表面增強拉曼散射(SERS)光譜可將材料表面所吸附分子的拉曼訊號增強數倍，且廣泛用於分子分析應用、醫藥及環境工程等。近年來，很多文獻利用不同金屬基板增加其表面積以達到訊號提升之效果。本研究利用微影製程、磁控濺鍍技術製造出規則的金屬玻璃奈米管(MGNT)陣列，得到在5 mm^2區域上擁有1,600,000,000個單獨的奈米管，其直徑約為650 nm，高度為650 nm。金屬玻璃具備優異的機械性質及化學性質，且為一非晶結構，相較於其他結晶金屬更可以避免在拉曼光譜中於晶界中產生的散射。
本研究中，首先探討9種不同金屬玻璃鍍層之介電常數作為SERS基材選用考量，並成功製備出5種不同金屬玻璃成分的奈米管陣列，分別為：鎳基(Ni38.5B1.0Si52.7Cr2.1Fe5.7)、鈦(Ti38Zr10.3Cu37.4Nb6.6Co7.7)、銅基(Cu48Zr42Al6Ti4)、鎢基(W82.9Ni9.9B7.2)及鈀基 (Pd73.8Cu12.5Si13.7)，由於鈀基金屬玻璃鍍層(TFMG)具備良好的介電常數及貴金屬不易氧化之性質，因此以鈀基為此研究之SERS基板。
本研究中主要選用結晶紫Crystal Violet (CV)分子做為檢測SERS增強效果之代測物，因為其廣泛被用於拉曼單分子研究，且具有非常大的拉曼散射截面積，此外為有效確定CV分子吸附於金屬玻璃奈米管，將進行未清洗及清洗兩組試驗分析，發現CV最低濃度可分別測得10^-11 M及10^-10 M，且相較於矽基板與TFMG靈敏許多，其增強因子高達6.39 × 10^8，這可以歸咎於MGNT的表面粗糙度為207 nm，遠高於TFMG的0.428 nm，因而提供了更多CV分子吸附的面積。除此之外，再經清洗過的奈米管中，藉由過SEM觀察浸泡CV溶液前後奈米管於相同位置的變化，發現當濃度為10^-3 M時管壁厚度增加約33％，且管壁厚度大都來自於奈米管外壁之吸附，隨著CV濃度的降低至10^-10 M，管壁厚度增加降低為22％，然而在10^-11 M時管壁僅僅增加約7% (可視為誤差範圍值內)，而造成無法於10^-11 M中檢測到CV的存在，因此確認了CV吸附量與拉曼增強之間的量化關係；本文亦討論未清洗之奈米管，發現當濃度為10-3 M時管壁厚度大幅增加約63％，當濃度降低至10^-10 M，管壁厚度增加降低為23％，然而在10^-11 M時管壁增加約20%，相較於清洗過後之奈米管有顯著差異。同時利用FIB及TEM做橫切的奈米管陣列的觀察，也進一步證實CV的吸附層隨著CV濃度增加而增厚，且附著於外徑。除此之外，透過FDTD模擬結果與Raman mapping結果相互證實了奈米管的熱點存在，不只在奈米管中及頂端可發現電磁增強效果，且於奈米管之間隙亦達到增強訊號。整體而言，金屬玻璃奈米管陣列除了提供大的表面積可增強拉曼強度外，亦可觀察到CV分子吸附的情形。本研究亦採用大分子的葉酸Folic Acid (FA)進行分析，作為與小分子CV吸附之對照組實驗，於 FA最低濃度可檢測得10^-7 M，進一步證明金屬玻璃奈米管陣列能有效使用於SERS分子吸附之檢測應用。

Surface-enhanced Raman scattering (SERS) is a way to significantly increase the intensity of Raman signals of the material molecules adsorbed on the surface, which is widely used in molecular analysis applications, medicine, and environmental engineering. Recently, many kinds of literature have used different metal substrates to increase the surface area and roughness to realize signal enhancement. Therefore, in this study, lithography was used in the patterning of a contact-hole array to fabricate a regular nanotube array by sputter-depositing a coating of metallic glass. The resulting metallic glass nanotube (MGNT) array possesses 1,600,000,000 individual nanotubes on a 5 mm^2 area with the hole diameter was ~650 nm, and height was ~650 nm. Moreover, metallic glasses with the disordered atomic structure have unique mechanical and chemical properties. Compared with the crystal metal, amorphous metallic glasses have no scattering at grain boundaries.
In this study, the dielectric constants were first investigated as the selection of SERS substrates of nine systems of thin film metallic glasses (TFMGs). After that, we successfully fabricated five systems of MGNTs arrays such as Ni- (Ni38.5B1.0Si52.7Cr2.1Fe5.7), Ti- (Ti38Zr10.3Cu37.4Nb6.6Co7.7), Cu- (Cu48Zr42Al6Ti4), W- (W82.9Ni9.9B7.2), and Pd- (Pd73.8Cu12.5Si13.7) based MGNTs. Pd-based TFMG is selected as the SERS substrate because it is a noble metal and has a negative dielectric constant.
In the experiment, the crystal violet (CV) is selected for probe molecule for its large Raman cross-section. There are two sets of samples (with and without DI water rinse) in order to effectively determine the adsorption of CV molecules on the metallic glass nanotubes. It is discovered that the limit of detection of CV solution are 10^-10 M and 10^-11 M, respectively, with and without water rinse. These are more sensitivity than Si substrate and TFMG, and the enhancement factor is 6.39 × 10^8. This can be attributed to the surface roughness of MGNT is 207 nm much higher than 0.428 nm of TFMG. Thus, it provides more CV molecule adsorption area. In addition, with DI water rinse, the samples were examined by SEM before and after immersing in CV solution with water rinse at exactly the same five locations. The increment in wall thickness is ~33% for 10^-3 M, and decreases of the CV concentration to 10^-10 M is ~22%. The increase in wall thickness is mostly due to the adsorption of CV molecules on the outer wall. However, the negligible increment of ~7% for 10^-11 M is considered to be within experimental error and insignificant in Raman signal. Therefore, the quantitative relationship between the amount of CV adsorption and Raman enhancement was confirmed. Moreover, CV adsorptions without water rinse are also discussed in the appendix. The increment in wall thickness is ~63% for 10^-3 M, and decreases of the CV concentration to 10^-10 M is ~23%. However, the wall thickness increases ~20% for 10^-11 M, which is more significantly different from that of with water rinse. Cross-sectional FIB-prepared TEM observations have been carried out to further characterize the CV-adsorption on the wall of nanotube, confirming the presence of CV molecules on the outer wall. Moreover, the simulation results and Raman mapping were confirmed the existence of hot spots in MGNTs. The EM field strongly enhances in the top of nanotube arrays and gradually decreases to the nanotube gaps. Overall, MGNTs not only provide the large surface area to enhance the Raman signal, but also allow us to quantify the adsorption of CV molecules. In this study, macromolecule folic acid (FA) was also selected for a comparison study. The limit of detection in this case was 10^-7 M. It thus is further confirmed that metal glass nanotube arrays can be effectively applied to the two different types of molecule adsorption for SERS applications.

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