掺杂对 ZnO 纳米线电子结构和热电性能影响的理论研究。

Theoretical investigation of the effects of doping on the electronic structure and thermoelectric properties of ZnO nanowires.

机构信息

Institute for Computational Materials Science, School of Physics and Electronics, Henan University, Kaifeng, 475004, China.

出版信息

Phys Chem Chem Phys. 2014 Feb 28;16(8):3771-6. doi: 10.1039/c3cp54289k.

DOI:10.1039/c3cp54289k

PMID:24430004

Abstract

The effects of doping ZnO nanowires with Al, Ga and Sb on their electronic structure and thermoelectric properties are investigated by first-principles calculations. We find that the band gap of ZnO nanowires is narrowed after doping with Al and Ga, while band gap broadening is observed in Sb doped ZnO nanowires. The lattice thermal conductivity of ZnO nanowires is obtained based on the Debye-Callaway model. The thermoelectric properties of ZnO nanowires were calculated using the BoltzTraP code. The results show that there exists an optimal carrier concentration yielding the maximum value of ZT for Al, Ga and Sb doped ZnO nanowires at room temperature. The maximum value of ZT, 0.147, is obtained for Ga doped ZnO nanowires, when the carrier concentration is 3.62 × 10(19) cm(-3). The figure of merit ZT of Sb doped ZnO nanowires is higher than that of Ga doped ZnO nanowires when the temperature is between 400 K and 1200 K. We also find that Al doped ZnO nanowires always have poor thermoelectric properties, which means that the Al dopant may not be the optimal choice for ZnO nanowires in thermoelectric applications.

摘要

采用第一性原理计算研究了 Al、Ga 和 Sb 掺杂 ZnO 纳米线对其电子结构和热电性能的影响。我们发现，Al 和 Ga 掺杂后 ZnO 纳米线的带隙变窄，而 Sb 掺杂的 ZnO 纳米线的带隙变宽。基于德拜-卡洛尔模型获得了 ZnO 纳米线的晶格热导率。采用 BoltzTraP 代码计算了 ZnO 纳米线的热电性能。结果表明，在室温下，Al、Ga 和 Sb 掺杂 ZnO 纳米线存在一个最佳的载流子浓度，可获得最大的 ZT 值。当载流子浓度为 3.62×10(19)cm(-3)时，Ga 掺杂 ZnO 纳米线的 ZT 值最大，为 0.147。当温度在 400 K 到 1200 K 之间时，Sb 掺杂 ZnO 纳米线的品质因数 ZT 高于 Ga 掺杂 ZnO 纳米线。我们还发现，Al 掺杂 ZnO 纳米线的热电性能一直较差，这意味着在热电应用中，Al 掺杂剂可能不是 ZnO 纳米线的最佳选择。