Spatially mapping thermal transport in graphene by an opto-thermal method

• Published in: NPJ 2D materials and applications Vol. 6; no. 1; pp. 1 - 7
• Main Authors: Braun, Oliver, Furrer, Roman, Butti, Pascal, Thodkar, Kishan, Shorubalko, Ivan, Zardo, Ilaria, Calame, Michel, Perrin, Mickael L.
• Format: Journal Article
• Language: English
• Published: London Nature Publishing Group UK 17-01-2022; Nature Publishing Group; Nature Portfolio
• Subjects: 639/766/930/12; 639/925/918/1053; Chemistry and Materials Science; Circuit design; Conduction heating; Conductive heat transfer; Graphene; Heat conductivity; Helium ions; Layered materials; Mapping; Material properties; Materials Science; Mathematical analysis; Nanotechnology; Nanotechnology devices; Surfaces and Interfaces; Thermal conductivity; Thermal energy; Thin Films; Transport properties
• ISSN: 2397-7132; 2397-7132
• DOI: 10.1038/s41699-021-00277-2

Mapping the thermal transport properties of materials at the nanoscale is of critical importance for optimizing heat conduction in nanoscale devices. Several methods to determine the thermal conductivity of materials have been developed, most of them yielding an average value across the sample, thereby disregarding the role of local variations. Here, we present a method for the spatially resolved assessment of the thermal conductivity of suspended graphene by using a combination of confocal Raman thermometry and a finite-element calculations-based fitting procedure. We demonstrate the working principle of our method by extracting the two-dimensional thermal conductivity map of one pristine suspended single-layer graphene sheet and one irradiated using helium ions. Our method paves the way for spatially resolving the thermal conductivity of other types of layered materials. This is particularly relevant for the design and engineering of nanoscale thermal circuits (e.g. thermal diodes).