Thermoelectric transport and magnetoresistance of electrochemical deposited Bi2Te3 films at micrometer thickness
Thermoelectric transport and magnetoresistance of electrochemical deposited Bi2Te3 films at micrometer thickness
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DOI：
10.1016/j.ceramint.2019.10.043
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发表时间：
2020-02
影响因子：
5.2
通讯作者：
Dandan Zhao;Jikun Chen;Z. Ren;Jinhao Chen;Qingfeng Song;Qihao Zhang;N. Chen;Yong Jiang
中科院分区：
文献类型：
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作者：
Dandan Zhao;Jikun Chen;Z. Ren;Jinhao Chen;Qingfeng Song;Qihao Zhang;N. Chen;Yong Jiang
碲化铋（Bi_2Te_3）是迄今为止最适合室温附近应用的热电材料，并且还表现出大的磁电阻。虽然电化学沉积方法可以实现微米厚度的Bi 2 Te 3薄膜的有效生长，但电化学沉积的Bi 2 Te 3薄膜的磁阻输运行为尚不清楚。在这项工作中，我们展示了热电和磁阻行为的微米厚的Bi 2 Te 3薄膜通过电化学沉积方法沉积。在Bi 2 Te 3样品中观察到最佳的热电功率因数，其电化学沉积厚度为~6 μm，然后进行快速光子退火处理，达到~1 μWcm− 1 K − 2的量级，这与以前的报道相似。与单晶或真空沉积的Bi_2Te_3或Bi_2Se_3薄膜相比，电化学沉积的Bi_2Te_3薄膜的电子输运更多地受到晶界和晶格缺陷对载流子散射的影响。其结果是，它们的磁阻（MR）显示出显着的非单调行为时，变化的磁场，而其MR的大小表现出正的温度依赖性。这些MR行为在很大程度上不同于以前报道的单晶或真空沉积的Bi 2 Te 3或Bi 2Se 3，在这种情况下，它们的MR单调增加与磁场，并表现出负的温度依赖性。这项工作揭示了以前被忽视的晶界的作用，也调节铋硫属化物在磁场的存在下的运输性能。
Bismuth telluride (Bi2Te3) is so far the best thermoelectric material for applications near room temperature, and also exhibits large magnetoresistance. While the electrochemical deposition approach can achieve effective growth of the Bi2Te3films at micrometer thickness, the magnetoresistance transportation behavior of the electrochemically deposited Bi2Te3films is yet not clear. In this work, we demonstrate the thermoelectric and magnetoresistance behaviors of the micrometer thick Bi2Te3films deposited via electrochemical deposition approach. The optimum thermoelectric power factor is observed in the Bi2Te3sample with electrochemical deposition thickness of ~6 μm followed by rapid photon annealing treatment, reaching the magnitude of ~1 μWcm−1K−2that is similar to the previous reports. In contrast to the single crystalline or vacuum deposited Bi2Te3or Bi2Se3films, the electronic transportations of the electrochemically deposited Bi2Te3are more influenced by the carrier scatterings by the grain boundaries and lattice defect. As a result, their magnetoresistance (MR) shows a distinguished non-monotonic behavior when varying the magnetic field, while the magnitude of their MR exhibits a positive temperature dependence. These MR behaviors largely differ to the previously reported ones from the single crystalline or vacuum deposited Bi2Te3or Bi2Se3, in which cases their MR monotonically increases with the magnetic field and exhibits negative temperature dependence. This work reveals the previously overlooked role of grain boundary that also regulates the transportation properties of bismuth chalcogenides in the presence of magnetic field.