采用金属单质靶和直流反应溅射制备了不同Al含量(摩尔分数)掺杂的ZnO薄膜,得到的薄膜均为c-轴择优取向的纤锌矿结构,在可见波段具有很高的透过率。薄膜的晶面间距、光学折射率和带隙在掺Al的起始阶段变化很大,待Al掺杂量达到一定值后,光学折射率和带隙的变化不大,薄膜的晶面间距趋于一稳定值0.266 nm。分析表明掺杂的Al均作为施主对载流子浓度作出了贡献,影响薄膜导电性能的主要原因被推断为晶格中的缺陷等因素导致了载流子的局域束缚。
ZnO films with c-orientation and high transmission were grown by dc reaction sputtering with Zn and Al element targets. In the initial stage of Al doping, the inter-planar distance, the optical refractive index and the band-gap changed significantly. Then, as Al content increases, the optical refractive index and the band-gap change slowly, and the inter-planar distance reaches a stable value of 0. 266 nm. The analyses reveal that all of doped Al atoms provide carries as donors, and the results also indicate that the conductivity of the films mainly depends on the carrier localization caused by the lattice defects.