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Semiconducting two-dimensional materials might one day be used in scaled semiconductor technology. Andras Kis recounts how the first transistor based on a single layer of molybdenum disulfide was created.

Here, the authors demonstrate the electrical tunability of the nonlinear interactions, ultrafast formation and decay dynamics of layer-hybridized excitons in a field-effect device based on natural homobilayer MoS₂.

Metallic 2D transition metal dichalcogenides are appealing for their practical applications and fundamental properties, but their large-scale synthesis remains challenging. Here, the authors report a dual-precursor metal–organic chemical vapor deposition strategy to grow superconducting single-crystalline NbS₂ and NbSe₂ multilayers at the wafer scale.

Rhenium disulphide, ReS₂, is a member of the two-dimensional dichalcogenide family. Here, the authors find a suppression of conductivity at high charge density levels in devices with polymer electrolyte gates. The effects of doping and disorder are explored theoretically and experimentally.

Graphene nanoelectromechanical systems enable the study of the interplay between electrical conductivity and mechanical properties. Here, the authors observe oscillations in the electromechanical response of bilayer graphene due to wrinkling, rather than the linear response seen in single layers.

This work advances excitonic optoelectronics by demonstrating electrically tunable cavity coupling of interlayer excitons in a van der Waals heterobilayer. Through electrostatic control, a 5-fold increase in exciton lifetime and a 50-fold boost in photoluminescence intensity have been achieved, which highlights the role of in-plane optical dipoles in weak coupling and provides momentum-resolved insights into exciton emission.

Suitable materials for nanoelectromechanical systems should possess excellent mechanical properties and allow displacement self-sensing. Here, the authors fabricate electromechanical resonators based on single-layer MoS₂ with electrical readout, operating in the very high frequency range.

Single nucleotides can be identified with atomically thin MoS₂ nanopores by regulating molecular translocation speeds using a viscosity gradient system based on room-temperature ionic liquids.

The electronic band structure of van der Waals crystals is strongly sensitive to the number of layers. Here, the authors observe a thickness-dependent metal-to-semiconductor transition in layered PtSe₂ by means of electrical transport measurements.

In monolayer transition-metal dichalcogenides, lack of inversion symmetry results in spin-split valence and conduction bands, but the small conduction band splitting is hard to probe experimentally. Here, the authors extract a sub-band spacing energy of 0.8 meV in the conduction band of monolayer MoS₂ via quantum transport measurements.

Field-effect transistors based on molybdenum disulphide have latterly garnered significant interest. Their electrical transport characteristics are now studied for different dielectric configurations, and as a function of temperature.

Light chirality and electron spin interactions and the dependence of tunnelling photocurrent on the magnetic field are studied in indium selenide, exploiting its non-symmetric response to circularly polarized light to electrically detect chirality.

A highly tunable Nernst effect has been demonstrated in graphene/indium selenide devices, achieving a record Nernst coefficient at ultralow temperatures, highlighting its potential for quantum technologies and low-temperature applications.

An in-memory computing chip for vector–matrix multiplication and discrete signal processing applications can be fabricated using floating-gate field-effect transistors based on monolayer molybdenum disulfide.

The dipole-dependent propagation of hybrid excitons in a van der Waals heterostructure containing a WSe₂ bilayer is characterized by modulating the layer hybridization and interplay between many-body interactions of excitons with an applied vertical electric field.

The energy position of the van Hove singularity in a van der Waals flat-band system is detected by tunnelling (photo)currents within a field-effect structure.

Deep level transient spectroscopy (DLTS) is an established characterization technique used to study electrically active defects in 3D semiconductors. Here, the authors show that DLTS can also be applied to monolayer semiconductors, enabling in-situ characterization of the energy states of different defects and their interactions.

2D semiconductors offer a promising platform for the realization of compact and CMOS-compatible optoelectronic components. Here, the authors report the realization of light-emitting diodes based on 2D WSe2 integrated with a planar cavity, showing the electrical control of the emission angle and polarization at room temperature.

Spatially and temporally resolved exciton diffusion experiments on a two-dimensional WSe₂/hBN/MoSe₂ heterostructure are reported, where an excitation-power-dependent exciton diffusion pattern is observed and phenomena with dipole–dipole repulsive interaction are quantitatively modelled.

