Na-induced (7×7)-to-(3×1) structural transformation on a Si(111)7×7 surface and the resulting passivation of the surface towards interaction with oxygen

Abstract

Auger-electron spectroscopy, electron-energy-loss spectroscopy, low-energy electron-diffraction, and thermal-programmed-desorption measurements were performed in order to characterize the effect of small amounts of Na on the Si(111) surface structure and reactivity towards oxygen. We have observed a passivation effect of Na with respect to the oxygen adsorption rate and surface oxidation in the case when Na induces a (7\ifmmode\times\else\texttimes\fi{}7)-to-(3\ifmmode\times\else\texttimes\fi{}1) structural transformation of the initial Si(111)7\ifmmode\times\else\texttimes\fi{}7 surface.