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O: Fachverband Oberflächenphysik

O 40: Semiconductor substrates: Adsorption

O 40.2: Talk

Tuesday, March 13, 2018, 15:30–15:45, MA 005

Predicting the surface phase diagram of redox-active adsorbates on semiconductor surfaces: The case of ZnO — •Matti Hellström and Jörg Behler — Universität Göttingen, Institut für Physikalische Chemie, Theoretische Chemie, Tammanstr. 6, 37077 Göttingen

We propose an efficient method for calculating surface phase diagrams for redox-active adsorbates on semiconductors, that we apply to the important example of proton (H⁺) and hydride (H⁻) adsorbates on a ZnO surface [1]. We identify the leading cause for the coverage dependence of the adsorption energies to be the filling and depletion of the disperse substrate conduction band. From only four DFT calculations, coupled with an analysis of the substrate electronic band structure and changes in the electrostatic potential within the substrate upon adsorption, we derive a phenomenological model that well describes the coverage-dependent adsorption energies. We expect that such models can be applied to a wide range of semiconductor substrates and redox-active adsorbates.

[1]. M. Hellström, J. Behler. Phys. Chem. Chem. Phys. 19 (2017) 28731