Electronic states and chemical reactivity of Si(100)c(4 x 2) surface at low temperature studied by high resolution Si 2p core level photoelectron spectroscopy

We have investigated the electronic states of clean and BF3 adsorbed Si(l 0 0) surfaces at low temperature by means of high resolution Si 2p photoelectron spectroscopy. The peak intensities of upper atom and lower atom of the asymmetric dimer in Si 2p spectra do not change even at 30 K compared with those at higher temperature up to 300 K, indicating that the dimer is asymmetric in the ground state. In order to investigate chemical reactivity of asymmetric dimer on Si(I 0 0), a typical Lewis acid molecule BF3 is adsorbed on Si(I 0 0). We have found that BF3 molecules are dissociated into BF2 and F on Si(I 0 0) and dissociated species (BF2 and F) are adsorbed predominantly on the up dimer atoms of the asymmetric dimers. (C) 2003 Elsevier Science B.V. All rights reserved.