scholarly journals Fabrication and Characterization of MoS2/h-BN and WS2/h-BN Heterostructures

Micromachines ◽  
2020 ◽  
Vol 11 (12) ◽  
pp. 1114
Author(s):  
Tao Han ◽  
Hongxia Liu ◽  
Shupeng Chen ◽  
Yanning Chen ◽  
Shulong Wang ◽  
...  
Keyword(s):  
Preparation Method ◽  
Chemical Vapor ◽  
Local Strain ◽  
Optical Microscope ◽  
Peak Position ◽  
Emission Peak ◽  
Large Area ◽  
Vdw Heterostructure ◽  
Pl Spectrum

The general preparation method of large-area, continuous, uniform, and controllable vdW heterostructure materials is provided in this paper. To obtain the preparation of MoS2/h-BN and WS2/h-BN heterostructures, MoS2 and WS2 material are directly grown on the insulating h-BN substrate by atmospheric pressure chemical vapor deposition (APCVD) method, which does not require any intermediate transfer steps. The test characterization of MoS2/h-BN and WS2/h-BN vdW heterostructure materials can be accomplished by optical microscope, AFM, Raman and PL spectroscopy. The Raman peak signal of h-BN material is stronger when the h-BN film is thicker. Compared to the spectrum of MoS2 or WS2 material on SiO2/Si substrate, the Raman and PL spectrum peak positions of MoS2/h-BN heterostructure are blue-shifted, which is due to the presence of local strain, charged impurities and the vdW heterostructure interaction. Additionally, the PL spectrum of WS2 material shows the strong emission peak at 1.96 eV, while the full width half maximum (FWHM) is only 56 meV. The sharp emission peak indicates that WS2/h-BN heterostructure material has the high crystallinity and clean interface. In addition, the peak position and shape of IPM mode characteristic peak are not obvious, which can be explained by the Van der Waals interaction of WS2/h-BN heterostructure. From the above experimental results, the preparation method of heterostructure material is efficient and scalable, which can provide the important support for the subsequent application of TMDs/h-BN heterostructure in nanoelectronics and optoelectronics.

Synthesis of Graphene-ZnO Heterogeneous Nanostructures by Chemical Vapor Deposition

2011 ◽  
Vol 1348 ◽  
Author(s):  
Jian Lin ◽  
Miroslav Penchev ◽  
Guoping Wang ◽  
Rajat K Paul ◽  
Jiebin Zhong ◽  
...  
Keyword(s):  
Optical Properties ◽  
Chemical Vapor Deposition ◽  
Vapor Deposition ◽  
Three Dimensional ◽  
Chemical Vapor ◽  
Building Blocks ◽  
Zno Nanostructures ◽  
Large Area ◽  
Graphene Layers

ABSTRACTIn this work, we report the synthesis and characterization of three dimensional heterostructures graphene nanostructures (HGN) comprising continuous large area graphene layers and ZnO nanostructures, fabricated via chemical vapor deposition. Characterization of large area HGN demonstrates that it consists of 1-5 layers of graphene, and exhibits high optical transmittance and enhanced electrical conductivity. Electron microscopy investigation of the three dimensional heterostructures shows that the morphology of ZnO nanostructures is highly dependent on the growth temperature. It is observed that ordered crystalline ZnO nanostructures are preferably grown along the <0001> direction. Ultraviolet spectroscopy indicates that the CVD grown HGN layers has excellent optical properties. A combination of electrical and optical properties of graphene and ZnO building blocks in ZnO based HGN provides unique characteristics for opportunities in future optoelectronic devices.

scholarly journals Facile and Controllable Synthesis of Large-Area Monolayer WS2 Flakes Based on WO3 Precursor Drop-Casted Substrates by Chemical Vapor Deposition

Nanomaterials ◽  
2019 ◽  
Vol 9 (4) ◽  
pp. 578 ◽  
Author(s):  
Biao Shi ◽  
Daming Zhou ◽  
Shaoxi Fang ◽  
Khouloud Djebbi ◽  
Shuanglong Feng ◽  
...  
Keyword(s):  
Energy Gap ◽  
Growth Parameters ◽  
Fluorescence Emission ◽  
Chemical Vapor ◽  
Optical Microscope ◽  
Edge Length ◽  
Controllable Synthesis ◽  
Large Area ◽  
Si Substrates ◽  
Potential Applications

Monolayer WS2 (Tungsten Disulfide) with a direct-energy gap and excellent photoluminescence quantum yield at room temperature shows potential applications in optoelectronics. However, controllable synthesis of large-area monolayer WS2 is still challenging because of the difficulty in controlling the interrelated growth parameters. Herein, we report a facile and controllable method for synthesis of large-area monolayer WS2 flakes by direct sulfurization of powdered WO3 (Tungsten Trioxide) drop-casted on SiO2/Si substrates in a one-end sealed quartz tube. The samples were thoroughly characterized by an optical microscope, atomic force microscope, transmission electron microscope, fluorescence microscope, photoluminescence spectrometer, and Raman spectrometer. The obtained results indicate that large triangular monolayer WS2 flakes with an edge length up to 250 to 370 μm and homogeneous crystallinity were readily synthesized within 5 min of growth. We demonstrate that the as-grown monolayer WS2 flakes show distinctly size-dependent fluorescence emission, which is mainly attributed to the heterogeneous release of intrinsic tensile strain after growth.

