Enhancement of Emission Efficiency of Deep-Ultraviolet AlGaN Quantum Wells Through Surface Plasmon Coupling with an Al Nanograting Structure
Journal
Plasmonics
Journal Volume
13
Journal Issue
3
Pages
863-872
Date Issued
2018
Author(s)
Chia-Ying Su
Wei-Han Chen
Yang Kuo
Chun-Han Lin
Ming-Yen Su
Meng-Che Tsai
Wen-Yen Chang
Chieh Hsieh
Charng-Gan Tu
Yu-Feng Yao
Hao-Tsung Chen
Abstract
The enhancement of the internal quantum efficiency (IQE) of deep-ultraviolet AlxGa1-xN/AlyGa1-yN (x < y) quantum wells (QWs) by fabricating one-dimensional Al nanogratings on a QW structure for inducing surface plasmon (SP) coupling is demonstrated. Through temperature-dependent photoluminescence (PL) measurement, the enhancements of IQE in different emission polarizations are illustrated. Due to the small difference in energy band level between the heavy/light hole and split-off valence bands, the IQEs of the transverse electric- (TE-) and transverse magnetic- (TM-) polarized emissions are about the same. When emission polarization is perpendicular to Al-grating ridges, the SP resonance mode for coupling with the QWs is dominated by localized surface plasmon (LSP). When emission polarization is parallel with Al-grating ridges, the coupled SP resonance mode may mix LSP and SP polariton. In this polarization, LSP can be excited because of the width fluctuation of a grating ridge. When the excitation laser polarization is perpendicular to Al-grating ridges, the strong LSP resonance at the excitation laser wavelength leads to stronger excitation and hence higher IQE levels. © 2017, Springer Science+Business Media New York.
Subjects
Deep ultraviolet; Internal quantum efficiency; Light-emitting diode; Localized surface plasmon; Surface plasmon resonance
Type
journal article