SURFACE PLASMON POLARITON-AIDED RAMAN SPECTROSCOPIC STUDY ON FILM GROWTH MECHANISMS

表面等离子体偏振辅助拉曼光谱研究薄膜生长机制

基本信息

批准号：
05453083
负责人：
HATTA Aritada
金额：
$ 3.97万
依托单位：
TOHOKU UNIVERSITY
依托单位国家：
日本
项目类别：
Grant-in-Aid for General Scientific Research (B)
财政年份：
1993
资助国家：
日本
起止时间：
1993 至 1995
项目状态：
已结题

项目摘要

1) In order to investigate the adsorption of p-aminothiophenol (PATP) on silver, Raman scattering experiments were performed by exciting surface plasmon polaritons on Ag island films. The silver films were prepared by vacuum evaporation as a mass thickness of 5nm on BaF_2 plates. The plates were dipped into ethanol solutions containing 1 mM PATP.The Raman spectra were measured as a function of dipping time. At the initial stages of the adsorption of PATP on Ag, the Raman signals from PATP increased in proprtion to the square root of dipping time, suggesting that the adsorption rate was conditioned by the diffusion of PATP in the solution. The Raman band due to the Ag-S stretching vibration was also detected at near 220cm^<-1>, which demonstrates a direct contact of the S atom with Ag. These results were supported by our FT-IR experiments.2) Raman scattering was measured for iron pentacarbonyl (IPC) deposited in vacuum at 120K on flat and rough Ag film surfaces. At elevated temperatures IPC was molecularly desorbed from the surface. Illumination of IPC with UV light from a low pressure Hg lamp decreased the Raman signals, but no significant changes were observed in the spectra. Upon heating the substrate up to 200K under UV irradiation, the two C-O stretch bands in the 2000 cm^<-1> region disappeared and, instead, two novel bands appeared. These spectral changes are thought to arise from a structural change of IPC or its conversion into other Fe-carbonyl species. Another spectral change was found near 260K under UV illumination. It should be noted that the Raman signals were more intense on rough silver surfaces than on flat ones. This enhancement of Raman signals from the rough surfaces are explained by the SPP excitations of Ag. Thus, through these investigations, we could demonstrate the usefulness of the SPP-aided Raman spectroscopy in getting information on surface reactions and deposition processes, most of which had been ambiguous.

1）为了研究对氨基苯硫酚（PATP）在银上的吸附，通过激发银岛膜上的表面等离子体激元进行拉曼散射实验。通过真空蒸镀在BaF_2板上制备厚度为5nm的银膜。将板浸入含有 1 mM PATP 的乙醇溶液中。测量拉曼光谱作为浸渍时间的函数。在 PATP 吸附在 Ag 上的初始阶段，PATP 的拉曼信号与浸渍时间的平方根成正比增加，表明吸附速率受溶液中 PATP 扩散的影响。在220cm ^ -1 附近还检测到由于Ag-S伸缩振动而产生的拉曼带，这表明S原子与Ag直接接触。这些结果得到了我们的 FT-IR 实验的支持。2) 测量了 120K 真空中沉积在平坦和粗糙银膜表面上的五羰基铁 (IPC) 的拉曼散射。在高温下，IPC 从表面分子解吸。用低压汞灯发出的紫外光照射 IPC 会降低拉曼信号，但在光谱中未观察到显着变化。当在UV照射下将基底加热至200K时，2000cm ^ -1 区域中的两个C-O拉伸带消失，取而代之的是，出现了两个新的带。这些光谱变化被认为是由 IPC 的结构变化或其转化为其他铁羰基物质引起的。在紫外线照射下，在 260K 附近发现了另一个光谱变化。应该指出的是，拉曼信号在粗糙的银表面上比在平坦的表面上更强烈。粗糙表面拉曼信号的增强可以通过 Ag 的 SPP 激发来解释。因此，通过这些研究，我们可以证明 SPP 辅助拉曼光谱在获取表面反应和沉积过程信息方面的有用性，其中大部分信息是不明确的。