Chemical Vapor Deposition Synthesis and Raman Spectroscopic Characterization of Large-Area Graphene Sheets

2013 ◽  
Vol 117 (39) ◽  
pp. 9454-9461 ◽  
Author(s):  
Chun-Da Liao ◽  
Yi-Ying Lu ◽  
Srinivasa Reddy Tamalampudi ◽  
Hung-Chieh Cheng ◽  
Yit-Tsong Chen
Keyword(s):  
Chemical Vapor Deposition ◽  
Vapor Deposition ◽  
Chemical Vapor ◽  
Spectroscopic Characterization ◽  
Graphene Sheets ◽  
Large Area ◽  
Raman Spectroscopic

Preparation and Characterization of SiC Coating on Graphite Substrate

2014 ◽  
Vol 602-603 ◽  
pp. 412-415 ◽  
Author(s):  
Yan Li Huo ◽  
Shu Guang Chen ◽  
Hai Long Liang ◽  
Chun Peng Wang ◽  
Jian Zhou ◽  
...  
Keyword(s):  
Thermal Conductivity ◽  
Cross Section ◽  
Vapor Deposition ◽  
Chemical Vapor ◽  
Optical Microscope ◽  
Chemical Vapor Infiltration ◽  
Good Combination ◽  
Graphite Substrate

High thermal conductivity and dense SiC coating were fabricated by chemical vapor deposition (CVD) on surface of different graphite at temperature of 1100°C. The results indicated that the thickness of the coating influences the quality of coating. There was no crack in coating when thickness of the coating is less than 0.3mm. The structure of graphite affected the reaction badly. When the graphite is coarse and porous the reaction is chemical vapor infiltration (CVI) and the interface of coating and substrate isnt obvious. When the graphite is dense and smooth, the coating is covered in surface of graphite, the interface is found between the coating and substrate. Optical microscope and SEM were used to observe the surface and cross-section morphology and microstructure of coatings. It shown coating and substrate had a good combination and the deposited grains mainly showed equiaxed form with the crystallite size of 30 nm at 1100°C.

scholarly journals Production and Mechanical Characterization of Graphene Micro-Ribbons

2019 ◽  
Vol 3 (2) ◽  
pp. 42
Author(s):  
Maria Giovanna Pastore Carbone ◽  
Georgia Tsoukleri ◽  
Anastasios C. Manikas ◽  
Eleni Makarona ◽  
Christos Tsamis ◽  
...  
Keyword(s):  
Mechanical Response ◽  
Mechanical Characterization ◽  
Chemical Vapor ◽  
Large Area ◽  
Mechanical Investigation ◽  
Raman Spectral ◽  
Compressive Tests

Patterning of graphene into micro- and nano-ribbons allows for tunability in emerging fields such as flexible electronic and optoelectronic devices, and is gaining interest for the production of more efficient reinforcement for composite materials. In this work we fabricate micro-ribbons from graphene synthesized via chemical vapor deposition (CVD) by combining ultraviolet (UV) photolithography and dry etching oxygen plasma treatments. We used Raman spectral imaging to confirm the effectiveness of the patterning procedure, which is suitable for large-area patterning of graphene on wafer-scale, and confirms that the quality of graphene remains unaltered. The produced micro-ribbons were finally transferred and embedded into a polymeric matrix and the mechanical response was investigated by in-situ mechanical investigation combining Raman spectroscopy and tensile/compressive tests.

MOCVD Growth and Characterization of (BaxSr1−x)Ti1+yO3+z Thin Films for High Frequency Devices

1999 ◽  
Vol 603 ◽  
Author(s):  
P.K. Baumann ◽  
D.Y. Kaufman ◽  
S.K. Streiffer ◽  
J. IM ◽  
O. Auciello ◽  
...  
Keyword(s):  
Thin Films ◽  
Rutherford Backscattering Spectrometry ◽  
Substantial Reduction ◽  
Chemical Vapor ◽  
Electron Beam Evaporation ◽  
Large Area ◽  
Bst Thin Films ◽  
Mocvd Growth ◽  
Bst Films

AbstractWe have investigated the structural and electrical characteristics of (BaxSr1−x)Ti1+yO3+z (BST) thin films. The BST thin films were deposited at 650°C on platinized silicon with good thickness and composition uniformity using a large area, vertical liquid-delivery metalorganic chemical vapor deposition (MOCVD) system. The (Ba+Sr)/Ti ratio of the BST films was varied from 0.96 to 1.05 at a fixed Ba/Sr ratio of 70/30, as determined using x-ray fluorescence spectroscopy (XRF) and Rutherford backscattering spectrometry (RBS). Patterned Pt top electrodes were deposited onto the BST films at 350°C through a shadow mask using electron beam evaporation. Annealing the entire capacitor structure in air at 700°C after deposition of top electrodes resulted in a substantial reduction of the dielectric loss. Useful dielectric tunability as high as 2.3:1 was measured.

