XPS Characterization Onion-Like Carbon from Nanodiamonds and Carbon Structure from Onion-Like Carbon after High-Pressure High-Temperature Treatment

Abstract

In this work, we report the results of X-ray photoelectron spectroscopy research into the relative concentrations of sp³ and sp² hybridization type atoms in onion-like carbon (ONC) specimens and in structures synthesized by high pressure and high temperature treatment (HPHT structures). The experimental method was based on the analysis of C1s core line and plasmon loss spectra. ONC specimen graphitization degree was analyzed as a function of treatment temperature for the 1000–1600°C range. Reverse processes, that is, sp³ bond formation, were observed in HPHT structures at 7.7 and 15 GPa and 500–1500°C.

Keywords:

• Onion-like carbon
• XPS
• sp³ and sp² hybridization
• HPHT structures