An Extensive Thermal Conductivity Measurement Method Based on Atomic Force Microscopy

Abstract

Heat transport in low-dimensional solids can significantly differ from their bulk counterpart due to various size-related effects. This offers rich heat transport phenomena to emerge. However, finding an appropriate thermometry method for thermal conductivity measurements at the reduced size and dimensionality of the samples is a challenge. Here, we propose and study the feasibility of a nanoscale resolution thermal conductivity measurement method based on bolometric thermometry implemented on an atomic force microscopy (AFM). The local heat exchange between the AFM tip and the sample occurs at a suspended section of the sample, and thermal modeling of the measured electrical resistance change resulting from the bolometric effect provides a unique value for thermal conductivity. As we illustrate via thermal simulations, the proposed method can measure thermal conductivity with thermal disturbance to the sample in as little as 0.2 K at ~20 nm lateral resolution. Our in-depth analysis shows the feasibility and extensive applicability of the proposed AFM-based bolometric thermometry method on low-dimensional materials both in diffusive and ballistic heat transport regimes from cryogenic to above-room temperature. Consequently, the proposed method can lead to a deeper experimental understanding of fundamental questions in nanoscale and low-dimensional heat transport phenomena in many different material classes, as well as Fourier and non-Fourier heat transfer regimes.

Keywords: Thermal conductivity, bolometric thermometry, two-dimensional materials, atomic force microscopy