Practical implementation of m-Plane GaN resonant-phonon Terahertz quantum cascade laser.

In this study, we analyze a novel m-plane GaN Terahertz Quantum Cascade Laser (THz QCL) with a resonant phonon depopulation scheme using the Non-equilibrium Green's Function (NEGF) approach. This design offers a more practical alternative to the previously proposed Two-Well (TW) GaN THz QCL, featuring significantly lower operating currents, reducing the risk of thermal damage, and greatly enhances the feasibility of experimental realization. The addition of an extra barrier also reduces leakage into the continuum and into the excited states. Accounting for leakage into excited states, a factor often neglected in prior works, a peak gain of ~ 76 cm⁻¹ was observed at low temperatures, decreasing to ~ 24 cm⁻¹ at 300 K, comparable to the expected losses, making the structure suitable for near -room-temperature applications. Our results predict promising high temperature operation at ~ 6.5 THz, surpassing the frequency coverage of standard GaAs-based THz QCLs. This work advances the development of GaN-based THz QCLs towards room-temperature performance and expanded frequency coverage compared to GaAs/AlGaAs THz-QCL, addressing key challenges in Terahertz technology.