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ID 19369
file
creator
Sakamoto, Kazuyuki
Kondo, Daiyu
Ushimi, Yoshimitsu
Harada, Masashi
Kakizaki, Akito
Suto, Shozo
abstract
We report here the temperature-dependent measurements of the valence spectra, the C 1s and the Si 2p core level spectra of the one monolayer C60 film adsorbed on Si(001)-(2x1) and Si(111)-(7x7) surfaces, using photoelectron spectroscopy. At 300 K, most C60 molecules are physisorbed with the coexistence of minority chemisorbed species on both Si(001)-(2x1) and Si(111)-(7x7) surfaces. After annealing the samples at 670 K, C60 molecules change the bonding nature to a chemisorption that has both covalent and ionic characters. The covalent bonding orbital is observed at a binding energy of 2.10 eV on both Si surfaces. The amount of charge transfer is estimated to be 0.19 electrons per C60 molecule on the Si(001) surface, and to be 0.21 electrons per molecule on the Si(111) surface. We consider the origin of the change in bonding nature to the different distance between two dangling bonds that results from the rearrangement of the surface Si atoms. After annealing at 1070 K, C60 molecules decompose and the SiC formation takes progress at the interface. On the Si(001) surface, the molecular orbitals (MO's) disappear at 1120 K and the binding energies of peaks observed in the valence spectra indicate the formation of SiC islands at this temperature. On the Si(111) surface, the disappearance of MO's and the formation of SiC islands are verified at 1170 K. The difference in formation temperature is attributed to the different surface structure.
journal title
Physical Review B - Condensed Matter and Materials Physics
volume
Volume 60
issue
Issue 4
start page
2579
end page
2591
date of issued
1999-01-25
publisher
American Physical Society
issn
0163-1829
ncid
publisher doi
language
eng
nii type
Journal Article
HU type
Journal Articles
DCMI type
text
format
application/pdf
text version
publisher
rights
Copyright (c) 1999 The American Physical Society.
relation url
department
Graduate School of Science



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