摘要
The temperature in the high-pressure high-temperature(HPHT) synthesis is optimized to enhance the thermoelectric properties of high-density Zn O ceramic, Zn_(0.98)Al_(0.02)O. X-ray diffraction, scanning electron microscopy, and transmission electron microscopy show that HPHT can be utilized to control the crystal structure and relative density of the material.High pressure can be utilized to change the energy band structure of the samples via changing the lattice constant of samples, which decreases the thermal conductivity due to the formation of a multi-scale hierarchical structure and defects. The electrical conductivity of the material reaches 6×10^(4) S/m at 373 K, and all doped samples behave as n-type semiconductors. The highest power factor(6.42 μW·cm^(-1)·K^(-2)) and dimensionless figure of merit(z T = 0.09) are obtained when Zn_(0.98)Al_(0.02)O is produced at 973 K using HPHT, which is superior to previously reported power factors for similar materials at the same temperature. Hall measurements indicate a high carrier concentration, which is the reason for the enhanced electrical performance.
作者
陈启
李欣健
王遥
常立杰
王健
张跃文
马红安
贾晓鹏
Qi Chen;Xinjian Li;Yao Wang;Lijie Chang;Jian Wang;Yuewen Zhang;Hongan Ma;Xiaopeng Jia(State Key Laboratory of Superhard Materials,College of Physics,Jilin University,Changchun 130012,China;Key Laboratory of Material Physics of Ministry of Education,School of Physics and Microeletronics,Zhengzhou University,Zhengzhou 450052,China)
基金
Project supported by the National Natural Science Foundation of China(Grant No.51171070)
the Project of Jilin Science and Technology Development Plan,China(Grant No.20170101045JC)。