Molecular-beam epitaxy growth and characterization of mid-infrared quantum cascade laser structures

The development of molecular-beam epitaxy (MBE) of GaAs/AlGaAs heterostructures, used for fabrication of ∼9 μm quantum cascade lasers (QCLs), is reported. The X-ray diffractometry (XRD) structural characterization, as an integral part of this process, is presented as well. Some conclusions, concerning the relationships between the used type of epitaxial technology and the necessity of special procedures of growth rate (Vgr) calibration, are reached. The influence of the structural features of the QCL active region on the electronic band structure is calculated, and consequently some predictions as to the device electrical properties are presented as well.