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

Autor: Dellis, S., Kalfagiannis, N., Kassavetis, S., Bazioti, C., Dimitrakopulos, G. P., Koutsogeorgis, D. C., Patsalas, P.
Předmět:
Zdroj: Journal of Applied Physics; 2017, Vol. 121 Issue 10, p1-6, 6p, 1 Diagram, 5 Graphs
Abstrakt: 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 backreflected 248 nm laser beam. [ABSTRACT FROM AUTHOR]
Databáze: Complementary Index