High Doping Concentration and Variable Al Composition THz Quantum Cascade Lasers with 1.39-Watt Operation

A 1.39 W peak power and 60 mW average power THz QCL is presented by variable Al composition active structure with high doping concentration based on NEGF method design, including the realignment of resonant tunneling and suppression of leakages via high energy confined levels. Re-aligning the resonant tunneling which can be serious degraded due to a band bending from this heavy local doping. With variable quantum well and barrier height, the design owns an improved parameter tuning freedoms, and a saturation of peak gain can be achieved at a relative high doping concentration.