Logic operations and reconfigurable circuits are demonstrated that can be directly implemented using memory elements based on floating-gate field-effect transistors with monolayer MoS₂ as the active channel material.

Beneficiary defects could be utilized to introduce magnetism into materials that are not intrinsically magnetic. Here, the authors demonstrate long range magnetic order in the air-stable, defective Platinum Diselenide in the ultimate limit of thickness by using proximitized graphene as a probe.

A device capable of inverting the polarization of light by efficient control of interlayer excitons in a van der Waals heterostructure is demonstrated, representing an important step towards implementing logic operations in valleytronics.

Electronically accessible states in vanadium dioxide can be arbitrarily manipulated on short timescales and tracked beyond 10,000 s after excitation.

Nanofluidic devices with a large entrance asymmetry can function as memristive switches—operating on the second timescale and with a conductance ratio of up to sixty—and can be assembled into basic logic circuits.

Magneto-transport measurements on thin metallic crystals of the transition metal dichalcogenide PtSe₂ show signatures of ferro- and antiferromagnetic order depending on the number of layers and first-principles calculations suggest Pt vacancies at the surface as a plausible cause.

Zero-dimensional photonic quantum emitters can be realized using defects in the two-dimensional dichalcogenides.

Charge carriers in transition metal dichalcogenides have an extra degree of freedom known as valley pseudospin, which is associated with the shape of the energy bands. Experiments show that this pseudospin can be manipulated using magnetic fields.

A very sensitive photodector based on molybdenum disulphide with potential for integrated optoelectronic circuits, light sensing, biomedical imaging, video recording or spectroscopy is now demonstrated.

Ionic Coulomb blockade—the ionic counterpart of the electronic Coulomb blockade—has been observed in a single subnanometre MoS₂ pore junction.

Improving the performance of 2D transistors is essential to enable their future application for beyond-silicon electronics. Here, the authors report a method to induce localized tensile strain in monolayer MoS₂ transistors, leading to enhanced electron mobilities up to 185 cm²/Vs and an 8-fold increase of the on-state current densities.

Two-dimensional transition metal dichalcogenides (TMDCs) exhibit attractive electronic and mechanical properties. In this Review, the charge density wave, superconductive and topological phases of TMCDs are discussed, along with their synthesis and applications in devices with enhanced mobility and with the use of strain engineering to improve their properties.

Single-molecule-terminated scanning probes typically operate under ultra-high vacuum conditions at low temperatures. Here, the authors show that tips functionalized with C₆₀ can image single-layer graphene and MoS₂with high definition in a liquid environment at room temperature

Thermal scanning probe lithography can be used to pattern metal electrodes in direct contact with monolayer MoS₂, creating field-effect transistors that exhibit vanishing Schottky barrier heights, high on/off ratios of 10¹⁰, no hysteresis, and subthreshold swings as low as 64 mV per decade.

The large bandgap of a single layer of molybdenum disulphide can be exploited to construct transistors with high on/off ratios and high mobilities.

Engineering the interlayer coupling in a van der Waals heterostructure enables electrical control over the transport and density of valley-polarized interlayer excitons.

Heterobilayer excitonic devices consisting of two different van der Waals materials, in which excitons are shared between the layers, exhibit electrically controlled switching actions at room temperature.

Single-layer metal dichalcogenides are two-dimensional semiconductors that present strong potential for electronic and sensing applications complementary to that of graphene.

The ability to control interlayer excitons in van der Waals heterostructures provides a practical way to address the spin and valley degrees of freedom in solid-state devices. This Review surveys the recent progress in this field, with a focus on devices and engineering techniques.

This Review discusses the physics of electrical contacts to 2D semiconductors and the strategies adopted to improve charge injection in these materials. The requirements for efficient spin injection in spintronic devices are also presented.

Blue energy is a desirable renewable resource, involving the osmotic transport of ions through a membrane from seawater to fresh water; here, nanopores have been created in two-dimensional molybdenum-disulfide membranes, and shown to generate a substantial osmotic power output.