An electrical thermometry platform for measuring cross-plane thermal conductivity of 2D flakes on substrate

Abstract

It is highly desired to efficiently probe the cross-plane thermal conductivities of two-dimensional (2D) flakes with a considerably small temperature increase, avoiding the difficulty of suspending the atomically thin samples. A thermometry platform was proposed for measuring the cross-plane thermal conductivity of irregular dielectric and semiconductor 2D flakes on a substrate. Two metal heaters with identical configurations were fabricated on the same chip, one deposited on the sample and the other was directly on the substrate as a reference. The value of cross-plane thermal conductivity could be derived by fitting the heaters' effective thermal resistances with finite-element-method simulations. The measurement error of the heaters' effective thermal resistances was approximately 1% with the imposed temperature increase of less than 1 K. This platform was used to measure the cross-plane thermal conductivity of WSe2 2D flakes. The measured values were about eightfold smaller than those of bulk material, which agreed well with the model's predictions.