Thermal conductivity measurement of few layer graphene film by a micropipette sensor with laser point heating source

Abstract

We report a thermal characterization method for a large-scale free-standing chemical vapor deposited few layer graphene (FLG), in which a micropipette temperature sensor with an inbuilt laser point heating source was used. The technique is unique as it exhibits in general the characteristic features of high accuracy measurement of thermal conductivity of free-standing ultrathin films. Using the micropipette sensor we successfully implemented the characterization technique to show high thermal transport behavior in free-standing graphene. For accurate and successful measurement of thermal conductivity, FLG grown on Ni was transferred to a polycarbonate (PC) membrane with holes (average diameter of 100 mu m) in order to isolate the graphene film from heat spreading through the bottom of the film by the laser point heating. The thermal conductivity of FLG by this method was measured at 2868 +/- 932 W/m degrees C. The large uncertainty of 32% in thermal conductivity measurement is mainly due to the non-uniform (similar to 30% deviation) thickness of the film.