Suspended micro thermometer for anisotropic thermal transport measurements

Abstract

The investigation of heat flow in nanostructures and low-dimensional system is still a challenging task, though it becomes more and more important for an effective thermal management of microdevices. In this work, we present the fabrication and characterization of a device designed to measure the in-plane thermal properties of nanomaterials in multiple directions. Additionally, the device allows to perform electrical and optical measurements simultaneously. This allows to spatially resolve eventual thermal property anisotropies and the correction of measurements by accounting for the contact resistances. The fabrication has no element that is related to the specific nanostructure to be investigated. The presented concept can be extended for other (quasi-) two dimensional systems and other nanostructures. Finally, we validated the accuracy of the device using a 250 nm thick silicon lamella, which serves as a reference system and offers the possibility to explore the impact of a dominant thermal contact resistance. We have used Raman thermometry to calculate the effective lattice temperature of the lamella as a function of the applied temperature on the membranes. We extracted an average interfacial thermal conductance of 2.4±0.8×104WK−1m−2.