Talk - Moritz Brehm: Lasing from defect-engineered Ge dots on Si(001)
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Lasing from defect-engineered Ge dots on Si(001)
Moritz Brehm, Institute of Semiconductor and Solid State Physics, Johannes Kepler University Linz, Altenbergerstrasse 69, A-4040 Linz, Austria
Implementation of Si-based lasers for on-chip and inter-chip optical interconnects will be crucial for the next generation digital devices: It aims at faster data transfer with increased circuit clock speeds, accompanied by reduced power consumption.
Here we demonstrate lasing from epitaxially grown Ge quantum dots (QDs) in a defect-free Si matrix. These modified Stranski-Krastanow QDs show such extraordinary optical properties if partially amorphized by Ge-ion bombardment (GIB) and further recrystallized into a minimum-energy configuration. We will elaborate on the microscopic origin of the enhanced PL-emission properties from GIB-QDs and highlight the role of single extended point defects for effective electron confinement. In this presentation, we will present that - in contrast to conventional epitaxial SiGe nanostructures - these GIB-QDs exhibit dramatically shortened carrier lifetimes and negligible thermal quenching of the photoluminescence (PL) up to room temperature and above . Strategies to further improve the room-temperature PL emission from GIB-QDs will be presented.
Microdisk resonators with embedded GIB-QDs exhibit threshold behavior as well as a superlinear increase of the integrated PL intensity with concomitant linewidth narrowing as the pump power increases. These findings demonstrate light amplification by stimulated emission in a group-IV nanosystem that is fully compatible with Si integration technology.
 M. Grydlik, F. Hackl, H. Groiss, M. Glaser, A. Halilovic, T. Fromherz, W. Jantsch, F. Scha?ffler, and M. Brehm, ACS Photonics 3, 298 – 303 (2016).