The nature of surface defects in Xe ion-implanted glassy carbon annealed at high temperatures: Raman spectroscopy analysis

Abstract

The mechanically polished glassy carbon (GC) samples were implanted with 200 keV Xe ions to a fluence of 1 × 1016 cm−2 at room temperature. The Monte Carlo simulation code, Stopping and Range of Ions in Matter (SRIM) was used to simulate the Xe ions implanted in GC. At the surface of the implanted GC, a dose of 6.53 displacements per atom which corresponds to the nuclear energy loss of 0.142 keV/nm (SRIM prediction) amorphized the GC structure. Raman spectroscopy, a well-established tool to probe disorder in carbonaceous materials through Raman-based disorder signature (D-band) relative to the Raman-allowed first-order band (G-band), confirmed that ion bombardment resulted in GC amorphization. And also showed that during mechanical polishing of the GC the sp3-type of defects were introduced which describe the out-of-plane atoms bonded to carbon atoms. This sp3-type of defects was modified by ion implantation to boundary-like defects in graphite. The Xe implanted GC (Xe-GC) samples were annealed from 100 up to 500, 1000 and 1500 °C in steps of 100 °C for 5 h per step under vacuum. Recovery of the amorphized structure of the Xe-GC samples was not observed at temperatures ≤1000 °C, however, at 1500 °C about 54% of the structure was recovered.