Written by: Shawn.Adams2@unt.edu
Dr. Thomas Cundari and Dr. Jeffry Kelber (Chemistry) recently published "Plasma modification
of vanadium oxynitride surfaces: Characterization by in situ XPS experiments and DFT
calculations" in the Journal of Chemical Physics.
Abstract: Plasma modification of transition metal nitride/oxynitride (MOxNy) surfaces
for enhanced surface properties is highly desirable, given the scalability of such
methods and limitations of thermal treatments. In situ x-ray excited photoelectron
spectroscopy demonstrates that the O2 plasma oxidation of VOxNy films generates non-lattice
N1s surface features with binding energies near 396.5 eV, which are associated with
the nitrogen reduction reaction activity but not observed upon thermal oxidation.
The NH3 plasma generates N1s surface features near 400.5 eV binding energy. The O2+NH3
plasma generates both types of N1s features. Annealing in UHV to < 1000 K reverses
plasma-induced changes to N1s spectra. Density functional theory (DFT) calculations
integrated with the experiments indicate that the plasma-induced N1s features at ~396.5
eV and 400.5 eV are V≡N: and V--NH2 sites, respectively, with significantly lower
thermal stabilities than lattice N sites. These results provide practical insight
regarding the plasma modification of MOxNy surfaces for important applications.
You can view the article here: https://aip.scitation.org/doi/full/10.1063/5.0027996