碲化铋基热电薄膜的非平衡载流子输运和相干声子振荡的研究

项目名称： 碲化铋基热电薄膜的非平衡载流子输运和相干声子振荡的研究

项目编号： No.61204007

项目类型： 青年科学基金项目

立项/批准年度： 2013

项目学科： 信息四处

项目作者： 吴文智

作者单位： 黑龙江大学

项目金额： 31万元

中文摘要： 热电薄膜是将热能转换为电能的一种新型能量转换器件，可实现废弃热能、太阳能开发利用，已部分商品化，但热电转换效率低是其核心问题。为能够通过热电薄膜结构优化和性能设计来提高转换效率，迫切需要对热电薄膜的载流子输运和声子弛豫动力学过程进行深入剖析。本项目针对室温下性能最好的热电转换材料-碲化铋(Bi2Te3)，使用机械合金化法配合磁控和真空溅射法合成多种掺杂组分Bi2Te3热电薄膜，将微弱信号检测技术与飞秒时间分辨光谱学手段结合搭建高灵敏度瞬态反射实验装置，观测系列热电薄膜的超快动力学过程，研究薄膜的非平衡载流子热输运和耗散过程，着重讨论载流子弛豫速率和相干声子振荡频率的变化特性。改变薄膜材料的Bi/Te比例或掺杂元素，揭示散射、掺杂和界面热阻等因素对薄膜热电优值的影响规律，为设计与研发热电转换性能优异的功能器件提供理论基础和技术支撑。

中文关键词： 相干声子；电子-声子耦合；超快动力学；能量转移；

英文摘要： Thermoelectric thin film is a kind of new and prospective device for energy conversion,which is used to develop and utilize waste heat and solar energy. It has become commercialized partly.However, there still exists one big defect, which is low thermoelectric conversion efficiency. In the cause of optimum structure of material and functional design of device, the relaxation dynamics of excited carriers and phonons need to be understood elaborately in order to improve the efficiency of energy conversion. In this proposal, Bismuth Telluride (Bi2Te3) film，a representative high-performance thermoelectric film materials at room temperature, with different component ratios and impurities are fabricated by magnetron sputtering and evaporation coating. Transient reflectivity experiment setup is combined two kind of technique, which are detection of weak signal and femtosecond time resolved spectrum The ultrafast dynamics of film is measured by use of high-sensitive transient reflectivity technique so as to study heat transport and dissipation of nonequilibrium carriers. The main focus of proposed research is to discuss the relaxation rate and coherent phonon of this thermoeletric film.With the change of Bi/Te component ratio and doping, scattering of impurity and resistor of interface are taken into account for the im

英文关键词： Coherent phonon；electron-phonon coupling；ultrafast dynamics；energy transfer；