Evolution of spectroscopy features in layered MoSxSe(2-x) solid solutions. (1st April 2022)

• Record Type: Journal Article
• Authors: Fajardo-Peralta, Alejandro; Nguyen, Minh An T; Valenzuela-Benavides, J; Brodie, Alexander; Gontijo, Rafael Nunes; Elías, Ana Laura; Perea-Lopez, Néstor; Mallouk, Thomas E; Terrones, Mauricio
• Is Part Of: Materials research express. Volume 9:Number 4(2022)
• Publication Date: 2022-04-01
• Subjects: transition metal dichalcogenides -- MoSxSe2-x -- Raman spectroscopy; Materials science -- Research -- Periodicals; Materials science -- Periodicals; 620.11
• DOI: 10.1088/2053-1591/ac5ef3
• Languages: English
• ISSNs: 2053-1591

Abstract

Abstract: In this work we report the structural and spectroscopic characterization of the bulk MoSx Se2-x solid solutions synthesized by chemical vapor transport. The bulk crystals were analyzed by scanning electron microscopy (SEM), x-ray diffraction (XRD), energy dispersive spectroscopy (EDS), atomic force microscopy (AFM), x-ray photoelectron spectroscopy (XPS) and Raman spectroscopy. Electron microscopy evaluation of the layered materials shows two distinct types of crystals: flat and easily cleavable hexagonal microcrystals up to 50 μ m in size, and agglomerated irregular crystals of 5–10 μ m in size. XRD shows a consistent increase in interplanar spacing as the Se content is increased in the sample series. Raman spectra of bulk MoSx Se2-x obtained with three different excitation energies revealed first order phonon modes associated with pure MoS2 (x = 2) and MoSe2 (x = 0) along with a complex behavior of vibrational modes when x had intermediate values. XPS Mo3d line scans indicate a slight shift towards lower binding energies as the Se/S ratio increases, consistent with the expected energies of MoSe2 . A simple and direct relationship can be established between the characteristic Raman peaks and the value of x, which can be useful for identifying the compositions of TMD crystals.