利用原子層沉積技術探討表面電漿子在金屬微結構上之表現

Plasmonic Activity of Metallic Nanostructures Grown by Atomic Layer Deposition

柯忠廷(Chung-Ting Ko)

指導教授 ： 謝宗霖

共同指導教授 ： 陳敏璋

國立臺灣大學/工學院/材料科學與工程學研究所/博士(2014年)

https://doi.org/10.6342/NTU.2014.10171

摘要

原子層沉積技術 (atomic layer deposition, ALD) 是當今製備高品質表面電漿子 (plasmonics) 奈米微結構中，非常受到重視與仰賴之具有原子級精準度 (monolayer accuracy) 的沉積技術。自我侷限反應 (self-limiting reaction) 與逐層 (layer-by-layer) 薄膜成長的特性，提供 ALD 製程許多優勢，包含原子級精準的厚度控制、高深寬比結構上的保形與階梯覆蓋能力 (conformal step coverage)、大面積均勻度、低缺陷密度、高製程重複度、以及低製程沉積溫度。因此，藉由 ALD 的數位化 (digitally) 精準控制能力，可以製備出高品質的表面電漿子多層膜奈米微結構。此外，藉由自我侷限反應與寬廣的 ALD 製程窗口 (ALD window) 的特性，可以沉積具有大面積均勻度與高製程重複度的金屬奈米微結構。
另一方面，存在於金屬奈米微結構中的侷域表面電漿子共振 (localized surface plasmon resonance, LSPR) 波長，可以藉由下面兩項因素去調整：(1) 金屬奈米微結構的大小與形狀、(2) 金屬奈米微結構周圍的介電系數。由於 ALD 製程技術的特性，可以以數位化的方式，逐步改變金屬奈米微結構周圍的介電系數，使侷域表面電漿子共振波長可以與激發雷射光的波長，或是與螢光材料的發光波長重合。在本論文中，將侷域表面電漿子共振效應用來增強氧化鋅奈米薄膜發光強度，與增強氧化鋯高介電系數閘極氧化層之拉曼訊號。並利用此方法成功觀察到厚度僅有 2 nm 的氧化鋅薄膜的量子井效應，以及僅有 6 nm 的氧化鋯薄膜的單斜晶體與四方晶體拉曼訊號。
藉由 ALD 技術製備的高品質表面電漿子奈米多層膜微結構，具有高增強係數、高精準度、可調性、高均勻度、與高製程重複性的特性，並且在未來的研究上，可以應用於敏感的生物檢定與固態發光材料、以及檢測固態奈米薄膜與元件。

關鍵字

原子層沈積技術 ； 表面電漿子 ； 侷域表面電漿子共振 ； 表面增強拉曼散射 ； 表面增強發光 ； 高介電系數閘極氧化層

並列摘要

Atomic layer deposition (ALD) has been recognized as one of the most promising techniques for preparing high quality plasmonic nanostructures with monolayer accuracy. Self-limiting reaction and layer-by-layer growth of ALD provide a lot of advantages, including accurate thickness control, conformal step coverage, excellent uniformity, low defect density, good reproducibility, and low deposition temperatures. Thus the plasmonic nanostructures and multilayer structures can be prepared “digitally” in a precise and well-controlled manner by ALD. In addition, the self-limiting growth and wide process window of ALD is of great benefit to the precise fabrication of the uniformly-dispersed metallic nanostructures with high reproducibility and uniformity over a large area.
On the other hand, since the localized surface plasmon resonance (LSPR) of the plasmonic nanostructures can be spectrally tuned by engineering the (1) size and shape of the plasmonic nanostructures, and (2) dielectric environment, the “digital” growth of the plasmonic nanostructures and the surrounding dielectrics by ALD offers an alternative way to accurately tailor the LSPR wavelength for spectral matching with the excitation wavelengths and luminescence/absorbance of the light emitter. In this thesis, giant enhancement of photoluminescence from the ZnO emitter and Raman scattering from ZrO2 high-K dielectrics were achieved, which facilitates the observation of significant quantum confinement effect in the nanoscale ZnO layer as thin as ~2 nm and the monoclinic/tetragonal phases in the nanoscale ZrO2 high-K dielectrics as thin as ~6 nm, respectively.
The accurate plasmonic nanostructures and multilayer structures, grown by ALD with high enhancement, accuracy, tunability, uniformity, and reproducibility, can be further applied to sensitive bioassays/biosensing and efficient solid-state lighting, and materials characterization of a variety of solid-state ultrathin films in nanosclae materials and devices in future studies.

並列關鍵字

Atomic Layer Deposition ； Plasmonics ； Localized Surface Plasmon Resonance ； Surface-Enhanced Luminescence ； Surface-Enhanced Raman Scattering ； High-K Gate Dielectrics

參考文獻

Reference

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