拉曼光譜自從1970年後被發現後開始廣泛在研究中探討，主因就是拉曼散射是一個強力的分析技術，能將檢測物分子結構的資訊轉換成光譜圖，因而判斷檢測結果。近年來表面增強拉曼散射為一項主要開發的領域，從推陳出新的製程方式到後續的量測方法都發展出了一些相關的手法，而近50年來表面拉曼散射一直無法被廣泛應用在產業鏈上，最大的問題來自基板效果穩定度不佳以及高成本的問題。
因此在此論文中，我們提出了一種成本相對於市售的商用基板Klarite來的更便宜，且性能及穩定度高的基板。此文中首先是利用低深寬比(aspect ratio, AR)週期性奈米結構作為底材，主要藉由奈米結構增加表面積的優勢來製造更好的SERS效果，雖底材為PC材質會造成拉曼背景，因而我們先利用磁控濺鍍方式先去進行拉曼背景之覆蓋，隨後再進行微電漿輔助奈米銀粒子鍍膜製程有效去增加銀奈米粒子，其目的為了增強效果。
經由實驗結果證實在週期性奈米結構基板上進行微電漿奈米顆粒製程，相對於平坦基板能有效的增強拉曼訊號，而能達到上述功效主因是奈米結構能有效增加表面積，並且縮小銀奈米粒子之間的間距。另證實利用磁控濺鍍的方式鍍膜後，可將原先PC材質所造成的拉曼背景抑制住，所達到金屬覆蓋層的目的。後續再利用微電漿鍍膜製造出大量的銀奈米粒子來增加能量熱點密度，進而達到增強拉曼散射訊號的效果。最後也證實微電漿製程是影響表面增強拉曼散射的關鍵因素之一。
基板經由以上製程後達到我們所需的條件，因而反覆進行批次製程之間再現能力的測試以及基板均勻度的測試，最終進行待測物濃度曲線量測，在此選擇孔雀石綠作為標的，而選擇孔雀石綠作為標的物，是因為此待測物為是養殖漁業中經常被濫用於殺菌的禁藥。
最後結果得知單塊基板(3cm^2)區域變異係數 (coefficient of variation, CV)落在8%左右，批次之間的變異係數(CV)為6%，並且基板放置防潮箱內保存超過2個月的訊號強度仍保有最初強度的85%，此表現已達到應有水準。此外對於孔雀石綠(Malachite Green)最低檢測濃度能達8.4*10^-7M(306.5ppb)，增強因子為2.69*10^6，是一個具有高性能、低成本、並且有高穩定度的SERS基板。

Raman spectroscopy has been widely applied since its discovery in 1970 because Raman scattering is a powerful analytical technique that can transfer spectrum from measuring the molecular structure information. In recent years, surface-enhanced Raman scattering (SERS) has been a major area of development, from the development of new process methods to subsequent measurement methods, and some related techniques. However, the challenge for SERS substrate to be applied in the industry is its low stability and high costs.
Therefore, in this paper, we proposed a SERS substrate that is cheaper than the commercial (KlariteTM) substrate, and it has high performance and high stability. Then, we used a low aspect ratio periodic nanostructure as the substrate, which has the advantage of increasing surface area and enhancing the SERS effect. Although the polymer substrate may suffer from complex Raman background, we can overcoat a metal by sputter process to suppress the background. Moreover, we used microplasma-assisted growth of silver nanoparticles to further enhance the SERS effect.
In our experiments, it is found that the periodic nanostructure substrate is more effective in enhancing the signal compared to the flat substrate. The periodic nanostructure substrate can effectively increase the surface area and reduce the gap between the silver nanoparticles. Moreover, it is demonstrated that there is an original Raman background by PC material, and we suppressed the Raman background by magnetron sputtering coating. Finally, a microplasmas coating process was used to produce a large number of silver nanoparticles to enhance the SERS effect.
After iterating and optimizing the above process, the SERS substrates reach our requirement, so the concentration curve can be measured base on a certain extent of batch-to-batch reproducibility and substrate uniformity. The test target for the concentration curve is malachite green (MG), which is abused in aquaculture fisheries for fungicide.
