Characterization of TiO2 thin films for photocatalysis applications using photoacoustic spectroscopy J.G. Mendoza-Alvarez, A. Cruz-Orea, O. Zelaya-Angel, G. Torres-Delgado, R. Castanedo-Perez, S.A. Mayen Hernandez and J. Marquez-Marin J. Phys. IV France, 125 (2005) 407-409 DOI: 10.1051/jp4:2005125095