Influence of the Preparation Conditions on the Thermoelectric Properties of Al-Doped ZnO
Influence of the Preparation Conditions on the Thermoelectric Properties of Al-Doped ZnO
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DOI：
10.1111/j.1551-2916.2010.03751.x
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发表时间：
2010-08-01
影响因子：
3.9
通讯作者：
Dragoe, Nita
中科院分区：
文献类型：
--
作者：
Berardan, David;Byl, Celine;Dragoe, Nita
zno基材料是迄今为止已知的最好的n型热电氧化物之一，其热电性能在高温下达到ZT=0.65。然而，在文献中报道的数据有很大的分散，最近出现了关于这些材料用于热电转换的真正潜力的争议。本文研究了制备条件，特别是退火气氛对al掺杂ZnO热电性能的影响。我们的热功率和电阻率测量表明，空气制备的样品和n -2制备的样品之间存在很大差异，后者的功率因数s2 Sigma是后者的两倍多。热重分析证明，这种差异与氮退火后氧空位的存在有关。循环实验表明，在不同气氛下连续退火可以可逆地改变载流子浓度。这些结果提出了在氮气条件下制备的最佳热电zno基材料在热电转换装置中在高温空气中长期使用的稳定性问题。
ZnO-based materials are among the best n-type thermoelectric oxides known to date, with a thermoelectric figure of merit that reaches ZT=0.65 at high temperature. However, there is a large dispersion of the data reported in the literature and a controversy recently appeared about the real potential of these materials for thermoelectric conversion. In this paper, we report on a careful study of the influence of the preparation conditions, particularly the annealing atmosphere, on the thermoelectric properties of Al-doped ZnO. Our thermopower and electrical resistivity measurements evidenced a large difference between air-prepared and N-2-prepared samples, the power factor S 2 Sigma being more than twice larger for the latter. This difference is linked to the presence of oxygen vacancies after annealing under nitrogen as evidenced by thermogravimetric analysis. Cycling experiments showed that the carrier concentration can be reversibly changed by successive annealing under different atmosphere. These results raise questions concerning the stability of the best thermoelectric ZnO-based materials, which are prepared under nitrogen, during long-term use at high temperature in air in thermoelectric conversion devices.