Temperature Dependence of Thermal Conductivity of Giant-Scale Supported Monolayer Graphene

Abstract

Past work has focused on the thermal properties of microscale/nanoscale suspended/supported graphene. However, for the thermal design of graphene-based devices, the thermal properties of giant-scale (~mm) graphene, which reflects the effect of grains, must also be investigated and are critical. In this work, the thermal conductivity variation with temperature of giant-scale chemical vapor decomposition (CVD) graphene supported by poly(methyl methacrylate) (PMMA) is characterized using the differential transient electrothermal technique (diff-TET). Compared to the commonly used optothermal Raman technique, diff-TET employs joule heating as the heating source, a situation under which the temperature difference between optical phonons and acoustic phonons is eased. The thermal conductivity of single-layer graphene (SLG) supported by PMMA was measured as 743 ± 167 W/(m·K) and 287 ± 63 W/(m·K) at 296 K and 125 K, respectively. As temperature decreased from 296 K to 275 K, the thermal conductivity of graphene was decreased by 36.5%, which can be partly explained by compressive strain buildup in graphene due to the thermal expansion mismatch.

Perspectives on Energy Transport at the Micro/Nanoscale

“…This indeed significantly extends the capability of the TET technique and provides unprecedented knowledge about thermal diffusivity evolution during fast heating. The work by Liu et al presents pioneering efforts in studying the thermal conductivity variation of giant-scale graphene depending on temperature [24]. This work is very challenging since the thermal expansion mismatch between graphene and the poly(methyl methacrylate) (PMMA) substrate could easily break the graphene layer when temperature goes down.…”