Berlin 2024 – wissenschaftliches Programm
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O: Fachverband Oberflächenphysik
O 66: Poster: Nanostructures at Surfaces
O 66.9: Poster
Mittwoch, 20. März 2024, 18:00–20:00, Poster C
An intermediate morphology in the patterning of the crystalline Ge(001) surface induced by ion irradiation — •Denise J. Erb1, Daniel A. Pearson2, Tomas Skeren3, Martin Engler1, R. Mark Bradley4, and Stefan Facsko1 — 1Helmholtz-Zentrum Dresden-Rossendorf, Germany — 2Pennsylvania State University, USA — 3Czech Technical University in Prague, Czech Republic — 4Colorado State University, USA
We investigate the self-organized nanopattern formation of the Ge(001) surface induced by ion beam bombardment at elevated surface temperatures. Two previously-observed kinds of topographies are seen, i.e., anisotropic patterns of rectangular pyramids and isotropic patterns of shallow round basins [1]. In addition, we unexpectedly observe an intermediate type of pattern, in which isolated rectangular pyramids stand above a landscape of shallow basins. The observed morphology depends on the chosen ion energy and flux and surface temperature. To model the observed pattern morphologies, we extend the equation of motion to include a second order correction term resulting from the curvature dependence of the sputter yield from a patterned surface [2]. This term produces the isolated peaks in the intermediate patterns, while the formation of spike singularities is averted by the Ehrlich-Schwoebel effect. For a range of parameter values, the resulting continuum model of the surface dynamics produces patterns that are remarkably similar to the experimentally observed morphologies (manuscript in review). [1] X. Ou et al., Phys. Rev. Lett. 111 (2013) [2] R.M. Bradley and G. Hobler, J. Appl. Phys. 129 (2021)