Synthesis and characterization of nanostructured molybdenum oxynitride films fabricated by sub-atmospheric chemical vapor deposition

• Published in: Journal of alloys and compounds 2019-11, Vol.808, p.151470, Article 151470
• Main Authors: Dřínek, Vladislav, Klementová, Mariana, Palatinus, Lukáš, Dytrych, Pavel, Fajgar, Radek, Jandová, Věra, Koštejn, Martin, Kupčík, Jaroslav
• Format: Article
• Language: English
• Subjects: Ammonia; Chemical vapor deposition; Clean energy; Electron diffraction; Gold; Molybdenum; Molybdenum oxides; Molybdenum trioxide; Nanorods; Nanostructured materials; Nitride materials; Nitrogen; Organic chemistry; Palladium; Photoelectron microscopies; Photoelectrons; Platelets; Platinum; Raman spectroscopy; Silver; Spectrum analysis; Vapor deposition; X ray photoelectron spectroscopy
• ISSN: 0925-8388; 1873-4669
• DOI: 10.1016/j.jallcom.2019.07.182

To support the trend of a new green energy introduction in economics it has become urgent nowadays that more available and cheaper materials would substitute noble and/or expensive materials (Au, Ag, Pt, Pd, Ga …). Therefore, we studied molybdenum oxynitride films due to their catalytic properties. Molybdenum oxynitride films were fabricated by sub-atmospheric chemical vapor deposition (SACVD). According to Raman spectroscopy, grown platelets possessed MoO3 structure up to 12 at. % NH3 in NH3/air mixture. With the increasing amount of NH3 in the reaction atmosphere (16–25 at. % NH3), the films became heterogeneous containing Mo4O11 and MoO2 suboxides. Nanostructures – nanorods, nanoribbons - developed gradually at those samples with highest concentrations of NH3 in the atmosphere (25–33 at. % NH3) whose structure was built by blocks of corner-sharing Mo-octaedra separated by double layers of edge-sharing Mo-octaedra, which was revealed by Electron Diffraction Tomography (EDT). X-ray Photoelectron Spectroscopy (XPS), similarly to Raman spectroscopy, showed a gradual rise of molybdenum suboxides with NH3 increase in the atmosphere, which was indicated by the successive appearance of Mo6+ → Mo5+ → Mo4+ species. As N 1s XPS signal was fully overlapped by the Mo 3d5/2 one, a new procedure of a standard selected was used for the estimation of the nitrogen content in the films. This material was capable of reducing water under illumination as found by Cycling Votammetry (CV). [Display omitted] •MoOxNy nanostructures (nanowires, -rods …) were synthetized via SACVD.•A new, not reported crystallographic structure was found for some nanostructures.•XPS N content in Mo based material was quantified using a novel procedure.