Regensburg 2025 – scientific programme
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HL: Fachverband Halbleiterphysik
HL 13: Heterostructures, Interfaces and Surfaces
HL 13.4: Talk
Monday, March 17, 2025, 17:30–17:45, H17
Strain gradients in bent GaAs nanowires as a new way of engineering electronic transitions — •Francisca Marín1, Yiannis Hadjimichael2, Christian Merdon2, Patricio Farrell2, Constanza Manganelli3, Oliver Brandt1, and Lutz Geelhaar1 — 1Paul-Drude-Institut für Festkörperelektronik, Leibniz-Institut im Forschungsverbund Berlin e. V. Berlin, Germany — 2Weierstraß-Institut für angewandte Analysis und Stochastik. Berlin, Germany — 3Institut für Halbleiterphysik, Leibniz-Institut für innovative Mikroelektronik. Frankfurt (Oder), Germany
Strain gradients open up a new degree of freedom in strain engineering, enabling polarization in all dielectric materials through the flexoelectric effect. However, flexoelectric coefficients remain unknown for many inorganic semiconductors, including GaAs, leaving this phenomenon unexplored in this material system.
Here, we exploit the pronounced strain gradient in bent GaAs nanowires grown by molecular beam epitaxy to study this effect using photoluminescence spectroscopy. Strain and strain gradients in these nanowires influence the bandgap and generate electric fields from piezoelectric and flexoelectric effects. By combining experiments with a simple one-dimensional model to calculate the expected shift of the electronic transitions, and finite element simulations of piezoelectricity, we provide new insights into flexoelectricity in GaAs.
Keywords: nanowires; strain gradients; piezoelectricity; flexoelectricity