Jiuxiang Dai

Nature Electronics, Published online: 17 November 2022; doi:10.1038/s41928-022-00861-4

A reconfigurable device based on two-dimensional materials can function as both a transistor and a memory.

Nature Electronics, Published online: 17 November 2022; doi:10.1038/s41928-022-00858-z

A van der Waals heterostructure that has a partial floating-gate field-effect transistor device architecture can function as both reconfigurable transistor and reconfigurable non-volatile memory, and can provide reconfigurable logic-in-memory capabilities.

Nature Electronics, Published online: 17 November 2022; doi:10.1038/s41928-022-00860-5

This Review examines the use of multidimensional architectures—such as superjunction, multi-channel and multi-gate technologies—in power electronics devices, exploring the performance limits, scaling and material figure of merits of the different architectures.

Nature Communications, Published online: 17 November 2022; doi:10.1038/s41467-022-34774-9

The scalability of neuromorphic devices depends on the dismissal of capacitors and additional circuits. Here Liu et al. report an artificial neuron based on the polarization and depolarization of an anti-ferroelectric film, avoiding additional elements and reaching 37 fJ/spike of power consumption.

Lattice-matched InSb/CdTe heterostructures are utilized to tailor the nonreciprocal charge transport up to room temperature. Benefiting from both the inversion symmetry breaking and interfacial Rashba spin–orbit coupling, this nonmagnetic hybrid system not only warrants a pronounced unidirectional magnetoresistance effect, but also enables highly efficient gate tuning of the rectification response, hence offering feasible strategies for controllable spin–orbit applications.

Abstract

Symmetry manipulation can be used to effectively tailor the physical order in solid-state systems. With the breaking of both the inversion and time-reversal symmetries, nonreciprocal magneto-transport may arise in nonmagnetic systems to enrich spin–orbit effects. Here, the observation of unidirectional magnetoresistance (UMR) in lattice-matched InSb/CdTe films is investigated up to room temperature. Benefiting from the strong built-in electric field of 0.13 V nm⁻¹ in the heterojunction region, the resulting Rashba-type spin–orbit coupling and quantum confinement result in a distinct sinusoidal UMR signal with a nonreciprocal coefficient that is 1–2 orders of magnitude larger than most non-centrosymmetric materials at 298 K. Moreover, this heterostructure configuration enables highly efficient gate tuning of the rectification response, wherein the UMR amplitude is enhanced by 40%. The results of this study advocate the use of narrow-bandgap semiconductor-based hybrid systems with robust spin textures as suitable platforms for the pursuit of controllable chiral spin–orbit applications.

npj 2D Materials and Applications, Published online: 16 November 2022; doi:10.1038/s41699-022-00352-2

2D materials-based nanoscale tunneling field effect transistors: current developments and future prospects

Author(s): Noriki Terada, Dmitry D. Khalyavin, Pascal Manuel, Fabio Orlandi, Christopher J. Ridley, Craig L. Bull, Ryota Ono, Igor Solovyev, Takashi Naka, Dharmalingam Prabhakaran, and Andrew T. Boothroyd

According to previous theoretical work, the binary oxide CuO can become a room-temperature multiferroic via tuning of the superexchange interactions by application of pressure. Thus far, however, there has been no experimental evidence for the predicted room-temperature multiferroicity. Here, we sho…

[Phys. Rev. Lett. 129, 217601] Published Tue Nov 15, 2022

Abstract

Two-dimensional (2D) twisted moiré materials, a new class of van der Waals (vdW) layered heterostructures with different twist angles between neighboring layers, have attracted tremendous attention due to their rich emerging properties. In this review, we systematically summarize the recent progress of 2D twisted moiré materials. Firstly, we introduce several representative fabrication methods and the fascinating topographies of the twisted moiré materials. Specifically, we discuss various remarkable physical properties related to twisted angles, including flat bands, unconventional superconductivity, ferromagnetism, and ferroelectricity. We also analyze the potential applications in various twisted moiré systems. Finally, the challenges and future perspectives of the twisted moiré materials are discussed. This work would spur edge-cutting ideas and related achievements in the scientific and technological frontiers of 2D twisted moiré materials.

npj 2D Materials and Applications, Published online: 15 November 2022; doi:10.1038/s41699-022-00360-2

Electrochemically exfoliated phosphorene nanosheet thin films for wafer-scale near-infrared phototransistor array

Interferometric Scattering Microscopy

Rayleigh scattering of the nanoparticles can be engineered by doping lanthanide ions, which is based on the enhanced polarizability of the nanoparticles when the excitation wavelength matches the ion resonance frequency of the lanthanide ions. More details can be found in article number 2203354 by Baolei Liu, Chaohao Chen, Xiaoxue Xu, Fan Wang, and co-workers.

