scholarly journals Synthesis and Characterization of Free-Stand Graphene/Silver Nanowire/Graphene Nano Composite as Transparent Conductive Film with Enhanced Stiffness

2020 ◽  
Vol 10 (14) ◽  
pp. 4802
Author(s):  
Chuanrui Guo ◽  
Yanxiao Li ◽  
Yanping Zhu ◽  
Chenglin Wu ◽  
Genda Chen
Keyword(s):  
Electrical Conductivity ◽  
Chemical Vapor ◽  
Optical Transmittance ◽  
Silver Nanowire ◽  
Sandwich Composite ◽  
Graphene Layers ◽  
Behavior Study ◽  
Transmission Electron ◽  
Grown Graphene ◽  
Film Stiffness

As-grown graphene via chemical vapor deposition (CVD) has potential defects, cracks, and disordered grain boundaries induced by the synthesis and transfer process. Graphene/silver nanowire/graphene (Gr/AgNW/Gr) sandwich composite has been proposed to overcome these drawbacks significantly as the AgNW network can provide extra connections on graphene layers to enhance the stiffness and electrical conductivity. However, the existing substrate (polyethylene terephthalate (PET), glass, silicon, and so on) for composite production limits its application and mechanics behavior study. In this work, a vacuum annealing method is proposed and validated to synthesize the free-stand Gr/AgNW/Gr nanocomposite film on transmission electron microscopy (TEM) grids. AgNW average spacing, optical transmittance, and electrical conductivity are characterized and correlated with different AgNW concentrations. Atomic force microscope (AFM) indentation on the free-stand composite indicates that the AgNW network can increase the composite film stiffness by approximately 460% with the AgNW concentration higher than 0.6 mg/mL. Raman spectroscopy shows the existence of a graphene layer and the disturbance of the AgNW network. The proposed method provides a robust way to synthesize free-stand Gr/AgNW/Gr nanocomposite and the characterization results can be utilized to optimize the nanocomposite design for future applications.

Controlled Growth of Carbon Spheres by Chemical Vapor Deposition Based on Anodic Aluminum Oxide Nano-Template

2012 ◽  
Vol 184-185 ◽  
pp. 924-927
Author(s):  
Lei Shan Chen ◽  
Cun Jing Wang ◽  
Gai Rong Chen
Keyword(s):  
Electron Microscopy ◽  
Vapor Deposition ◽  
Anodic Aluminum Oxide ◽  
Chemical Vapor ◽  
Average Diameter ◽  
Carbon Spheres ◽  
Aao Template ◽  
Graphene Layers ◽  
Anodic Aluminum ◽  
Transmission Electron

The reactions were carried out by decomposing acetylene at 1000 °C in a two-stage furnace system for 10 min. In the first furnace no catalyst was placed and an AAO template with the average diameter about 50 nm was placed in the second furnace whose temperature was designed to be 500 °C, 600 °C and 700 °C. The samples were characterized by scanning electron microscopy and high resolution transmission electron microscopy. The results show that carbon spheres with average diameter about 50 nm on the AAO template surface were obtained when the temperature of the second furnace was designed to be 700 °C. These carbon spheres are composed of unclosed graphene layers with an interlayer distance of 0.33–0.35 nm between the layers.

Low-Temperature Chemical Vapor Deposition Growth of Graphene Layers on Copper Substrate Using Camphor Precursor

2020 ◽  
Vol 20 (12) ◽  
pp. 7698-7704
Author(s):  
K. Kavitha ◽  
Akanksha R. Urade ◽  
Gurjinder Kaur ◽  
Indranil Lahiri
Keyword(s):  
Chemical Vapor Deposition ◽  
Low Temperature ◽  
Vapor Deposition ◽  
Graphene Layer ◽  
Copper Substrate ◽  
Chemical Vapor ◽  
Large Area ◽  
Chemical Vapor Deposition Growth ◽  
Graphene Layers ◽  
Grown Graphene

A two-step, low-temperature thermal chemical vapor deposition (CVD) process, which uses camphor for synthesizing continuous graphene layer on Cu substrate is reported. The growth process was performed at lower temperature (800 °C) using camphor as the source of carbon. A threezone CVD system was used for controlled heating of precursor, in order to obtain uniform graphene layer. As-grown samples were characterized by X-ray diffraction (XRD), Raman spectroscopy and transmission electron microscopy (TEM). The results show the presence of 4–5 layers of graphene. As-grown graphene transferred onto a glass substrate through a polymer-free wet-etching process, demonstrated transmittance ~91% in visible spectra. This process of synthesizing large area, 4–5 layer graphene at reduced temperature represents an energy-efficient method of producing graphene for possible applications in opto-electronic industry.

