Disassembling 2D van der Waals crystals into macroscopic monolayers and reassembling into artificial lattices

Science ◽  
2020 ◽  
Vol 367 (6480) ◽  
pp. 903-906 ◽  
Author(s):  
Fang Liu ◽  
Wenjing Wu ◽  
Yusong Bai ◽  
Sang Hoon Chae ◽  
Qiuyang Li ◽  
...  
Keyword(s):  
Mass Production ◽  
Van Der Waals ◽  
Great Promise ◽  
Layer By Layer ◽  
Transition Metal Dichalcogenide ◽  
High Quality ◽  
Quantum Devices ◽  
Artificial Materials ◽  
Two Dimensional Materials ◽  
One Step

Two-dimensional materials from layered van der Waals (vdW) crystals hold great promise for electronic, optoelectronic, and quantum devices, but technological implementation will be hampered by the lack of high-throughput techniques for exfoliating single-crystal monolayers with sufficient size and high quality. Here, we report a facile method to disassemble vdW single crystals layer by layer into monolayers with near-unity yield and with dimensions limited only by bulk crystal sizes. The macroscopic monolayers are comparable in quality to microscopic monolayers from conventional Scotch tape exfoliation. The monolayers can be assembled into macroscopic artificial structures, including transition metal dichalcogenide multilayers with broken inversion symmetry and substantially enhanced nonlinear optical response. This approach takes us one step closer to mass production of macroscopic monolayers and bulk-like artificial materials with controllable properties.

scholarly journals Heteroepitaxial van der Waals semiconductor superlattices

2021 ◽  
Author(s):  
Gangtae Jin ◽  
Chang-Soo Lee ◽  
Odongo Francis Okello ◽  
Suk-Ho Lee ◽  
Min Yeong Park ◽  
...  
Keyword(s):  
Van Der Waals ◽  
Chemical Vapour ◽  
Atomic Layer ◽  
Electronic Systems ◽  
Layer By Layer ◽  
Transition Metal Dichalcogenide ◽  
Semiconductor Superlattices ◽  
Equilibrium Limit ◽  
Band Alignments ◽  
Atomic Mixing

Abstract We report atomic layer-by-layer epitaxial growth of van der Waals (vdW) semiconductor superlattices (SLs) with programmable stacking periodicities, composed of more than two kinds of dissimilar transition-metal dichalcogenide monolayers (MLs), such as MoS2, WS2 and WSe2. The kinetics-controlled vdW epitaxy in the near equilibrium limit by metalorganic chemical vapour depositions enables to achieve accurate ML-by-ML stacking, free of interlayer atomic mixing, resulting in the tunable two-dimensional (2D) vdW electronic systems. We identified coherent atomic stacking orders at the vdW heterointerfaces, and present scaling valley polarized optical excitations that only pertain to a series of 2D type II band alignments.

The interlocked in situ fabrication of graphene@prussian blue nanocomposite as high-performance supercapacitor

2018 ◽  
Vol 47 (37) ◽  
pp. 13126-13134 ◽  
Author(s):  
Shi-Cheng Wang ◽  
Minli Gu ◽  
Luqing Pan ◽  
Junfeng Xu ◽  
Lei Han ◽  
...  
Keyword(s):  
Prussian Blue ◽  
High Performance ◽  
Great Promise ◽  
High Quality ◽  
In Situ Fabrication ◽  
Excellent Electrochemical Performance ◽  
One Step ◽  
The One ◽  
Method Show

High-quality graphene@prussian blue (G@PB) nanocomposite sheets fabricated via the one-step in situ hydrothermal method show great promise for energy-storage hybrid electrodes with excellent electrochemical performance.

Layer-by-layer assembly of porphyrin-fullerene dyads

2003 ◽  
Vol 07 (05) ◽  
pp. 357-364 ◽  
Author(s):  
Israel Zilbermann ◽  
Gregory A. Anderson ◽  
Dirk M. Guldi ◽  
Hiroko Yamada ◽  
Hiroshi Imahori ◽  
...  
Keyword(s):  
Active Layer ◽  
Van Der Waals ◽  
Van Der Waals Interactions ◽  
Layer By Layer ◽  
High Quality ◽  
Layer By Layer Assembly ◽  
Layer Assembly

The fabrication of high quality, robust and photoactive ITO electrodes is reported. Electrostatic and van-der-Waals interactions have been used for the step-by-step deposition of layers containing a fullerene-porphyrin dyad as the active layer.

