Dissociative chemisorption of water on the Si(111) 7*7 surface studied at 150 K by X-ray photoelectron spectroscopy and energy loss spectroscopy

Abstract

The dissociative chemisorption of water vapour on the Si(111) 7*7 surface at 150 K and the effect of annealing have been studied using X-ray photoelectron spectroscopy and energy loss spectroscopy. From the data the authors may deduce that at 0.25 L the water molecule begins to adsorb on the adatom site and 'rest'-atom site of the unit cell and immediately dissociates to form a silicon hydroxyl Si-OH group (and probably an SiN group), but no evidence for molecularly adsorbed water is observed. After subsequent annealing from 150 K up to 900 K, they observe decomposition of the Si-OH group, oxidation of the silicon surface and then re-establishment of the clean surface.