Abstract

Recently, metal nanoparticle surface coatings have been found to significantly enhance the ultra-violet luminescence intensity from ZnO, providing a viable means to mitigate optical losses and improve LED performance. Although there is general agreement that resonantly excited Localized Surface Plasmons (LSPs) in metal nanoparticles can directly couple to excitons in the semiconductor increasing their spontaneous emission rate, the exact mechanisms involved in this phenomenon are currently not fully understood. In this work, LSP-exciton coupling in bulk and nanostructured ZnO coated with a 2 nm Al nanoparticle layer is investigated using correlative photoluminescence and depth-resolved cathodoluminescence and time-resolved photoluminescence spectroscopy. Temperature-resolved cathodoluminescence and photoluminescence measurements from 10 K to 250 K show free exciton (FX) emission enhancement factors up to 12x at 80 K, and reveal that the FX couple more efficiently to the LSPs compared to the localized donor-bound excitons. A strong polarization dependence between the LSPs and FX is observed where FX transitions are more strongly enhanced when polarized in the same direction as the electric field of the incident excitation, which is different for laser and electron beam sources. This result indicates that selective enhancement of the excitonic emission peaks in the ZnO coated with Al nanoparticles can be achieved by choosing the appropriate ZnO substrate orientation.

Details

Title
Correlative Study of Enhanced Excitonic Emission in ZnO Coated with Al Nanoparticles using Electron and Laser Excitation
Author
Fiedler Saskia 1 ; Lem Laurent O Lee Cheong 2 ; Ton-That Cuong 3 ; Schleuning Markus 4 ; Hoffmann, Axel 4 ; Phillips, Matthew R 3 

 University of Technology Sydney, 15 Broadway, School of Mathematical and Physical Sciences, Ultimo, Australia (GRID:grid.117476.2) (ISNI:0000 0004 1936 7611); University of Southern Denmark, Campusvej 55, Centre for Nano Optics, Odense M, Denmark (GRID:grid.10825.3e) (ISNI:0000 0001 0728 0170) 
 University of Technology Sydney, 15 Broadway, School of Mathematical and Physical Sciences, Ultimo, Australia (GRID:grid.117476.2) (ISNI:0000 0004 1936 7611); Australian National University, Australian National Fabrication Facility, Canberra, Australia (GRID:grid.1001.0) (ISNI:0000 0001 2180 7477) 
 University of Technology Sydney, 15 Broadway, School of Mathematical and Physical Sciences, Ultimo, Australia (GRID:grid.117476.2) (ISNI:0000 0004 1936 7611) 
 Technische Universität Berlin, Fakultät II, Institut für Festkörperphysik, Sekretariat EW 5-4, Hardenbergstr. 36, Berlin, Germany (GRID:grid.6734.6) (ISNI:0000 0001 2292 8254) 
Publication year
2020
Publication date
2020
Publisher
Nature Publishing Group
e-ISSN
20452322
Source type
Scholarly Journal
Language of publication
English
ProQuest document ID
2354717554
Copyright
This work is published under http://creativecommons.org/licenses/by/4.0/ (the “License”). Notwithstanding the ProQuest Terms and Conditions, you may use this content in accordance with the terms of the License.