在氮化銦鎵/氮化鎵量子井奈米柱結構上膠體量子點的光色轉換行為

Abstract

本論文中，我們在藍光氮化銦鎵/氮化鎵量子井模板上製作奈米柱結構，並讓表面貼附紅光量子點及銀奈米顆粒，以研究量子井及量子點之間的光色轉換行為。銀奈米顆粒的侷域表面電漿子共振會產生表面電漿子耦合效應並提升量子點的光色轉換效率。同時，當量子點貼附在奈米柱側壁上，量子井與量子點之間極短的距離會造成福斯特共振能量轉移，能再進一步提升光色轉換效率。我們通過改變奈米柱的高度來控制貼附在奈米柱側壁上的量子點與銀奈米顆粒的相對位置，以研究量子井與量子點在不同情況下的發光行為。福斯特共振能量轉移的過程能同時增大量子點的內部量子效率及光致發螢光衰減時間，這與量子井的行為不同。藉由同時在奈米柱表面接上銀奈米顆粒與量子點，表面電漿子耦合效應能進一步提升量子井及量子點的內部量子效率，並降低它們的光致發螢光衰減時間。表面電漿子耦合能夠提升福斯特能量轉移效率。

Nanorod (NR) structures on a blue-emitting InGaN/GaN quantum-well (QW) templates with linked red-emitting quantum dots (QDs) and Ag nanoparticles (NPs) onto NR surface are fabricated for studying the color conversion behaviors from QW emission into QD emission. The localized surface plasmon (LSP) resonance of the Ag NPs produces surface plasmon (SP) coupling effects for enhancing QD color conversion efficiency. Also, the short distance between QWs and QDs when QDs attach onto the sidewalls of NRs leads to the Förster resonance energy transfer (FRET) process from QW into QD for further enhancing the color conversion efficiency. We change the NR height for controlling the relative positions of QWs and sidewall-linked QDs and Ag NPs to observe the different emission behaviors of QW and QD. The FRET process can simultaneously increase QD internal quantum efficiency (IQE) and photoluminescence (PL) decay time that shows a different variation trend from that of QW. By applying Ag NPs together with QDs onto NR surface, the SP coupling effect can further enhance the IQEs of QW and QD, and reduce their PL decay times.The SP coupling can increase the FRET efficiency.