Direct CVD Growth of Multi-Layered Graphene Closed Shells around Alumina Nanofibers

2016 ◽  
Vol 674 ◽  
pp. 77-80 ◽  
Author(s):  
Roman Ivanov ◽  
Valdek Mikli ◽  
Jakob Kübarsepp ◽  
Irina Hussainova
Keyword(s):  
Carbon Nanostructures ◽  
Chemical Vapor ◽  
Deposition Process ◽  
Single Step ◽  
Graphene Layers ◽  
Alumina Nanofibers ◽  
Carbon Structures ◽  
Transmission Electron ◽  
Cvd Growth ◽  
Closed Shells

In this work, a catalyst-free direct deposition of multi-layered graphene closed shells around highly aligned alumina nanofibers with aspect ratio of 107 is demonstrated for the first time. A single – step chemical vapor deposition process of specified parameters was used for development of hybrid structures of carbon shells around the core alumina nanofibers. Transmission electron microscopy and Raman spectroscopy were used to confirm formation of graphene layers and to understand the morphology of the various structures. The developed routine for growth of peculiar carbon nanostructures opens new opportunities for deposition of the tailored carbon structures on dielectric substrates.

In Situ CCVD Grown Graphene Transistors with Ultra-High On/Off-Current Ratio in Silicon CMOS Compatible Processing

2012 ◽  
Vol 77 ◽  
pp. 258-265 ◽  
Author(s):  
Pia Juliane Wessely ◽  
Frank Wessely ◽  
Emrah Birinci ◽  
Bernadette Riedinger ◽  
Udo Schwalke
Keyword(s):  
Field Effect Transistors ◽  
Chemical Vapor ◽  
Monolayer Graphene ◽  
Current Ratio ◽  
Electron Conduction ◽  
Graphene Layers ◽  
Cmos Compatible ◽  
Grown Graphene ◽  
Silicon Cmos

We invented a novel method to fabricate graphene transistors on oxidized silicon wafers without the need to transfer graphene layers. By means of catalytic chemical vapor deposition (CCVD) the in-situ grown monolayer graphene field-effect transistors (MoLGFETs) and bilayer graphene transistors (BiLGFETs) are realized directly on oxidized silicon substrate, whereby the number of stacked graphene layers is determined by the selected CCVD process parameters. In-situ grown MoLGFETs exhibit the expected Dirac point together with the typical low on/off-current ratios between 16 (hole conduction) and 8 (electron conduction), respectively. In contrast, our BiLGFETs possess unipolar p-type device characteristics with an extremely high on/off-current ratio up to 1E7 exceeding previously reported values by several orders of magnitude. We explain the improved device characteristics by a combination of effects, in particular graphene-substrate interactions, hydrogen doping and Schottky-barrier effects at the source/drain contacts as well. Besides the excellent device characteristics, the complete CCVD fabrication process is silicon CMOS compatible. This will allow the usage of BiLGFETs for digital applications in a hybrid silicon CMOS environment.

Rapid large-scale Characterization of CVD Graphene Layers on Glass using Fluorescence Quenching Microscopy

2011 ◽  
Vol 1344 ◽  
Author(s):  
Jennifer Reiber Kyle ◽  
Ali Guvenc ◽  
Wei Wang ◽  
Jian Lin ◽  
Maziar Ghazinejad ◽  
...  
Keyword(s):  
Chemical Vapor Deposition ◽  
Fluorescence Quenching ◽  
High Throughput ◽  
Vapor Deposition ◽  
Glass Substrate ◽  
Chemical Vapor ◽  
Chemical Vapor Deposition Growth ◽  
Graphene Layers ◽  
Grown Graphene

ABSTRACTThe exceptional electrical, optical, and mechanical properties of graphene make it a promising material for many industrial applications such as solar cells, semiconductor devices, and thermal heat sinks. However, the greatest obstacle in the use of graphene in industry is high-throughput scaling of its production and characterization. Chemical-vapor deposition growth of graphene has allowed for industrial-scale graphene production. In this work we introduce complimentary high-throughput metrology technique for characterization of chemical-vapor deposition-grown graphene. This metrology technique provides quick identification of thickness and uniformity of entire large-area chemical-vapor deposition-grown graphene sheets on a glass substrate and allows for easy identification of folds and cracks in the graphene samples. This metrology technique utilizes fluorescence quenching microscopy, which is based on resonant energy transfer between a dye molecule and graphene, to increase allow graphene visualization on the glass substrate and increase the contrast between graphene layers.

scholarly journals Graphene/Silver Nanowires/Graphene Sandwich Composite for Stretchable Transparent Electrodes and Its Fracture Mechanism

Micromachines ◽  
2021 ◽  
Vol 12 (5) ◽  
pp. 512
Author(s):  
Chi-Hsien Huang ◽  
Hong-Cing Wu ◽  
Bo-Feng Chen ◽  
Yen-Cheng Li
Keyword(s):  
Sandwich Structure ◽  
Silver Nanowires ◽  
High Surface ◽  
Chemical Vapor ◽  
Electrical Performance ◽  
Sandwich Composite ◽  
Transparent Electrodes ◽  
Graphene Layers ◽  
Force Microscopy ◽  
Conductivity Loss

