Determining by Raman spectroscopy the average thickness and N -layer-specific surface coverages of MoS 2 thin films with domains much smaller than the laser spot size.

Autor: Wasem Klein F; Laboratoire Charles Coulomb, Université de Montpellier, CNRS, F-34095, Montpellier, France., Huntzinger JR; Laboratoire Charles Coulomb, Université de Montpellier, CNRS, F-34095, Montpellier, France., Astié V; Annealsys, 139 Rue des Walkyries, 34000 Montpellier, France., Voiry D; Institut Européen des Membranes, IEM, UMR 5635, Université Montpellier, ENSCM, CNRS, Montpellier, France., Parret R; Aix Marseille Université, CNRS, CINAM, UMR 7325, Campus de Luminy, 13288, Marseille, France., Makhlouf H; Laboratoire Charles Coulomb, Université de Montpellier, CNRS, F-34095, Montpellier, France., Juillaguet S; Laboratoire Charles Coulomb, Université de Montpellier, CNRS, F-34095, Montpellier, France., Decams JM; Annealsys, 139 Rue des Walkyries, 34000 Montpellier, France., Contreras S; Laboratoire Charles Coulomb, Université de Montpellier, CNRS, F-34095, Montpellier, France., Landois P; Laboratoire Charles Coulomb, Université de Montpellier, CNRS, F-34095, Montpellier, France., Zahab AA; Laboratoire Charles Coulomb, Université de Montpellier, CNRS, F-34095, Montpellier, France., Sauvajol JL; Laboratoire Charles Coulomb, Université de Montpellier, CNRS, F-34095, Montpellier, France., Paillet M; Laboratoire Charles Coulomb, Université de Montpellier, CNRS, F-34095, Montpellier, France.
Jazyk: angličtina
Zdroj: Beilstein journal of nanotechnology [Beilstein J Nanotechnol] 2024 Mar 07; Vol. 15, pp. 279-296. Date of Electronic Publication: 2024 Mar 07 (Print Publication: 2024).
DOI: 10.3762/bjnano.15.26
Abstrakt: Raman spectroscopy is a widely used technique to characterize nanomaterials because of its convenience, non-destructiveness, and sensitivity to materials change. The primary purpose of this work is to determine via Raman spectroscopy the average thickness of MoS 2 thin films synthesized by direct liquid injection pulsed-pressure chemical vapor deposition (DLI-PP-CVD). Such samples are constituted of nanoflakes (with a lateral size of typically 50 nm, i.e., well below the laser spot size), with possibly a distribution of thicknesses and twist angles between stacked layers. As an essential preliminary, we first reassess the applicability of different Raman criteria to determine the thicknesses (or layer number, N ) of MoS 2 flakes from measurements performed on reference samples, namely well-characterized mechanically exfoliated or standard chemical vapor deposition MoS 2 large flakes deposited on 90 ± 6 nm SiO 2 on Si substrates. Then, we discuss the applicability of the same criteria for significantly different DLI-PP-CVD MoS 2 samples with average thicknesses ranging from sub-monolayer up to three layers. Finally, an original procedure based on the measurement of the intensity of the layer breathing modes is proposed to evaluate the surface coverage for each N (i.e., the ratio between the surface covered by exactly N layers and the total surface) in DLI-PP-CVD MoS 2 samples.
(Copyright © 2024, Wasem Klein et al.)
Databáze: MEDLINE
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