Dresden 2009 – wissenschaftliches Programm

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O: Fachverband Oberflächenphysik

O 27: Poster Session I (Methods: Scanning probe techniques; Methods: Atomic and electronic structure; Methods: Molecular simulations and statistical mechanics; Oxides and Insulators: Clean surfaces; Oxides and Insulators: Adsorption; Oxides and Insulators: Epitaxy and growth; Semiconductor substrates: Clean surfaces; Semiconductor substrates: Epitaxy and growth; Semiconductor substrates: Adsorption; Nano- optics of metallic and semiconducting nanostructures; Electronic structure; Methods: Electronic structure theory; Methods: other (experimental); Methods: other (theory); Solutions on surfaces; Epitaxial Graphene; Surface oder interface magnetism; Phase transitions; Time-resolved spectroscopies)

O 27.62: Poster

Dienstag, 24. März 2009, 18:30–21:00, P2

Band bending via H₂O adsorption on titanium dichalcogenide surfaces — •Stephan Thürmer, Alexander Paulheim, Lenart Dudy, Beate Müller, Hendrik Vita, Christoph Janowitz, and Recardo Manzke — Humboldt-Universität zu Berlin, Institut für Physik, Newtonstr. 15, 12489 Berlin

With the method of photoemission it is possible to measure occupied electronic states of a material by detection of the emitted electrons. By means of angle-resolved photoemission (ARPES) the complex electronic structures in reciprocal k-space, such as energy-band dispersion, are accessible. Band bending can be induced by Schottky contacts and therefore normally unoccupied electronic states can be reached. Here, water adsorption onto the van der Waals-like surface of Ti compounds served as contact. Photoemission analysis of the TiSe₂ transition metal dichalcogenide has shown interesting effects of dipole induced band bending [1]. Presuming Schottky contact like effects, the semiconducting behavior of this material was revealed. In accordance, preliminary ARPES measurments of the semimetal TiTe₂ in similar conditions showed no bending of the bands due to charge carrier screening of the dipole field. To further investigate the effects of water physisorption, detailed measurements and comparisons of the isostructural Ti compounds TiSe₂, TiTe₂, and TiS₂ with high resolution ARPES will be shown.

[1] J. Rasch et al., Phys. Rev. Lett. 102 (2008)