Thermal behavior of GaAs/AlGaAs quantum-cascade-lasers: effect of the Al content in the barrier layers

Recently, room temperature (RT) operation of GaAs-based quantum cascade (QC) lasers emitting at /spl sim/9 /spl mu/m was obtained by increasing the Al content in the barrier material. This allowed a stronger electron confinement and the reduction of the thermally activated leakage processes. Today, these devices operate up to 60/spl deg/C. Here, we present an in-depth study of the influence of the Al content on the thermal behavior of QC lasers. Also, we present new designs of QC structures based on the possibility to change the Al content during the MBE growth.