Effects of Surface Band Bending and Scattering on Thermoelectric Transport in Suspended Bismuth Telluride Nanoplates
Effects of Surface Band Bending and Scattering on Thermoelectric Transport in Suspended Bismuth Telluride Nanoplates
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DOI：
10.1021/nl402828s
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发表时间：
2013-11-01
期刊：
影响因子：
10.8
通讯作者：
Shi, Li
中科院分区：
文献类型：
--
作者：
Pettes, Michael Thompson;Maassen, Jesse;Shi, Li
采用微型器件测量了厚度为9 ~ 25 nm的碲化铋纳米片的面内热电性能。结果表明，随着厚度的减小，塞贝克系数被抑制，电导率和热导率总体呈下降趋势。虽然纳米片的电导率仍然在所报道的块体Bi 2 Te 3的范围内，但是小于20 nm厚的纳米片的总热导率远低于所报道的块体范围。这些结果被解释为存在的表面能带弯曲和扩散表面散射的电子和声子的纳米片，其中明显的n型表面能带弯曲可以产生抑制，甚至负塞贝克系数在无意中p型掺杂的纳米片。
A microdevice was used to measure the in-plane thermoelectric properties of suspended bismuth telluride nanoplates from 9 to 25 nm thick. The results reveal a suppressed Seebeck coefficient together with a general trend of decreasing electrical conductivity and thermal conductivity with decreasing thickness. While the electrical conductivity of the nanoplates is still within the range reported for bulk Bi2Te3, the total thermal conductivity for nanoplates less than 20 nm thick is well below the reported bulk range. These results are explained by the presence of surface band bending and diffuse surface scattering of electrons and phonons in the nanoplates, where pronounced n-type surface band bending can yield suppressed and even negative Seebeck coefficient in unintentionally p-type doped nanoplates.