Room-temperature terahertz emission from ZnSe-based quantum cascade structures: A simulation study

We identified conditions for room-temperature operation of terahertz quantum cascade lasers (THz QCLs) where variable barrier heights are used on ZnSe/Zn1–xMgx Se material systems. The THz QCL devices are based on three-level two-well design schemes. The THz QCL lasers with alternating quantum barriers with different heights were compared with THz QCL laser structures with fixed quantum barrier heights. It is found that the THz QCL device with novel design employing variable barrier heights achieved the terahertz emission of about 1.45 THz at room-temperature (300 K), and has improved laser performance due to the suppression of thermally activated carrier leakage via higher-energy parasitic levels. Thus, THz QCL devices employing the design with variable barrier heights may lead to future improvements of the operating temperature and performance of THz QCL lasers. (© 2016 WILEY-VCH Verlag GmbH &Co. KGaA, Weinheim)