Preparation of ZAO film by low-temperature hydrothermal approach and its electrical property

Al-doped ZnO （ZAO） films were successfully deposited on the surface of common glasses by using low-temperature hydrothermal approach. In the reaction solution, the molar ratio of Al3＋ to Zn2＋ was 1∶100, the annealing temperature and time were 200 ℃ and 2-6 h, respectively. The structure of the thin films was identified by X-ray diffraction （XRD）, the surface morphology and thickness of the thin films were observed by scanning electron microscopy （SEM）, and the electrical performance of the thin films was measured by four-point probes. It was shown that the films with an average particle size of 27.53 nm had a preferential orientation along （002）, Al3＋ had replaced the position of Zn2＋ in the lattice without forming the Al2O3 phase and its thickness was 20-25 μm. With the increased annealing time, the intensity of diffraction peaks was decreased, the film exhibited irregular surface morphology gradually, and the resistivity of ZAO films was increased. The lowest resistivity obtained in this study was 3.45×10-5Ω·cm.