The effects of annealing with H-2 and N-2 on the photoelectrochemical (PEC) properties of annealed Nb-doped TiO2 (ann-TNO) film were investigated. The photocurrent density of the ann-TNO film was 2 to 3 orders of magnitude higher than that of u-TiO2 film To understand this phenomenon, ann-TNO film was investigated by comparing u-TiO2 and Nb-doped TiO2 (TNO) films. An investigation was conducted using Hall effect estimation, photoluminescence (PL) analysis, and band-gap calculation. (C) 2013 The Electrochemical Society. All rights reserved.