Dresden 2026 – wissenschaftliches Programm

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HL: Fachverband Halbleiterphysik

HL 23: Transport Properties

HL 23.10: Vortrag

Mittwoch, 11. März 2026, 12:00–12:15, POT/0051

Investigation of exciton diffusion in GaAs nanowires via cathodoluminescence spectroscopy — •Mikel Gómez Ruiz, Vladimir Kaganer, Jesús Herranz, Lutz Geelhaar, Oliver Brandt, and Jonas Lähnemann — Paul-Drude-Institut für Festkörperelektronik, Leibniz-Institut im Forschungsverbund Berlin e.V., Hausvogteiplatz 5-7, 10117 Berlin, Germany

Semiconductor nanowire (NW) structures emitting at tailored wavelengths have attracted notable interest for integration with silicon-on-insulator waveguides. For many of these applications, the efficiency with which carriers are injected into the active region of the sample is relevant.

In this context, carrier transport in phase-pure GaAs nanowires is investigated by spatially-resolved cathodoluminescence spectroscopy. Emission intensity profiles along the nanowire axis are measured to study carrier transfer from the GaAs segment to the axial interfaces at both ends of the nanowire. These interfaces are formed at the top with the axially grown (Al,Ga)As shell and at the bottom with the Si substrate. The recorded intensity profiles are predominantly asymmetric, indicating that carrier recombination at the two interfaces occurs in a different fashion.

These profiles are analyzed using a mathematical model that accounts for carrier generation, diffusion, and recombination. Fitting this model to the experimental profiles reveals a diffusion length exceeding one micron at 10 K, an unprecedented value for GaAs nanowires. This reflects the high crystal quality of our nanowires.

Keywords: Nanowires; Transport; Diffusion; Cathodoluminescence