| Autor: |
Rudno-Rudziński W; Department of Experimental Physics, Wrocław University of Science and Technology, St. Wyspiańskiego 27, 50-370 Wrocław, Poland., Gawełczyk M; Institute of Theoretical Physics, Wrocław University of Science and Technology, St. Wyspiańskiego 27, 50-370 Wrocław, Poland., Podemski P; Department of Experimental Physics, Wrocław University of Science and Technology, St. Wyspiańskiego 27, 50-370 Wrocław, Poland., Cybula E; Department of Experimental Physics, Wrocław University of Science and Technology, St. Wyspiańskiego 27, 50-370 Wrocław, Poland., Gorantla S; Łukasiewicz Research Network─PORT Polish Center for Technology Development, Stabłowicka 147, 54-066 Wrocław, Poland., Balasubramanian R; Technological Physics, Institute of Nanostructure Technologies and Analytics, CINSaT, University of Kassel, 34132 Kassel, Germany., Sichkovskyi V; Technological Physics, Institute of Nanostructure Technologies and Analytics, CINSaT, University of Kassel, 34132 Kassel, Germany., Willinger AJ; Electrical and Computer Engineering Department and Russell Berrie Nanotechnology Institute, Technion-Israel Institute of Technology, Haifa 32000, Israel., Eisenstein G; Electrical and Computer Engineering Department and Russell Berrie Nanotechnology Institute, Technion-Israel Institute of Technology, Haifa 32000, Israel., Reithmaier JP; Technological Physics, Institute of Nanostructure Technologies and Analytics, CINSaT, University of Kassel, 34132 Kassel, Germany., Sęk G; Department of Experimental Physics, Wrocław University of Science and Technology, St. Wyspiańskiego 27, 50-370 Wrocław, Poland. |
| Abstrakt: |
Integrating light emitters based on III-V materials with silicon-based electronics is crucial for further increase in data transfer rates in communication systems since the indirect bandgap of silicon prevents its direct use as a light source. We investigate here InAs/InGaAlAs quantum dot (QD) structures grown directly on 5° off-cut Si substrate and emitting light at 1.5 μm, compatible with established telecom platform. Using different dislocation defect filtering layers, exploiting strained superlattices, and supplementary QD layers, we mitigate the effects of lattice constant and thermal expansion mismatches between III-V materials and Si during growth. Complementary optical spectroscopy techniques, i.e. photoreflectance and temperature-, time- and polarization-resolved photoluminescence, allow us to determine the optical quality and application potential of the obtained structures by comparing them to a reference sample-state-of-the-art QDs grown on InP. Experimental findings are supported by calculations of excitonic states and optical transitions by combining multiband k • p and configuration-interaction methods. We show that our design of structures prevents the generation of a considerable density of defects, as intended. The emission of Si-based structures appears to be much broader than for the reference dots, due to the creation of different QD populations which might be a disadvantage in particular laser applications, however, could be favorable for others, e.g., in broadly tunable devices, sensors, or optical amplifiers. Eventually, we identify the overall most promising combination of defect filtering layers and discuss its advantages and limitations and prospects for further improvements. |
