Low-energy electron diffraction analysis of the structure of a Cs-O/Ru(0001) coadsorbate phase

The structure of the (√3 × √3 )R30° overlayer formed by coadsorption of Cs and O atoms (θCs=θ0=0.33) on a Ru(0001) surface was determined by low-energy electron diffraction. Both adsorbates occupy hcp-type hollow sites. If compared with the structures of the respective pure adsorbate phases, the bond lengths are modified in a way consistent with an effective transfer of electronic charge from Cs to O

Der Halbleiter CsAu: Struktur und elektronische Eigenschaften duenner Filme auf Ru(001)

Available from TIB Hannover: MA 6497 / FIZ - Fachinformationszzentrum Karlsruhe / TIB - Technische InformationsbibliothekSIGLEDEGerman

Preparation and characterization of thin CsAu films

The formation of CsAu films by successive evaporation of gold and caesium atoms onto a clean Ru(001) substrate surface was followed by UV photoelectron spectroscopy and (subsequent) thermal desorption spectroscopy. No compound but only a chemisorbed layer (and eventually bulk caesium) is formed if caesium is deposited onto a gold layer, if the quantity of the latter itself does not exceed the monolayer capacity. With thicker gold layers, on the contrary, semiconducting CsAu (with a band gap of 2.6 eV and the Fermi level close to the conduction band edge) is formed by interdiffusion at T > 250 K, but the outer surface consists always of a layer of chemisorbed caesium. This even holds for a \u201csandwich\u201d system for which a thick gold film was evaporated onto a CsAu layer. The surface region of CsAu is highly reactive towards oxygen