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K72

Scientific achievements

Most important scientific achievements:
significant participation in the development of technology of semiconductor heterostructures containing diluted nitrides layers (GaInNAs and GaNAs), including modernization of the gas manifold of the MOVPE system, calibration of the epitaxial system and wide material characterization of grown structures;
significant participation in the development of the technology of GaInNAs/GaAs semiconductor high-power edge-emitting lasers for pumping applications (l = 1240 nm) and lasers emitting in the ranges of second and third telecommunication transmission windows;
significant participation in the development of the first singlemode DFB laser emitting radiation with a wavelength of 1.5 mm working in CW-mode, with the antimony-free GaInNAs/GaAs quantum wells;
development of the new algorithm for the structural characterization of epitaxial heterostructures, containing quantum wells made of multicomponent alloys, which combines the analysis of HRXRD measurements with the analysis of full electronic structure of quantum wells based on contactless electroreflectance or photoreflectance (CER or PR) measurements as well as on calculations;
analysis of the impact of the GaInNAs/GaAs quantum wells inhomogeneities on the optical properties of heterostructures and experimental verification of relations between layers inhomogeneities and optical properties of the real epitaxial structures;
implementation of calculations of electronic structures of inhomogeneous quantum wells made of multicomponent semiconductor alloys, exhibiting continuous or/and step–like changes in composition profiles in the direction of growth, to the elaborated new structural characterization algorithm. Such development of the proposed algorithm resulted in a significant improvement in the accuracy of the structural characterization of the GaInNAs/GaAs quantum well structures;
a proposal of increasing efficiency of photodetectors based on GaInNAs/GaAs quantum wells, as a result of compensation of adverse impact of the quantum confined Stark effect, obtained due to appropriate modifications of the quantum wells construction and their electronic structure;
elaboration of a methodology for investigation of the rapid thermal annealing impact on the optical properties of GaInNAs/GaAs MQW quantum active areas of the laser structures, taking into consideration: in-situ annealing of the quantum wells during deposition of upper waveguides of the lasers, influence of highly doped top layers of the laser structures on the possibility of measurements and comparisons of QWs photoluminescence signal, and short annealing time of GaInNAs quantum wells that results in overannealing and significant degradation of their optical properties. As a result of my intense studies of RTA annealing of GaInNAs/GaAs MQW structures, the overannealing effect was eliminated and the efficiency of the edge emitting lasers fabricated by MBE was increased - these works significantly contributed to technology development of both: high-power lasers and singlemode DFB lasers operating in CW mode as well.

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