Chemical reactions of N2+ ion beams with first-row transition metals

Abstract

Ion beam studies of chemical reactions between nitrogen and surfaces of the first-row transition metals are reported. X-ray photoelectron spectroscopy (XPS) and thermal desorption mass spectrometry under ultra-high vacuum conditions are used to examine the products induced by 30-3000-eV N2+ beams on the polycrystalline metal foils. The reaction results in the formation of metal nitrides which are similar to the pure metal nitride compounds. The amount of nitrogen reacting with the metal can be correlated to the enthalpy of formation of the metal nitride. Estimates of the thickness of the reacted layer are obtained from LSS projected ion range calculations. The chemical nature of the reaction is supported by identification of the products through energy level shifts and by the agreement with thermodynamic predictions. A mechanism is proposed for the reaction which involves charge exchange neutralization and dissociation of the ion at the surface followed by penetration into the lattice, thermalization, and finally chemical reaction.

CRITICAL REVIEW OF N, N + , N + 2 , N ++ , And N ++ 2 MAIN PRODUCTION PROCESSES AND REACTIONS OF RELEVANCE TO TITAN'S ATMOSPHERE

“…This interaction is well known since the beginning of the 20th century and has been used for the catalytic production of ammonia and nitrogen-rich fertilizers (Haber-Bosch process) with substantial socio-economical consequences. However, it is possible to overcome the requirement of high temperature if the surface interacts with N 2 molecular ions (Lancaster & Rabalais 1979). Concerning neutral nitrogen surface reactions, a very effective heterogeneous chemistry has been indirectly observed in experimental simulations at low temperatures of the first steps of Titan's ion chemistry (Thissen et al 2009).…”

Nitrogen ion irradiation ofAu(110): Photoemission spectroscopy and possible crystal structures of gold nitride

“…However, until a short time ago, there had been clear evidence only for the formation of copper and silver nitrides. [5][6][7][8][9][10][11] Although attempts to form gold nitrides have been recorded for the past 20 years, this compound has been observed only recently by Šiller et al 12 In that work, irradiation of a gold surface with lowenergy ͑500 eV͒ nitrogen ions was used to produce a surface nitride layer which was then investigated with highresolution x-ray photoelectron spectroscopy. Two N1s core lines were observed after irradiation.…”

Direct Reaction between Copper and Nitrogen at High Pressures and Temperatures

“…The coinage metals (group 11: Cu, Ag, and Au) have so far shown a limited propensity to form nitrogen-bearing compounds despite intense efforts utilizing an array of synthesis techniques including nitrogen-ion irradiation. − Copper is known to form two nitrogen-containing compounds: copper azide (CuN 3 ), a highly sensitive explosive, and copper nitride (Cu 3 N), a stable semiconductor finding applications in a wide range of areas from lithium-ion battery electrodes to conductive ink and solar energy harvesting. − Under compression, the narrow band gap (0.6 eV) of Cu 3 N closes by ≈5 GPa, and no structural phase transitions are observed up to 26.7 GPa . Silver also forms an explosive azide (AgN 3 ), and attempts at forming stable gold nitrides have been limited to ion-irradiated surfaces. , …”