At the ICMM we are glad to present a new seminar given by David Saleta, from Institut Català de Nanociència i Nanotecnologia (ICN2).
Title: Thermal transport properties of 2D transition metal dichalcogenides.
Abstract: Thinning conventional three-dimensional (3D) materials, such as silicon, typically leads to a dramatic reduction in thermal conductivity due to enhanced surface phonon scattering. Transition metal dichalcogenides (TMDs) are layered semiconducting two-dimensional (2D) materials that can be thinned down to sub-nanometer thicknesses. In contrast to 3D materials, their thermal properties can exhibit distinct thickness-dependent behavior, arising from the van der Waals nature of interlayer interactions. However, the influence of flake thickness and the surrounding environment on the in- and out-of-plane thermal properties of TMDs remained unclear. Here, we experimentally investigate the in- and out-of-plane thermal transport of the layered TMD MoSe2 down to the monolayer limit, using free-standing flakes and Raman thermometry measurements performed in vacuum and in air. In vacuum, our results reveal a weak dependence of the in-plane thermal conductivity on thickness. Our ab initio simulations indicate that this weak thickness dependence originates from the appearance of low-frequency phonon modes with long mean free paths, which contribute significantly to in-plane heat transport in the thinnest flakes. At the same time, the thinnest MoSe2 flakes exhibit efficient heat dissipation to ambient air molecules due to their large surface-to-volume ratio. These findings are relevant for (opto)electronic applications based on layered quantum materials, and contribute more broadly to the understanding of heat transport in two-dimensional systems.
Biography: David Saleta Reig (born in Mallorca in 1993) is a postdoctoral researcher at the Institut Català de Nanociència i Nanotecnologia (ICN2). He received his BSc in Nanoscience and Nanotechnology from the Universitat Autònoma de Barcelona (UAB) in 2015, followed by a two-year Erasmus Mundus Master’s degree in Photonics, with studies in Marseille, Barcelona, and Berlin. He earned his PhD in Physics (cum laude) from UAB in 2025, with a dissertation entitled “Optothermal Studies of Heat in van der Waals Materials”, which involved building an optical laboratory from scratch, first in ICN2 (Barcelona) and later in TU/e (Eindhoven). So far, David has authored 15 peer-reviewed publications, with over 600 citations (h=14), in leading international journals.
