快速微波輔助合成氧化鋅奈米線陣列於表面增強拉曼散射之應用

Abstract

氧化鋅奈米結構具備有獨特的化學與物理特性，導致其可以廣泛的應用於各種領域。氧化鋅奈米結構已經成功被透過各種方式所製備，如熱蒸鍍、化學氣相沈積、電沈積與水熱法。在眾多的成長方式當中以水熱法最受矚目，其具備有反應溫度低、簡單、成本低廉與環境保護。在水熱法成長氧化鋅奈米線陣列往往受限於反應儀器，導致其需要較長的反應時間才能有效進行成長。對照於過去常見的水熱法，利用微波輔助的水熱法合成因具備有很多優點，導致在材料科學上引起廣泛的興趣，其優點如快速加熱、低反應溫度、同質熱傳導與純度佳。在本論文已經成功利用微波輔助加熱方式成長氧化鋅奈米線陣列於表面包覆有氧化鋅核種之矽基板上，並且氧化鋅奈米線陣列長度可以透過微波加熱參數可以得到有效控制，如反應溫度、反應時間、反應瓦數、1,3-二胺基丙烷的量與反應程序步驟。氧化鋅奈米線陣列的特性可以透過穿透式電子顯微鏡、掃瞄式電子顯微鏡、光激發光譜儀、陰極激發光譜儀與紫外可見光光譜儀觀察。 透過濺鍍方式沈積銀奈米粒子均勻沈積於最佳化的微波輔助水熱法成長之氧化鋅奈米線陣列上，此三維結構之氧化鋅與銀奈米粒子的複合奈米線陣列可以做為表面增強拉曼散射之基材。藉由適當的銀濺鍍沈積時間可以得到最佳化基材於表面增強拉曼散射在偵測羅丹明6G分子上。這最佳化之基材也可以用於偵測其他分子如：羅丹明B與馬來酸（順丁烯二酸）。透過結合氧化鋅奈米線陣列與銀奈米粒子可以提供一個簡易、高增強效率、低偵測極限（羅丹明6G（1 nM）），低成本，此方法可能有效於在偵測其他分子的應用。

ZnO nanostructures have received lots of interests in various areas of novel applications induced by their unique chemical and physical properties. ZnO nanostructures have been successfully synthesized by thermal evaporation, chemical vapor deposition (CVD), electrodeposition and hydrothermal method. Among these synthetic methods, hydrothermal method is low temperature, simple, inexpensive and environment friendly method. However, it takes for a long time to grow well-aligned ZnO nanowire arrays for hydrothermal method due to the restriction of heating devices. Compared with conventional hydrothermal method, microwave hydrothermal synthesis has attracted wide interests as a novel heating model in material science due to its many advantages, including rapid heating, low reaction temperature, homogeneous thermal transmission, and the phase purity with better yield. In this thesis, ZnO nanowire arrays were successfully grown on ZnO seeds coated silicon substrate by a microwave-assisted hydrothermal process. The length of ZnO nanowire arrays can be significantly controlled by temperature, time, power, volume of 1, 3-Diaminopropane (DAP), and program steps. Transmission electron microscopy (TEM), scanning electron microscopy (SEM), photoluminescence (PL) spectroscopy, cathodoluminescence (CL) spectroscopy and UV–vis spectroscopy are utilized to characterize the ZnO nanowire arrays. The well-aligned ZnO nanowire arrays synthesized in optimized condition were coated with silver nanoparticles by sputtering process. The three-dimensional (3D) structure of ZnO/Ag composite nanowire arrays can be used as the substrate of surface-enhanced Raman scattering (SERS). The appropriate sputtering time of Ag were optimized to yield the greatest SERS effect in rhodamine 6G molecule. The optimizing substrate can also be used to detect rhodamine B and maleic acid. The combination of ZnO nanowire arrays and Ag nanoparticles provides a facile, high enhancement, low detection limit (rhodamine 6G (1 nM)) and low cost fabrication, which shall be of significant value for practical applications of other molecular sensing systems.