銀蒸鍍於不同基板之表面形貌對表面增強拉曼散射效應的影響

Abstract

本實驗以銀蒸鍍於AAO、玻璃基板、碳化矽及氮化鈦等基材，觀察銀在具有不同表面能的材料上所形成的表面形貌之差異，以及鍍銀量的多寡對其表面形貌的影響。經由掃瞄式電子顯微鏡與原子力顯微鏡觀察其表面形貌，與銀之接觸角較大的基板上會形成起伏較大的表面，而各基材最適合拉曼增強效應之鍍銀量亦不同。接著以表面上之奈米銀顆粒為表面增強拉曼散射效應之活化因子，使用氬雷射激發光源的拉曼光譜儀對稀薄濃度之生物染色分子Rhodamine 6G 進行偵測實驗。探討鍍銀量多寡、分子濃度高低、及分子於偵測基板的吸附時間長短等變因對於拉曼散射的表面增強效應之影響。從拉曼譜線中發現，偵測該分子最適宜的濃度約為1x10-5M，而偵測的濃度極限約為1x10-6M。當SiC基板表面銀鍍層30nm厚，TiN基板銀鍍層40nm厚，銀顆粒之間距近似於顆粒直徑(d≒2R)，且Rhodamine 6G分子吸附時間約30分鐘時，該分子之各個特徵峰值得到最大的增強效果。

Silver was deposited on the SiC and TiN substrates by thermal evaporation method. The silver morphology on the surface of various substrates was observed by scanning electron microscopy and atomic force microscopy. The morphology was different, owing to the different surface energy of substrates. The nanoscale silver particles on the surface of substrate were defined as an activation factor of Surface Enhanced Raman Scattering (SERS) effect, then the Raman scattering spectrometer by using an argon laser was used to detect the Rhodamine 6G molecule, to discuss the influence of silver amount, Rhodamine 6G molecule concentration, and adsorption time of molecules on SERS effect. From the Raman spectrum, it was revealed that the most suitable concentration to detect the Rhodamine 6G molecule is about 1x10-5M, and the utmost concentration is about 1x10-6M. That the thickness of silver on the surface of SiC and TiN substrates were 30nm and 40nm, respectively, had the optimal SERS effect.