Preparation and Photoelectric Properties of Al-Ti Codoped ZnO Thin Films with[100]Preferred Orientation

AI-Ti codoped ZnO(ZATO)films with(100)preferred orientation were grown on the glass substrates at room temperature by RF magnetron sputtering.The Al-Ti codoped ZnO ceramic targets used for sputtering were prepared by the conventional solid-state sintering process.The growth mecha- nism,microstructures and surface figures of ZATO films were investigated by X-ray diffraction(XRD) and scanning electronic microscope(SEM),and its optical and electrical properties were respectively measured using a four-point probe technique and UV-756 spectrophotometer at room temperature.Af- ter the ZATO films annealed at 500℃for 3h,the preferred growth orientation of the films changes from (002)to(100)orientation,and the optic band gap reduces from 3.29eV to 2.86eV,and the average trans- mittance reduces from 90% to 70%,but the room-temperature resistivity reduces from 1.89×10~(-2)Ω·cm to 1.25x 10-3Ω·cm.And at the same time,there is a super-lattice diffraction ray in the XRD patterns of annealed the ZATO films.The photoluminescence(PL)spectra confirm that there exhibit the near- band-edge(NBE)emission peaks at 380nm,and 410nm,564nm PL peaks of all the films.After the films are annealed at 500℃for 3h,the strength of these PL peaks drops,but its positions change little. The above experimental mechanisms were discussed.