Barrier Height Tuning of Terahertz Quantum Cascade Lasers for High-Temperature Operation
Barrier Height Tuning of Terahertz Quantum Cascade Lasers for High-Temperature Operation
复制标题
DOI：
10.1021/acsphotonics.8b01280
复制
发表时间：
2018-11-01
期刊：
影响因子：
7
通讯作者：
Unterrainer, Karl
中科院分区：
文献类型：
--
作者：
Kainz, Martin Alexander;Schoenhuber, Sebastian;Unterrainer, Karl
太赫兹量子级联激光器（QCL）是一种优秀的相干光源，但其工作温度仍限于200 K以下。为了解决这个问题，我们通过比较GaAs/AlxGaiAs材料系统中不同铝浓度（x = 0.12-0.24），分析了势垒高度对相同三阱太赫兹QCL层序列的影响，并在此基础上提出了一种优化结构。电子注入和提取机制，以及LO-声子的人口减少过程中发挥了至关重要的作用，这些激光器的有效运作，并在这项研究中进行了调查。势垒高度研究的实验结果表明，具有21%铝势垒的结构的最高工作温度为186.5 K，对于三阱有源区设计，具有1.36的记录lcBT max/ hco值。设计了一种优化的异质结构，铝浓度为21%，降低了腔波导损耗，并使3.8 THz QCL的工作温度达到196 K。
Terahertz quantum cascade lasers (QCLs) are excellent coherent light sources, but are still limited to an operating temperature below 200 K. To tackle this, we analyze the influence of the barrier height for the identical three-well terahertz QCL layer sequence by comparing different aluminum concentrations (x = 0.12-0.24) in the GaAs/AlxGai_ As material system, and then we present an optimized structure based on these findings. Electron injection and extraction mechanisms as well as LO-phonon depopulation processes play crucial roles in the efficient operation of these lasers and are investigated in this study. Experimental results of the barrier height study show the highest operating temperature of 186.5 K for the structure with 21% aluminum barriers, with a record lcBT max/ hco value of 1.36 for a three-well active region design. An optimized heterostructure with 21% aluminum concentration and reduced cavity waveguide losses is designed and enables a record operating temperature of 196 K for a 3.8 THz QCL.