Thermally induced mechanical strain of graphene on copper and other substrates

Raman spectroscopy is employed to investigate the temperature dependence of the phonon frequencies of the G and 2D modes of monolayer graphene grown on copper foil by chemical vapor deposition. Both the G and 2D modes exhibit significant red shift as temperature increases, and the extracted values of the temperature coefficients of the G and 2D modes are about -0.07 cm- 1K-1 and -0.15 cm- 1K-1, respectively. In addition, we extracted the intrinsic Raman shift of the G mode by determining the thermally induced mechanical strain that is transmitted from the copper substrate to graphene. The extracted intrinsic G mode frequency shift is in very good agreement with earlier reported first principles calculations. Finally, we have calculated the temperature dependence of the substrate-induced strain on graphene when it is deposited or grown to various technologically important substrates, showing that strains as high as 1.1% can be imparted to graphene within a temperature range of 500 K.

Automated summary

Raman spectroscopy was used to study the temperature dependence of monolayer graphene grown on copper foil. Both the G and 2D modes showed significant red shift with increasing temperature, with temperature coefficients of -0.07 cm-1K-1 and -0.15 cm-1K-1, respectively. The intrinsic Raman shift of the G mode was determined by analyzing the thermally induced mechanical strain from the copper substrate, and it closely matched previous first principles calculations. The study also showed that graphene could experience strains as high as 1.1% when deposited or grown on various technologically important substrates within a temperature range of 500 K.