In situ epitaxial engineering of graphene and h-BN lateral heterostructure with a tunable morphology comprising h-BN domains

Abstract Graphene and hexagonal boron nitride (h-BN), as typical two-dimensional (2D) materials, have long attracted substantial attention due to their unique properties and promise in a wide range of applications. Although they have a rather large difference in their intrinsic bandgaps, they share a very similar atomic lattice; thus, there is great potential in constructing heterostructures by lateral stitching. Herein, we present the in situ growth of graphene and h-BN lateral heterostructures with tunable morphologies that range from a regular hexagon to highly symmetrical star-like structure on the surface of liquid Cu. The chemical vapor deposition (CVD) method is used, where the growth of the h-BN is demonstrated to be highly templated by the graphene. Furthermore, large-area production of lateral G-h-BN heterostructures at the centimeter scale with uniform orientation is realized by precisely tuning the CVD conditions. We found that the growth of h-BN is determined by the initial graphene and symmetrical features are produced that demonstrate heteroepitaxy. Simulations based on the phase field and density functional theories are carried out to elucidate the growth processes of G-h-BN flakes with various morphologies, and they have a striking consistency with experimental observations. The growth of a lateral G-h-BN heterostructure and an understanding of the growth mechanism can accelerate the construction of various heterostructures based on 2D materials.

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Chlorosulfuric acid-assisted production of functional 2D materials

npj 2D Materials and Applications ◽

10.1038/s41699-021-00215-2 ◽

2021 ◽

Vol 5 (1) ◽

Author(s):

Mohsen Moazzami Gudarzi ◽

Maryana Asaad ◽

Boyang Mao ◽

Gergo Pinter ◽

Jianqiang Guo ◽

...

Keyword(s):

Hexagonal Boron Nitride ◽

2D Materials ◽

Real Life ◽

Large Area ◽

Polar Solvents ◽

Aspect Ratios ◽

Two Dimensional Materials ◽

Liquid Phase Exfoliation

AbstractThe use of two-dimensional materials in bulk functional applications requires the ability to fabricate defect-free 2D sheets with large aspect ratios. Despite huge research efforts, current bulk exfoliation methods require a compromise between the quality of the final flakes and their lateral size, restricting the effectiveness of the product. In this work, we describe an intercalation-assisted exfoliation route, which allows the production of high-quality graphene, hexagonal boron nitride, and molybdenum disulfide 2D sheets with average aspect ratios 30 times larger than that obtained via conventional liquid-phase exfoliation. The combination of chlorosulfuric acid intercalation with in situ pyrene sulfonate functionalisation produces a suspension of thin large-area flakes, which are stable in various polar solvents. The described method is simple and requires no special laboratory conditions. We demonstrate that these suspensions can be used for fabrication of laminates and coatings with electrical properties suitable for a number of real-life applications.

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Large-area integration of two-dimensional materials and their heterostructures by wafer bonding

Nature Communications ◽

10.1038/s41467-021-21136-0 ◽

2021 ◽

Vol 12 (1) ◽

Author(s):

Arne Quellmalz ◽

Xiaojing Wang ◽

Simon Sawallich ◽

Burkay Uzlu ◽

Martin Otto ◽

...

Keyword(s):

Wafer Bonding ◽

Semiconductor Manufacturing ◽

Large Scale ◽

Hexagonal Boron Nitride ◽

2D Materials ◽

High Volume ◽

Two Dimensional ◽

Wafer Level ◽

Large Area ◽

Wide Range

AbstractIntegrating two-dimensional (2D) materials into semiconductor manufacturing lines is essential to exploit their material properties in a wide range of application areas. However, current approaches are not compatible with high-volume manufacturing on wafer level. Here, we report a generic methodology for large-area integration of 2D materials by adhesive wafer bonding. Our approach avoids manual handling and uses equipment, processes, and materials that are readily available in large-scale semiconductor manufacturing lines. We demonstrate the transfer of CVD graphene from copper foils (100-mm diameter) and molybdenum disulfide (MoS2) from SiO2/Si chips (centimeter-sized) to silicon wafers (100-mm diameter). Furthermore, we stack graphene with CVD hexagonal boron nitride and MoS2 layers to heterostructures, and fabricate encapsulated field-effect graphene devices, with high carrier mobilities of up to $$4520\;{\mathrm{cm}}^2{\mathrm{V}}^{ - 1}{\mathrm{s}}^{ - 1}$$ 4520 cm 2 V − 1 s − 1 . Thus, our approach is suited for backend of the line integration of 2D materials on top of integrated circuits, with potential to accelerate progress in electronics, photonics, and sensing.

