The nano-TiO2 electrode with a p-n homojunction device was designed and fabricated by coating of the Fe3+-doped TiO2 (p-type) film on top of the nano-TiO2 (n-type) film. These films were prepared from synthesized sol-gel TiO2 samples which were verified as anatase with nano-size particles. The semiconductor characteristics of the p-type and n-type films were demonstrated by current-voltage (I-V) measurements. Results show that the rectifying curves of undoped TiO2 and Fe3+-doped TiO2 sample films were observed from the I-V data illustration for both the n-type and p-type films. In addition, the shapes of the rectifying curves were influenced by the fabrication conditions of the sample films, such as the doping concentration of the metal ions, and thermal treatments. Moreover, the p-n homojunction films heating at different temperatures were produced and analyzed by the I-V measurements. From the I-V data analysis, the rectifying current of this p-n junction diode has a 10 mA order higher than the current of the n-type film. The p-n homojunction TiO2 electrode demonstrated greater performance of electronic properties than the n-type TiO2 electrode. (c) 2007 Elsevier B.V. All rights reserved.