锑化物超晶格的载流子寿命及其在红外探测器件中的应用研究

Antimonide based superlattice materials have high quantum efficiency and cover the wide range for infrared detection. It has developed into the best material for the new generation high-performance infrared Focal Plane Array(FPA) devices. However, recent molecular beam epitaxy(MBE) material growth and device fabrication studys have shown that the primary limiting factor of this material is the short carrier lifetime. Thereby, The carrier transport and lifetime characteristics of antimonide superlattices are proposed in this research project. Firstly, the band structure and carrier tronsport characteristics of antimonide superlattices are modeled in k.p and emperical tight binding theoretical calculation.Secondly, antimonide based superlattice material is growthed by specific designed MBE technology on GaSb(100) and GaSb(111)B substrates. As the core analysis technique in this project, carrier lifetime of suplerlattices is measured in horizontal and vertical direction, and at different temperature, different doping level by time-resolved FTIR spectrometer. Based on the conclusion and other analysis techniques, such as High Resolution X-ray Diffraction(HRXRD) and Transmission Electron Microscope(TEM), modified material epitaxy technology and the new device structure designing method are proposed to increase the carrier lifetime. Finally, based on the results of this study, the new designed high conversion efficiency longwave infrared detectors are fabricated tentatively.

锑化物超晶格具有光电转换效率高、红外波段覆盖范围宽等独特优越性，是目 前国际上研制新一代红外焦平面探测器的热点材料体系。随着材料生长和器件制备研究的不 断深入，人们认识到锑化物超晶格载流子寿命较短是制约红外探测器效率的核心因素。本项 目提出开展锑化物超晶格载流子输运和寿命特征研究，首先基于k.p 微扰和经验紧束缚理论，建立锑化物超晶格能带结构及输运特征模型；采用分子束外延技术在GaSb(100)和（111）B 衬底上设计和生长锑化物超晶格材料；以基于傅里叶分析仪的时间分辨光谱为主要测试分析手段，并结合X 射线衍射及电镜分析等技术，深入研究不同周期和应力结构超晶格的纵向、横向载流子输运特性，通过优化生长条件、掺杂浓度等提升其载流子寿命。最后，以上述研究结果为依据，设计和试制新型高转换效率长波红外探测器。

锑化物超晶格材料在红外光电器件中的应用近年来不断取得进展，逐渐发展成为新一代高性能红外光电器件的最佳材料。然而随着研究不断深入，锑化物超晶格材料较短的载流子寿命成为制约该材料基器件性能的主要素因，因此该材料的载流子疏运特征研究逐渐受到了众多研究机构的重视。本项目主要开展锑化物超晶格材料载流子寿命特征研究，经过三年的努力，研究完成了以k.p微扰和紧束缚理论为基础的锑化物超晶格能带结构及输运特征理论模拟计算。结合理论计算的相关结论，在本实验室发展的锑化物分子束外延技术基础上实现了多个波段，长载流子寿命锑化物超晶格材料的生长制备。本项目研究过程中以时间分辨光谱为核心材料分析手段，对GaSb衬底上不同外延参数下超晶格结构在纵向及横向，不同温度和掺杂浓度等多种材料学参数条件下的载流子输运特征进行了细致研究。掌握了通过控制外延参数提高锑化物超晶格材料的载流子寿命的技术方法，达到了项目的技术指标要求。本项目研究得到的技术成果在锑化物红外焦平面芯片制造及应用中得到了初步验证。