Polycrystalline graphene grown by chemical vapor deposition (CVD) is characterized by line defects and disruptions at the grain boundaries and nucleation sites. This adversely affects the stretchability and conductivity of graphene, which limits its applications in the field of flexible, stretchable, and transparent electrodes. We demonstrate a composite electrode comprised of a graphene/silver nanowires (AgNWs)/graphene sandwich structure on a polydimethylsiloxane substrate to overcome this limitation. The sandwich structure exhibits high transparency (>90%) and excellent conductivity improvement of the graphene layers. The use of AgNWs significantly suppresses the conductivity loss resulting from stretching. The mechanism of the suppression of the conductivity loss was investigated using scanning electron microscopy, atomic force microscopy, and lateral force microscopy. The results suggest that the high surface friction of the sandwich structure causes a sliding effect between the graphene layers would produce low crack or hole formation to maintain the conductivity. In addition to acting as conductive layers, the top and bottom graphene layers can also protect the AgNWs from oxidation, thereby enabling maintenance of the electrical performance of the electrodes over a prolonged period. We also confirmed the applicability of the sandwich structure electrode to the human body, such as on the wrist, finger, and elbow.

scholarly journals Flexible Transparent Electrode Characteristics of Graphene Oxide/Cysteamine/AgNP/AgNW Structure

Nanomaterials ◽  
2020 ◽  
Vol 10 (12) ◽  
pp. 2352
Author(s):  
Junhwan Jang ◽  
Ju-Young Choi ◽  
Jihyun Jeon ◽  
Jeongjun Lee ◽  
Jaehyuk Im ◽  
...  
Keyword(s):  
Electron Microscopy ◽  
Graphene Oxide ◽  
Optical Transmittance ◽  
Transparent Electrode ◽  
Silver Nanowire ◽  
Bending Test ◽  
Force Microscopy ◽  
Atomic Force ◽  
Transmission Electron ◽  
Current Voltage

Graphene oxide (GO)–cysteamine–Ag nanoparticles (GCA)–silver nanowire (AgNW) fabricated by depositing GCA over sprayed AgNWs on PET films were proposed for transparent and flexible electrodes, and their optical, electrical, and mechanical properties were analyzed by energy-dispersive X-ray spectroscopy, Fourier-transform infrared spectroscopy, Raman spectroscopy, atomic force microscopy, scanning electron microscopy, transmission electron microscopy, current-voltage measurements, and bending test. GCA–AgNW electrodes show optical transmittance of >80% at 550 nm and exhibit a high figure-of-merit value of up to 116.13 in the samples with sheet resistances of 20–40 Ω/◻. It was observed that the detrimental oxidation of bare AgNWs over time was considerably decreased, and the mechanical robustness was improved. To apply the layer as an actual electrode in working devices, a Pt/GO/poly(3,4-ethylenedioxythiophene) polystyrene sulfonate/GCA–AgNW/polyethylene terephthalate structure was fabricated, and resistive switching memory was demonstrated. On the basis of these results, we confirm that the proposed GCA–AgNW layer can be used as transparent and flexible electrode.

scholarly journals Pattern Pick and Place Method for Twisted Bi- and Multi-Layer Graphene

Materials ◽  
2019 ◽  
Vol 12 (22) ◽  
pp. 3740 ◽  
Author(s):  
Jae-Young Lim ◽  
Hyeon-Sik Jang ◽  
Hyun-Jae Yoo ◽  
Seung-il Kim ◽  
Dongmok Whang
Keyword(s):  
Graphene Layer ◽  
Twist Angle ◽  
Fabrication Method ◽  
Single Crystalline ◽  
Graphene Layers ◽  
Layer Graphene ◽  
Transmission Electron ◽  
Pick And Place ◽  
Grown Graphene ◽  
Unique Band

Twisted bi-layer graphene (tBLG) has attracted much attention because of its unique band structure and properties. The properties of tBLG vary with small differences in the interlayer twist angle, but it is difficult to accurately adjust the interlayer twist angle of tBLG with the conventional fabrication method. In this study, we introduce a facile tBLG fabrication method that directly picks up a single-crystalline graphene layer from a growth substrate and places it on another graphene layer with a pre-designed twist angle. Using this approach, we stacked single-crystalline graphene layers with controlled twist angles and thus fabricated tBLG and twisted multi-layer graphene (tMLG). The structural, optical and electrical properties depending on the twist angle and number of layers, were investigated using transmission electron microscopy (TEM), micro–Raman spectroscopy, and gate-dependent sheet resistance measurements. The obtained results show that the pick and place approach enables the direct dry transfer of the top graphene layer on the as-grown graphene to fabricate uniform tBLG and tMLG with minimal interlayer contamination and pre-defined twist angles.

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