Investigating the impact of molecular beam epitaxy growth properties on the temperature performance of cutting-edge terahertz quantum cascade lasers

This research compares two two-well (TW) Terahertz Quantum Cascade Lasers (THz QCLs) using non-equilibrium Green's functions (NEGF) in order to understand the discrepancy in their maximum operating temperatures (T_max). Despite similar designs and simulation findings, the devices show a substantial performance difference. This is connected to variations in interface roughness (IFR) caused by different Molecular Beam Epitaxy (MBE) reactors. Our findings highlight the necessity of accurate MBE growth control for high-performance THz QCLs and propose approaches for interface modification to improve device temperature performance, providing a clearer path to meeting and exceeding current T_max records.