Reactivity towards O-2 and H2O of the alkali-metal induced Ge(111)-3 x 1 surfaces: contrasting adsorption rates for different alkali metals

Abstract

Using photoemission and Auger-electron spectroscopies, we investigated the reactivity towards oxygen and water of the alkali-metal induced Ge(I 11)-3 x I surface at room temperature. The adsorption of both gases on the Ge(I 11)3 x I surfaces induced by Na and K are significantly suppressed, but greatly enhanced on the Li-induced Ge(I 11)73 x I surface. This difference in the surface reactivity of the alkali-metal induced Ge(I 11)-3 x I surfaces contrasts not only to the expectation of the similar reactivity inferred from the common 3 x I reconstruction structure, but to the trends in the elemental alkali metals. It is proposed that the competition of the dangling-bond saturation and the AM-mediated oxidation determine the surface reactivity of the Ge(I 1 l)-3 x 1 surfaces. (C) 2003 Elsevier Science B.V. All rights reserved.