Ruthenium ion modification of glassy carbon: Implication on the structural evolution and migration behaviour of implanted Ru atoms

Abstract

Glassy carbon samples were implanted with ruthenium ions to a fluence of 1 × 1016 cm−2 at room temperature (at 150 keV). The implanted samples were annealed isochronally in vacuum from 1000 to 1300 °C for 5 h. The resulting microstructural changes were investigated using X-ray diffraction (XRD), Raman spectroscopy and atomic force microscopy (AFM). The diffusion behaviour of ruthenium in glassy carbon was investigated using secondary-ion mass spectrometry (SIMS). Raman results showed that the implantation of ruthenium into glassy carbon caused amorphization and increase the tensile stress in the implanted region. XRD showed that the amount of tensile stress in virgin glassy carbon increased from 0.016 GPa to 0.19 GPa after ion implantation which is in qualitative agreement with the Raman results. Annealing of the samples exhibited more recrystallization and changed the tensile stress to compressive stress. SIMS results showed that annealing of the as-implanted samples at 1000 °C caused aggregation of the ruthenium atoms, while annealing at higher temperatures led to some segregation of ruthenium atoms at a depth of 155 nm below the glassy carbon surface. The aggregation of ruthenium atoms after annealing (as observed by SIMS) played a role in the surface roughness as observed by AFM.