Inelastic Hydrogen Atom Scattering from Semiconductor Surfaces
von Kerstin Krüger
Datum der mündl. Prüfung:2023-06-01
Erschienen:2023-12-11
Betreuer:Prof. Dr. Alec M. Wodtke
Gutachter:Prof. Dr. Alec M. Wodtke
Gutachter:Prof. Dr. Dirk Schwarzer
Gutachter:Prof. Dr. Burkhard Geil
Gutachter:Prof. Dr. Christian Jooß
Gutachter:Prof. Dr. Daniel J. Obenchain
Gutachter:Prof. Dr. Martin Suhm
Dateien
Name:Dissertation_Kerstin_Krüger.pdf
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Format:PDF
Zusammenfassung
Englisch
The adiabatic approximation is widely applied to describe interactions of atoms and molecules with solid surfaces. It assumes that the electronic system stays in the lowest-energy ground state during the interaction and energy is exclusively distributed via lattice vibrations in the solid. However, in case of light hydrogen atoms, it predicts inefficient energy transfer to the atoms of heavier solids, contradicting experimental findings of inelastic H atom scattering from germanium surfaces. Germanium is an elemental semiconductor and, unlike frequently studied metals, does not have partly-filled electronic states around the Fermi level, but filled and empty states separated by a fundamental energy gap, the band gap. Using H atom beams with incidence translational energies ranging from around 0.4 eV to more than 6 eV, a non-adiabatic scattering channel is observed at high energy-losses, provided that the incidence energy exceeds the value of the surface band gap. This scattering channel is studied at a variety of experimental conditions, including H/D isotope substitution, varying surface temperatures and different surface structures, leading to the conclusion that it involves electronic interband excitations of the semiconductor surface. An electronically adiabatic low energy-loss channel is consistently observed at all scattering conditions.
Keywords: Dynamics at Surfaces; Inelastic Hydrogen Atom Scattering; Rydberg Atom Tagging; Energy Transfer; Semiconductor Surfaces