Berlin 2005 – wissenschaftliches Programm

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O: Oberflächenphysik

O 52: Elektronische Struktur IV

O 52.1: Vortrag

Mittwoch, 9. März 2005, 10:45–11:00, TU EB301

A photoelectron spectro-microscopy investigation of singleMoS₂ nanotubes — •A. Gloskovskii¹, M. Chincetti¹, S. A. Nepijko¹, G. Schönhense¹, H. A. Therese², G. H. Fecher², H. C. Kandpal², C. Felser², W. Tremel², and M. Klimiankou³ — ¹Institut für Physik, Johannes Gutenberg -Universität, 55099 Mainz — ²Institut für Anorganische und Analytische Chemie,Johannes Gutenberg - Universität, 55099 Mainz — ³Institut für Materialforschung I, Forschungszentrum Karlsruhe GmbH, 76021 Karlsruhe

Nanostructured MoS₂ was prepared by thermal decomposition of (NH₄)₂Mo₃S₁₃ x H₂O in sealed tubes and nanotubes of MoS₂ were prepared by coating technique using SiO₂ rods as template. The samples were characterized by XRD, HRTEM, EELS, and XANES techniques. The electronic structure of MoS₂ was investigated by means of two photon photoemission spectroscopy (2-PPE) performed with a time-of-flight photoemission electron microscope (TOF-PEEM). The spatially resolved 2-PPE spectra show distinguished features arising in emission from the nanotubes. These features are explained by emission from the valence band via resonant excitation of an intermediate state in the conduction band. The size of the gap in semiconducting nanotubes will be discussed on hand of the 2-PPE spectra in comparison to electronic structure calculations. The electronic structure was calculated self-consistently by means of LMTO and FLAPW techniques. Comparing experimental and theoretical findings, we conclude that full potential methods are necessary to calculate electronic properties in particular for sulfide and oxide based nanotubes. (Funded by DFG in SFB 625 TP9.)