Synthesis and Characterization of Metallic Janus MoSH Monolayer

Abstract

Janus transition-metal dichalcogenides (TMDCs) are emerging as special 2D materials with different chalcogen atoms covalently bonded on each side of the unit cell, resulting in interesting properties. To date, several synthetic strategies have been developed to realize Janus TMDCs, which first involves stripping the top-layer S of MoS2 with H atoms. However, there has been little discussion on the intermediate Janus MoSH. It is critical to find the appropriate plasma treatment time to avoid sample damage. A thorough understanding of the formation and properties of MoSH is highly desirable. In this work, a controlled H2-plasma treatment has been developed to gradually synthesize a Janus MoSH monolayer, which was confirmed by the TOF-SIMS analysis as well as the subsequent fabrication of MoSSe. The electronic properties of MoSH, including the high intrinsic carrier concentration (∼2 × 1013 cm–2) and the Fermi level (∼ – 4.11 eV), have been systematically investigated by the combination of FET device study, KPFM, and DFT calculations. The results demonstrate a method for the creation of Janus MoSH and present the essential electronic parameters which have great significance for device applications. Furthermore, owing to the metallicity, 2D Janus MoSH might be a potential platform to observe the SPR behavior in the mid-infrared region.

Atomic Layer Deposition of Large-Area Polycrystalline Transition Metal Dichalcogenides from 100 °C through Control of Plasma Chemistry

“…Recently, it has been suggested that H could even replace S in MoS 2 structure, resulting in n-type MoSH. 77 …”

“…Recently, it has been suggested that H could even replace S in MoS 2 structure, resulting in n-type MoSH. 77 Our efforts to locate H using infrared and Raman spectroscopy measurements were unsuccessful, as no evidence of either Mo−H or S−H bonding was observed. However, this is not evidence for the absence of such bonding.…”

Lateral layered semiconductor multijunctions for novel electronic devices

“…10 Furthermore, the transition from an indirect bandgap in bulk 11 and few-layer 12 TMDs to a direct bandgap in monolayer 12 TMDs offer new opportunities for fundamental [13][14][15] and technological 16,17 research beyond silicon optoelectronics. Besides, the electronic structures and properties of monolayer TMDs can be further tuned and designed via surface doping, 18 alloying, [19][20][21] strain, [22][23][24] external fields, 25 and forming Janus a State Key Laboratory of New Ceramics and Fine Processing, Key Laboratory of TMDs, [26][27][28][29] making them desirable for functional and customized device applications. Specifically, the construction of heterostructures can be a very effective and novel route to modulate the electronic structure and corresponding device physics.…”

“…27 A step further, it has been proven that it is possible to obtain MoSH via H 2 plasma treatment. 28 In the case of multijunctions, vertical Janus WSSe/MoSSe heterostructures 49 and lateral MoS 2 /MoSSe/MoSe 2 junctions 29 have been achieved. A step further, the new structure of lateral Janus junctions can be constructed by synthesizing two Janus crystal regions with an opposite atomic layer configuration, where one layer of S (Se) atoms is replaced by Se (S) atoms to form an MSSe structure (Fig.…”

A first principles study of a van der Waals heterostructure based on MS2 (M = Mo, W) and Janus CrSSe monolayers

“…In parallel with the search for new 2D materials, the formation of Janus congurations of TMDCs has been recently achieved as an alternative technique to tune the intrinsic behavior of already existing 2D TMDC systems. For instance, the Janus TMDC MoSSe monolayer has been practically realized through the chemical vapor deposition (CVD) technique by replacing sulfur with selenium in the MoS 2 monolayer 12 and replacing selenium with sulfur in the MoSe 2 monolayer. 13 Recently, Janus WSSe monolayers have been fabricated through the CVD method.…”