Electrical and optical properties of TiO2-doped ZnO films prepared by radio-frequency magnetron sputtering

TiO2-doped zinc oxide (ZnO) films were prepared by radio frequency (RF) magnetron sputtering in argon gas. The electrical and optical properties in the TiO2-doped ZnO films as functions of the TiO2 content were investigated. It was observed that the (0 0 2) preferred orientation had a significant value of 34–35° for a Ti content of 0.71, 1.38, and 1.97 at%. When the Ti content of the TiO2-doped ZnO films was above 2.81 at%, the films became amorphous. The 1.38 at% TiO2-doped ZnO films had the lowest resistivity: 9.02×10−3 Ω cm. All of the TiO2-doped ZnO films had 85% transmittance in the visible wavelength range. The optical energy band gap increased from 3.33 eV for 0.71 at% Ti to 3.43 eV for 3.43 at% Ti.