction, scanning electron microscopy (SEM), and cyclic voltammetry. The samples displayed a uniformity of the films appropriate for AFM characterization. The smoother the substrate the less cracks in the coating. Using easily broken silicon wafers as substrate, a straightforward sample preparation technique was demonstrated for cross-section SEM. In addition, using high spinning velocities we have deposited the oxide films directly on silicon-nitride grids, thin enough to allow for studies with transmission electron microscopy without further sample preparation.