Regensburg 2000 – wissenschaftliches Programm

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O: Oberflächenphysik

O 11: Postersession (Eröffnung)

O 11.25: Poster

Montag, 27. März 2000, 19:00–22:00, Bereich C

Metal adsorption on MgO: Investigation with MIES and UPS — •Patric Stracke, Stefan Krischok, Christiane Nutz, Oliver Höfft und Volker Kempter — Physikalisches Institut, TU Clausthal, Leibnizstraße 4, 38678 Clausthal-Zellerfeld, Germany

MgO films (2nm) thick were grown a W(110) substrate while metastable impact electron (MIES) and UPS(HeI+HeII) spectra were collected in situ. Different metals (Ag, Cu, Ti and Pd) were adsorbed on these surfaces. Due to the high surface sensitivity of MIES, only the outermost layer of the surface is investigated [1]. Thus, MIES combined with UPS gives a good insight in the beginning of the metal growth on MgO. The results are compared with earlier theoretical and experimental results for Mg/MgO [2]. The metal induced contribution to the MIES spectra depends strongly on the work function of the metal/MgO surface: Auger deexcitation spectra are only obtained for work functions ≤3.6eV. UPS is found to be very insensitive to the presence of the metal adsorbates in all cases where the emission is due to the ionization of s-valence orbitals of the metal atoms. We also compare the results of our experiment with conclusions made from GIXS [3] and EELS [4] measurements.

[1] Y. Harada, S. Masuda and H. Ozaki, Chemical Reviews, Vol.97, 1997

[2] J. Günster et. al., J. Vac. Sci. Technol. A, 19 (1999) 1657-1662

[3] G. Renaud, Surf. Sci. Rep. 32, 1998

[4] M.-H. Schaffner, F. Patthey and W.-D. Schneider, Surf. Sci, 417, 1998