The Si-rich 3C-type (001) 3 x 2 surface was studied by using high-resolution core-level photo-emission methods. Well-resolved Si 2p and C 1s core-level spectra were measured at a temperature of about 120K. Three different Si 2p surface components were clearly identified, with binding-energy shifts of -0.58, -0.92 and -1.27eV. The presence of these components, and their intensity ratios, were consistent with a structural model which involved 2/3 of a monolayer of additional Si dimers, but were incompatible with another model which assumed only 1/3 of a monolayer of Si dimers.

H.W.Yeom, Y.C.Chao, S.Terada, S.Hara, S.Yoshida, R.I.G.Uhrberg: Physical Review B, 1997, 56[24], R15525-8