離子束合成法於二氧化矽基板合成金奈米粒子之光學性質研究

近年來，金奈米粒子的表面電漿子共振特性（Surface Plasmon Resonance，簡稱SPR），在訊號增強及生物檢測上，有著極大的應用潛力。此特性最明顯的表徵為在可見光波段具一強烈吸收區，並會將入射光侷限於奈米粒子周圍，並強化奈米粒子局域的電磁場，因而具有放大原有信號的效果，進而期望能增強材料光致發光（Photoluminescence，簡稱PL）的發光效率。在本論文中，透過離子束合成法於二氧化矽薄膜中合成金奈米粒子，輔以熱退火氣體及退火溫度等參數調變，形成不同尺寸及分佈的金奈米粒子，並於吸收光譜520 nm處觀察到金奈米粒子的特定吸收峰，同時觀察不同退火條件下，材料光致發光特性的變化。在PL圖譜中，出現多處明顯尖峰值，分別為310 nm、380 nm、450 nm及600 nm，分別代表類型不同類型之發光中心，而該類發光中心係源自於金奈米佈植二氧化矽基板所產生的氧缺陷中心（Oxygen Deficiency Centers，簡稱ODC）及未橋接氧空穴中心（Non-Bridging Oxygen Hole Centers，簡稱NBOHC）。研究結果顯示，不同退火氣體對於缺陷修復、金奈米粒子尺寸以及其分佈具有顯著的影響。發光中心等缺陷結構隨退火溫度的升高而逐漸修復，然PL強度卻隨之而上升，此乃因為金奈米粒子的SPR效應，對PL強度產生顯著的增幅作用，此外，在使用氮氣退火的狀況下，其缺陷的修復較使用空氣退火者緩慢，保留較多的發光缺陷結構，因此其PL強度較空氣退火者為強，值得一提的是，在使用氮氣退火的狀況下，形成較密集的金奈米粒子陣列，由SPR所貢獻的電場增幅效應亦較明顯，在此雙重效應的影響之下，使用氮氣退火較使用空氣退火者出現較為明顯的PL強度。總而言之，透過離子佈植並輔以適當的退火處理，金奈米粒子的SPR效應會增強局域性電磁場，並將原有信號放大作用，使得PL強度呈現明顯的增幅。

關鍵字

金奈米粒子；表面電漿子共振；離子束合成法

並列摘要

In recent years, gold (Au) nanoparticles have been synthesized by means of various methods and have received promising potential in optical and biomedical detection. Au nanoparticles contain some remarkable dimension-dependent optical properties due to surface plasmon resonance (SPR) in Au nanoparticles which causes strong absorption of the incident light in visible light regions. Since SPR in well-crystallized Au nanoparticles can enhance the local electromagnetic field, it is thus expected that a greater efficiency in the photoluminescence (PL), originating from oxygen deficiency centers (ODC), can be achieved in Au-implanted SiO2 matrix. In order to demonstrate the enhancement of PL, in this story, Au nanoparticles were formed in SiO2 film using ion beam synthesis and their optical and microstructural properties were also investigated as well. The results revealed that a clear absorption peak at approximately 520 nm was identified in the UV-Vis spectra and was attributed to SPR induced by Au nanoparticles in SiO2 film. The SPR of Au nanoparticles is also dependent on thermal treatment conditions, such as annealing gas, annealing temperature and annealing time. The Au nanoparticle-containing SiO2 film also displayed several distinctive peaks at approximately 310, 380, 450, and 600 nm in the PL spectra and were found to be associated with ODC-related defects and non-bridging oxygen hole centers (NBOHC) in SiO2 film. In addition, the PL peak intensities increase as annealing temperature increase, a finding contradictory to the defect recovery. The greatest PL emission was achieved when the Au-implanted SiO2 film was annealed at 1100 oC for 1 h under the nitrogen ambient. Therefore, the existence of Au nanoparticles in SiO2 film can induce SPR effects and enhance PL emission which was mainly due to defect dependent luminescence centers.

並列關鍵字

Au nanoparticles ； Surface plasmon resonance ； Ion beam synthesis

參考文獻

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離子束合成法於二氧化矽基板合成金奈米粒子之光學性質研究

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