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Device Applications of Metal-2D-Materials Interfaces A Short Review

European Journal of Engineering Research and Science ◽

10.24018/ejers.2018.3.4.524 ◽

2018 ◽

Vol 3 (4) ◽

pp. 1 ◽

Cited By ~ 1

Author(s):

Faisal Ahmad ◽

Amir Mansoori ◽

Sonia Bansal ◽

Th. S. Dhahi ◽

Shamim Ahmad

Keyword(s):

Charge Carrier ◽

Carrier Transport ◽

Hexagonal Boron Nitride ◽

2D Materials ◽

Electronic Energy ◽

Device Fabrication ◽

Current Status ◽

Large Area ◽

Wide Range ◽

Device Applications

The electronic energy band gaps of 2D-materials are known to spread over a wide range from zero in graphene to > 6eV in hexagonal boron nitride (h-BN). Various combinations of such engineered nanomaterials offer a number of novel device applications involving their unique optical, electronic, and thermal properties along with their higher charge carrier mobilities and saturation limited drift velocities. Structurally, these nanomaterials have single or multiple monolayers stuck together, which are not only suitable for flexible electron devices and circuits but also in preparing heterostructures (lateral as well as vertical configurations) that form super lattices with different kinds of band alignments. Such possibilities offer flexible control over the charge carrier transport in these materials via numerous types of exciton formations. Their extra sensitivity towards the presence of atomic, molecular and nanoparticulate species in their vicinity is the most significant aspect of these 2D-materials. This is the reason behind studying them in detail for detecting the presence of extremely low concentrations of the analyte that are not achievable in conventional sensors. For translating the above-said superlative properties of these fast emerging families of 2-D nanomaterials into usable devices and circuits, applying the conventional device fabrication technologies poses a real challenge. The experimental results reported in the context of forming usable interfaces between a metal and 2D-nanomaterial are examined here to assess their current status and future prospects. Their widespread applications are certainly anticipated in the fields like printed micro/nano sensors, large area electronics and printed intelligence with special reference to their emerging usages in Internet of Things (IoT) in the near future.

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Efficient Prediction of Structural and Electronic Properties of Hybrid 2D Materials Using DFT and Machine Learning

10.26434/chemrxiv.6254756.v1 ◽

2018 ◽

Author(s):

Sherif Tawfik ◽

Olexandr Isayev ◽

Catherine Stampfl ◽

Joseph Shapter ◽

David Winkler ◽

...

Keyword(s):

Machine Learning ◽

Band Gap ◽

Density Functional ◽

2D Materials ◽

Van Der Waals ◽

Building Blocks ◽

Machine Learning Techniques ◽

Interlayer Distance ◽

Computational Screening ◽

Wide Range

Materials constructed from different van der Waals two-dimensional (2D) heterostructures offer a wide range of benefits, but these systems have been little studied because of their experimental and computational complextiy, and because of the very large number of possible combinations of 2D building blocks. The simulation of the interface between two different 2D materials is computationally challenging due to the lattice mismatch problem, which sometimes necessitates the creation of very large simulation cells for performing density-functional theory (DFT) calculations. Here we use a combination of DFT, linear regression and machine learning techniques in order to rapidly determine the interlayer distance between two different 2D heterostructures that are stacked in a bilayer heterostructure, as well as the band gap of the bilayer. Our work provides an excellent proof of concept by quickly and accurately predicting a structural property (the interlayer distance) and an electronic property (the band gap) for a large number of hybrid 2D materials. This work paves the way for rapid computational screening of the vast parameter space of van der Waals heterostructures to identify new hybrid materials with useful and interesting properties.

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THE OPTICAL PROPERTIES OF NITROGENATED AMORPHOUS CARBON FILMS GROWN BY A NOVEL SURFACE WAVE MICROWAVE PLASMA CVD METHOD

Modern Physics Letters B ◽

10.1142/s0217984904007529 ◽

2004 ◽

Vol 18 (18) ◽

pp. 987-1001 ◽

Cited By ~ 9

Author(s):

M. RUSOP ◽

S. ADHIKARI ◽

A. M. M. OMER ◽

S. ADHIKARY ◽

H. UCHIDA ◽

...

Keyword(s):

Optical Properties ◽

Surface Wave ◽

Amorphous Carbon ◽

Annealing Temperature ◽

Microwave Plasma ◽

Chemical Vapor ◽

Carbon Films ◽

Cvd Method ◽

Wide Range ◽

Bonding Properties

The effects of annealing temperature on the optical properties of nitrogenated amorphous carbon (a-C:N) films grown on quartz substrates by a novel surface wave microwave plasma chemical vapor deposition (SWMP-CVD) method are reported. The thickness, optical, structural and bonding properties of the as-grown and anneal-treated a-C:N films were measured and compared. The film thickness decreased rapidly with increasing annealing temperature above 350°C. A wide range of optical absorption characteristics is observed, depending on the annealing temperature. The optical band gap of as-grown a-C:N films is approximately 2.8 eV, gradually decreasing to 2.5 eV for the films anneal-treated at 300°C, and beyond that decreasing rapidly down to 0.9 eV at 500°C. The Raman and FTIR spectroscopy measurements have shown that the structural and composition of the films can be tuned by optimizing the annealing temperature. The change of optical, structural and bonding properties of SWMP-CVD-grown a-C:N films with higher annealing temperature was attributed to the fundamental changes in the bonding and band structures of the films.

