注入区势垒厚度对THz量子级联激光器光电特性的影响  

Influence of injector barrier thickness on the photoelectric response characteristics for THz quantum cascade lasers

作　　者：祁昶[1] 艾勇[1] 石新智[1] 叶双莉[2] 

机构地区：[1]武汉大学电子信息学院,湖北武汉430079 [2]武汉大学印刷与包装系,湖北武汉430079

出　　处：《光电子．激光》2015年第12期2261-2266,共6页Journal of Optoelectronics·Laser

基　　金：国家自然科学基金(61106067;51107089;51371129);武汉市应用基础(2014010101010007)资助项目

摘　　要：为优化多量子阱结构THz量子级联激光器（QCL,quantum cascade laser）有源区的结构设计,本文运用自洽数值求解与电路建模相结合的方法研究了器件有源层注入区势垒厚度变化对器件光电及温度特性的影响。首先采用自洽数值求解获得注入区势垒厚为3.0~6.8nm器件非辐射散射时间、自激发射弛豫时间以及电子逃逸时间等描述器件有源区输运特性的重要参量;然后运用电路建模方法基于三能级速率方程建立了器件的等效电路模型;最后运用电路仿真工具PSPICE对注入区势垒厚为3.0~6.8nm器件的光电特性进行了模拟分析,并讨论了器件有源层注入区的势垒厚度参数变化对器件阈值电流、输出光功率和输入阻抗等性能参数的影响,分析结果与已报道的理论和实验结果一致,证明了通过合理优化有源区的结构参数可以进一步提高器件性能。In this paper, a novel method is introduced to optimize the active layer structure of the THz quantum cascade lasers （QCLs） with a multi--quantum well material, and the influence of injector barri- er thickness in device active layer on device performance is mainly studied by a novel equivalent circuit model. Firstly, transport characteristic parameters such as the nonradiative scattering times, radiative spontaneous relaxation time and electron escape time are obtained by a self--consistent scheme, and then an equivalent circuit model of THz QCLs is introduced by revising three level multi--mode rate equa- tions. Two critical model parameters of electron spontaneous emitting time and photon lifetime in the la- ser cavity are also presented. Finally, depending on the equivalent circuit model, the photoelectric respon- ses of THz QCLs with the thickness of injector barrier from 3.0 nm to 6.8 nm are obtained by using a general circuit simulator PSPICE,and the effects of injector barrier thickness on device performance pa- rameters such as threshold current,output optical power and input impedance are also discussed. Results indicate that the injector barrier thickness is a critical parameter for improving the device performance.

关 键 词：THz量子级联激光器(QCL) 注入区势垒厚度 等效电路模型 光电响应 

分 类 号：TN248.4[电子电信—物理电子学]