Characterization of the B/Si surface electronic structures

High resolution angle resolved core level and valence band photoelectron spectroscopy have been used to characterize the electronic structures of the B/Si(111)-(√3 x √3) surfaces. The results have been compared with theoretic calculations and other group III metals and Si terminated Si(111) surfaces that share the same type of surface reconstruction. We have observed a structure evolution from B-T4 to B-S5 and finally to Si- T4 as deposited boron atoms diffuse into the substrate with increasing annealing temperature. The chemically shifted component appearing in the Si 2p core level spectrum is attributed to charge transfer from the top layer Si and Si adatoms to the sublayer B-S5 atoms. For the Si/Si(111)-(√3 x √3) surface, a newly discovered chemically shifted component is associated with back bond formation between the Si adatoms and the underneath Si atoms. A new emission feature has been observed in the valence band spectra unique to the B/Si(111)-(√3 x √3) surface with B-S5 configuration. Thin Ge layer growth on this structure has also been performed, and we found that no epitaxial growth could be achieved and the underneath structure was little disturbed