Enhancement of Emission Efficiency of Deep-ultraviolet AlGaN Quantum Wells through Surface Plasmon Coupling with an Al Protrusion Array
| Autor: | Shih-Heng Sun, 孫士恆 |
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| Rok vydání: | 2016 |
| Druh dokumentu: | 學位論文 ; thesis |
| Popis: | 104 The enhancement of internal quantum efficiency (IQE) of deep-ultraviolet (UV) AlxGa1-xN/AlyGa1-yN (x < y) quantum wells (QWs) by fabricating Al nano-protrusion arrays 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. With SP coupling, the similar IQEs between different polarizations can also be attributed to the simultaneous SP couplings of the TE- and TM-polarized transitions. The SP resonance mode for coupling with the QWs is dominated by higher-order localized surface plasmon (LSP). The strong LSP resonance at the excitation laser wavelength may lead to stronger excitation and hence higher IQE levels of the QWs. The IQE enhancement decreases with the distance between Al-protrusion tip and the QWs. |
| Databáze: | Networked Digital Library of Theses & Dissertations |
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