Adsorption Properties of the Cu(115) Surface: Basic Interfaces

Abstract

The interfaces: K/Cu(115) and CO/Cu(115) have been characterized using surface sensitive techniques, including low energy electron diffraction and photoelectron spectroscopy. K adatoms show tendency to occupy the sites close to the step edges. At low temperature (near 125 K), after completion of two layers, potassium grows in 3D islands (the Stranski-Krastanov mode). At higher temperature, e.g. at room temperature, potassium introduces reconstruction of the substrate even at low coverages. Calibration of the alkali coverage, up to completion of the first layer, using the work function changes curve has been confirmed as a very convenient and precise procedure. The adsorbed state of CO at 130 K has been identified by registration of core levels obtained by the use synchrotron radiation photoelectron spectroscopy. The characteristics of the main 1s and satellite peaks have been analyzed in context of substrate geometry and compared with the ones of other copper planes. There are no indications of dissociative adsorption of CO, only residual carbon and oxygen were found after adsorbate desorption around 220 K. CO molecules show a strong tendency to "on top" adsorption in sites far from the step edges of the Cu(115) surface.

Work Function of Vicinal Copper Surfaces

“…Low temperature (123 K) adsorption of potassium on the Cu(100) leads to the Stranski Krastanov deposition mode, i.e. after completion of 13 layers, the growth is 3D islands [20]. It is expected that the complete monolayer of K on the (100), (119) and (115) From the slope of the rst part of the graph, the initial dipole moment of the potassium ions acquires the value from the 9.88.0 D interval as determined from the Helmholtz equation [21].…”

CO-Induced Photoemission Structures of the CO/Pt/Ru(0001) Interface

“…In the CO/Cu case, the 4σ satellite has an intensity near 36% of the main peak and the intensity ratio was indicative for the CO-substrate interaction [18,19]. Consequently, the registered 1s spectra of carbon and oxygen do not contain satellites [20,21] as it could be seen in Figs. 1 and 2 and due to that the synthesis of the spectra is greatly simplified.…”

Low temperature adsorption of CO on modified, vicinal Cu(100) surfaces: A comparative study

“…For the interface with pre-adsorbed K (0.40 AML), the area under the Cu 3d band decreases with exposure and at the saturated layer of CO molecules is 0.78(2) of the initial value (signal corresponding to the interface with K). This shows that free sites on the Cu substrates accept a smaller number of CO molecules compared with surfaces without K. Adsorption of CO also results in an increase of the K 3p signal by 1.53, 1.25, and 1.18 for the (100), (119), and (115) surfaces, respectively [11,15]. The behavior of the signal of the CO 4 is similar to that of the surface without K. The relative (with respect to Cu 3d) intensity signals are 0.195, 0.137, and 0.092 for the (100), (119), and (115) surfaces, respectively.…”

“…At low coverages, the adsorbate-substrate interaction dominates, resulting in the formation of a 2D gas (disordered arrangement) on the substrate. The stepped surfaces are similar because the size of the alkali atom is large enough not to "feel" the substrate irregularities [11]. The only difference is that K adatoms may be immobilized at the step edges, especially at the beginning of adsorption [12].…”