The bandgaps of monolayer and bulk molybdenum sulfide (MoS2) result in that they are far from suitable for application as a saturable absorption device. In this paper, the operation of a broadband ...MoS2 saturable absorber is demonstrated by the introduction of suitable defects. It is believed that the results provide some inspiration in the investigation of two‐dimensional optoelectronic materials.
1T-TaS₂ as a quantum spin liquid Law, K. T.; Lee, Patrick A.
Proceedings of the National Academy of Sciences - PNAS,
07/2017, Letnik:
114, Številka:
27
Journal Article
Recenzirano
Odprti dostop
1T-TaS₂ is unique among transition metal dichalcogenides in that it is understood to be a correlation-driven insulator, where the unpaired electron in a 13-site cluster experiences enough correlation ...to form a Mott insulator. We argue, based on existing data, that this well-known material should be considered as a quantum spin liquid, either a fully gapped Z2 spin liquid or a Dirac spin liquid. We discuss the exotic states that emerge upon doping and propose further experimental probes.
Transition‐metal dichalcogenides (TMDCs) monolayers have been considered a perfect platform for realizing exciton‐polariton at room temperature due to their direct bandgap and large binding energy of ...exciton. It is well established that strong coupling depends on the field enhancement induced by optical nanocavity with a high‐quality factor (Q‐factor). In this work, the enhanced strong coupling between the exciton of TMDC monolayer and the cavity resonance based on a symmetry protected magnetic dipole (MD) bound state in the continuum (BIC) and electric toroidal dipole (TD) BIC is demonstrated. It is found that strong coupling can be realized between the exciton in a TMDC monolayer and quasi‐BIC (QBIC) by varying the incidence angle, period of the grating, the width of the slit, and the position of the slit for symmetry protected BIC. Besides, strong coupling between exciton and TD BIC is also demonstrated by integrating a WSe2 monolayer onto a compound grating. It is found that Rabi‐splitting strongly depends on the location of TMDC monolayer, Q‐factor of the resonator, and the thickness of the structure. By carefully adjusting these three critical parameters, Rabi‐splitting can be up to 38 (1L‐WSe2), 65 (1L‐WS2), 40 (1L‐MoSe2), and 60 meV(1L‐MoS2).
Enhanced strong coupling is realized between the exciton of transition‐metal dichalcogenide (TMDC) monolayers and bound states in the continuum. It is demonstrated that Rabi‐splitting strongly depends on the location of the TMDC monolayer, Q‐factor, and the thickness of the structure. After optimizing the structure, Rabi‐splitting of 38 (1L‐WSe2), 65 (1L‐WS2), 40 (1L‐MoSe2), and 60 meV(1L‐MoS2), have been achieved.
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•Systematic study of two-dimensional MoS2 layers during PMMA-assisted substrate transfers to assess the quality of wet-transfer process.•Chemical etchant such as KOH not only react to ...the growth substrate but also have unique influences on the 2D material.•2 to 5 M KOH concentrations allow rapid transfer with highest quality of MoS2 atomic layers.•A relationship between the use of optimal etchant concentrations and delamination time is established.
Two-dimensional (2D) MoS2 is an emerging alternative to traditional semiconductors, overcoming scaling limits in device fabrication. Ongoing efforts to realize the full potential of 2D MoS2 in CMOS back-end-of-line integration encounters notable challenges due to synthesis of such 2D materials requiring high temperature growth substrates and a transfer step. Consequently, lattice preservation of MoS2 atomic layers during transfer from growth substrate to a target substrate is crucial for fabrication and system integration. This work, investigates the impact of commonly used chemical etchant potassium hydroxide (KOH) on MoS2 during the poly(methylmethacrylate) (PMMA) assisted wet-transfer process from sapphire substrates. A systematic experimental framework involving Raman spectroscopy, Atomic Force Microscopy (AFM), Optical Microscopy, and X-ray Photoelectron Spectroscopy (XPS) was employed for comparative evaluation of MoS2 upon transfer. While the investigations highlight the relation of etchant concentration and exposure time to be the deterministic factors, topographic and spectroscopic evidence corroborate the role of K+ ions in etching and oxidation of MoS2 at higher concentrations affecting the MoS2 quality. Thorough characterizations of transfer process, while following the MoS2 quality in this work, provides crucial information on etchant concentration selection to achieve shorter substrate transfer time with minimal impact on material quality.
