Surface morphology and associated high temperature evolution of copper covered with vapor deposited graphene

Abstract

Copper (Cu) has been widely used as a conductor in the field of information-transport applications due to its high electrical conductivity. However, it is susceptible to high-temperature surface oxidation. In this work, we examined in detail about the effect of vapor-deposited graphene (Gr) coatings on the high-temperature evolution of Cu surfaces. Both morphology/chemical characterizations and electrical conductivity revealed significantly enhanced resistance to surface evolution, especially at temperatures below 300 °C, for Cu with Gr compared to pure Cu counterparts. Theoretical calculations suggested that the enhanced high-temperature stability of Gr/Cu was mainly attributed to the high energy barrier resistance of defects-containing Gr formation. Moreover, this barrier resistance weakened when the temperature approached 400 °C, leading to the formation of more defect-containing Gr, as confirmed by both quasi-static and statistical results of Raman spectra. The present findings may provide further insights into the surface protective mechanisms of Gr coatings on metals.