Adsorption sites at Cs nanowires grown on the InAs(110) surface

We present a high-resolution ultraviolet photoelectron spectroscopy study o f the room temperature Cs chain formation on InAs(110), analysing the valen ce band spectra and core levels in the whole coverage range from the self-a ssembling of the Cs chains to the cluster uptake at saturation coverage. Th e valence band data shows an insulating behaviour up to saturation coverage . The adsorption sites have been monitored by means of Cs-4d, In-4d and As- 3d core levels. The Cs-4d core-level data shows two distinct components, co nsistent with the presence of two unequivalent Cs adsorption sites in the C s nanowire. The In-4d and As-3d levels show Cs-induced extra components due to electronic level re-hybridization to the substrate atoms, and predomina nt charge transfer from Cs adatoms to In, in agreement with recent theoreti cal calculations. (C) 2001 Elsevier Science B.V. All rights reserved.