Polarization study of molecules at surfaces by scanning probe method

近年来，动态力显微镜（DFM）及其相关技术取得了很大的进展。原子力显微镜（AFM）已被证明是一种强大的工具，用于对包括有机分子在内的各种材料进行无损、原子分辨率的成像，这通常是扫描隧道显微镜（STM）难以研究的。一些基于AFM的技术，如开尔文探针力显微镜（KFM）能够研究纳米尺度的电学性质。此外，原子力显微镜探针基本上可以使我们能够直接访问一个对象，并修改结构和/或属性。另一方面，由于分子和衬底之间界面处的电极化或局部电场与电结性质或铁电畴形成密切相关，因此在工程方面，理解界面极化的物理起源实际上是不可或缺的，特别是在分子极化控制在分子电子学中的应用，本项目证明了分子极化的评估和控制通过新开发的技术进行，这些技术是（1）高分辨率原子力显微镜，（2）具有精确控制的分子取向的分子沉积和（3）用于分子的电性质的基于纳米级DFM的测量技术。

There has been a great progress in dynamic force microscopy(DFM) and the related techniques. Atomic force microscopy(AFM) has been proved to be a powerful tool for nondestructive, atomic-resolution imaging of various materials including organic molecules, which are often difficult to be investigated by scanning tunneling microscopy(STM). Some of AFM-based techniques such as Kelvin-probe force microscopy(KFM) are capable of investigating nanometer-scale electrical properties. In addition, AFM probe can basically enables us to directly access an object and to modify the structures and/or the properties. On the other hand, since electrical polarization or local electric field at the interface between molecules and a substrate are strongly related to electrical junction properties or ferroelectric domain formation, it is actually indispensable for understanding the physical origins of the interfacial polarization in the engineering aspect, especially in the application of the polarization control of molecules to the molecular electronics.In this project we demonstrated that evaluation and control of molecular polarization was performed by newly developed techniques, which were (1)high-resolution atomic force microscopy, (2)molecule deposition with precisely controlled molecular orientation and (3)nanoscale DFM-based measurement techniques for electrical properties of molecules.