Properties of self-oxidized single crystalline perovskite N : BaTiO3 oxynitride epitaxial thin films

Epitaxial perovskite self-oxidized oxynitride N : BaTiO3 thin films, deposited on 1% Nb-doped SrTiO3(001) single crystals, were obtained by atomic nitrogen assisted molecular beam epitaxy without supplying additional oxygen gas. Their growth, crystalline and electronic structures as well as photo-electrochemical and optical properties were investigated and compared to those of pure BaTiO3 films grown with atomic oxygen on the same substrate. More tetragonal perovskite crystalline structures, profound electronic structure modifications, improved photo-electrochemical properties and an enhanced (almost 10%) optical window for light absorption are demonstrated. This new class of compounds shows promise for a large panel of new applications based on visible light absorption.