Yuan Dachao, Guo Shuang, Hou Shuaihang, Ma Yuejin, Wang Jianglong, Wang Shufang
Hebei Key Lab of Optic-electronic Information and Materials, The College of Physics Science and Technology, Hebei University, Baoding, 071002, China.
College of Mechanical and Electrical Engineering, Agricultural University of Hebei, Baoding, 071001, China.
Nanoscale Res Lett. 2018 Nov 28;13(1):382. doi: 10.1186/s11671-018-2752-6.
We reported the epitaxial growth of c-axis-oriented BiBaCuSeO (0 ≤ x ≤ 10%) thin films and investigated the effect of Ba doping on the structure, valence state of elements, and thermoelectric properties of the films. X-ray photoelectron spectroscopy analysis reveal that Bi is partially reduced to the lower valence state after Ba doping, while Cu and Se ions still exist as + 1 and - 2 valence state, respectively. As the Ba doping content increases, both resistivity and Seebeck coefficient decrease because of the increased hole carrier concentration. A large power factor, as high as 1.24 mWm K at 673 K, has been achieved in the 7.5% Ba-doped BiCuSeO thin film, which is 1.5 times higher than those reported for the corresponding bulk samples. Considering that the nanoscale-thick Ba-doped films should have a very low thermal conductivity, high ZT can be expected in the films.
我们报道了c轴取向的BiBaCuSeO（0 ≤ x ≤ 10%）薄膜的外延生长，并研究了Ba掺杂对薄膜结构、元素价态和热电性能的影响。X射线光电子能谱分析表明，Ba掺杂后Bi部分还原为较低价态，而Cu和Se离子仍分别以+1和 -2价态存在。随着Ba掺杂含量的增加，由于空穴载流子浓度增加，电阻率和塞贝克系数均降低。在7.5% Ba掺杂的BiCuSeO薄膜中实现了高达1.24 mWm K的大功率因子，在673 K时，这比相应块体样品报道的值高1.5倍。考虑到纳米级厚度的Ba掺杂薄膜应具有非常低的热导率，预计薄膜中会有高的ZT值。
