Dresden 2009 – wissenschaftliches Programm

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O: Fachverband Oberflächenphysik

O 63: Semiconductor substrates: Adsorption

O 63.7: Vortrag

Freitag, 27. März 2009, 12:45–13:00, SCH A118

Interaction of as-grown InN(0001) surfaces with oxygen — •Anja Eisenhardt, Marcel Himmerlich, Juergen A. Schaefer, and Stefan Krischok — Institut für Physik and Institut für Mikro- und Nanotechnologien, TU Ilmenau, P.O. Box 100565, 98684 Ilmenau, Germany

The interaction of oxygen with clean (2x2) reconstructed InN(0001) surfaces is investigated by in-situ photoelectron spectroscopy (XPS, UPS). InN thin films were grown by plasma assisted molecular beam epitaxy. Directly following the growth an in-situ characterization of the pure InN samples as well as the investigation of the oxidation of the non-contaminated surfaces without any preparation was performed. Differences between the core levels as well as the valence band spectra of the clean in-situ grown and the oxygen treated InN samples will be presented. The comparison of the valence band structure shows the appearance of two electronic structures at 5.2 eV and 10.3 eV that can be assigned to oxygen adsorbates due to the impurity-free preconditions. Furthermore, the oxygen exposure leads to the disappearance of the InN(0001)-(2x2) surface reconstruction as well as the related surface state close to the Fermi level. This can be explained by the distortion of the (2x2) adatom reconstruction. In XPS two different states are observed in the O1s emission. Based on the detected chemical shifts, the chemical state of the adsorbed oxygen will be discussed. Furthermore, the oxidation has only minor influence on the position of the valence band maximum and the work function.