Modified series model for cross-plane thermal conductivity of short-period Si/Ge superlattices  

作　　者：FENG Yuan LIANG XinGang 

机构地区：[1]Department of Engineering Mechanics,Key Laboratory for Thermal Science and Power Engineering of Ministry of Education,Tsinghua University

出　　处：《Science China(Physics,Mechanics & Astronomy)》2015年第6期66-73,共8页中国科学：物理学、力学、天文学（英文版）

基　　金：supported by the National Basic Research Program of China(Grant No.2012CB933200);the National Natural Science Foundation of China(Grant No.51176091);Science Fund for Creative Research Groups of China(Grant No.51321002)

摘　　要：Superlattices have great application potentials in thermo-electric materials and solid laser techniques.Their complicated heat transport mechanisms due to size effects,multi-interfaces and mini-band are very important issues for the prediction of thermal conductivity.In this paper,the short-period Si/Ge superlattices are investigated by a modified series model based on the Debye-Callaway description.The Lambert Law is used to describe the phonon emission within hemisphere space.In addition,the phonon interface transmission coefficients obtained from the phonon wave packet simulation are incorporated into boundary condition of the model,which removes the fitting parameters in the model.Better agreement with experiment is obtained.The effects of temperature,wavelength-dependent phonon transmission,superlattice periods,as well as the thickness of Ge layer are considered in this paper.Superlattices have great application potentials in thermo-electric materials and solid laser techniques. Their complicated heat transport mechanisms due to size effects, multi-interfaces and mini-band are very important issues for the prediction of thermal conductivity. In this paper, the short-period Si/Ge superlattices are investigated by a modified series model based on the De- bye-Callaway description. The Lambert Law is used to describe the phonon emission within hemisphere space. In addition, the phonon interface transmission coefficients obtained from the phonon wave packet simulation are incorporated into boundary condition of the model, which removes the fitting parameters in the model. Better agreement with experiment is obtained. The effects of temperature, wavelength-dependent phonon transmission, superlattice periods, as well as the thickness of Ge layer are considered in this paper.

关 键 词：SUPERLATTICES thermal conductivity Debye-Callaway model Lambert Law 

分 类 号：O472.2[理学—半导体物理]