1. Micrometer-size crystalline monolayer MoS2 domains obtained by sulfurization of molybdenum oxide ultrathin films
- Author
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S.E. Panasci, E. Schilirò, A. Koos, M. Nemeth, M. Cannas, S. Agnello, F. Roccaforte, B. Pécz, F. Giannazzo, Panasci S.E., Schiliro E., Koos A., Nemeth M., Cannas M., Agnello S., Roccaforte F., Pecz B., and Giannazzo F.
- Subjects
Sulfurization ,Raman spectroscopy ,Settore FIS/01 - Fisica Sperimentale ,Electrical and Electronic Engineering ,Condensed Matter Physics ,MoS2 ,Photoluminescence ,Atomic and Molecular Physics, and Optics ,Transmission electron microscopy ,Surfaces, Coatings and Films ,Electronic, Optical and Magnetic Materials - Abstract
In this work, the formation of micrometer-size crystalline monolayer (1L) MoS2 flakes with triangular shape and a central multilayer core is obtained by the sulfurization at 800 °C of pre-deposited ultrathin MoOx films (1.2–1.8 nm) on c-sapphire substrates. The thickness uniformity, crystalline quality, doping and strain distribution in the MoS2 flakes as a function of the initial MoOx thickness was evaluated by micro-Raman (μR) mapping. The excellent crystalline quality of the triangular 1L-MoS2 flakes was confirmed by micro-photoluminescence (μPL) maps, showing a very intense peak at ∼1.85 eV, that decreases in the central part, as expected for multilayers MoS2. A biaxial strain of ∼0.38–0.4% was deduced from the μPL data, in perfect agreement with μR results. Our results show how the sulfurization of pre-deposited MoOx films on c-sapphire allows, under proper conditions, to obtain 1L-MoS2 flakes with quality comparable to the one typically reported by the conventional chemical vapour deposition, with important implications for device applications.
- Published
- 2023