AVS 50th International Symposium
    Surface Science Friday Sessions
       Session SS2-FrM

Paper SS2-FrM7
In situ-STM Experiments at Elevated Temperature (475K) on Growth, Atomic and Electronic Structure of Thin NiO Films on Ag(001)

Friday, November 7, 2003, 10:20 am, Room 328

Session: Oxide Surfaces and Interfaces
Presenter: Ch. Hagendorf, Martin-Luther-University, Germany
Authors: Ch. Hagendorf, Martin-Luther-University, Germany
H. Neddermeyer, Martin-Luther-University, Germany
Correspondent: Click to Email
New results will be presented on the growth behaviour as well as atomic and electronic structure of thin NiO films on Ag(001) by using scanning tunneling microscopy (STM) and spectroscopy (STS) at elevated temperatures. NiO films were deposited with a thickness of up to 3 monolayers by evaporation of Ni in an O@sub 2@ atmosphere of 10@super -6@ mbar. Deposition and heating of the NiO films were followed by in situ-STM measurements which allowed us to identify the various stages of the growth mode. A (1x2) reconstruction is observed at substrate temperatures of less than 475 K and submonolayer coverages. They show a transition to (1x1) double layer NiO(001) after completion of the first monolayer. Only the latter one exhibits a pronounced bias dependent contrast reversal.@footnote 1@ The electronic structure of Ag(001), NiO(001) and the NiO precursor has been mapped using I(V)-STS at elevated temperatures and will be discussed in reference to results obtained on CoO /Ag(001).@footnote 2@ At coverages of more than one double layer areas with metallic behaviour are identified using STS. This indicates the formation of Ag islands in a height of several monolayers by segregation. @FootnoteText@@footnote 1@ Th. Bertrams et al., J. Vac. Sci. Technol. B 14 (1996), 1141.@footnote 2@ Ch. Hagendorf et al., Surf. Sci. (2003), in press.