Dresden 2017 – wissenschaftliches Programm
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HL: Fachverband Halbleiterphysik
HL 37: III-V Semiconductors
HL 37.8: Vortrag
Dienstag, 21. März 2017, 11:45–12:00, POT 112
Strain distribution in highly mismatched GaAs/(In,Ga)As core/shell nanowires — •Leila Balaghi1,2, René Hübner1, Genziana Bussone3, Raphael Grifone3, Mahdi Ghorbani1, Arkady Krasheninnikov1, Gregor Hlawacek1, Jörg Grenzer1, Harald Schneider1, Manfred Helm1,2, and Emmanouil Dimakis1 — 1Institute of Ion Beam Physics and Materials Research, Helmholtz-Zentrum Dresden-Rossendorf, 01328 Dresden, Germany — 2cfaed, TU Dresden, 01062 Dresden, Germany — 3PETRA III , Deutsches Elektronen-Synchrotron (DESY), 22607 Hamburg, Germany
The core/shell nanowire (NW) geometry is suitable for the pseudomorphic growth of highly mismatched semiconductor heterostructures, where the shell thickness can exceed significantly the critical thickness in equivalent planar heterostructures. We have investigated the accommodation of misfit strain in self-catalyzed GaAs/(In,Ga)As core/shell NWs grown on Si(111) substrates by molecular beam epitaxy. The NWs have their axis along the [111] crystallographic direction, six {110} sidewalls, and their crystal structure is predominantly zinc blende. For strain analysis, we used Raman scattering spectroscopy, transmission electron microscopy, X-ray diffraction and photoluminescence spectroscopy. Within a certain range of core/shell dimensions and shell composition, our findings reveal that the elastic energy in NWs without misfit dislocations can be confined exclusively inside the core, allowing for the shell to be strain-free. The experimental results are also compared with theoretical simulations of the strain (continuum elasticity theory) and phonon energy (density functional theory).