Dresden 2003 – wissenschaftliches Programm
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O: Oberflächenphysik
O 16: Oxide und Isolatoren I
O 16.1: Vortrag
Dienstag, 25. März 2003, 11:15–11:30, FOE/ANOR
In-situ STM investigation of growth, atomic and electronic structure of thin NiO films on Ag(001) at elevated temperatures — •Christian Hagendorf, Karl-Michael Schindler, and Henning Neddermeyer — Martin-Luther-Universität Halle-Wittenberg, Fachbereich
Growth behavior as well as atomic and electronic structure of thin NiO films on Ag(001) are in-situ investigated using scanning tunneling microscopy (STM) at elevated temperatures. NiO films were deposited with a thickness ranging from 0.5 to 3 monolayers through evaporation of Ni in an O2 atmosphere of 10−6mbar. A c(1x2) reconstruction is observed at substrate temperatures of less then 475K and coverages in the submonolayer region, as shown by low energy electron diffraction (LEED) and STM. Above 475K regions with a 1x1 structure appear. Contrary to the c(1x2) reconstruction these areas show a pronounced STM contrast reversal depending on the tunneling voltage, due to the transition from a Ni/O/Ag(001) structure to NiO [1]. The electronic structure of Ag(001), NiO, Ni/O/Ag(001) near the fermi energy has been mapped using scanning tunneling spectroscopy (I(V)-STS) at elevated temperatures and will be discussed in reference to the STM imaging mechanism of oxide layers.
[1] Th. Bertrams et al., J. Vac. Sci. Technol. B 14 (1996), 1141