Controling of the atom-scale metallic low-dimensional structures and infrared response

该项目的目的是通过实现以原子尺度精度控制的人工和自组织过程，开发一种新的方法来测量和应用原子尺度微小金属物体中的低维等离子体。除了在超高真空条件下进行分子束外延外，我们还利用胶体悬浮液中的纳米颗粒沉积，在液固界面处生长金属覆盖层。利用红外吸收光谱法监测了金纳米颗粒的原位吸附，并利用非原位扫描选择显微镜和原子力显微镜对生长膜进行了表征。通过将实际空间微观信息与红外吸收光谱和可见光光谱获得的光谱信息相关联，研究了结构特性与光学特性之间的关系。特别是我们将红外光谱特征与生长的扁平金纳米片的结构特征联系起来，并将这些信息应用于金薄膜的优化，以便将该薄膜应用于表面增强红外吸收光谱（SEIRAS）。制备的薄膜对巯基分子单层具有很强的吸收增强，吸收强度达到20%。我们已经申请了一项专利，并通过学院公关部进行了新的发布。原子尺度等离子体项目已发展为硅衬底原子链上一维等离子体的研究。我们首次在台阶状硅表面上发现了自组织的Au和in原子链中的一维Tomonaga等离子体。我们还通过佩尔斯不稳定性澄清了等离子体在金属到绝缘体跃迁中的行为。研究结果发表在几篇论文中，并在欧洲的一些大学和一些会议上进行了邀请演讲和研讨会。

The aim of the project was to develop a new methodology for the measurement and application of low-dimensional-type plasmons confined in atomic- scale tiny metallic objects via realizing artificial and selforganizing processes which are controlled with atomic-scale precision. In addition to the molecular beam epitaxy in ultrahigh vacuum condition, we also adopted the metallic overlayer growth at the liquid solid interface by using nanoparticle deposition from colloidal suspension. We monitored in situ the adsorption of gold nanoparticles by using infrared absorption spectroscopy and also characterized the grown film by ex situ scanning election microscopy and atomic force microscopy. We have investigated the relation between structural characteristics and the optical characteristics by correlating the real space microscopic information and the spectral information obtained by infrared absorption spectroscopy as well as visible spectroscopy. Especially we have correlated the infrared spectral feature to the structural feature of the grown flat Au nanosheet, and applied this information to the optimization of the au film for applying this film to surface enhanced infrared absorption spectroscopy (SEIRAS). The fabricated film has shown very high enhancement showing 20 percent absorption intensity for monolayer of thiol molecule. We have applied a patent and did a new release thorough the institute public relations department. The project on the atom-scale plasmon is developed into the study of one-dimensional plasmons in atom chains on silicon substrates. We have detected for the first time the 1D Tomonaga plasmon in Au and In atom chains self organized on stepped silicon surfaces. We also clarified the behavior of plasmons at the metal-to-insulator transition via Peierls instability. The results have been published in several paper and invited talks and seminar were done in several conferences and in some universities in Europe.