Design and charactristics of ultraviolet nanowire plasmonic lasers

This thesis explores semiconductor nanowires as nanolasers for nanophotonic applications due to their unique structure, which enables scalable fabrication, on-chip integration, and effective generation of coherent radiation. In particular, this study focuses on the investigation of ultraviolet plasmonic nanolasers made from zinc oxide (ZnO) nanowires on silver (Ag) and aluminum (Al) substrates, employing a dual experimental approach combining single-nanowire photoluminescence (PL) measurements with high-throughput PL spectroscopy. Specifically, an intermediate nanowire diameter region is identified, marking the transition between purely plasmonic'' and purely photonic'' nanolasers. These insights can facilitate a more rational design of hybrid cavities that merges the robust lasing performance of photonic devices with the hybrid mode characteristics of plasmonic nanolasers. Furthermore, modifying the standard semiconductor-insulator-metal (SIM) planar architecture by patterning linear gratings into the metallic substrate provides an effective tailoring scheme for the emission of such hybrid nanolasers. As a result, coupling a semiconductor nanowire with an Al grating demonstrates the potential for attaining bespoke distributed-feedback schemes that can enable single-frequency operation by suppressing the mode competition in inherently multimode lasing nanowires. Ultimately, a core-shell structure is proposed as an alternative design for modified planar architectures, featuring ZnO nanowires with the dielectric spacer and the Al layer coated all around. Preliminary theoretical and experimental results demonstrate that this hybrid structure supports plasmon-like modes for metallic shells above a certain critical thickness. In conclusion, these findings can pave the way for a more efficient and strategic design of hybrid plasmonic nanolasers, in an attempt to advance their in-device integration for real-world applications.