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

该项目的目的是通过实现原子尺度精确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型等离子激元。除了在超高真空条件下的分子束外延外，我们还采用了胶体悬浮液中纳米粒子沉积的液-固界面金属覆盖层生长方法。我们用红外吸收光谱原位监测了金纳米颗粒的吸附，并用非原位扫描电子显微镜和原子力显微镜对生长的薄膜进行了表征。我们通过将红外吸收光谱和可见光光谱获得的光谱信息与实际空间微观信息进行关联，研究了结构特征与光学特性之间的关系。特别是，我们将生长的平坦Au纳米片的红外光谱特征与结构特征进行了关联，并将此信息应用于Au薄膜的优化，从而将其应用于表面增强红外吸收光谱(SEIRAS)。所制备的薄膜具有很高的增强效果，对硫醇分子的单分子层有20%的吸收强度。我们已经申请了一项专利，并通过研究所公关部进行了新的发布。原子尺度的等离子体激元计划被发展为研究硅衬底上原子链中的一维等离子体激元。我们首次在Au和台阶硅表面自组织的原子链中发现了一维Tomonaga等离激元。我们还通过Peierls不稳定性阐明了等离子体在金属到绝缘体转变过程中的行为。研究结果已发表在几篇论文上，并在欧洲的几个会议和一些大学进行了应邀演讲和研讨会。

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.