The effect of a distinct diameter variation on the thermoelectric properties of individual Bi0.39Te0.61 nanowires
The effect of a distinct diameter variation on the thermoelectric properties of individual Bi0.39Te0.61 nanowires
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DOI：
10.1088/0268-1242/29/12/124006
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发表时间：
2014-11
影响因子：
1.9
通讯作者：
D. Kojda;R. Mitdank;A. Mogilatenko;W. Töllner;Z. Wang;M. Kröner;P. Woias;K. Nielsch;S. F. Fischer
中科院分区：
文献类型：
--
作者：
D. Kojda;R. Mitdank;A. Mogilatenko;W. Töllner;Z. Wang;M. Kröner;P. Woias;K. Nielsch;S. F. Fischer
通过纳米图案化降低热电材料的热导率是实现热电材料性能定制的主要途径之一。特别是，表面粗糙度和形态的作用正在辩论中。在这里，我们选择了两个单独的碲化铋纳米线（NW），一个直径在190 nm和320 nm之间变化很大（NW1），另一个直径为187 nm，侧壁光滑（NW2）。两者都作为模型系统，如果表面性质不起作用，则预期其整体性质。我们调查的直径变化的作用相结合的全热电，结构和化学表征的装置。通过透射电子显微镜的结构，化学成分和形态确定后的热电调查。纳米线呈现出沿着[ 110 ]？>方向相同，成分相同。两个NW的Seebeck系数彼此相当。这两个纳米线的电导率超过散装值，表明存在的拓扑表面状态。尽管NW2的热导率与块体相比，但NW1的热导率约为NW2的一半，这是关于其明显的直径变化进行讨论的。
The reduction of the thermal conductivity induced by nano-patterning is one of the major approaches for tailoring thermoelectric material properties. In particular, the role of surface roughness and morphology is under debate. Here, we choose two individual bismuth telluride nanowires (NWs), one with a strong diameter variation between 190 nm and 320 nm (NW1) and the other of 187 nm diameter with smooth sidewalls (NW2). Both serve as model systems for which bulk properties are expected if surface properties do not contribute. We investigate the role of the diameter variation by means of a combined full-thermoelectrical, structural and chemical characterization. By transmission electron microscopy the structure, chemical composition and morphology were determined after the thermoelectrical investigation. The NWs showed an oriented growth along the [ 110 ] ?> direction and the same composition. The Seebeck coefficients of both NWs are comparable to each other. The electrical conductivity of both NWs exceeds the bulk value indicating the presence of a topological surface state. Whereas the thermal conductivity of NW2 compares to the bulk, the thermal conductivity of NW1 is about half of NW2 which is discussed with respect to its distinct diameter variation.