Room temperature operation of Ge/Si <i>x</i> Ge1− <i>x</i> − <i>y</i> Sn <i>y</i> terahertz quantum cascade lasers predicted using extended combined resonant tunneling and rate equation model

Abstract

Raising operation temperature of terahertz (THz) quantum cascade lasers (QCLs) to room temperature remains a key challenge in QCL community. Group-IV semiconductors are believed to be a promising solution to this problem since the polar phonon–electron scattering is negligible at elevated temperature. Here, we develop a theoretical model for Ge/SixGe1−x−ySny THz QCL development. This model is established on the combined resonant tunneling and rate equation framework and is extended to be applicable for group-IV QCL design through introducing new scattering mechanisms and continuum states carrier leakage. A two-well Ge/Si0.3Ge0.618Sn0.082 THz QCL based on a direct phonon extraction strategy is designed and predicted to be capable of working above 300 K. This result lays the foundation for future room temperature THz QCL devices development using group-IV semiconductors.