Dresden 2009 – wissenschaftliches Programm
Bereiche | Tage | Auswahl | Suche | Downloads | Hilfe
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 27.56: Poster
Dienstag, 24. März 2009, 18:30–21:00, P2
2D electrical conductivity in the Bi(111) surface state — •Hichem Hattab1, Giriraj Jnawali1, Thorsten Wagner2, Rolf Möller1, and Michael Horn-von Hoegen1 — 1Fachbereich Physik, Universität Duisburg-Essen, Lotharstr. 1, 47048 Duisburg, Germany — 2Johannes Kepler University Linz, Institute of Experimental Physics, Altenberger Str. 69, A-4040 Linz, Austria.
Bismuth is a semi metal with unique electronic properties. Recent investigations show that for atomically smooth ultra thin Bi(111) films the electronic density of states near the Fermi level is dominated by a highly metallic surface state [1]. Such films are ideally suited to study 2D electronic transport and roughness induced scattering effects.
Epitaxial Bi(111) films are grown on Si(001) at 150 K and annealed at 450 K [2]. The electric contact to the Bi surface is established by 4-point WSi2 contacts. Since the conductivity of the Bi-films does not depend on the thickness for up to 60 nm, it has to be attributed to the electronic surface state.
Additional Bi deposition ΘBi at 80 K produces a high density of 2D-Bi islands. The island density in the sub-bilayer regime is determined by STM and increases with ΘBi1/3. This short scale roughness significantly decreases the surface state conductivity with ΘBi1/2. This behavior is explained by a simple Boltzmann transport theory for a 2D electron gas.
[1] Hirahara et al., Appl. Phys. Lett. 91, 202106 (2007)
[2] Jnawali et al., Phys. Rev. B 78, 035321 (2008)