ALKALI-METALS ADSORPTION-KINETICS ON SPUTTERED AND CLEAVED GAAS(110) SURFACES

We comparatively investigated the room temperature adsorption kinetics of Cs and K on the GaAs(110) surface either cleaved or sputter processed. Ar+ induced surface modifications have been characterized in terms of stoichiometry, crystalline order and chemical bonding. After metal deposition, interfaces were analyzed by Auger electron spectroscopy. Differences in the amount of adsorbate atoms, in the interfacial reactivity and segregation behaviour have been found between simply cleaved or cleaved + sputter-processed substrates. On the contrary, the sticking coefficient in the early adsorption stage, the active adsorption sites and the reaction products are very similar.