The development of 1D transition metal dichalcogenides (TMDs) devices rolled from 2D TMDs in a variety ways.

Abstract

Transition metal dichalcogenides (TMDs) van der Waals (vdW) 1D heterostructures are recently synthesized from 2D nanosheets, which open up new opportunities for potential applications in electronic and optoelectronic devices. The most recent and promising strategies in regards to forming 1D TMDs nanotubes (NTs) or nanoscrolls (NSs) in this review article as well as their heterostructures that are produced from 2D TMDs are summarized. In order to improve the functionality of ultrathin 1D TMDs that are coaxially combined with boron nitride nanotubes and single-walled carbon nanotubes. 1D heterostructured devices perform better than 2D TMD nanosheets when the two devices are compared. The photovoltaic effect in WS₂ or MoS₂ NTs without a junction may exceed the Shockley–Queisser limit for the above-band-gap photovoltage generation. Photoelectrochemical hydrogen evolution is accelerated when monolayer WS₂ or MoS₂ NSs are incorporated into a heterojunction. In addition, the photovoltaic performance of the WSe₂/MoS₂ NSs junction is superior to that of the performance of MoS₂ NSs. The summary of the current research about 1D TMDs can be used in a variety of ways, which assists in the development of new types of nanoscale optoelectronic devices. Finally, it also summarizes the current challenges and prospects.

Oxidation leads to the degradation of 2D MoTe₂ under in situ electron microscopy at low oxygen pressures, while 2D MoS₂ surface remains inert. The etching is facilitated by abundant oxygen at partial oxygen pressures above 1 × 10⁻⁷ torr. The atomic scale etching mechanism is revealed computationally. Hydrocarbon contamination, commonly found on surfaces, accelerates etching by over forty times.

Abstract

Oxidation is the main cause of degradation of many 2D materials, including transition metal dichalcogenides (TMDs), under ambient conditions. Some of the materials are more affected by oxidation than others. To elucidate the oxidation-induced degradation mechanisms in TMDs, the chemical effects in single layer MoS₂ and MoTe₂ are studied in situ in an electron microscope under controlled low-pressure oxygen environments at room temperature. MoTe₂ is found to be reactive to oxygen, leading to significant degradation above a pressure of 1 × 10⁻⁷ torr. Curiously, the common hydrocarbon contamination found on practically all surfaces accelerates the damage rate significantly, by up to a factor of forty. In contrast to MoTe₂, MoS₂ is found to be inert under oxygen environment, with all observed structural changes being caused by electron irradiation only, leading to well-defined pores with high proportion of molybdenum nanowire-terminated edges. Using density functional theory calculations, a further atomic-scale mechanism leading to the observed oxygen-related degradation in MoTe₂ is proposed, and the role of the carbon in the etching is explored. Together, the results provide an important insight into the oxygen-related deterioration of 2D materials under ambient conditions relevant in many fields.

Abstract

The unipolar photocurrent in conventional photodiodes (PDs) based on photovoltaic effect limits the output modes and potential versatility of these devices in photodetection. Bipolar photodiodes with photocurrent switching are emerging as a promising solution for obtaining photoelectric devices with unique and attractive functions, such as optical logic operation. Here, we design an all-solid-state chip-scale ultraviolet (UV) PD based on a hybrid GaN heterojunction with engineered bipolar polarized electric field. By introducing the polarization-induced photocurrent switching effect, the photocurrent direction can be switched in response to the wavelength of incident light at 0 V bias. In particular, the photocurrent direction exhibits negative when the irradiation wavelength is less than 315 nm, but positive when the wavelength is longer than 315 nm. The device shows a responsivity of up to −6.7 mA/W at 300 nm and 5.3 mA/W at 340 nm, respectively. In particular, three special logic gates in response to different dual UV light inputs are demonstrated via a single bipolar PD, which may be beneficial for future multifunctional UV photonic integrated devices and systems.

Nature Synthesis, Published online: 14 November 2022; doi:10.1038/s44160-022-00182-6

Mechanical cleavage of layered materials to obtain two-dimensional (2D) sheets is restricted to materials with interlayer interactions dominated by van der Waals (vdW) forces. Here, calendering is used to weaken interlayer binding in non-vdW layered structures (metals, semiconductors and superconductors) allowing mechanical exfoliation to obtain 2D sheets with thickness-dependent properties.

Nature Communications, Published online: 14 November 2022; doi:10.1038/s41467-022-34734-3

Focused-ion beam (FIB) lithography enables high-resolution nanopatterning of 2D materials, but usually introduces significant damage. Here, the authors report a FIB-based fabrication technique to obtain high quality graphene superlattices with 18-nm pitch, which exhibit electronic transport properties similar to those of natural moiré systems.