[10p-Z05-1~19] 6.4 Thin films and New materials

[10p-Z05-3] Characterization of Surface diffusion in Na₂B₁₂H₁₁SH monolayer on Au(111)

〇(D)Takanori Harashima¹, Yoshihide Hattori², Hiroshi Shiigi³, Tomoaki Nishino¹ (1.Tokyo Institute of Technology, 2.Research Center of BNCT, Osaka Prefecture Univ., 3.Graduate School of Engineering, Osaka Prefecture Univ.)

Keywords:Scanning Probe Microscope, Self-Assembled Monolayer, Surface Diffusion

We demonstrate the first characterization of the surface structure of Na₂[B₁₂H₁₁SH] (Na₂BSH) on Au(111) using scanning tunneling microscopy (STM). The STM imaging clearly resolved the single BSH molecules and their partial hexagonal lattice. The time-lapse STM imaging allowed us to track the diffusion of the BSH molecules. Statistical evaluation of the movements of individual BSH molecules evaluated the diffusion coefficient of 4 × 10^-21 cm² s^-1. Furthermore, the coverage of BSH molecules is independent on the time. This result suggests that the diffusion of BSH is under the macroscopic equilibrium. These properties are distinctly different from the typical behavior of a self-assembled monolayer of e.g., alkanethiol in which the molecular diffusion is almost absent. The unique features of the BSH adlayer found in the present study provide novel strategies for the surface functionalization.