N incorporation, composition and electronic structure in N-doped TiO2(0 0 1) anatase epitaxial films grown on LaAlO3(0 0 1)

We have investigated the properties of N-doped TiO2 anatase grown by plasma-assisted molecular beam epitaxy on LaAlO3(0 0 1) substrates. Phase-pure epitaxial films in which N substitutes for O with no secondary phase formation nucleate only over a narrow range of fluxes. N substitution for O results in N 2p derived states off the top of the anatase valence band and the associated red shift in the optical bandgap.