Effect of crystallinity and thickness on thermal transport in layered PtSe2
Sachat, Alexandros el (Institut Català de Nanociència i Nanotecnologia)
Xiao, Peng (Universitat Autònoma de Barcelona. Departament de Física)
Donadio, Davide (University of California. Department of Chemistry)
Bonell, Frédéric (Université Grenoble Alpes. Commissariat à l'énergie atomique et aux énergies alternatives)
Sledzinska, Marianna (Institut Català de Nanociència i Nanotecnologia)
Marty, Alain (Université Grenoble Alpes. Commissariat à l'énergie atomique et aux énergies alternatives)
Vergnaud, Céline (Université Grenoble Alpes. Commissariat à l'énergie atomique et aux énergies alternatives)
Boukari, Hervé (Université Grenoble Alpes. Commissariat à l'énergie atomique et aux énergies alternatives)
Jamet, Matthieu (Université Grenoble Alpes. Commissariat à l'énergie atomique et aux énergies alternatives)
Arregui Bravo, Guillermo (Institut Català de Nanociència i Nanotecnologia)
Chen, Zekun (University of California. Department of Chemistry)
Alzina, Francesc (Institut Català de Nanociència i Nanotecnologia)
Sotomayor Torres, Clivia M. (Institut Català de Nanociència i Nanotecnologia)
Chávez Ángel, Emigdio (Institut Català de Nanociència i Nanotecnologia)

Date:	2022
Abstract:	We present a comparative investigation of the influence of crystallinity and film thickness on the acoustic and thermal properties of layered PtSe films of varying thickness (1-40 layers) using frequency-domain thermo-reflectance, low-frequency Raman, and pump-probe coherent phonon spectroscopy. We find ballistic cross-plane heat transport up to ~30 layers PtSe and a 35% reduction in the cross-plane thermal conductivity of polycrystalline films with thickness larger than 20 layers compared to the crystalline films of the same thickness. First-principles calculations further reveal a high degree of thermal conductivity anisotropy and a remarkable large contribution of the optical phonons to the thermal conductivity in bulk (~20%) and thin PtSe films (~30%). Moreover, we show strong interlayer interactions in PtSe, short acoustic phonon lifetimes in the range of picoseconds, an out-of-plane elastic constant of 31. 8 GPa, and a layer-dependent group velocity ranging from 1340 ms in bilayer to 1873 ms in eight layers of PtSe. The potential of tuning the lattice thermal conductivity of layered materials with the level of crystallinity and the real-time observation of coherent phonon dynamics open a new playground for research in 2D thermoelectric devices and provides guidelines for thermal management in 2D electronics.
Grants:	European Commission 754558 European Commission 289061 Agencia Estatal de Investigación SEV-2017-0706 Agencia Estatal de Investigación PGC2018-101743-B-I00
Note:	Altres ajuts: this work has been supported by the CERCA Program/Generalitat de Catalunya. AES acknowledges support by the H2020-MSCA-IF project THERMIC-GA No. 101029727.
Rights:	Aquest document està subjecte a una llicència d'ús Creative Commons. Es permet la reproducció total o parcial, la distribució, la comunicació pública de l'obra i la creació d'obres derivades, fins i tot amb finalitats comercials, sempre i quan es reconegui l'autoria de l'obra original.
Language:	Anglès
Document:	Article ; recerca ; Versió publicada
Subject:	Cristallinity ; Cross planes ; Film-thickness ; Frequency domains ; Low-frequency Raman ; Pump probe ; Raman probe ; Thermal transport ; Thermoreflectance ; Varying thickness
Published in:	npj 2D Materials and Applications, Vol. 6 (2022) , art. 32, ISSN 2397-7132

DOI: 10.1038/s41699-022-00311-x

9 p, 2.0 MB

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Research literature > UAB research groups literature > Research Centres and Groups (research output) > Experimental sciences > Catalan Institute of Nanoscience and Nanotechnology (ICN2)
Articles > Research articles
Articles > Published articles