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Updated: Feb 21, 2026
Probe Type II Band Alignment in One-Dimensional Van Der Waals Heterostructures Using First-Principles Calculations
Published on: October 12, 2019
Atomically Resolved Band Bending Effects in a p-n Heterojunction of Cu2O and a Cobalt Macrocycle
Dominik Leuenberger1, Wolf-D Zabka1, Oliver-F R Shah1
1Physics Institute, ‡Department of Chemistry, University of Zürich , Winterthurerstrasse 190, CH-8057 Zürich, Switzerland.
Abstract:
We present a hetero junction based on macrocyclic hydrogen evolution catalysts (HEC) physisorbed on a single crystalline Cu2O(111) surface. Angle-resolved X-ray photoelectron spectroscopy (ARXPS) provides the spatial resolution of the band bending within the first nanometer of the subsurface region. Oxygen vacancies on the Cu2O(111) surface cause a downward band bending which is conserved upon adsorption of HEC layers of various thicknesses. This allows photoexcited electrons to be directed toward the surface where they can be made available for the reduction of protons by the HEC. Furthermore, Poisson's equation relates more subtle changes in the measured ARXPS spectra to the local charge density profile within the first 7 Å away from the surface and with atomic resolution. All observations are consistent with a polarization of the molecular layer in response to the electrical field at the oxide surface, which should be a general phenomenon at such organic-oxide heterointerfaces.
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