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O: Fachverband Oberflächenphysik
O 26: Poster Session II: Nanostructures at surfaces II
O 26.2: Poster
Monday, March 1, 2021, 13:30–15:30, P
Selective Area Growth of III-V Nanowires on High-Index GaAs Substrates — •Gunjan Nagda1,2, Daria Beznasiuk1,2, Tobias Saerkjaer1,2, Martin Espineira1,2, Sara Martí-Sanchez3, Jordi Arbiol3, and Peter Krogstrup1,2 — 1Center for Quantum Devices, Niels Bohr Institute, University of Copenhagen, 2100 Copenhagen, Denmark — 2Microsoft Quantum Materials Lab, 2800 Lyngby, Denmark — 3Catalan Institute of Nanoscience and Nanotechnology (ICN2), CSIC and BIST, Campus UAB, 08193 Bellaterra, Barcelona, Catalonia, Spain
Using a patterned SiO2 mask we report on selective area growth of III-V materials on high-index GaAs substrates using molecular beam epitaxy (MBE). This platform is used to define 1D semiconductor nanowire (NW) networks with excellent surface selectivity for quantum transport studies. Due to the dependence of NW faceting on the substrate orientation and the trench direction within the oxide mask, non-standard substrate orientations such as (211)A and (211)B, and (311)A and (311)B open the pathway to obtain a multitude of geometries. The NW faceting observed using atomic force microscopy (AFM) and cross-sectional transmission electron microscopy (TEM) is in good agreement with the facets predicted on the basis of the stereographic projections of the substrate orientations. The equilibrium shapes are determined using Wulff construction along with constraints imposed by the oxide mask. Comparison with experimental findings is used to determine whether a particular growth is driven by thermodynamically determined surface energy minimization or by kinetic parameters.