Significant performance enhancement of InGaN/GaN nanorod LEDs with multi-layer graphene transparent electrodes by alumina surface passivation

Journal article


Publication Details

Author(s): Latzel M, Buettner P, Sarau G, Hoeflich K, Heilmann M, Chen W, Wen X, Conibeer G, Christiansen SH
Journal: Nanotechnology
Publication year: 2017
Volume: 28
Journal issue: 5
ISSN: 1361-6528


Abstract

Nanotextured surfaces provide an ideal platform for efficiently capturing and emitting light. However, the increased surface area in combination with surface defects induced by nanostructuring e.g. using reactive ion etching (RIE) negatively affects the device's active region and, thus, drastically decreases device performance. In this work, the influence of structural defects and surface states on the optical and electrical performance of InGaN/GaN nanorod (NR) light emitting diodes (LEDs) fabricated by top-down RIE of c-plane GaN with InGaN quantum wells was investigated. After proper surface treatment a significantly improved device performance could be shown. Therefore, wet chemical removal of damaged material in KOH solution followed by atomic layer deposition of only 10 nm alumina as wide bandgap oxide for passivation were successfully applied. Raman spectroscopy revealed that the initially compressively strained InGaN/GaN LED layer stack turned into a virtually completely relaxed GaN and partially relaxed InGaN combination after RIE etching of NRs. Time-correlated single photon counting provides evidence that both treatments---chemical etching and alumina deposition---reduce the number of pathways for non-radiative recombination. Steady-state photoluminescence revealed that the luminescent performance of the NR LEDs is increased by about 50% after KOH and 80% after additional alumina passivation. Finally, complete NR LED devices with a suspended graphene contact were fabricated, for which the effectiveness of the alumina passivation was successfully demonstrated by electroluminescence measurements.


FAU Authors / FAU Editors

Latzel, Michael
Institut für Optik, Information und Photonik


Additional Organisation
Exzellenz-Cluster Engineering of Advanced Materials


External institutions with authors

Max-Planck-Institut für die Physik des Lichts (MPL) / Max Planck Institute for the Science of Light
University of New South Wales (UNSW)


Research Fields

C Photonic and Optical Materials
Exzellenz-Cluster Engineering of Advanced Materials


How to cite

APA:
Latzel, M., Buettner, P., Sarau, G., Hoeflich, K., Heilmann, M., Chen, W.,... Christiansen, S.H. (2017). Significant performance enhancement of InGaN/GaN nanorod LEDs with multi-layer graphene transparent electrodes by alumina surface passivation. Nanotechnology, 28(5). https://dx.doi.org/10.1088/1361-6528/28/5/055201

MLA:
Latzel, Michael, et al. "Significant performance enhancement of InGaN/GaN nanorod LEDs with multi-layer graphene transparent electrodes by alumina surface passivation." Nanotechnology 28.5 (2017).

BibTeX: 

Last updated on 2019-25-03 at 09:18