Berlin 2005 – wissenschaftliches Programm
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O: Oberflächenphysik
O 38: Halbleiteroberfl
ächen und -grenzfl
ächen
O 38.3: Vortrag
Dienstag, 8. März 2005, 11:15–11:30, TU EB301
A study on the surface structure of CuInSe2 (001) — •thalia Deniozou1, Norbert Esser1, Thomas Schulmeyer2, and Ralf Hunger2 — 1Institute for Analytical Sciences, Albert-Einstein-Str. 9, 12489 Berlin-Adlershof, Germany — 2Surface Science Division, Institute of Materials Science, Darmstadt University of Technology, Petersenstr. 23, 64287 Darmstadt, Germany
In contrast to most other semiconductor surfaces the atomic structure of chalcopyrite (001) surfaces is practically unresolved. Reconstructions have not been reported yet. The (001) surface structure of the chalcopyrite semiconductor CuInSe2 was studied by means of Low Energy Electron Diffraction, Auger Electron Spectroscopy and Synchrotron X-ray Photoelectron Spectroscopy. For the study heteroepitaxial CuInSe2/GaAs (001) films were employed which were grown by molecular beam epitaxy and capped with a protective Se layer. The CuInSe2 surfaces were initially decapped and then treated by simultaneous Ar+-ion bombardment and annealing. Two different reconstructions in dependence of the preparation time were observed for the first time, namely a (2x4) and a mixed (2x4)/(4x2) reconstruction. The chemical state and composition of the CuInSe2(001) surfaces were monitored by the photoelectron spectra of the Cu2p, Se3d, and In4d core levels. The observed surface core level shifts are discussed in relation to possible surface geometries.