材料科学
双层
红外光谱学
X射线光电子能谱
光谱学
分析化学(期刊)
微晶
吸收光谱法
衰减全反射
薄膜
红外线的
纳米技术
化学工程
化学
光学
膜
有机化学
物理
工程类
量子力学
冶金
生物化学
作者
Nobuto Ohta,Kamba Nomura,Ichizo Yagi
出处
期刊:Langmuir
[American Chemical Society]
日期:2010-11-02
卷期号:26 (23): 18097-18104
被引量:16
摘要
Surface-enhanced infrared absorption (SEIRA)-active Au/Ti bilayer films sputter deposited on Si substrates have been prepared by an electrochemical annealing (ECA) treatment for the first time. The application of Au/Ti bilayer films on Si substrates to the spectroscopic technique is a promising alternative to the conventional technique using directly deposited Au films on Si substrates, offering excellent adhesive durability of the deposited metal films. However, Au/Ti bilayer films have never been selected for the spectroscopy technique because the films in the as-prepared state exhibit relatively smooth surface morphology: the excitation of the localized surface plasmon is vital to achieving SEIRA enhancements but could hardly be observed on the smooth morphology. It is shown by ex situ scanning tunneling microscopy measurements that the unfavorable smooth morphology of the as-prepared Au/Ti bilayer films can be modified by the ECA treatment to a reasonably rough, island-structure morphology similar to that of the conventional SEIRA-active Au films. In situ infrared absorption spectroscopy of adsorbed sulfate anions has been conducted on the Au/Ti bilayer film both before and after ECA treatment. The spectroscopy measurements demonstrate that the SEIRA activity of the film after being subjected to the treatment is significantly improved so that the technique could detect adsorbates on the film electrodes even with the submonolayer coverage. As an additional benefit, the ECA treatment has brought about a substantial increase in the fraction of Au(111) domains on the polycrystalline Au film surfaces. Accordingly, this approach enables us to prepare SEIRA-active Au films having sufficient adhesion to the Si substrates as well as the highly preferred (111) orientation.
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