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International Journal of Photoenergy
Volume 2015, Article ID 140617, 6 pages
http://dx.doi.org/10.1155/2015/140617
Research Article

Plasmon-Enhanced Photoluminescence of an Amorphous Silicon Quantum Dot Light-Emitting Device by Localized Surface Plasmon Polaritons in Ag/SiOx:a-Si QDs/Ag Sandwich Nanostructures

Graduate Institute of Photonics and Optoelectronics and Department of Electrical Engineering, National Taiwan University, No. 1, Section 4, Roosevelt Road, Taipei 106, Taiwan

Received 19 December 2014; Accepted 30 March 2015

Academic Editor: Jun Zhu

Copyright © 2015 Tsung-Han Tsai et al. This is an open access article distributed under the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.

Abstract

We investigated experimentally the plasmon-enhanced photoluminescence of the amorphous silicon quantum dots (a-Si QDs) light-emitting devices (LEDs) with the :a-Si QDs/Ag sandwich nanostructures, through the coupling between the a-Si QDs and localized surface plasmons polaritons (LSPPs) mode, by tuning a one-dimensional (1D) Ag grating on the top. The coupling of surface plasmons at the top and bottom :a-Si QDs interfaces resulted in the localized surface plasmon polaritons (LSPPs) confined underneath the Ag lines, which exhibit the Fabry-Pérot resonance. From the Raman spectrum, it proves the existence of a-Si QDs embedded in Si-rich film (:a-Si QDs) at a low annealing temperature (300°C) to prevent the possible diffusion of Ag atoms from Ag film. The photoluminescence (PL) spectra of a-Si QDs can be precisely tuned by a 1D Ag grating with different pitches and Ag line widths were investigated. An optimized Ag grating structure, with 500 nm pitch and 125 nm Ag line width, was found to achieve up to 4.8-fold PL enhancement at 526 nm and 2.46-fold PL integrated intensity compared to the a-Si QDs LEDs without Ag grating structure, due to the strong a-Si QDs-LSPPs coupling.