Structure of ultra-thin silicon film on HOPG studied by polarization-dependence of X-ray absorption fine structure

• Published in: Chemical physics letters Vol. 594; pp. 64 - 68
• Main Authors: Baba, Y., Shimoyama, I., Hirao, N., Sekiguchi, T.
• Format: Journal Article
• Language: English
• Published: Elsevier B.V 20.02.2014
• ISSN: 0009-2614; 1873-4448
• DOI: 10.1016/j.cplett.2014.01.025

•Structures of mono-layered silicon on HOPG have been investigated.•XANES spectra show the existence of π∗ and σ∗ orbitals in 0.15 monolayered silicon.•Polarization dependences of XANES show that a part of Si film lies flat on surface.•The results support the existence of graphene-like structure in mono-layered silicon. Structures of mono-layered silicon on a highly oriented pyrolytic graphite (HOPG) have been investigated by X-ray photoelectron spectroscopy and X-ray absorption near edge structure (XANES). For the Si K-edge XANES spectrum of the 0.15 mono-layered film, two distinct peaks were observed, which were assigned to the resonant excitations from the Si 1s into the valence unoccupied orbitals with π∗ and σ∗ characters. On the basis of the polarization dependences of the peak intensities, it was concluded that a part of the Si film lies flat on the HOPG surface, which supports the existence of two-dimensional graphene-like structure in mono-layered silicon.