High‐Throughput Computational Characterization of 2D Compositionally Complex Transition‐Metal Chalcogenide Alloys

Abstract

2D binary transition‐metal chalcogenides (TMCs) such as molybdenum disulfide exhibit excellent properties required for energy conversion applications. Alloying binary TMCs can form 2D compositionally complex TMC alloys (CCTMCAs) that possess remarkable properties from the constituent TMCs. High‐throughput workflow performing density functional theory (DFT) calculations based on the virtual crystal approximation (VCA) model (VCA‐DFT) is designed. The workflow is tested by predicting properties including in‐plane lattice constants, band gaps, effective masses, spin–orbit coupling, and band alignments of the Mo‐W‐S‐Se, Mo‐W‐S‐Te, and Mo‐W‐Se‐Te 2D CCTMCAs. The VCA‐DFT results are validated by computing the same properties using unit cells and supercells of selected compositions. The VCA‐DFT results of the abovementioned five properties are comparable to that of DFT calculations, with some inaccuracies in several properties of MoSTe and WSTe. Moreover, 2D CCTMCAs can form type II heterostructures as used in photovoltaics. Finally, Mo0.5W0.5SSe, Mo0.5W0.5STe, and Mo0.5W0.5SeTe 2D CCTMCAs are used to demonstrate the room‐temperature entropy‐stabilized alloys. They also exhibit high electrical conductivities at 300 K, promising for light adsorption devices. This work shows that the high‐throughput workflow using VCA‐DFT calculations provides a tradeoff between efficiency and accuracy, opening up opportunities in the computational design of other 2D CCTMCAs for various applications.

First principles assessment of the phase stability and transition mechanisms of designated crystal structures of pristine and Janus transition metal dichalcogenides

“…The calculated lattice parameters are in very good agreement (less than 2% differences in general) with the existing literature for all considered pristine TMD phases 37–40 and the Janus phases of H and T′. 41–43…”

“…The calculated lattice parameters are in very good agreement (less than 2% differences in general) with the existing literature for all considered pristine TMD phases [37][38][39][40] and the Janus phases of H and T 0 . [41][42][43] In general, the calculated lattice parameters both for MX 2 and MXY monolayers increase with the increasing atomic radius of the chalcogen atoms. It is found that the optimized b lattice parameters of pristine and Janus TMDs are very close to half of the b 0 lattice parameters for T 00 phases as the conventional unit cell for the T 00 phase is double that of other phases in the y direction.…”

MoxWx–1S2 Nanotubes for Advanced Field Emission Application

“…Most of the research so far has been done on flat, 2D structures, both theoretically and experimentally. [17][18][19][20] Individual multiwalled WS 2 and MoS 2 nanotubes are having a resurgence of interest, as interesting optical and electrical properties have been reported in recent years such as quasi-1D superconductivity, [21] electroluminescence, [22] confined optical cavity modes within the nanotube core, [23,24] whispering gallery modes, [25] as well as the lowtemperature Coulomb blockade, [26] field-effect transistors, [27,28] and field emitters, [29] making them promising components for nanoelectronic devices. In recent years, TMDCs have opened a new frontier in the area of field emission devices, due to their layered structure and the presence of thin and sharp edges with high aspect ratios which enhance local electric field.…”

High-throughput characterization of transition metal dichalcogenide alloys: Thermodynamic stability and electronic band alignment

“…* erhart@chalmers.se All of the binary alloys based on (Mo, W)(S, Se) 2 have been synthesized [19], usually in the hexagonal H structure (spacegroup P 6m2, ITCA number 187; Fig. 1b), and have been thoroughly studied in the context of band gap engineering by composition control [18,[20][21][22][23][24][25]. It has been shown that these alloys are random at ambient conditions due to (very) small mixing energies [18].…”