Photoluminescence enhancement of ZnO via coupling with surface plasmons on Al thin films

Dellis, S., Kalfagiannis, N. ORCID: 0000-0002-4030-5525, Kassavetis, S., Bazioti, C., Dimitrakopulos, G.P., Koutsogeorgis, D.C. ORCID: 0000-0001-6167-1084 and Patsalas, P., 2017. Photoluminescence enhancement of ZnO via coupling with surface plasmons on Al thin films. Journal of Applied Physics, 121 (10), p. 103104. ISSN 0021-8979

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Abstract

We present that the ultra-violet emission of ZnO can be enhanced, as much as six-times its integral intensity, using an Al thin interlayer film between the Si substrate and ZnO thin film and a postfabrication laser annealing process. The laser annealing is a cold process that preserves the chemical state and integrity of the underlying aluminum layer, while it is essential for the improvement of the ZnO performance as a light emitter and leads to enhanced emission in the visible and in the
ultraviolet spectral ranges. In all cases, the metal interlayer enhances the intensity of the emitted light, either through coupling of the surface plasmon that is excited at the Al/ZnO interface, in the case of light-emitting ZnO in the ultraviolet region, or by the increased back reflection from the Al layer, in the case of the visible emission. In order to evaluate the process and develop a solid understanding of the relevant physical phenomena, we investigated the effects of various metals as interlayers (Al, Ag, and Au), the metal interlayer thickness, and the incorporation of a dielectric spacer layer between Al and ZnO. Based on these experiments, Al emerged as the undisputable best
choice of metal interlayers because of its compatibility with the laser annealing process, as well as due to its high optical reflectivity at 380 and 248 nm, which leads to the effective coupling with surface plasmons at the Al/ZnO interfaces at 380 nm and the secondary annealing of ZnO by the back-reflected 248 nm laser beam.

Item Type:	Journal article
Publication Title:	Journal of Applied Physics
Creators:	Dellis, S., Kalfagiannis, N., Kassavetis, S., Bazioti, C., Dimitrakopulos, G.P., Koutsogeorgis, D.C. and Patsalas, P.
Publisher:	AIP Publishing (American Institute of Physics)
Date:	14 March 2017
Volume:	121
Number:	10
ISSN:	0021-8979
Identifiers:	Number Type 10.1063/1.4977954 DOI
Divisions:	Schools > School of Science and Technology
Record created by:	Jill Tomkinson
Date Added:	07 Apr 2017 14:15
Last Modified:	10 Mar 2018 03:00
URI:	https://irep.ntu.ac.uk/id/eprint/30497

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