Browsing by Author "Anttu, Nicklas, Dr., Åbo Akademi University, Finland"
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- Nanophotonics with Group III–V Compound Semiconductor Nanowires
School of Electrical Engineering | Doctoral dissertation (article-based)(2022) Mäntynen, HenrikCrystalline group III–V compound semiconductor nanowires have gained considerable research interest towards nanoscale devices in optoelectronics and other nanophotonics applications due to the unique opportunities presented by their bottom-up growth methods. For research and design of such nanophotonics devices, numerical optics modeling is an invaluable tool which helps to increase the physical understanding of the device operation and to reduce costly and time-consuming prototyping. This thesis presents the results of the studies conducted on III–V nanowires for nanophotonics applications and efficient numerical optics modeling techniques for the analysis and design of light manipulation in such applications. The fabrication and performance of III–V nanowire single-photon sources with an embedded quantum dot emitter were reviewed with comparison to other, top-down-fabricated semiconductor quantum-dot-based designs. This work addressed the previous lack of a detailed nanowire-focused single-photon source comparison, especially taking into consideration their fabrication. The benefits and challenges of nanowire single-photon sources together with potential future research directions were elucidated. Novel waveguide modes in vertical nanowire oligomers were investigated with numerical simulations, and the suitability of such modes for lasing was considered based on their modal properties. So far, previously reported studies had largely considered guided modes and laser applications for only single nanowires. Hybridized guided modes with improved modal properties compared to single-nanowire modes were found for the studied oligomers and further research was suggested. A method was also presented in this work for extending the symmetry reduction of finite element method models for linear optics scattering problems to the case of nonsymmetric plane-wave incidence. The achieved computational cost reduction was also demonstrated with numerical examples. Such a symmetry reduction method was found to be previously missing from the literature. Additionally, the issue of relative numerical performance and choosing between the Fourier modal method, finite element method, and finite-difference time-domain method in various incident light absorption simulation cases was addressed.