Enhanced photoanode properties of epitaxial Ti doped α-Fe2O3 (0001) thin films

The growth, crystal and electronic structures, and photo-electrochemical properties of undoped and Ti doped hematite epitaxial films were studied. We evidence that Ti4+ substitutes Fe3+ in the hematite lattice inducing a slight modification of the oxygen octahedron. Ti doping is shown to induce a shift of the valence band toward higher binding energy due to a movement of the Fermi level toward the conduction band. The resulting modification of electrical conductivity appears as a possible origin of the improvement of photo-electrochemical properties in the doped sample.