| Abstract [eng] |
The dissertation is dedicated to the study of InGaAs quantum dots (QDs), rings (QRings), and rods (QRods) of various morphology using modulation spectroscopy, photoluminescence (PL) and photoluminescence excitation (PLE) techniques. The first part of the work presents optical investigations of InAs QDs embedded in InGaAs/GaAs quantum well (QW). In addition, effect of stress-relieving InGaAs layer on QD optical properties and electronic structure has been revealed. Comparing experimental results and digital calculations, a detailed temperature-dependent analysis of the optical transitions, taking place in QWs and QDs, was performed. Second part of the work is devoted to the investigation of the electronic structure and optical transitions of InGaAs QRods embedded in the InGaAs QW using methods of photoreflection and PL. The influence of As source on InGaAs QRods and the surrounding InGaAs QW was experimentally investigated. Increase in PL intensity was shown, which is explained by the improved quantum localization of the electronic states of InGaAs QRods. Third part presents optical studies of InAs quantum ring (QRing) structures, which showed a significant energy blueshift of the interband transitions between the ground states of QRings. Mentioned blueshift is associated with the small size of the quantum ring (compared to the characteristic height of QDs). The reduction of the electron localization results in a ground state energy shift toward continuum. |
