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

1)为了研究对氨基噻吩（PATP）对银的吸附，在银岛膜上进行了激发表面等离子激元的拉曼散射实验。采用真空蒸发法制备了质量厚度为5nm的银膜。将板浸入含有1mm PATP的乙醇溶液中。拉曼光谱随浸渍时间的变化而变化。在PATP吸附Ag的初始阶段，来自PATP的拉曼信号与浸渍时间的平方根成正比增加，表明吸附速率取决于PATP在溶液中的扩散。在220cm^<-1>附近还检测到Ag-S拉伸振动引起的拉曼带，这表明S原子与Ag直接接触。这些结果得到了FT-IR实验的支持。2)测定了真空下沉积的五羰基铁（IPC）在平坦和粗糙银膜表面的拉曼散射。在高温下，IPC分子从表面解吸。低压汞灯紫外光照射下，IPC的拉曼信号降低，但光谱没有明显变化。当基材在UV照射下加热至200K时，2000 cm^<-1>区域的两个C-O拉伸带消失，取而代之的是两个新的条带。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。应该注意的是，拉曼信号在粗糙的银表面上比在平坦的银表面上更强烈。Ag的SPP激发解释了粗糙表面拉曼信号的增强。因此，通过这些研究，我们可以证明spp辅助拉曼光谱在获得表面反应和沉积过程信息方面的有用性，其中大多数是模糊的。

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.