Structural and electronic properties of a van der Waals heterostructure based on silicene and gallium selenide: effect of strain and electric field

2018 ◽  
Vol 20 (44) ◽  
pp. 27856-27864 ◽  
Author(s):  
P. T. T. Le ◽  
Nguyen N. Hieu ◽  
Le M. Bui ◽  
Huynh V. Phuc ◽  
Bui D. Hoi ◽  
...  
Keyword(s):  
Electric Field ◽  
Electronic Properties ◽  
Van Der Waals ◽  
Layer By Layer ◽  
Gallium Selenide ◽  
Two Dimensional ◽  
Parent Materials ◽  
Van Der Waals Heterostructure ◽  
Two Dimensional Materials ◽  
Structural And Electronic Properties

Combining van der Waals heterostructures by stacking different two-dimensional materials on top of each other layer-by-layer can enhance their desired properties and greatly extend the applications of the parent materials.

scholarly journals Recent progress in the assembly of nanodevices and van der Waals heterostructures by deterministic placement of 2D materials

2018 ◽  
Vol 47 (1) ◽  
pp. 53-68 ◽  
Author(s):  
Riccardo Frisenda ◽  
Efrén Navarro-Moratalla ◽  
Patricia Gant ◽  
David Pérez De Lara ◽  
Pablo Jarillo-Herrero ◽  
...  
Keyword(s):  
Recent Progress ◽  
2D Materials ◽  
Van Der Waals ◽  
Layer By Layer ◽  
Two Dimensional ◽  
Van Der Waals Heterostructures ◽  
Two Dimensional Materials

Designer heterostructures can be assembled layer-by-layer with unmatched precision thanks to the recently developed deterministic placement methods to transfer two-dimensional materials.

scholarly journals Moiré excitons in MoSe2-WSe2 heterobilayers and heterotrilayers

2021 ◽  
Vol 12 (1) ◽  
Author(s):  
Michael Förg ◽  
Anvar S. Baimuratov ◽  
Stanislav Yu. Kruchinin ◽  
Ilia A. Vovk ◽  
Johannes Scherzer ◽  
...  
Keyword(s):  
Transition Metal ◽  
Van Der Waals ◽  
Transition Metal Dichalcogenides ◽  
Transition Metal Dichalcogenide ◽  
Hybrid Layer ◽  
Layered Semiconductor ◽  
Two Dimensional Materials ◽  
Metal Dichalcogenides ◽  
Experimental And Theoretical Studies

AbstractLayered two-dimensional materials exhibit rich transport and optical phenomena in twisted or lattice-incommensurate heterostructures with spatial variations of interlayer hybridization arising from moiré interference effects. Here, we report experimental and theoretical studies of excitons in twisted heterobilayers and heterotrilayers of transition metal dichalcogenides. Using MoSe2-WSe2 stacks as representative realizations of twisted van der Waals bilayer and trilayer heterostructures, we observe contrasting optical signatures and interpret them in the theoretical framework of interlayer moiré excitons in different spin and valley configurations. We conclude that the photoluminescence of MoSe2-WSe2 heterobilayer is consistent with joint contributions from radiatively decaying valley-direct interlayer excitons and phonon-assisted emission from momentum-indirect reservoirs that reside in spatially distinct regions of moiré supercells, whereas the heterotrilayer emission is entirely due to momentum-dark interlayer excitons of hybrid-layer valleys. Our results highlight the profound role of interlayer hybridization for transition metal dichalcogenide heterostacks and other realizations of multi-layered semiconductor van der Waals heterostructures.

scholarly journals Making high-quality quantum microwave devices with van der Waals superconductors

2021 ◽  
Author(s):  
Abhinandan Antony ◽  
Martin V. Gustafsson ◽  
Anjaly Rajendran ◽  
Avishai Benyamini ◽  
Guilhem Ribeill ◽  
...  
Keyword(s):  
Quantum Coherence ◽  
Van Der Waals ◽  
Layered Materials ◽  
Low Loss ◽  
High Quality ◽  
Quantum Devices ◽  
2D Layered Materials ◽  
Value Sets ◽  
Microwave Regime ◽  
Quality Factor Q

Abstract Ultra low-loss microwave materials are crucial for enhancing quantum coherence and scalability of superconducting qubits. Van der Waals (vdW) heterostructure is an attractive platform for quantum devices due to the single-crystal structure of the constituent two-dimensional (2D) layered materials and the lack of dangling bonds at their atomically sharp interfaces. However, new fabrication and characterization techniques are required to determine whether these structures can achieve low loss in the microwave regime. Here we report the fabrication of superconducting microwave resonators using NbSe$_2$ that achieve a quality factor $Q > 10^5$. This value sets an upper bound that corresponds to a resistance of $\leq 192 \mu\Omega$ when considering the additional loss introduced by integrating NbSe$_2$ into a standard transmon circuit. This work demonstrates the compatibility of 2D layered materials with high-quality microwave quantum devices.

