Phase-driven magneto-electrical characteristics of single-layer MoS₂

Abstract

Magnetism of the MoS2 semiconducting atomic layer was highlighted for its great potential in the applications of spintronics and valleytronics. In this study, we demonstrate an evolution of magneto-electrical properties of single layer MoS2 with the modulation of defect configurations and formation of a partial 1T phase. With Ar treatment, sulfur was depleted within the MoS2 flake leading to a 2H (low-spin) → partial 1T (high-spin) phase transition. The phase transition was accompanied by the development of a ferromagnetic phase. Alternatively, the phase transition could be driven by the desorption of S atoms at the edge of MoS2via O2 treatment while with a different ordering magnitude in magnetism. The edge-sensitive magnetism of the single-layer MoS2 was monitored by magnetic force microscopy and validated by a first-principle calculation with graded-Vs (sulfur vacancy) terminals set at the edge, where band-splitting appeared more prominent with increasing Vs. Treatment with Ar and O2 enabled a dual electrical characteristic of the field effect transistor (FET) that featured linear and saturated responses of different magnitudes in the Ids-Vds curves, whereas the pristine MoS2 FET displayed only a linear electrical dependency. The correlation and tuning of the Vs-1T phase transition would provide a playground for tailoring the phase-driven properties of MoS2 semiconducting atomic layers in spintronic applications.

Direct synthesis of metastable phases of 2D transition metal dichalcogenides

“…205 The incorporation of domains of the 1T phase in the 2H matrix induces a robust ferromagnetism in the intrinsically nonmagnetic semiconducting TMDs, further expanding the range of potential applications to spintronic devices. 206,207 The difficulty in accessing the input of the metastable phase is commonly associated with the fact that in many cases, the 1T(1T 0 ) phase co-exists with the thermodynamically stable 2H phase in these produced materials. Here, we review the state-of-the-art research articles related to the understanding of how the intrinsic properties of the 1T(1T 0 ) phases can enable novel applications.…”

Hydrogenation-controlled phase transition on two-dimensional transition metal dichalcogenides and their unique physical and catalytic properties

“…1d ) 2 , where M is the transition metal element and X is a chalcogen element (S, Se, and Te). These 2D TMDs show rich physical and chemical properties and can be metallic, half-metallic, semiconducting, magnetic, and catalytic, which can be tuned by phase transition, composition engineering, surface functionalization, and external fields (strain and electrical field) 2 9 19 20 21 22 23 24 25 26 27 28 29 30 31 32 . For example, 2H MoS 2 and WS 2 monolayers are semiconductor, while their 1T phases are metallic 32 33 34 .…”

“…Vanadium disulfide monolayer showed better catalytic performance than its selenides and tellurides counterparts 25 and tensile strain can enhance the ability dramatically 26 . The catalytic performance of MX 2 monolayers can be strongly improved by phase transition 30 31 32 33 34 35 36 37 38 . For example, the 1T phase MoS 2 and WS 2 nanosheet was proven to be more catalytically active in facilitating hydrogen production in electrolysis of water than their 2H counterpart, although 2H phase is more stable than its 1T phase 30 .…”

“…Theoretically, it was reported that hydrogen-functionalization can trigger the 2H to 1T phase transition of MoS 2 28 and the catalytic activity of 1T-MoS 2 mainly arises from its affinity for binding H at the surface S sites 28 39 40 41 . Recently, 1T phase domains were formed in 2H-MX 2 monolayer by creating X vacancies and these 2H-1T mixed monolayer showed ferromagnetism 31 . Although oxidization is a simple way to create the vacancy for the phase transition, it may also result in a lot of defects in the monolayers.…”

Phase transition and electronic structure investigation of MoS2-reduced graphene oxide nanocomposite decorated with Au nanoparticles

“…Peak 2 (2471 eV) at resonance maximum can be attributed, according to previous reports, [63][64][65] to electronic transitions from the S1s core level to unoccupied hybridized S3p-Mo4d electronic states. The pre-edge shoulder at 2468.5 eV (peak 1) can be associated with the presence of S-O bond species [52,60,66]. A third peak, located at 2472.1 eV and attributed to S1s-3p z electronic transitions has been observed for the MoS 2 monolayer sample (black line spectrum in Figure 7) showed here as comparison [63,65].…”