Electrical and thermal conductivity of low temperature CVD graphene: the effect of disorder

In this paper we present a study of graphene produced by chemical vapor deposition (CVD) under different conditions with the main emphasis on correlating the thermal and electrical properties with the degree of disorder. Graphene grown by CVD on Cu and Ni catalysts demonstrates the increasing extent of disorder at low deposition temperatures as revealed by the Raman peak ratio, I_G/I_D. We relate this ratio to the characteristic domain size, L_a, and investigate the electrical and thermal conductivity of graphene as a function of L_a. The electrical resistivity, ρ, measured on graphene samples transferred onto SiO₂/Si substrates shows linear correlation with L_a ^{− 1}. The thermal conductivity, K, measured on the same graphene samples suspended on silicon pillars, on the other hand, appears to have a much weaker dependence on L_a, close to K ∼ L_a^1/3. It results in an apparent ρ ∼ K³ correlation between them. Despite the progressively increasing structural disorder in graphene grown at lower temperatures, it shows remarkably high thermal conductivity (10²–10³ W K ^{− 1} m ^{− 1}) and low electrical (10³–3 × 10⁵ Ω) resistivities suitable for various applications.