Berlin 2015 – scientific programme
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TT: Fachverband Tiefe Temperaturen
TT 24: Focus Session: Functional Semiconductor Nanowires II (organized by HL)
TT 24.2: Talk
Monday, March 16, 2015, 15:30–15:45, EW 201
GaAs/AlGaAs core shell nanowire lasers and their inte- gration on Si — •Sabrina Sterzl1, Benedikt Mayer1, Lisa Janker1, Bernhard Loitsch1, Gerhard Abstreiter1,2, Christopher Gies3, Gregor Koblmüller1, and Jonathan Finley1 — 1Walter Schottky Institut and Physik Department, TU München, Garching, Germany — 2Institute of Advanced Studies, TU München, Garching, Germany — 3Institute for Theoretical Physics, University of Bremen, Bremen, Germany
We present lasing from individual GaAs/AlGaAs core shell nanowires (NWs) under pulsed and continuous wave (CW) optical excitation. The tailored composition profile of the NW lasers studied by photolumines- cence measurements reveals highly efficient fundamental mode lasing with emission coupling efficiencies (β) up to 0.1, ultrafast pulse emission down to 5ps as well as CW operation. Monolithic integration of the NW lasers is achieved by a universally applicable porous dielectric SiO2 reflection layer on top of the Silicon growth substrate. The SiO2 layer maintains direct contact of the NW core to the substrate and provides sufficient reflectivities for lasing operation directly on Si. The fast pulse emission found in our experiments are in good agreement with theoretical calculations predicting possible repetition rates up to 33GHz. The findings demonstrate the versatility and high functionality of the coherent on-chip NW light sources.