Semiconductor characterization of Cr 3+-doped titania electrodes with p–n homojunction devices

Abstract

A nano-TiO 2 electrode with a p–n homojunction device was designed and fabricated by coating of the nano-TiO 2 (n-type) film together with the Cr 3+-doped TiO 2 (p-type) film. The sample films were prepared with synthesized sol–gel TiO 2 which were verified as nano-size particles with anatase structure. The semiconductor characteristic of the p-type and n-type films was analyzed by current–voltage ( I– V) measurements. Results show that the rectifying characteristic of the TiO 2 films was observed from the I– V data illustration for both the n-type and p-type films. In addition, the characteristic of the rectifying curves was influenced by the fabrication conditions of the sample films, such as the doping concentration of Cr 3+, heating temperature of the films, and film thickness. From the I– V analysis, the rectifying current of this diode showed a 10 2 mA order higher than the one of the n-type film. The p–n homojunction TiO 2 electrode showed greater performance of electronic properties than the n-type TiO 2 electrode.