Berlin 2008 – wissenschaftliches Programm
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O: Fachverband Oberflächenphysik
O 55: Poster Session III - MA 141/144 (Methods: Atomic and Electronic Structure; Particles and Clusters; Heterogeneous Catalysis; Semiconductor Substrates: Epitaxy and Growth+Adsorption+Clean Surfaces+Solid-Liquid Interfaces; Oxides and Insulators: Solid-Liquid Interfaces+Epitaxy and Growth; Phase Transitions; Metal Substrates: Adsorption of Inorganic Molecules+Epitaxy and Growth; Surface Chemical Reactions; Bimetallic Nanosystems: Tuning Physical and Chemical Properties; Oxides and insulators: Adsorption; Organic, polymeric, biomolecular films; etc.)
O 55.6: Poster
Mittwoch, 27. Februar 2008, 18:30–19:30, Poster F
Electronic structure of the non-polar GaN(1100) surface — •Marco Bertelli1, Peter Löptien1, Jörg Malindretos1, Martin Wenderoth1, Rainer G. Ulbrich1, Angela Rizzi1, Maria Clelia Righi2, and Alessandra Catellani2, 3 — 1IV. Physikalisches Institut and Virtual Institute of Spin Electronics (VISel), Georg-August Universität Göttingen, D-37077 Göttingen, Germany — 2CNR-INFM National Center on nanoStructures and bioSystems at Surfaces (S3) and Dipartimento di Fisica, Università di Modena e Reggio Emilia, I-41100 Modena, Italy — 3CNR-IMEM, Parco Area delle Scienze, 37A, I-43010 Parma, and (S3), Italy
Cross-section scanning tunneling microscopy (STM) and scanning tunneling spectroscopy (STS) have been performed on the non-polar GaN(1100) surface (m-plane).
The unintentionally n-doped GaN(0001) samples were thinned down to ∼100 µm , cleaved along the m-plane in ultra high vacuum and measured in-situ by STM at room temperature. The experimental empty state topographies collected with sample bias from +2.9 V to +4.0 V show an unreconstructed surface.
First principle DFT-LDA calculations of the surface electronic properties were performed. In agreement with experiment, the calculations predict a relaxed surface but no reconstruction. Two surface bands appear inside the semiconductor band gap at the borders of the surface Brillouin zone, one empty band localized on the Ga-atoms and one filled band on the N-atoms. Up to now this theoretical prediction has not been confirmed by the STS experiment.