scholarly journals Anisotropic moiré optical transitions in twisted monolayer/bilayer phosphorene heterostructures

2021 ◽  
Vol 12 (1) ◽  
Author(s):  
Shilong Zhao ◽  
Erqing Wang ◽  
Ebru Alime Üzer ◽  
Shuaifei Guo ◽  
Ruishi Qi ◽  
...  
Keyword(s):  
Electronic Structures ◽  
Twist Angle ◽  
Van Der Waals ◽  
Rectangular Lattice ◽  
Transition Metal Dichalcogenide ◽  
Optical Transitions ◽  
Van Der Waals Heterostructures ◽  
Optical Resonances ◽  
Two Dimensional Materials ◽  
Quantum Phenomena

AbstractMoiré superlattices of van der Waals heterostructures provide a powerful way to engineer electronic structures of two-dimensional materials. Many novel quantum phenomena have emerged in graphene and transition metal dichalcogenide moiré systems. Twisted phosphorene offers another attractive system to explore moiré physics because phosphorene features an anisotropic rectangular lattice, different from isotropic hexagonal lattices previously reported. Here we report emerging anisotropic moiré optical transitions in twisted monolayer/bilayer phosphorenes. The optical resonances in phosphorene moiré superlattice depend sensitively on twist angle and are completely different from those in the constitute monolayer and bilayer phosphorene even for a twist angle as large as 19°. Our calculations reveal that the Γ-point direct bandgap and the rectangular lattice of phosphorene give rise to the remarkably strong moiré physics in large-twist-angle phosphorene heterostructures. This work highlights fresh opportunities to explore moiré physics in phosphorene and other van der Waals heterostructures with different lattice configurations.

Epitaxial growth manner and structure of superconducting oxide films

1990 ◽  
Vol 48 (4) ◽  
pp. 2-3
Author(s):  
Yoshichika Bando ◽  
Takahito Terashima ◽  
Kenji Iijima ◽  
Kazunuki Yamamoto ◽  
Kazuto Hirata ◽  
...  
Keyword(s):  
Ultrathin Films ◽  
Film Surface ◽  
High Energy ◽  
Epitaxial Films ◽  
Layer By Layer ◽  
Initial Growth ◽  
In Situ Growth ◽  
High Quality ◽  
Activated Reactive Evaporation

The high quality thin films of high-Tc superconducting oxide are necessary for elucidating the superconducting mechanism and for device application. The recent trend in the preparation of high-Tc films has been toward “in-situ” growth of the superconducting phase at relatively low temperatures. The purpose of “in-situ” growth is to attain surface smoothness suitable for fabricating film devices but also to obtain high quality film. We present the investigation on the initial growth manner of YBCO by in-situ reflective high energy electron diffraction (RHEED) technique and on the structural and superconducting properties of the resulting ultrathin films below 100Å. The epitaxial films have been grown on (100) plane of MgO and SrTiO, heated below 650°C by activated reactive evaporation. The in-situ RHEED observation and the intensity measurement was carried out during deposition of YBCO on the substrate at 650°C. The deposition rate was 0.8Å/s. Fig. 1 shows the RHEED patterns at every stage of deposition of YBCO on MgO(100). All the patterns exhibit the sharp streaks, indicating that the film surface is atomically smooth and the growth manner is layer-by-layer.

Constructed reed beds: appropriate technology for small communities

1995 ◽  
Vol 32 (3) ◽  
pp. 339-348 ◽  
Author(s):  
M. B. Green ◽  
J. Upton
Keyword(s):  
Sewage Treatment ◽  
Appropriate Technology ◽  
Great Promise ◽  
High Quality ◽  
Reed Beds ◽  
Small Communities ◽  
Operational Information ◽  
Reed Bed ◽  
Small Sites ◽  
Very High

Reed bed treatment is put in the context of a major water company’s need to provide reliable, high quality, effluents from small sewage treatment works whilst seeking to minimise running costs. Design and operational information is given for reed bed applications in Severn Trent Water. Performance details are provided for application to secondary, tertiary and storm overflow treatment. The results give particular confidence in the system’s ability to deliver very high quality effluents when used for tertiary treatment, the company’s biggest application. Reed beds work well against less demanding criteria for secondary treatment at small sites and show great promise for storm overflow treatment.

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