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Koblmüller, Gregor (TUB)
Date
Thursday, January 30, 2025, 12:00 pm

Special Nitrides Seminar - Dr. Gregor Koblmüller, Professor at TU Berlin

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Special Nitrides Seminar

Thursday, January 30, 2025, 12:00PM
Attend in person at Elings Hall 1601
Zoom option also available https://ucsb.zoom.us/j/82521088079?pwd=t4K4puRCvaPuoMbc60eaFDprzLdXaU.1

Meeting ID: 825 2108 8079           Passcode: 507685

Dr. Gregor Koblmüller
Progress in monolithically integrated III-V nanolasers on silicon

Walter Schottky Institute and School of Natural Sciences, Technical University of Munich, Am Coulombwall 4, 85748 Garching, Germany

Recent advancements in III-V semiconductor nanowire (NW) lasers integrated on silicon (Si) and silicon-on-insulator (SOI) photonic waveguides and circuits have highlighted their promising potentials as ultracompact light sources for on-chip optical signal processing and sensing.

In this talk, I present our recent progress on new generations of Si-integrated GaAs-based NW-lasers with their emission wavelengths tuned into the telecom-band spectral range. Starting with numerical modelling, first the design guidelines for compact vertical-cavity NW-laser architectures coupled to Si waveguides with optimized coupling efficiency will be provided. In logical flow, some of the key materials challenges will then be addressed and selective-area epitaxial (SAE) growth of two types of multi-quantum well (MQW) based NW-laser structures demonstrated with low-threshold lasing emission in the telecom O-band (1.3 µm): (i) strain-engineered GaAs-InGaAs NW-lasers, and (ii) GaAsSb-based NW-lasers that not only present the first true ternary NW-lasers at Si transparent wavelengths but which further allow for entirely defect-free InGaAs MQWs with high In-content. Optically pumped lasing from coaxially p-i-n doped GaAs(Sb)/InGaAs core-shell NW-laser diode structures is also presented, and some of the challenges of electrically driven devices discussed. Finally, an outlook is provided that shows the versatility of on-chip integrated NW-cavities for other optically active systems, including direct-bandgap, hexagonal SiGe and deterministic quantum emitters coupled to Si waveguides.

BIO: Gregor Koblmüller is a faculty member at the Walter Schottky Institute (WSI) and Physics Department at the Technical University of Munich (TUM). He received his doctoral degree (2005) in Applied Physics from the Vienna University of Technology. From 2005-2008 he joined the Materials Department at UCSB as a postdoctoral fellow and project scientist, working extensively on group-III nitrides in the group of Prof. Speck. In 2009 he joined the WSI-TUM where he has been heading the “Semiconductor Quantum Nanomaterials” Group with recent activities on monolithically integrated nanolasers and related devices. He comple-ted his habilitation in Experimental Physics at TUM in 2017. He is the recipient of numerous awards, including the ERC Consolidator Grant Award, the Arnold Sommerfeld Prize, the Intl’ Young Investigator MBE Award, and the Marie Curie Grant Award. He recently accepted an offer as Full Professor at TU Berlin, starting his new position in 02/2025.

HOST: Dr. James Speck