Electronic and thermal transport in GeTe: A versatile base for thermoelectric materials
Electronic and thermal transport in GeTe: A versatile base for thermoelectric materials
复制标题
DOI：
10.1063/1.4819222
复制
发表时间：
2013-08-28
影响因子：
3.2
通讯作者：
Hanus, R.
中科院分区：
文献类型：
--
作者：
Levin, E. M.;Besser, M. F.;Hanus, R.
GeTe是一种窄带隙半导体，其中Ge空位产生自由载流子、空穴，形成具有p型导电性的自掺杂简并体系，可作为高性能多组分热电材料的基础。文献报道的GeTe基材料的电子和热传输数据之间存在显着差异，这模糊了基线知识并妨碍了对GeTe与各种元素合金化的影响的清晰理解。对多个 GeTe 样品进行了综合研究，包括 XRD、SEM、EDS、塞贝克系数、电阻率、热导率和 Te-125 NMR。对于所有使用的 GeTe 样品都观察到类似的塞贝克系数和电阻率，这表明产生载流子的 Ge 空位的浓度沿着铸锭是恒定的。非常短的 Te-125 NMR 自旋弛豫时间与霍尔效应测量获得的高载流子浓度非常吻合。我们的数据表明，在接近700 K的温度下，GeTe具有非常大的功率因数，为42 mu Wcm(-1)K(-2)，远大于这些温度下任何高效热电碲化物的功率因数。 GeTe 的电子和热性能与另一种众所周知的热电材料 PbTe 进行了比较，PbTe 中的自由载流子、空穴或电子分别由 Pb 或 Te 位点上的空位产生。文献中报道的 GeTe 数据的差异可归因于固化样品的 Ge:Te 比率的变化以及测量条件的不同。 (C) 2013 AIP 出版有限责任公司。
GeTe is a narrow-band gap semiconductor, where Ge vacancies generate free charge carriers, holes, forming a self-dopant degenerate system with p-type conductivity, and serves as a base for high-performance multicomponent thermoelectric materials. There is a significant discrepancy between the electronic and thermal transport data for GeTe-based materials reported in the literature, which obscures the baseline knowledge and prevents a clear understanding of the effect of alloying GeTe with various elements. A comprehensive study including XRD, SEM, EDS, Seebeck coefficient, electrical resistivity, thermal conductivity, and Te-125 NMR of several GeTe samples was conducted. Similar Seebeck coefficient and electrical resistivity are observed for all GeTe samples used showing that the concentration of Ge vacancies generating charge carriers is constant along the ingot. Very short Te-125 NMR spin-relaxation time agrees well with high carrier concentration obtained from the Hall effect measurements. Our data show that at similar to 700 K, GeTe has a very large power factor, 42 mu Wcm(-1)K(-2), much larger than that of any high efficiency thermoelectric telluride at these temperatures. Electronic and thermal properties of GeTe are compared to PbTe, another well-known thermoelectric material, where free charge carriers, holes or electrons, are generated by vacancies on Pb or Te sites, respectively. Discrepancy in the data for GeTe reported in literature can be attributed to the variation in the Ge: Te ratio of solidified samples as well as to different conditions of measurements. (C) 2013 AIP Publishing LLC.