2D Monolayer of the 1T’ Phase of Alloyed WSSe from Colloidal Synthesis

Abstract

We explore the colloidal growth of monolayers of WSSe alloy in their 1T’ phase with various Se contents. We develop a synthetic procedure leading to reduced aggregation of the flakes. The presence of a narrow band-gap close to the top of the valence band has been evidenced combining photoemission spectroscopy and density functional theory (DFT). The electronic structure is weakly affected by the variation of the alloy content and atomic ordering. μ-Raman spectroscopy and STEM are used to confirm the obtained 1T’ phase, while simulations of the Raman spectra suggest contribution from both the S and Se atoms in the Raman spectra. Finally, we use electronic transport and photoconduction and reveal a short coherence length, consistent with the defective nature of the flakes.

Layer-Structured Anisotropic Metal Chalcogenides: Recent Advances in Synthesis, Modulation, and Applications

“…The metal or chalcogen atoms in a parent MC crystals can be substituted by other metal or chalcogen atoms to achieve desired properties . In the wet chemical synthesis, various 1D and 2D MC NSs were successfully synthesized by simple mixing of precursors. ,,− Sun et al synthesized 2D MCs nanocrystals with a wide range of compositions of metals and chalcogens in MoSe 2 –WSe 2 and WS 2 –WSe 2 nanocrystals (Figure a) . The MoSe 2 –WSe 2 solid solution (Mo x W 1– x Se 2 ) was synthesized at 300 °C by introducing dropwise metal precursors (MoCl 5 , WCl 6 ) dissolved in oleic acid in a mixed solution containing oleylamine, HMDS, and diphenyl diselenide.…”

Recent Progress on Phase Engineering of Nanomaterials

“…The colloidal synthesis method has been widely used for the preparation of TMD nanomaterials. , The proper combination of precursors, temperature, and gas atmosphere could effectively engineer the phase of the final products. Recently, increasing efforts have been devoted to developing new solution-based synthesis methods to prepare TMD nanomaterials with unconventional phases. − For example, Mahler et al . reported a colloidal synthesis method to prepare 1T-WS 2 nanosheets by the injection of WCl 6 and CS 2 mixed in oleic acid into hot oleylamine (320 °C) under argon atmosphere (Figure a) .…”

Unidirectional Rashba spin splitting in single layer WS2(1−x)Se2x alloy

“…The use of the VCA in the context of planewave DFT using pseudopotentials is justified when the atoms composing the alloy are similar and when the pseudopotentials use the same number of valence orbitals for each angular momentum, as in the case of S and Se. Recently, the VCA method has been successfully employed in simulating the electronic properties of transition metal chalcogenide alloys [81,82]. and EL analyzed the data.…”