Two dimensional (2D) transition-metal dichalcogenides and their heterostructures are important materials for future electronic device applications. By using the first-principles calculations we ...investigate how the electronic and magnetic properties of MoS2 bilayer is modified by intercalating transition-metals (Fe, Co, and Ni). The Fe-intercalated MoS2 bilayer is found to be a non-magnetic gapless semimetal. Without spin–orbit coupling it has the Dirac state on the Γ-M line in k space at the Fermi level. The spin degeneracy of the Dirac state is removed by spin–orbit coupling. However, the bottom of the conduction band and the top of the valence band are in contact with the Fermi level making the system a non-magnetic gapless semimetal. The Dirac state is also observed in both Co-intercalated and Ni-intercalated MoS2 bilayers because they have the same symmetry in crystal structure as the Fe-intercalated MoS2 bilayer. The difference in the number of valence electrons in the intercalated atoms drastically change the electronic and magnetic properties. The Co-intercalated MoS2 bilayer is a ferromagnetic metal, where the Dirac state is below the Fermi level. The Ni-intercalated MoS2 bilayer is a non-magnetic narrow gap semiconductor, where the Dirac state is far below the Fermi level. The results revealed the electronic and magnetic properties of the transition-metal-intercalated MoS2 bilayers and will be useful for designing a variety of 2D materials.
•The Dirac states of transition-metal (TM)-intercalated MoS2 bilayers are studied.•The Fe-intercalated MoS2 bilayer is a non-magnetic gapless semimetal.•Electronic and magnetic properties can be tuned by the type of TM intercalation.
The efficient disinfection of bacterial contaminants in wastewater is a critical challenge in the field of environmental remediation. Herein, we present a novel approach for efficient bacterial ...disinfection using hydrothermally integrated MoO2–MoS2@rGO nanoframe networks. The developed nanoframe networks exhibit a unique architecture comprising of molybdenum dioxide (MoO2) and molybdenum disulfide (MoS2) impregnated on algae biomass reduced graphene oxide (rGO). The as-synthesized nanoframe networks demonstrate exceptional antibacterial activity against Escherichia coli bacteria. The disinfection efficiency was evaluated by measuring the bacterial viability and observing the morphological changes using scanning electron microscopy. The MoO2–MoS2@rGO nanoframe networks exhibited a remarkable antibacterial effect, achieving a high disinfection rate of 95.8% within a short contact time of 10 min. The efficient bacterial disinfection capability of the nanoframe networks can be attributed to the synergistic effects of MoO2, MoS2, and rGO components. The MoO2 nanoparticles generate reactive oxygen species (ROS), persuading oxidative stress and leading to bacterial inactivation. The MoS2 nanoparticles possess inherent antibacterial properties through the release of Mo and S ions. The rGO nanosheets provide a conductive and stable platform, facilitating the charge transfer during the antibacterial process. Furthermore, the hydrothermal integration method enables easy scalability and cost-effectiveness of the MoO2–MoS2@rGO nanoframe networks. The nanoframe networks can be easily recovered and reused, reducing waste generation and promoting sustainability. Overall, this study presents a promising approach for efficient bacterial disinfection in wastewater using hydrothermally integrated MoO2–MoS2@rGO nanoframe networks. The remarkable antibacterial performance, along with the advantages of scalability and reusability, makes these nanoframe networks a potential candidate for practical applications in environmental remediation and water treatment processes.
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•Design of Novel hydrothermal integration of MoO2–MoS2@rGO nanoframe networks.•Nanocomposite exhibits antibacterial activity against common microbes in wastewater.•Cost-effective and sustainable approach using biomass of green algae Chlorophyta.•Potential for large-scale production and application in wastewater treatment.
The performance limits of monolayer transition metal dichalcogenide ( MX 2 ) transistors are examined with a ballistic MOSFET model. Using an ab initio theory, we calculate the band structures of 2-D ...transition MX 2 . We find the lattice structures of monolayer MX 2 remain the same as the bulk MX 2 . Within the ballistic regime, the performances of monolayer MX 2 transistors are better compared with those of the silicon transistors if a thin high-κ gate insulator is used. This makes monolayer MX 2 promising 2-D materials for future nanoelectronic device applications.
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