  This paper reports on the thermal properties of reduced graphite oxide (RGO)
flakes, studied by means of scanning thermal microscopy (SThM). This technique
was demonstrated to allow thermal characterization of the flakes with a spatial
resolution of the order of a few tens of nanometers, while recording nanoscale
topography at the same time. Several individual RGO flakes were analyzed by
SThM, both as obtained after conventional thermal reduction and after a
subsequent annealing at 1700{\deg}C. Significant differences in the thermal
maps were observed between pristine and annealed flakes, reflecting higher heat
dissipation on annealed RGO flakes compared with pristine ones. This result was
correlated with the reduction of RGO structure defectiveness. In particular, a
substantial reduction of oxidized groups and sp3 carbons upon annealing was
proven by X-ray photoelectron and Raman spectroscopies, while the increase of
crystalline order was demonstrated by X-ray diffraction, in terms of higher
correlation lengths both along and perpendicular to the graphene planes.
Results presented in this paper provide experimental evidence for the
qualitative correlation between the defectiveness of graphene-related materials
and their thermal conductivity, which is clearly crucial for the exploitation
of these materials into thermally conductive nanocomposites.
