Molecular Nanocorrals on Si(111)-(7x7): Temperature-Dependent Site Selectivity

作者：Mao, Wei; He, Jing Hui; Xi, Yong Jie; Chen, Wei; Wu, Kai; Zhang, Chun; Tok, Eng Soon; Xu, Guo Qin^*

来源：Journal of Physical Chemistry C, 2016, 120(43): 24780-24788.

DOI：10.1021/acs.jpcc.6b07477

• SCANNING-TUNNELING-MICROSCOPY
• LOCALIZED ATOMIC REACTION
• SURFACE DANGLING BONDS
• AUGMENTED-WAVE METHOD
• X 7
• ELECTRON-DIFFRACTION
• ORGANIC-MOLECULES
• ADSORPTION
• CHEMISORPTION
• CHEMISTRY

Chemisorbed molecular nanocorrals on semiconductor surfaces are of both fundamental and technical importance. 1-Propanethiol molecules adsorbed on Si(111)-(7X7) were investigated using high-resolution energy loss spectroscopy (HREELS), scanning tunneling microscopy (STM), and periodic density functional theory (DFT) calculations. HREELS spectra show that the 1-propanethiol molecules undergo S-H bond dissociative adsorption on Si(111)-(7X7). STM images reveal the temperature-dependent site selectivity for the binding of C3H7S- fragments. At room temperature, C3H7S-prefers to bind to faulted subunits compared to Unfaulted subunits. At 110 K, C3H7S- binding on center adatoms over corner adatoms is dominant, resulting in an ordered array of molecular nanocorrals. DFT calculations were performed on a periodic slab including the entire 7X7 reconstruction rather than on a cluster model. The theoretical studies suggest that the temperature-dependent site selectivity originates from the thermal-plus-electron-induced diffusion of dissociative products and the site-preferential accommodation of the mobile physisorbed precursors. Our results provide a fundamental understanding on the origin of site selectivity of molecular binding on Si(111)-(7x7).

• 出版日期2016-11-3
• 单位苏州大学; 北京大学