Regensburg 2013 – wissenschaftliches Programm
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HL: Fachverband Halbleiterphysik
HL 4: III-V semiconductors: mainly wells and surfaces
HL 4.9: Vortrag
Montag, 11. März 2013, 11:45–12:00, H15
Interaction of potassium with InN(0001)-(2×2)-surfaces — •Stephanie Reiß, Anja Eisenhardt, Stefan Krischok, and Marcel Himmerlich — Institut für Physik and Institut für Mikro- und Nanotechnologien, TU Ilmenau, PF 100565, 98684 Ilmenau, Germany
In this work we investigate the interaction of potassium with InN(0001)-(2×2)-surfaces. The 2×2 reconstructed InN-films were grown by plasma assisted molecular beam epitaxy (PAMBE) on GaN/Sapphire-templates. Immediately after epitaxy the samples were in-situ characterised by photoelectron spectroscopy (PES). Potassium was offered via an alkali metal dispenser while performing PES-measurements. The potassium adsorption leads to a strong reduction of the work function of the InN indicating the formation of a positive potassium-induced surface dipole acting as an electron donator. In parallel, the core levels and valence band (VB) maximum shift by 0.2 eV towards lower binding energies. Thus potassium adsorption leads to a reduction of the surface downward band bending from originally 0.6 eV to 0.4 eV. Furthermore, complex changes in the valence band region are observed and will be discussed with particular emphasis on the occupied states close to EF. Here, the potassium adsorption leads to the appearance of new states at 1.2 eV and 0.6 eV whereas a depletion of the surface state at the Fermi edge caused by the 2×2-surface reconstruction is observed.