Dresden 2020 – scientific programme
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HL: Fachverband Halbleiterphysik
HL 62: Focus Session: Functional Metal Oxides for Novel Applications and Devices II (joint session HL/DS)
HL 62.6: Invited Talk
Thursday, March 19, 2020, 11:30–12:00, POT 81
Ultra-thin oxides on InGaN nanowires: Passivation layers for nanostructured photoelectrodes and optical analysis of chemical processes — Paula Neuderth2, Mariona Coll3, Jörg Schörmann2, Christian Reitz6, Jordi Arbiol4, Roland Marschall5, and •Martin Eickhoff1,2 — 1Institute of Solid State Physics, University of Bremen, Germany — 2Institute of Experimental Physics I Justus Liebig University Giessen Germany — 3Institut de Ciencia de Materials de Barcelona ICMAB-CSIC, Spain — 4ICREA Pg. Lluís Companys 23 08010 Barcelona, Spain — 5Physical Chemistry III, University of Bayreuth, Germany — 6Institute of Nanotechnology (INT), Karlsruhe Institute of Technology, Germany
We demonstrate an experimental strategy for systematically assessing the influence of surface passivation layers on the photocatalytic properties of InGaN nanowire (NW) photoanodes by combining photocurrent analysis, photoluminescence spectroscopy and high resolution transmission electron microscopy. We apply this approach to separate the influence of different mechanisms recombination and transport processes of photogenerated carriers and to compare the effect of TiO2, CeO2 and Al2O3 coatings deposited by atomic layer deposition. Due to efficient charge transfer from the InGaN NW core a stable TiO2-covered photoanode with visible light excitation is realized. As a second application we demonstrate that due to the sensitivity of the InGaN NW photoluminescence to surface adsorbed oxygen the optical analysis of oxygen diffusion in ultrathin ceria coatings deposited by atomic layer deposition is possible.