Synthesis of Graphene-CNT Hybrid Nanostructures

2011 ◽  
Vol 1344 ◽  
Author(s):  
Maziar Ghazinejad ◽  
Shirui Guo ◽  
Rajat K. Paul ◽  
Aaron S. George ◽  
Miroslav Penchev ◽  
...  
Keyword(s):  
Chemical Vapor ◽  
Hybrid Structure ◽  
Hybrid Nanostructures ◽  
Carbon Nanostructure ◽  
Large Area ◽  
Detailed Characterization ◽  
Vapor Deposition Technique ◽  
Cvd Growth

ABSTRACTUsing chemical vapor deposition technique, a novel 3D carbon nano-architecture called a pillared graphene nanostructure (PGN) is in situ synthesized. The fabricated novel carbon nanostructure consists of CNT pillars of variable length grown vertically from large-area graphene planes. The formation of CNTs and graphene occurs simultaneously in one CVD growth treatment. The detailed characterization of synthesized pillared graphene shows the cohesive structure and seamless contact between graphene and CNTs in the hybrid structure. The synthesized graphene-CNT hybrid has a tunable architecture and attractive material properties, as it is solely built from sp2 hybridized carbon atoms in form of graphene and CNT. Our methodology provides a pathway for fabricating novel 3D nanostructures which are envisioned for applications in hydrogen storage, nanoelectronics, and supercapacitors.

scholarly journals Probing the Optical Properties of MoS2 on SiO2/Si and Sapphire Substrates

Nanomaterials ◽  
2019 ◽  
Vol 9 (5) ◽  
pp. 740 ◽  
Author(s):  
Tao Han ◽  
Hongxia Liu ◽  
Shulong Wang ◽  
Shupeng Chen ◽  
Wei Li ◽  
...  
Keyword(s):  
Optical Properties ◽  
Chemical Vapor ◽  
Peak Shift ◽  
Peak Position ◽  
Absorption Capacity ◽  
Exciton Peak ◽  
Monolayer Mos2 ◽  
Si Substrate ◽  
Sapphire Substrates ◽  
Pl Spectrum

As an important supplementary material to graphene in the optoelectronics field, molybdenum disulfide (MoS2) has attracted attention from researchers due to its good light absorption capacity and adjustable bandgap. In this paper, MoS2 layers are respectively grown on SiO2/Si and sapphire substrates by atmospheric pressure chemical vapor deposition (APCVD). Atomic force microscopy, optical microscopy, and Raman and photoluminescence spectroscopy are used to probe the optical properties of MoS2 on SiO2/Si and sapphire substrates systematically. The peak shift between the characteristic A1g and E12g peaks increases, and the I peak of the PL spectrum on the SiO2/Si substrate redshifts slightly when the layer numbers were increased, which can help in obtaining the layer number and peak position of MoS2. Moreover, the difference from monolayer MoS2 on the SiO2/Si substrate is that the B peak of the PL spectrum has a blueshift of 56 meV and the characteristic E12g peak of the Raman spectrum has no blueshift. The 1- and 2-layer MoS2 on a sapphire substrate had a higher PL peak intensity than that of the SiO2/Si substrate. When the laser wavelength is transformed from 532 to 633 nm, the position of I exciton peak has a blueshift of 16 meV, and the PL intensity of monolayer MoS2 on the SiO2/Si substrate increases. The optical properties of MoS2 can be obtained, which is helpful for the fabrication of optoelectronic devices.

scholarly journals Synthesis and characterization of WS2/graphene/SiC van der Waals heterostructures via WO3−x thin film sulfurization

2020 ◽  
Vol 10 (1) ◽  
Author(s):  
Jonathan Bradford ◽  
Mahnaz Shafiei ◽  
Jennifer MacLeod ◽  
Nunzio Motta
Keyword(s):  
Vapor Deposition ◽  
Van Der Waals ◽  
Transition Metal Dichalcogenides ◽  
Chemical Vapor ◽  
Large Area ◽  
Van Der Waals Heterostructures ◽  
Metal Dichalcogenides ◽  
Direct Growth ◽  
Cvd Growth

Abstract Van der Waals heterostructures of monolayer transition metal dichalcogenides (TMDs) and graphene have attracted keen scientific interest due to the complementary properties of the materials, which have wide reaching technological applications. Direct growth of uniform, large area TMDs on graphene substrates by chemical vapor deposition (CVD) is limited by slow lateral growth rates, which result in a tendency for non-uniform multilayer growth. In this work, monolayer and few-layer WS2 was grown on epitaxial graphene on SiC by sulfurization of WO3−x thin films deposited directly onto the substrate. Using this method, WS2 growth was achieved at temperatures as low as 700 °C – significantly less than the temperature required for conventional CVD. Achieving long-range uniformity remains a challenge, but this process could provide a route to synthesize a broad range of TMD/graphene van der Waals heterostructures with novel properties and functionality not accessible by conventional CVD growth.

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