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Multiscale Investigation of the Structural, Electrical and Photoluminescence Properties of MoS(2) Obtained by MoO(3) Sulfurization

In this paper, we report a multiscale investigation of the compositional, morphological, structural, electrical, and optical emission properties of 2H-MoS(2) obtained by sulfurization at 800 °C of very thin MoO(3) films (with thickness ranging from ~2.8 nm to ~4.2 nm) on a SiO(2)/Si substrate. XPS a...

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Detalles Bibliográficos
Autores principales: Panasci, Salvatore E., Koos, Antal, Schilirò, Emanuela, Di Franco, Salvatore, Greco, Giuseppe, Fiorenza, Patrick, Roccaforte, Fabrizio, Agnello, Simonpietro, Cannas, Marco, Gelardi, Franco M., Sulyok, Attila, Nemeth, Miklos, Pécz, Béla, Giannazzo, Filippo
Formato: Online Artículo Texto
Lenguaje:English
Publicado: MDPI 2022
Materias:
Acceso en línea:https://www.ncbi.nlm.nih.gov/pmc/articles/PMC8778062/
https://www.ncbi.nlm.nih.gov/pubmed/35055201
http://dx.doi.org/10.3390/nano12020182
Descripción
Sumario:In this paper, we report a multiscale investigation of the compositional, morphological, structural, electrical, and optical emission properties of 2H-MoS(2) obtained by sulfurization at 800 °C of very thin MoO(3) films (with thickness ranging from ~2.8 nm to ~4.2 nm) on a SiO(2)/Si substrate. XPS analyses confirmed that the sulfurization was very effective in the reduction of the oxide to MoS(2,) with only a small percentage of residual MoO(3) present in the final film. High-resolution TEM/STEM analyses revealed the formation of few (i.e., 2–3 layers) of MoS(2) nearly aligned with the SiO(2) surface in the case of the thinnest (~2.8 nm) MoO(3) film, whereas multilayers of MoS(2) partially standing up with respect to the substrate were observed for the ~4.2 nm one. Such different configurations indicate the prevalence of different mechanisms (i.e., vapour-solid surface reaction or S diffusion within the film) as a function of the thickness. The uniform thickness distribution of the few-layer and multilayer MoS(2) was confirmed by Raman mapping. Furthermore, the correlative plot of the characteristic A(1g)-E(2g) Raman modes revealed a compressive strain (ε ≈ −0.78 ± 0.18%) and the coexistence of n- and p-type doped areas in the few-layer MoS(2) on SiO(2), where the p-type doping is probably due to the presence of residual MoO(3). Nanoscale resolution current mapping by C-AFM showed local inhomogeneities in the conductivity of the few-layer MoS(2), which are well correlated to the lateral changes in the strain detected by Raman. Finally, characteristic spectroscopic signatures of the defects/disorder in MoS(2) films produced by sulfurization were identified by a comparative analysis of Raman and photoluminescence (PL) spectra with CVD grown MoS(2) flakes.