The final results showed that the coefficient of variation (CV) of the SERS substrate uniformity was about 8% in a single substrate (3cm^2), the CV value of the batch-to-batch reproducibility was within 6%. In addition, when the substrate was stored in a moisture-proof box for two months, the performance of the SERS substrate still remained 85% of its initial condition. The limit of detection (LOD) of Malachite Green can reach 8.4*10^-7M(306.5ppb), and the enhancement factor of the SERS substrate is 2.69*10^6, which is a high performance, low cost, and highly stable SERS substrate.

[1] Liu, K., Zhao, Q., Li, B., and Zhao, X., 2022, “Raman Spectroscopy: A Novel Technology for Gastric Cancer Diagnosis,” Front. Bioeng. Biotechnol., 10, p. 856591.
[2] Willets, K. A., and Van Duyne, R. P., 2007, “Localized Surface Plasmon Resonance Spectroscopy and Sensing,” Annu. Rev. Phys. Chem., 58(1), pp. 267–297.
[3] Lee, P. C., and Meisel, D., 1982, “Adsorption and Surface-Enhanced Raman of Dyes on Silver and Gold Sols,” J. Phys. Chem., 86(17), pp. 3391–3395.
[4] Li, J. F., Huang, Y. F., Ding, Y., Yang, Z. L., Li, S. B., Zhou, X. S., Fan, F. R., Zhang, W., Zhou, Z. Y., Wu, D. Y., Ren, B., Wang, Z. L., and Tian, Z. Q., 2010, “Shell-Isolated Nanoparticle-Enhanced Raman Spectroscopy,” Nature, 464(7287), pp. 392–395.
[5] Li, J. F., Tian, X. D., Li, S. B., Anema, J. R., Yang, Z. L., Ding, Y., Wu, Y. F., Zeng, Y. M., Chen, Q. Z., Ren, B., Wang, Z. L., and Tian, Z. Q., 2013, “Surface Analysis Using Shell-Isolated Nanoparticle-Enhanced Raman Spectroscopy,” Nat. Protoc., 8(1), pp. 52–65.
[6] Panneerselvam, R., Liu, G.-K., Wang, Y.-H., Liu, J.-Y., Ding, S.-Y., Li, J.-F., Wu, D.-Y., and Tian, Z.-Q., 2018, “Surface-Enhanced Raman Spectroscopy: Bottlenecks and Future Directions,” Chem. Commun., 54(1), pp. 10–25.
[7] Wang, A., and Kong, X., 2015, “Review of Recent Progress of Plasmonic Materials and Nano-Structures for Surface-Enhanced Raman Scattering,” Materials, 8(6), pp. 3024–3052.
[8] Lu, Y.-C., Chiang, W.-H., Liu, C.-Y., Chu, J. P., Ho, H.-C., and Hsueh, C.-H., 2021, “Wafer-Scale SERS Metallic Nanotube Arrays with Highly Ordered Periodicity,” Sens. Actuators B Chem., 329, p. 129132.
[9] Goetz, S., Bauch, M., Dimopoulos, T., and Trassl, S., 2020, “Ultrathin Sputter-Deposited Plasmonic Silver Nanostructures,” Nanoscale Adv., 2(2), pp. 869–877.
[10] Huang, J.-A., Zhao, Y.-Q., Zhang, X.-J., He, L.-F., Wong, T.-L., Chui, Y.-S., Zhang, W.-J., and Lee, S.-T., 2013, “Ordered Ag/Si Nanowires Array: Wide-Range Surface-Enhanced Raman Spectroscopy for Reproducible Biomolecule Detection,” Nano Lett., 13(11), pp. 5039–5045.
[11] Kang, G., Matikainen, A., Stenberg, P., Färm, E., Li, P., Ritala, M., Vahimaa, P., Honkanen, S., and Tan, X., 2015, “High Aspect-Ratio Iridium-Coated Nanopillars for Highly Reproducible Surface-Enhanced Raman Scattering (SERS),” ACS Appl. Mater. Interfaces, 7(21), pp. 11452–11459.
