Thermal resistance mapping along a single cup-stacked carbon nanotube with focused electron beam heating

The structural non-uniformity in low-dimensional materials, including interfaces and defects, makes it highly desirable to map the thermal property distribution with a high spatial resolution. Meanwhile, eliminating the error of thermal contact resistance at the sample-sensor junction has remained a critical challenge in nanoscale thermal conductivity measurement. Here, we combine the electron beam (EB) heating with two suspended line-shaped heat flux sensors and have achieved the in-situ thermal resistance mapping along a single cup-stacked carbon nanotube (CNT) in a scanning electron microscope (SEM). The CNT is anchored between the two suspended metal lines, and the focused electron beam heats the CNT locally with a nanometer-range spatial resolution, while the two metal lines simultaneously measure the heat fluxes induced by the EB heating. By sweeping the focused EB along the CNT, we can obtain the spatially resolved thermal resistance, from which the true thermal conductivity of the CNT was extracted to be around 40 W/m·K without the thermal contact resistance error. This SEM-based in-situ thermal measurement method can accelerate high-resolution nanomaterials characterization and the elucidation of nanoscale heat transfer.