Nitrogen ion irradiation of Au(1 1 0): formation of gold nitride

Often metal nitrides posses unique properties for applications, such as great hardness, high melting points, chemical stability, novel electrical and magnetic properties. One route to the formation of metal nitride films is through ion irradiation of metal surfaces. In this report, the results of irradiation of Au(1 1 0) surfaces by nitrogen ions with kinetic energies of 0.5 and 2 keV are studied with high resolution X-ray photoemission spectroscopy. N1s core level spectra show clear evidence for the formation of a gold nitride at, or in close vicinity to, the surface––the first direct observation of nitride formation by this element. Subsurface molecular nitrogen is also observed, the relative concentration of which increases with irradiation energy. We suggest that the subsurface molecular nitrogen is most likely present in the form of trapped bubbles.