Thermal Stability of Single-layer Graphene Subjected to Confocal Laser Heating Investigated by Using in situ Anti-Stokes and Stokes Raman Spectroscopy

Abstract

The thermal stability of graphene has a close relationship with defect generation, thermal oxidation, which in turn have a significant bearing on its properties and applications. This report discusses the effect of confocal laser heating on the structure of single-layer graphene (SLG) on the basal plane and the edge. The thermal stability of SLG basal plane and edge was demonstrated to be different by using in situ anti-Stokes and Stokes Raman spectroscopy. The basal plane was found to be unstable above 500°C, while the edge could not endure even 220°C. The variation in the intensity of D, G, and 2D peaks and the intensity ratios of I(D)/I(G) and I(2D)/I(G) indicated that the thermal instability started with defect generation at the basal plane. The initial point defects at edge were partially eliminated at low temperature and generated again at temperatures above 220°C.

In Situ Temperature Measurements of Sliding Surface by Raman Spectroscopy

“…In addition to measuring the chemical states, Raman spectroscopy can measure temperature using three independent parameters: peak shift, full width at half maximum (FWHM), and intensity ratio of Stokes/ anti-Stokes scattering, separately [34]. The measure of static surface temperature using the intensity ratio of Stokes/anti-Stokes scattering has been reported [35][36][37]. However, studies regarding in situ measurements of the sliding surface using Raman spectroscopy, such as grease temperature, are scarce [38].…”

Thermal failure of carbon nanostructures

“…Regarding the thermal stability of defects, disordered graphene is shown to have a lower oxidation temperature than its pristine counterpart [140,141]. This is consistent with the fact that carbon atoms in defect sites require less energy to break free than in perfect lattice sites (7eV vs 30 eV) [102].…”