粗糙界面对Bi_2Te_3/PbTe超晶格热电优值影响的理论分析

Effect of rough interface on the thermoelectric figure of merit of the Bi_2Te_3/PbTe superlattice

以Bi2Te3/PbTe超晶格薄膜为例,分析电子在Bi2Te3量子阱中的输运过程,综合了薄膜的经典散射效应和理想量子效应,并以此混合效应为基础,在PbTe障碍层厚度一定时,模拟计算了两种混合效应中量子效应占不同比例时,Bi2Te3/PbTe超晶格热电优值的变化.在镜面反射占混合效应的0.3时,得到的热电优值与当前报道的量子阱超晶格的实验值接近.

Electron transport is analysed in Bi2Te3 quantum well of Bi2Te3/PbTe superlattice. The hybrid quantum-classical size effect model, considering the Boltsmann transport equation and classical size effect, is introduced to analyse the effect of rough interface on the electron transport and scattering and the thermoelectric figure of merit of Bi2Te3/PbTe superlattice. The PbTe barrier thickness is kept constant to avoid the influence of the variation in tunnel effect on attenuation of the carrier concentration in Bi2Te3 quantum well of Bi2Te3/PbTe superlattice. The result shows that roughness has strong influence on the thermoelectric figure of merit of Bi2Te3/PbTe superlattice. The Bi2Te3/PbTe thermoelectric figure of merit decreases with the decreasing of the portion （p） of mirror reflection in the hybrid effects. And when p is 0.3, the figure of merit is close to the experiment value.