The atomic and electronic structures of NiO(001)/Au(001) interfaces

Abstract

The atomic and electronic structures of NiO(001)∕Au(001) interfaces were analyzed by high-resolution medium energy ion scattering (MEIS) and photoelectron spectroscopy using synchrotron-radiation-light. The MEIS analysis clearly showed that O atoms were located above Au atoms at the interface and the inter-planar distance of NiO(001)∕Au(001) was derived to be 2.30 ± 0.05 Å, which was consistent with the calculations based on the density functional theory (DFT). We measured the valence band spectra and found metallic features for the NiO thickness up to 3 monolayer (ML). Relevant to the metallic features, electron energy loss analysis revealed that the bandgap for NiO(001)∕Au(001) reduced with decreasing the NiO thickness from 10 down to 5 ML. We also observed Au 4f lines consisting of surface, bulk, and interface components and found a significant electronic charge transfer from Au(001) to NiO(001). The present DFT calculations demonstrated the presence of an image charge beneath Ni atoms at the interface just like alkali-halide∕metal interface, which may be a key issue to explain the core level shift and band structure.

Observation and Origin of Extraordinary Atomic Mobility at Metal-Semiconductor Interfaces at Low Temperatures

“…The theoretical prediction, together with recent experimental confirmations using ultrathin-film systems (see, e.g., Ref. [37]), agrees very well with the present experimental observations for ultrathin Ge films on the Al metal. However, these theoretical calculations on band-gap modification provide no direct information on the change of the nature of the chemical bonding in the semiconductor close to the interface with the metal.…”

Transition‐Metal Dichalcogenide NiTe2: An Ambient‐Stable Material for Catalysis and Nanoelectronics

“…Air exposure also induces a shift of the Ni‐derived states in valence‐band spectra due to surface oxidation [ 39,40 ] (see experimental data measured with a photon energy of 596 eV reported in Figure S9b and Figure S11 for the assignment in the Supporting Information). Using a photon energy of 380 eV (Figure S10a, Supporting Information), a broad feature at a BE of about 5 eV, which is associated with O‐2p states, [ 39 ] is also detected.…”

Core–Shell Charge Transfer in Plasmonic Fe@Ag Nanoparticles on MgO Film

“…Fermi-Dirac distribution for the MgO interband transition. 36 A more detailed description of the experimental spectra. The small contribution at 2.8 eV that is visible in the fit for Fe@Ag is due to the presence of Ag NPs nucleated without Fe core, as evidenced from the slightly larger NP density after Ag deposition on Fe.…”