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In Situ Monitoring of Growth of Vertically Stacked h-BN/Graphene Heterostructures on Ni Substrates and Their Interface Interaction

Surfaces ◽

10.3390/surfaces3030024 ◽

2020 ◽

Vol 3 (3) ◽

pp. 328-336

Author(s):

Wei Wei ◽

Guanhua Zhang ◽

Jiaqi Pan ◽

Yi Cui ◽

Qiang Fu

Keyword(s):

Hexagonal Boron Nitride ◽

Chemical Vapor ◽

In Situ Monitoring ◽

High Coverage ◽

Interface Interaction ◽

Domain Boundaries ◽

Potential Applications ◽

Surface Microscopy ◽

Mechanical Devices

Vertically stacked hexagonal boron nitride (h-BN)/graphene heterostructures present potential applications in electronic, photonic, and mechanical devices, and their interface interaction is one of the critical factors that affect the performances. In this work, the vertical h-BN/graphene heterostructures with high coverage are synthesized by chemical vapor deposition (CVD) of h-BN on Ni substrates followed by segregation growth of graphene at the h-BN/Ni interfaces, which are monitored by in situ surface microscopy and surface spectroscopy. We find that h-BN overlayers can be decoupled from Ni substrates by the graphene interlayers. Furthermore, the h-BN domain boundaries exhibit a confinement effect on the graphene interlayer growth and the lower graphene domains are limited within the upper h-BN domains. This work provides new insights into the formation mechanism and interface interaction of the vertical heterostructures.

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Ultraclean and large-area monolayer hexagonal boron nitride on Cu foil using chemical vapor deposition

Nanotechnology ◽

10.1088/0957-4484/26/27/275601 ◽

2015 ◽

Vol 26 (27) ◽

pp. 275601 ◽

Cited By ~ 18

Author(s):

Yao Wen ◽

Xunzhong Shang ◽

Ji Dong ◽

Kai Xu ◽

Jun He ◽

...

Keyword(s):

Chemical Vapor Deposition ◽

Boron Nitride ◽

Vapor Deposition ◽

Hexagonal Boron Nitride ◽

Chemical Vapor ◽

Large Area ◽

Cu Foil

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Electrical Homogeneity of Large-Area Chemical Vapor Deposited Multilayer Hexagonal Boron Nitride Sheets

ACS Applied Materials & Interfaces ◽

10.1021/acsami.7b09417 ◽

2017 ◽

Vol 9 (46) ◽

pp. 39895-39900 ◽

Cited By ~ 11

Author(s):

Fei Hui ◽

Wenjing Fang ◽

Wei Sun Leong ◽

Tewa Kpulun ◽

Haozhe Wang ◽

...

Keyword(s):

Boron Nitride ◽

Hexagonal Boron Nitride ◽

Chemical Vapor ◽

Large Area ◽

Chemical Vapor Deposited

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Giant power factors in p- and n-type large-area graphene films on a flexible plastic substrate

npj 2D Materials and Applications ◽

10.1038/s41699-019-0128-0 ◽

2019 ◽

Vol 3 (1) ◽

Cited By ~ 11

Author(s):

Kaito Kanahashi ◽

Masatou Ishihara ◽

Masataka Hasegawa ◽

Hiromichi Ohta ◽

Taishi Takenobu

Keyword(s):

Vapor Deposition ◽

Large Scale ◽

Chemical Vapor ◽

Plastic Substrate ◽

Large Area ◽

Flexible Materials ◽

Graphene Films ◽

Wide Range ◽

Carrier Doping ◽

Electron Carriers

Abstract This study reports on the thermoelectric properties of large-area graphene films grown by chemical vapor deposition (CVD) methods. Using the electric double layer gating technique, both the continuous doping of hole or electron carriers and modulation of the Fermi energy are achieved, leading to wide-range control of the Seebeck coefficient and electrical conductivity. Consequently, the maximum power factors of the CVD-grown large-area graphene films are 6.93 and 3.29 mW m–1 K–2 for p- and n-type carrier doping, respectively. These results are the best values among large-scale flexible materials, such as organic conducting polymers and carbon nanotubes, suggesting that CVD-grown large-area graphene films have potential for thermoelectric applications.

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