製作週期性氧化鋅奈米柱懸架式金圓盤形雙子奈米結構應用於表面增強拉曼散射

本論文成功以電子束微影系統製作週期性氧化鋅奈米柱懸架式金圓盤形雙子奈米結構並且研究此結構於表面增強拉曼散射之應用。利用水熱法成長氧化鋅奈米柱於經電子束微影設計後的基板上，再鍍金圓盤形雙子於氧化鋅奈米柱上表面而形成此具有電漿奈米共振腔效應之結構。此外，利用金圓盤形雙子/氧化鋅奈米柱異質結構中氧化鋅促發載子傳遞增強機制來進一步提升表面增強拉曼散射。以實驗手法搭配理論模擬探討週期性氧化鋅奈米柱懸架式金圓盤形雙子奈米結構中圓盤半徑、雙子間隙距離以及奈米柱高度對暗場顯微散射光譜及表面增強拉曼散射光譜之效應。當實驗製作的奈米結構有著較大的圓盤半徑、較近的雙子間隙距離以及200奈米高的奈米柱時會產生更好的表面增強拉曼散射增益效果。在實驗製作的不同奈米柱高度奈米結構中，由於侷域表面電漿共振產生的表面增強拉曼散射光譜，其增益因子可以利用時域有限差分法進行探討。經由模擬計算而得的增益因子對奈米柱高度呈現週期性變化趨勢並且與實驗所得拉曼光譜結果相符。除此之外，利用照射紫外光而誘發氧化鋅奈米柱的光觸媒效果，便能夠有效地降解待測分子，使此表面增強拉曼散射基板具有可重複使用之功能。

關鍵字

電漿子學；氧化鋅奈米柱懸架式金圓盤形雙子；表面增強拉曼散射光譜；電子束微影；電漿奈米共振腔效應

並列摘要

The EBL-defined periodic ZnO-elevated gold dimer nanostructures for surface-enhanced Raman spectroscopy with strong electromagnetic field enhancement were successfully fabricated and studied in the present work. The ZnO nanorods were grown on patterned substrate through hydrothermal process and the Au dimers were deposited on the top surface of ZnO nanorods, forming suspended gold dimer providing plasmonic hot-spots with nanocavity effect. Moreover, the Au/ZnO heterostructure could further enhance SERS signals with the chemical enhancement of ZnO to charge-transfer induced surface-enhanced Raman scattering. The effects of dimer radius, gap size and ZnO nanorod height on the dark-field scattering spectra and SERS were investigated experimentally and theoretically. The performance of fabricated substrates in SERS response was enhanced with increasing dimer radius, decreasing gap size and ZnO nanorod height at 200 nm. The enhancement factor of surface-enhanced Raman spectroscopy due to the localized surface plasmon resonance with different ZnO nanorod height was also calculated using finite-element time-domain (FDTD) method. The simulated EF as the functions of ZnO nanorod height showed the periodic trend of Raman intensity which was in agreement with the SERS response in experiments. In addition, the photocatalytic properties of Au/ZnO hybrid system were exploited through the degradation of probed molecules under UV-irradiation to demonstrate a reusable SERS-active substrate.

並列關鍵字

Plasmonics ； ZnO-elevated gold dimer ； Surface-enhanced Raman Spectroscopy ； Electron beam lithography ； Plasmonic nanocavity effect

參考文獻

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[2] L.B. Yang, W.D. Ruan, X. Jiang, B. Zhao, W.Q. Xu, J.R. Lombardi, Contribution of ZnO to Charge-Transfer Induced Surface-Enhanced Raman Scattering in Au/ZnO/PATP Assembly, J Phys Chem C 113(1) (2009) 117-120.

[3] A.V. Zayats, I.I. Smolyaninov, Near-field photonics: surface plasmon polaritons and localized surface plasmons, J Opt a-Pure Appl Op 5(4) (2003) S16-S50.

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[5] S.A. Maier, H.A. Atwater, Plasmonics: Localization and guiding of electromagnetic energy in metal/dielectric structures, J Appl Phys 98(1) (2005).

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製作週期性氧化鋅奈米柱懸架式金圓盤形雙子奈米結構應用於表面增強拉曼散射

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