Resonant PhotoEmission Spectroscopy Investigation of Fe2O3 - TiO2 Heterojunctions for Solar Water Splitting

The implementation of semiconductor heterojunctions photo-anodes appears as a very promising way to improve the performances of devices for solar water splitting (sun light assisted hydrogen production from water). However, assembling different materials together results in the existence of interfaces which usually do not have the same electronic structure than the simply stacked individual layers. The electronic structure of the valence band being a key parameter for water splitting, it is necessary to investigate it for each layer and for the interfaces. A very powerful technique to tackle these issues is Resonant PhotoEmissionSpectroscopy (RPES). In this work, we present RPES results of the valence band performed on epitaxial TiO2/Ti-doped Fe2O3 heterojunctions. The provided insights concerning the interface and the electronic structure are correlated to the water splitting performances.