PbTe/CdTe纳米颗粒界面和能带的“人工裁剪”对热电性能影响的研究

项目名称： PbTe/CdTe纳米颗粒界面和能带的“人工裁剪”对热电性能影响的研究

项目编号： No.51302248

项目类型： 青年科学基金项目

立项/批准年度： 2014

项目学科： 一般工业技术

项目作者： 斯剑霄

作者单位： 浙江师范大学

项目金额： 25万元

中文摘要： 在热电材料纳米化研究中，如何通过纳米颗粒界面、尺寸、分布的优化来进一步降低晶格热导率和提高功率因子成为人们普遍关注的问题，本项目拟针对PbTe/CdTe纳米体系的特点，通过PbTe/CdTe量子阱结构和高温真空热处理工艺，在PbTe中实现不同界面、尺寸、分布特性的CdTe纳米颗粒生长。1.研究CdTe纳米颗粒不同界面对声子散射的各项异性调节，探究界面晶向调控对晶格热导率降低的影响；2.利用CdTe纳米颗粒尺寸对能带简并的调节，研究纳米颗粒尺寸对PbTe能带汇聚的调节以及功率因子提高的影响；3.研究CdTe纳米颗粒之间间隔改变对PbTe/CdTe纳米体系电声子散射机理的影响，研究纳米颗粒分布优化对PbTe"共振能级"形成及其功率因子提高的影响。通过对CdTe纳米颗粒界面、尺寸、分布的优化实现纳米颗粒的"人工裁剪"，为提高PbTe/CdTe纳米体系热电性能提供新思路和新方法。

中文关键词： 热电材料；PbTe-CdTe；纳米结构；离轴共溅射；熔体旋甩

英文摘要： With the development of the nanostructured thermoelectrics ,how to maximize the power factor and minimize the thermal conductivity by manipulating the interfacial structure,size,and concentration of the nanoparticle has recently attracted considerable attentions.In this research project,we will present a controlled way to vary the CdTe nanoparticles in interfacial structure, size and concentration,which involve the molecular beam epitaxy (MBE)growth of a designed PbTe/CdTe quantum well,followed by a nanostructure forming in high-vacuum annealing procedure. We focus ,in particular on (1)the investigation of the dependent of the interfacial structure on the reduction of the lattice thermal conductivity and the relationship between the anisotropic interfaces and phonon scattering. (2) the measurements and ananlysis of the effect of the CdTe size on the power factor increasing through modulating the convergence of PbTe valence bands.(3)the role played by the concentration and spacing of the CdTe nanoparticles in increasing the thermopower due to the formation of resonant level.These interfacial and band engineering strategies should be the alternative routes to improve the performance of nanostructred materials and provide the insights and guidances for designing new materials with potential applications.

英文关键词： Thermoelectric materials；PbTe-CdTe；nano-structure；off-axis co-sputtering；Melt-Spinning