Adsorption State of 4,4 ''-Diamino-p-terphenyl through an Amino Group Bound to Si(111)-7 x 7 Surface Examined by X-ray Photoelectron Spectroscopy and Scanning Tunneling Microscopy

作者：Nishimura Takashi; Itabashi Atsushi; Sasahara Akira; Murata Hideyuki; Arai Toyoko; Tomitori Masahiko^*

来源：Journal of Physical Chemistry C, 2010, 114(25): 11109-11114.

DOI：10.1021/jp102976a

The adsorption of 4,4 ''-diamino-p-terphenyl (DAT) on Si(111)-7 x 7 at room temperature (RT) is examined using X-ray photoelectron spectroscopy (XPS) and scanning tunneling microscopy (STM). At low coverages of DAT, the XPS peak from N(1s) in two amino groups of a DAT is decomposed into two peaks with almost the same intensity, corresponding to the binding state of a N atom in Si-NH-terphenyl and to that in NH(2)-terphenyl, respectively. This indicates that the DAT is chemically bonded to the Si surface even at RT through one amino group at one end of the DAT, and the other amino group at the other end is intact. In empty-state STM images, round protrusions of similar to 0.3 nm high are found over center Si adatom sites, possibly attributed to the binding site of DAT. The positions of some protrusions in the empty-state STM images slightly shift in the filled-state images. To compare the empty and the filled-state STM images, we propose a model for the DAT aslant bound to the Si surface through an amino group at the one end of DAT with a preferential orientation within the half cell of 7 x 7.

• 出版日期2010-7-1