Highly Occupied Surface States at Deuterium-Grown Boron-Doped Diamond Interfaces for Efficient Photoelectrochemistry |
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Authors: | Michał Sobaszek Maria Brzhezinskaya Adrian Olejnik Vincent Mortet Mahebub Alam Mirosław Sawczak Mateusz Ficek Maria Gazda Zdeněk Weiss Robert Bogdanowicz |
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Affiliation: | 1. Gdańsk University of Technology, Faculty of Electronics, Telecommunications and Informatics, Department of Metrology and Optoelectronics, 11/12 Narutowicza Str., Gdansk, 80–233 Poland;2. Helmholtz-Zentrum Berlin für Materialien und Energie, Hahn-Meitner-Platz 1, 14109 Berlin, Germany;3. Czech Technical University in Prague, Faculty of Electrical Engineering, Technická 1902/2, Prague 6, 166 27 Czech Republic;4. The Szewalski Institute of Fluid-Flow Machinery, Polish Academy of Sciences, Fiszera 14, Gdansk, 80–231 Poland;5. Department of Solid State Physics, Faculty of Applied Physics and Mathematics, Gdańsk University of Technology, Narutowicza 11/12, Gdańsk, 80–233 Poland;6. CSc, FZU – Institute of Physics of the Czech Academy of Sciences, Na Slovance 2, Praha 8, 182 21 Czech Republic |
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Abstract: | Polycrystalline boron-doped diamond is a promising material for high-power aqueous electrochemical applications in bioanalytics, catalysis, and energy storage. The chemical vapor deposition (CVD) process of diamond formation and doping is totally diversified by using high kinetic energies of deuterium substituting habitually applied hydrogen. The high concentration of deuterium in plasma induces atomic arrangements and steric hindrance during synthesis reactions, which in consequence leads to a preferential (111) texture and more effective boron incorporation into the lattice, reaching a one order of magnitude higher density of charge carriers. This provides the surface reconstruction impacting surficial populations of C C dimers, C H, CO groups, and COOH termination along with enhanced kinetics of their abstraction, as revealed by high-resolution core-level spectroscopies. A series of local densities of states were computed, showing a rich set of highly occupied and localized surface states for samples deposited in deuterium, negating the connotations of band bending. The introduction of enhanced incorporation of boron into (111) facet of diamond leads to the manifestation of surface electronic states below the Fermi level and above the bulk valence band edge. This unique electronic band structure affects the charge transfer kinetics, electron affinity, and diffusion field geometry critical for efficient electrolysis, electrocatalysis, and photoelectrochemistry. |
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Keywords: | core-level spectroscopies deuterium-based plasma density functional theory (DFT)  calculations polycrystalline diamonds Raman spectroscopy |
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