Four-probe thermal measurement of a carbon nanotube sheet

As advances are made in top-down nanofabrication and bottom-up syntheses of nanostructures, the characteristic length scales encountered in these structures are on the order of the mean free path of the heat carriers or smaller. Therefore, the thermal transport properties of these nanostructures can be different from the bulk counterparts. A number of experimental techniques have been developed for characterizing the size-dependent thermal transport properties of nanostructures. However, it is difficult to eliminate contact thermal resistance, an important error source, from the measurement results. Recently, a four-probe thermal measurement technique has been developed to measure the intrinsic thermal conductance of a suspended sample as well as isolate the values of contact resistance between the sample and measurement device. Here, the fabrication process of the four-probe measurement device is described. In addition, numerical heat conduction simulation is used to verify the analytical model of the measurement method. This method is further used to measure the thermal conductance of a carbon nanotube sheet.