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HL: Fachverband Halbleiterphysik

HL 13: Heterostructures, Interfaces and Surfaces

HL 13.4: Vortrag

Montag, 17. März 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