N-doped TiO2 nanothin films: photocatalytic and hydrophilicity properties Salimeh Kimiagar and Mohammad Reza Mohammadizadeh Eur. Phys. J. Appl. Phys., 61 1 (2013) 10303 Published online: 25 January 2013 DOI: 10.1051/epjap/2012120294