Band Gap Narrowing versus Formation of Electronic States in the Gap in N-TiO2 Thin
P. Romero-Gómez, S. Hamad, J.C. González, A. Barranco, J.P. Espinós, J. Cotrino, A.R. González-Elipe
Journal of Physical Chemistry C, 114 (2010) 22546–22557
doi: 10.1021/jp104634j