Issue 2, 2018

Passivation layers for nanostructured photoanodes: ultra-thin oxides on InGaN nanowires

Abstract

An experimental strategy for systematically assessing the influence of surface passivation layers on the photocatalytic properties of nanowire photoanodes by combining photocurrent analysis, photoluminescence spectroscopy and high resolution transmission electron microscopy with a systematic variation of sample structure and the surrounding electrolyte is demonstrated. Following this approach we can separate the impact on recombination and transport processes of photogenerated carriers. We apply this strategy to analyze the influence of ultra-thin TiO2, CeO2 and Al2O3 coatings deposited by atomic layer deposition on the photoelectrochemical performance of InxGa1−xN/GaN nanowire (NW) photoelectrodes. The passivation of surface states results in an increase of the anodic photocurrent (PC) by a factor of 2.5 for the deposition of 5 nm TiO2. In contrast, the PC is reduced for CeO2- and Al2O3-coated NWs due to enhanced defect recombination in the passivation layer or increased band discontinuities. Furthermore, photoelectrochemical oxidation of the InxGa1−xN/GaN NW photoelectrode is attenuated by the TiO2 layer and completely suppressed for a layer thickness of 7 nm or more. Due to efficient charge transfer from the InxGa1−xN NW core a stable TiO2-covered photoanode with visible light excitation is realized.

Graphical abstract: Passivation layers for nanostructured photoanodes: ultra-thin oxides on InGaN nanowires

Supplementary files

Article information

Article type
Paper
Submitted
13 Sep 2017
Accepted
06 Dec 2017
First published
06 Dec 2017

J. Mater. Chem. A, 2018,6, 565-573

Passivation layers for nanostructured photoanodes: ultra-thin oxides on InGaN nanowires

P. Neuderth, P. Hille, J. Schörmann, A. Frank, C. Reitz, S. Martí-Sánchez, M. D. L. Mata, M. Coll, J. Arbiol, R. Marschall and M. Eickhoff, J. Mater. Chem. A, 2018, 6, 565 DOI: 10.1039/C7TA08071A

To request permission to reproduce material from this article, please go to the Copyright Clearance Center request page.

If you are an author contributing to an RSC publication, you do not need to request permission provided correct acknowledgement is given.

If you are the author of this article, you do not need to request permission to reproduce figures and diagrams provided correct acknowledgement is given. If you want to reproduce the whole article in a third-party publication (excluding your thesis/dissertation for which permission is not required) please go to the Copyright Clearance Center request page.

Read more about how to correctly acknowledge RSC content.

Social activity

Spotlight

Advertisements