Origin of weak Fermi level pinning at the graphene/silicon interface
| Autor: | S. Tricot, J. C. Le Breton, B. Lépine, J. Courtin, Philippe Schieffer, Pascal Turban, G. Delhaye |
|---|---|
| Přispěvatelé: | Institut de Physique de Rennes (IPR), Université de Rennes 1 (UR1), Université de Rennes (UNIV-RENNES)-Université de Rennes (UNIV-RENNES)-Centre National de la Recherche Scientifique (CNRS), ANR-14-CE26-0028-03, Agence Nationale de la Recherche, Université de Rennes (UR)-Centre National de la Recherche Scientifique (CNRS), ANR-14-CE26-0028,ENSEMBLE,Transport du spin des électrons et communication avec le spin nucléaire dans des structures verticales métal-SiGe-métal fabriqué par collage moléculaire(2014) |
| Jazyk: | angličtina |
| Rok vydání: | 2020 |
| Předmět: |
Materials science
Condensed matter physics Silicon Photoemission spectroscopy Graphene business.industry Fermi level Schottky diode chemistry.chemical_element 02 engineering and technology 021001 nanoscience & nanotechnology 01 natural sciences law.invention symbols.namesake Semiconductor chemistry law [PHYS.COND.CM-GEN]Physics [physics]/Condensed Matter [cond-mat]/Other [cond-mat.other] 0103 physical sciences symbols Density functional theory Work function 010306 general physics 0210 nano-technology business |
| Zdroj: | Physical Review B Physical Review B, American Physical Society, 2020, 102 (24), pp.245301. ⟨10.1103/PhysRevB.102.245301⟩ Physical Review B, 2020, 102 (24), pp.245301. ⟨10.1103/PhysRevB.102.245301⟩ |
| ISSN: | 2469-9950 2469-9969 |
| Popis: | The mechanisms governing the formation of Schottky barriers at graphene/hydrogen-passivated silicon interfaces where the graphene plays the role of a two-dimensional (2D) metal electrode have been investigated by means of x-ray photoemission spectroscopy and density functional theory (DFT) calculations. To control the graphene work function without altering either the structure or the band dispersion of graphene we used a method that consists in depositing small amounts of gold forming clusters on the graphene/hydrogen-passivated silicon system under an ultra-high-vacuum environment. We observe from experimental measurements that the Fermi level is mainly free from pinning at the graphene/hydrogen-silicon interface whereas for a semi-infinite metal on silicon the Fermi level is almost fully pinned. This alleviation of the Fermi level pinning observed with the graphene layer is explained by DFT calculations showing that the graphene and the semiconductor are decoupled and that the metal-induced gap states (MIGS) density at the silicon midgap at the interface is very low ($l5\ifmmode\times\else\texttimes\fi{}{10}^{10}\phantom{\rule{0.16em}{0ex}}\mathrm{states}/(\mathrm{eV}\phantom{\rule{0.28em}{0ex}}\mathrm{c}{\mathrm{m}}^{2})$]. The important conclusion that stems from the DFT results analysis is that the low MIGS density at the semiconductor midgap is related to the 2D nature of the graphene layer. More precisely, the MIGS density is low owing to the lack of propagating states perpendicular to the graphene layer. This finding brings important information to understand the mechanisms that govern the formation and the electronic properties of Schottky barriers at 2D-metal/three-dimensional-semiconductor interfaces. |
| Databáze: | OpenAIRE |
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