Abstract
Quantum cascade lasers (QCLs) are unipolar semiconductor lasers employing radiative transitions between electron subbands in multiple quantum well structures. QCLs can deliver high optical powers in a large spectral range from mid-IR to THz. The best QCL performances have been achieved using III-V materials that can be grown on InP substrates. The InAs/AlSb material system represents an alternative solution for the elaboration of QCLs. While it is still much less explored compared with the InP family, some properties of these materials are very attractive for the development of QCLs.This thesis contributed to better understanding of the InAs/AlSb system, as well as to physics and technology QCLs based on these materials.Much attention has been paid to the performance improvement of InAs/AlSb QCLs, especially to the increasing of operation temperature of these lasers. A model of electronic transport in such devices, which is in good agreement with obtained experimental data, has been developed. This model has been used for optimization of the QCL design and, in consequence, to the improvement of the lasers performances.The main application of infrared lasers is molecular spectroscopy requiring high spectral purity of the laser emission. To make InAs-based QCLs suitable for spectroscopic applications we have developed a technology of distributed feedback (DFB) lasers for the 3-10 µm range with single frequency emission. Continuous wave (cw) operation of InAs/AlSb QCLs has been achieved for the first time in lasers emitting near 9 µm at temperatures up to 255 K. These lasers have been optimized for cw operation using predictive modeling of heat balance in the device. In order to improve performances of short wavelength InAs/AlSb QCLs emitting below 4 µm we proposed to replace a plasmon enhanced waveguide employing heavily doped InAs and exhibiting strong free carrier absorption by a low loss dielectric waveguide with AlGaSbAs cladding layers. These lasers grown for the first time on GaSb substrates and operated between 2.8 and 3.3 µm demonstrated performances proving the attractiveness of this approach to achieve further progress in InAs/AlSb QCLs.