AVS 50th International Symposium
    Surface Science Tuesday Sessions
       Session SS2-TuA

Paper SS2-TuA7
First Principles Study of the Stability of Ag Ultra-thin Films on III-V Substrates: An Interfacial Study

Tuesday, November 4, 2003, 4:00 pm, Room 327

Session: Surfaces and Interfaces of Semiconductors and Compound Materials
Presenter: D.L. Irving, University of Florida
Authors: D.L. Irving, University of Florida
S.B. Sinnott, University of Florida
R.F. Wood, Oak Ridge National Laboratory
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Under normal deposition conditions, most metals grow on semiconducting and insulating substrates in either a Volmer-Weber or a Stranski-Krastinow fashion. However, recent experiments on Ag/GaAs(110) show that atomically flat Ag overlayers can be grown by use of a two-step deposition process. The final morphology of these films is not only dependent on the deposition temperature, but also on the amount of metal initially deposited. Quantum size effects have been proposed as the reason for the preferential stability of the metallic overlayer and a simple theory has been used to predict whether a material system will exhibit it. This study compares the adhesion energy trends predicted by this theory with those calculated by first principles density functional theory calculations. The first principles calculations are performed on both the Ag(111)/GaAs(110) and the Ag(111)/GaSb(110) interfacial systems. The results show how the stability and electronic structure of the Ag films changes as a function of film thickness.