Aarhus University Seal / Aarhus Universitets segl

Talk - Moritz Brehm: Lasing from defect-engineered Ge dots on Si(001)

Info about event


Wednesday 12 October 2016,  at 14:15 - 15:00



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 [1]. 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.




[1] 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).