Regensburg 2019 – scientific programme

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HL: Fachverband Halbleiterphysik

HL 24: Nitrides: Preparation and characterization I

HL 24.5: Talk

Wednesday, April 3, 2019, 10:30–10:45, H31

Photo-induced selective etching of GaN nanowires in water — •Florian Pantle, Max Kraut, Julia Winnerl, Martin Hetzl, Felix Eckmann, and Martin Stutzmann — Walter Schottky Institut and Physics Department, Technische Universität München, Garching, Germany

GaN nanowires (NWs) have gained much interest in current research as they are promising candidates for photo-catalytic water splitting devices. A key requirement is the stability of these nanostructures under operational conditions. Despite many reports regarding anodic oxidation and photo-electrochemical stability of bulk GaN, both including p- and n-type material and different crystallographic facets in aqueous environments, these properties have remained widely unexplored for GaN NWs.

We have investigated the stability of GaN NWs under illumination in water. While the non-polar m-plane side walls of the NWs are decomposed under the applied conditions, the polar c-plane top facet is stable. Photo-induced holes are found to be responsible for this effect. Further, the crystal quality is found to be a decisive parameter. All hexagonal NWs show a characteristic etching morphology, which is explained by means of numerical band structure simulations. Additionally, we present a chemical and a structural pathway to stabilize the GaN NWs against the applied environments.