Interplay Between Thermoelectric and Thermionic Effects in Heterostructures
Interplay Between Thermoelectric and Thermionic Effects in Heterostructures
复制标题
异质结构中热电效应和热电子效应之间的相互作用
DOI：
10.1063/1.1499527
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发表时间：
2000
期刊：
影响因子：
--
通讯作者：
Gang Chen
中科院分区：
文献类型：
--
作者：
T. Zeng;Gang Chen
当电子扫过双异质结结构时，在结处存在热电子效应，薄膜中存在热电效应。虽然热电效应和热离子效应已经分别研究了制冷和发电应用，但它们在异质结构中的相互作用尚不清楚。本文基于电子的玻尔兹曼输运方程和电子与声子的非平衡相互作用，建立了包括热离子过程和热电过程的统一模型。得到了近似解，当薄膜厚度远小于电子平均自由程时，导致异质结构内部的电子温度和费米能级分布以及界面处由于高度非平衡输运而导致的不连续。研究发现，当薄膜厚度小于电子的平均自由程时，电子的输运受热离子发射控制。当电子平均自由程与薄膜厚度相当时，热电效应和热离子效应的共存会增加功率因数。
When electrons sweep through a double-heterojunction structure, there exist thermionic effects at the junctions and thermoelectric effects in the film. While both thermoelectric and thermionic effects have been studied for refrigeration and power generation applications separately, their interplay in heterostructures is not understood. This paper establishes a unified model including both thermionic and thermoelectric processes based on the Boltzmann transport equation for electrons, and the nonequilibrium interaction between electrons and phonons. Approximate solutions are obtained, leading to the electron temperature and Fermi level distributions inside heterostructures and discontinuities at the interfaces as a consequence of the highly nonequilibrium transport when the film thickness is much smaller than the electron mean free path. It is found that when the film thickness is smaller than the mean free path of electrons, the transport of electrons is controlled by thermionic emission. The coexistence of thermoelectric and thermionic effects may increase the power factor when the electron mean free path is comparable to the film thickness.