Luo Jing-Ting, Quan Ao-Jie, Zheng Zhuang-Hao, Liang Guang-Xing, Li Fu, Zhong Ai-Hua, Ma Hong-Li, Zhang Xiang-Hua, Fan Ping
Institute of Thin Film Physics and Applications, Shenzhen Key Laboratory of Advanced Thin Films and Applications, College of Physics and Energy, Shenzhen University 518060 China
Laboratory of Glasses and Ceramics, Institute of Chemical Science UMR CNRS 6226, University of Rennes 1 Rennes 35042 France.
RSC Adv. 2018 Feb 6;8(11):6063-6068. doi: 10.1039/c7ra12485f. eCollection 2018 Feb 2.
In this work, using a conventional magnetron sputtering system, Al-doped ZnO (AZO) films with (112̄0) and (0002) preferential orientations were grown on -sapphire and -sapphire substrates, respectively. The effect of substrate and deposition temperature on the growth of AZO films and their preferential orientations were investigated. The crystallographic characteristics of AZO films were characterized by X-ray diffraction (XRD). The surface morphology of AZO films was studied by scanning electron microscopy (SEM) and atomic force microscopy (AFM). It is found that the lattice mismatch between AZO and substrate determines the growth of AZO films and their preferential orientations. The thermoelectric properties are strongly dependent on the crystal grain shape and the grain boundaries induced by the preferred orientation. The highly connected and elongated grains lead to high thermoelectric properties. The in-plane anisotropy performances of thermoelectric characteristics were found in the (112̄0) preferential oriented ZnO films. The in-plane power factor of the (112̄0) preferential oriented ZnO films in the [0001] direction was more than 1.5 × 10 W m K at 573 K, which is larger than that of the (0002) preferential oriented ZnO films.
在本工作中，使用传统磁控溅射系统，分别在蓝宝石和蓝宝石衬底上生长了具有(112̄0)和(0002)择优取向的铝掺杂氧化锌（AZO）薄膜。研究了衬底和沉积温度对AZO薄膜生长及其择优取向的影响。通过X射线衍射（XRD）对AZO薄膜的晶体学特性进行了表征。利用扫描电子显微镜（SEM）和原子力显微镜（AFM）研究了AZO薄膜的表面形貌。发现AZO与衬底之间的晶格失配决定了AZO薄膜的生长及其择优取向。热电性能强烈依赖于晶粒形状和由择优取向引起的晶界。高度连通且细长的晶粒导致高热电性能。在(112̄0)择优取向的ZnO薄膜中发现了热电特性的面内各向异性性能。在573 K时，(112̄0)择优取向的ZnO薄膜在[0001]方向的面内功率因子大于1.5×10 W m K，大于(0002)择优取向的ZnO薄膜。
