Dresden 2026 – scientific programme

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O: Fachverband Oberflächenphysik

O 4: Metal & Semiconductor substrates: Adsorption and reaction of small molecules I

O 4.7: Talk

Monday, March 9, 2026, 12:00–12:15, HSZ/0401

Online monitoring of the oxygen adsorption on Cu(110) with PEEM and DRS — •Robert Heller, Thorsten Wagner, and Peter Zeppenfeld — Johannes Kepler University, Institute of Experimental Physics, Surface Science Division, 4040 Linz, Austria

We studied the dissociative adsorption of oxygen on the Cu(110) surface using Photoelectron Emission Microscopy (PEEM) and Differential Reflection Spectroscopy (DRS) simultaneously. Unlike many experiments carried out already in the 1970s and 1980s, our approach focusses on real-time monitoring. For oxygen exposures up to ∼100L, at temperatures between 350K and 420K, the process saturates at an oxygen coverage of 0.5 with a well-ordered (2×1)O superstructure. At intermediate coverages, a regular pattern of alternating Cu and CuO stripes is formed [1].
We used a PEEM with a xenon lamp (Xe) to study changes in the electron yield (EY) during the exposure. Oxygen adsorption causes a decrease in EY and, hence, an increase in the work function. Since our DRS setup uses the same light source as the PEEM, we can synchronously record the change of the reflectance and reliably compare the two signals. Interestingly, the normalised adsorption curves are not identical, indicating that the PEEM and/or the DRS signals are not directly proportional to the oxygen coverage. This could be related to the effect of the formation of the nanostructured Cu-CuO stripe pattern upon oxygen adsorption [1].
[1] K. Kern et al., Phys. Rev. Lett. 67, 855 (1991).

Keywords: oxidation; photoelectron emission microscopy; differential reflectance spectroscopy; Cu(110); CuO