Liu Shiying, Li Guojian, Lan Mingdi, Piao Yongjun, Miyazaki Koji, Wang Qiang
Key Laboratory of Electromagnetic Processing of Materials (Ministry of Education), Northeastern University, Shenyang, 110819, People's Republic of China.
Department of Mechanical and Control Engineering, Kyushu Institute of Technology, Kitakyushu, 804-8550, Japan.
Acta Crystallogr B Struct Sci Cryst Eng Mater. 2020 Apr 1;76(Pt 2):259-266. doi: 10.1107/S2052520620002383. Epub 2020 Mar 20.
Electrical and thermal transport controlled by growth mode can be used to optimize thermoelectric properties of ZnO:Al films, which was adjusted by the re-evaporation of Zn and Al via substrate temperatures. The growth modes include equiaxed crystal, columnar crystal and coexistence of both crystals. In the ZnO:Al film, equiaxed crystals improve the carrier mobility and reduce the lattice thermal conductivity. Thus, the carrier mobility and thermal conductivity are tuned by the ratio of equiaxed crystals to columnar crystals. The carrier mobility is dependent on the growth-mode-related defects of oxygen vacancies, zinc interstitials and the substitutional dopant of Al. Improved thermoelectric properties with a power factor of 198.45 µW m K at 510 K were achieved. This study presents a film with the structure of an equiaxed-crystal buffer layer to enhance its thermoelectric properties.
由生长模式控制的电输运和热输运可用于优化ZnO:Al薄膜的热电性能，该性能通过Zn和Al经由衬底温度的再蒸发来调节。生长模式包括等轴晶、柱状晶以及两种晶体的共存。在ZnO:Al薄膜中，等轴晶提高了载流子迁移率并降低了晶格热导率。因此，载流子迁移率和热导率可通过等轴晶与柱状晶的比例来调节。载流子迁移率取决于与生长模式相关的氧空位、锌间隙原子以及Al替代掺杂剂等缺陷。在510K时实现了功率因子为198.45 µW m K的改进热电性能。本研究提出了一种具有等轴晶缓冲层结构的薄膜以增强其热电性能。
