SKM 2023 – scientific programme

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O: Fachverband Oberflächenphysik

O 32: Semiconductor Substrates

O 32.7: Talk

Tuesday, March 28, 2023, 12:00–12:15, GER 39

About the excitation of island growth orthogonal to the surface in the substrate Pb/Si(111)-(7x7) — •Paul Philip Schmidt, Lea Faber, and Regina Hoffmann-Vogel — Institute of Physics and Astronomy, University of Potsdam, 14476 Potsdam-Golm, Germany

With the increasing miniaturization of systems, the phenomena of surface diffusion is becoming more and more relevant. Pb shows anormaly fast mass transport on Si(111)-(7x7) [1,2]. For this system island growth and the behaviour of the wetting layer must be taken into account in order to understand the physical processes at the surface. We investigate the growth of the islands. Si was cleaned by rapid heating to 1200°C. Pb was deposited on the sample by evaporation at room temperature or liquid nitrogen temperature (120K). We create local imbalances of Pb to draw conclusions about diffusion and selectively trigger island growth at individual islands. While we measure the topography with non contact atomic force microscopy, we simultaneously determine the local work function difference with Kelvin probe force microscopy. Our experiments show an energy barrier before ring growth occurs. Once atoms have reached an existing island, ring growth around occurs quickly. In experiments where we do not force this the islands hardly show any growth perpendicular to the surface. Part of the Pb comes from the restructuring of the island, which initially shrinks in the xy-direction.

[1] M. Hupalo et. al. Phys. Rev. B, 23, 235443 (2007)

[2] K. L. Man et al. Phys. Rev. Lett., 101 226102 (2008)