GaAs/AlGaAs (~9.4 žm) quantum cascade lasers operating at 260 K

The fabrication of Quantum Cascade Lasers (QCLs) emitting at 9.4 um is reported. The devices operated in pulsed mode at up to 260 K. The peak powers recorded in 77 K were over 1 W, and the slope efficiency 0.5–0.6 W/A per uncoated facet. This has been achieved by the use of GaAs/Al0.45Ga0.55As heterostructure, with 3QW anticrossed-diagonal design originally proposed by Page et al. [1]. Double plasmon planar confinement with Al-free waveguide has been used to minimize absorption losses. The double trench lasers were fabricated using standard processing technology, i.e., wet etching and Si3N4 for electrical insulation. The QCL structures have been grown by Molecular Beam Epitaxy (MBE), with Riber Compact 21T reactor. The stringent requirements – placed particularly on the epitaxial technology – and the influence of technological conditions on the device structure properties are presented and discussed in depth.