摻入金屬影響多孔矽及硒化鎘之光學性質研究

Influence of the incorporation of metals on the optical properties of MCM-41 and CdSe quantum dots

謝雅萍(Ya-Ping Hsieh)

指導教授 ： 梁啟德

共同指導教授 ： 陳永芳(YANG-FANG Chen)

國立臺灣大學/理學院/物理研究所/碩士(2005年)

https://doi.org/10.6342/NTU.2005.00021

摘要

在本論文中，我們詳細的研究了置入金屬對MCM-41和CdSe的光學性質影響。光激螢光光譜及光激營光激發光譜測量被用來探究其物理性質。這論文主要包括下面兩個部分：

1. 置入金屬對MCM-41和的光學性質影響

我們詳細的研究了置入金屬對MCM-4的光學性質影響。 利用光激螢光光譜及光激營光激發光譜探究一系列置入不同比例鋁成份的多孔氧化矽。我們發現當Si/Al比減少到14的時候，螢光增強了百倍以上。這原因機制來自於多孔氧化矽的帶電氧缺陷。而當金加入多孔氧化矽鋁之中時，利用電子順磁震盪及光激營光激發光譜的研究，我們發現在金奈米顆粒和多孔氧化矽鋁的帶電氧缺陷間有很強的交互作用力，也因此使得螢光光譜的強度劇烈的減弱。

2. Au/CdSe奈米複合物的巨大增強螢光的增強機制

內文討論金和硒化鎘奈米複合物的螢光增強和衰弱的機制。其機制被發現分別來自表面電漿波使得電子電動對變多以及電子由量子點硒化鎘轉移到金奈米粒子的費米能階。由我們提出的機制模型，量子點硒化鎘的螢光增強達到前所未有的140倍。我們的結果可以用來澄清以往利用金屬奈米結構的表面電漿現象在半導體奈米晶體在螢光增強機制上的困惑。我們呈現的機制在半導體奈米粒子在光電儀器上的運用和高效能生物標籤及固態發光體都相當的有用。

關鍵字

多孔氧化矽 ； 硒化鎘 ； 奈米粒子 ； 量子點 ； 螢光增強

並列摘要

In this thesis, we report the studies of Influence of the incorporation of metals on the optical properties of MCM-41 and CdSe will be reported. Photoluminescence (PL) and photoluminescence excitation (PLE) measurements are employed to characterize their physical properties. This thesis consists of two parts as described as following.

1. Influence of the incorporation of metals on the optical properties of
MCM-41

We presented the influence of the incorporation of metals on the optical properties of MCM-41. A series of Al-MCM-41 samples with different Al contents were investigated with photoluminescence (PL) and photoluminescence excitation (PLE). PL measurements revealed an enhancement in intensity by two orders as the Si : Al ratio decreases to 14. The transitions involved with charged oxygen vacancies as well as excess defects have been identified. When Au nanoparticles were deposited onto Al-MCM-41, the PL intensity decreases dramatically. With the help of electron paramagnetic resonance (EPR) and PLE, we found that there is a strong interaction between Au nanoparticles and charged oxygen defects, which is responsible for the reduction of related luminescent intensity.

2. Origin of giant emission enhancement in Au/CdSe nanocomposites

A mechanism responsible for the emission enhancement and quenching in Au and CdSe nanocomposites is presented. It is found that the underlying origin arises from the interlay between electron-hole pairs generation by surface plasmon wave and electrons transfer from CdSe quantum dots (QDs) to the Fermi level of Au nanoparticles. Based on our proposed mechanism, the enhancement of CdSe QDs emission can be tuned to reach a factor of up to 140 times, which is the largest value ever reported. It can be used to clarify the confusion in controlling the emission enhancement of semiconductor nanocrystals by using the interaction with surface plasmon of metal nanostructures. The mechanism presented here is very useful for the implementation of semiconductor nanoparticles in optoelectronic devices for applications as high efficiency biolabels and solid state emitters.

並列關鍵字

MCM-41 ； CdSe ； nanoparticle ； quantum dots ； Photoluminescence enhancement

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