Ning Suiting, Huang Shan, Zhang Ziye, Zhao Bin, Zhang Renqi, Qi Ning, Chen Zhiquan
Hubei Nuclear Solid Physics Key Laboratory, Department of Physics, Wuhan University, Wuhan 430072, China.
School of Science, Zhongyuan University of Technology, Zhengzhou 450007, China.
Phys Chem Chem Phys. 2022 May 18;24(19):12052-12062. doi: 10.1039/d2cp01003h.
The thermoelectric properties of intrinsic n-type β-GaO are evaluated by first-principles calculations combined with Boltzmann transport theory and relaxation time approximation. The electron mobility is predicted by considering polar optical phonon scattering in β-GaO. A temperature power law of is obtained for the intrinsic electron mobility. Due to the ultra-wide band gap of 4.7-4.9 eV, β-GaO has a large Seebeck coefficient. As a result, a maximum power factor of 3.1 × 10 W m K is obtained at 1600 K. A clear anisotropy in lattice thermal conductivity is observed, with the highest thermal conductivity of 23.1 W m K at 300 K along the [010] direction, and a lower value of 13.2 and 12.2 W m K along the [001] and [100] directions, respectively. A high value of 1.07 at 1600 K can be obtained at the optimal carrier concentration of 2.4 × 10 cm, which is superior to that of most other oxides such as ZnO. In addition, the lattice thermal conductivity can be reduced by precisely adjusting the grain size, and the lattice thermal conductivity at 300 K (1600 K) can be reduced by 73% (39%) when the grain size is decreased to 10 nm. The excellent thermoelectric properties of β-GaO have promoted its potential application in the field of high temperature thermoelectric conversion.
通过第一性原理计算结合玻尔兹曼输运理论和弛豫时间近似来评估本征n型β-GaO的热电性能。通过考虑β-GaO中的极性光学声子散射来预测电子迁移率。得到了本征电子迁移率的温度幂律。由于4.7-4.9 eV的超宽带隙，β-GaO具有较大的塞贝克系数。结果，在1600 K时获得了3.1×10 W m K的最大功率因子。观察到晶格热导率存在明显的各向异性，在300 K时沿[010]方向的热导率最高，为23.1 W m K，沿[001]和[100]方向的值较低，分别为13.2和12.2 W m K。在2.4×10 cm的最佳载流子浓度下，在1600 K时可获得1.07的高值，这优于大多数其他氧化物，如ZnO。此外，通过精确调整晶粒尺寸可以降低晶格热导率，当晶粒尺寸减小到10 nm时，300 K（1600 K）时的晶格热导率可降低73%（39%）。β-GaO优异的热电性能促进了其在高温热电转换领域的潜在应用。