[12] Shao, F., Lu, Z., Liu, C., Han, H., Chen, K., Li, W., He, Q., Peng, H., and Chen, J., 2014, “Hierarchical Nanogaps within Bioscaffold Arrays as a High-Performance SERS Substrate for Animal Virus Biosensing,” ACS Appl. Mater. Interfaces, 6(9), pp. 6281–6289.
[13] Jeon, H., Kang, N.-R., Gwak, E.-J., Jang, J., Han, H. N., Hwang, J. Y., Lee, S., and Kim, J.-Y., 2017, “Self-Similarity in the Structure of Coarsened Nanoporous Gold,” Scr. Mater., 137, pp. 46–49.
[14] Huang, J., He, Z., Liu, Y., Liu, L., He, X., Wang, T., Yi, Y., Xie, C., and Du, K., 2019, “Large Surface-Enhanced Raman Scattering from Nanoporous Gold Film over Nanosphere,” Appl. Surf. Sci., 478, pp. 793–801.
[15] Fang, C., Shapter, J. G., Voelcker, N. H., and Ellis, A. V., 2014, “Electrochemically Prepared Nanoporous Gold as a SERS Substrate with High Enhancement,” RSC Adv, 4(37), pp. 19502–19506.
[16] Shi, G., Wang, M., Zhu, Y., Wang, Y., and Ma, W., 2018, “Synthesis of Flexible and Stable SERS Substrate Based on Au Nanofilms/Cicada Wing Array for Rapid Detection of Pesticide Residues,” Opt. Commun., 425, pp. 49–57.
[17] Cai, J., Liu, R., Jia, S., Feng, Z., Lin, L., Zheng, Z., Wu, S., and Wang, Z., 2021, “SERS Hotspots Distribution of the Highly Ordered Noble Metal Arrays on Flexible Substrates,” Opt. Mater., 122, p. 111779.
[18] Chiang, W., Mariotti, D., Sankaran, R. M., Eden, J. G., and Ostrikov, K. (Ken), 2020, “Microplasmas for Advanced Materials and Devices,” Adv. Mater., 32(18), p. 1905508.
[19] Yeh, Y.-J., and Chiang, W.-H., 2021, “Ag Microplasma-Engineered Nanoassemblies on Cellulose Papers for Surface-Enhanced Raman Scattering and Catalytic Nitrophenol Reduction,” ACS Appl. Nano Mater., 4(6), pp. 6364–6375.
[20] “富優技研，檢自http://Www.Fortechgrps.Com/Index.Php?Option=com_content&view=article&id=87&Itemid=387&lang=tw.”
[21] 鄭錦華, “真空技術網，檢自http://Www.Chvacuum.Com/Application/Sputter-Coating/126017.Html.”
[22] “國立臺灣科技大學，檢自https://Sppic.Ntust.Edu.Tw/p/404-1058-74152.Php?Lang=zh-Tw.”
[23] Nergui, N., Chen, M.-J., Wang, J.-K., Hsing, C.-R., Wei, C.-M., and Takahashi, K., “Dependence of Adenine Raman Spectrum on Excitation Laser Wavelength: Comparison between Experiment and Theoretical Simulations,” J. Phys. Chem., p. 21.
[24] Chi, T. T. K., Le, N. T., Hien, B. T. T., Trung, D. Q., and Liem, N. Q., 2017, “Preparation of SERS Substrates for the Detection of Organic Molecules at Low Concentration,” Commun. Phys., 26(3), p. 261.
[25] Lin, D. Z., Chen, Y. P., Jhuang, P. J., Chu, J. Y., Yeh, J. T., and Wang, J.-K., 2011, “Optimizing Electromagnetic Enhancement of Flexible Nano-Imprinted Hexagonally Patterned Surface-Enhanced Raman Scattering Substrates,” Opt. Express, 19(5), p. 4337.