Effect of the Sulfate Concentration on the Graphene Film Produced by Electrochemical Exfoliation

2019 ◽  
Vol 290 ◽  
pp. 127-133
Author(s):  
Yu Zhang Ng ◽  
Khi Poay Beh ◽  
Faris Hidayat Ahmad Suhaimi ◽  
Raed Abdalraheem ◽  
Hwee San Lim ◽  
...  
Keyword(s):  
Large Scale ◽  
Graphene Film ◽  
Electrode System ◽  
Nanometer Scale ◽  
Sulfate Concentration ◽  
High Demand ◽  
Electrochemical Exfoliation ◽  
Exfoliated Graphene ◽  
Atomic Force ◽  
Graphene Films

Studies and production of anodic exfoliated graphene have been blossoming exponentially to meet the high demand for next generation optoelectronics devices. In this study, the effect of sulfate concentration on the graphene film is presented. The electrochemical exfoliation was conducted using a simple two-electrode system to study on the morphological and optical properties of graphene films using Atomic Force Microscope (AFM), Raman Spectroscopy and Ultraviolet–Visible (UV-Vis) spectrophotometer. Preliminary results show the presence of few layers graphene with nanometer-scale lateral dimension. The study suggests an alternative solution for the large-scale manufacturing capabilities of graphene is feasible

Surface Corrugation and Stacking Misorientation in Multilayers of Graphene on Nickel

2011 ◽  
Vol 178-179 ◽  
pp. 125-129 ◽  
Author(s):  
Vito Raineri ◽  
Corrado Bongiorno ◽  
Salvatore di Franco ◽  
Raffaella Lo Nigro ◽  
Emanuele Rimini ◽  
...  
Keyword(s):  
Film Formation ◽  
Graphene Film ◽  
Thermal Processes ◽  
Grown Film ◽  
Graphene Layers ◽  
Force Microscopy ◽  
Atomic Force ◽  
Graphene Films ◽  
Transmission Electron ◽  
Thin Polycrystalline

Graphene films were grown on thin polycrystalline Ni using a buried amorphous carbon (a-C) layer as C source. Rapid thermal processes (RTP) at temperatures from 600 to 800°C were used to promote C diffusion into Ni and its subsequent segregation on Ni surface, during the sample cool down. RTP at 800°C was the optimal condition for graphene film formation. Micro-Raman spectroscopy showed that the grown film is mostly composed by multilayers of graphene. Atomic force microscopy showed that the film presents peculiar corrugations (wrinkles), isotropically oriented and with heights ranging from from ~1 to ~15 nm. Selected area diffraction by transmission electron microscopy on the MLG membranes shows a rotational disorder between the stacked graphene layers.

scholarly journals Seed-Assisted Synthesis of Graphene Films on Insulating Substrate

Materials ◽  
2019 ◽  
Vol 12 (9) ◽  
pp. 1376
Author(s):  
Qiqi Zhuo ◽  
Yipeng Mao ◽  
Suwei Lu ◽  
Bolu Cui ◽  
Li Yu ◽  
...  
Keyword(s):  
Transfer Process ◽  
Large Scale ◽  
Direct Synthesis ◽  
Carbon Sources ◽  
Poly Vinyl Alcohol ◽  
Direct Production ◽  
Atomic Force ◽  
Graphene Films ◽  
Electronic Microscope ◽  
Insulating Substrates

Synthesizing graphene at a large-scale and of high quality on insulating substrate is a prerequisite for graphene applications in electronic devices. Typically, graphene is synthesized and then transferred to the proper substrate for subsequent device preparation. However, the complicated and skilled transfer process involves some issues such as wrinkles, residual contamination and breakage of graphene films, which will greatly degrade its performance. Direct synthesis of graphene on insulating substrates without a transfer process is highly desirable for device preparation. Here, we report a simple, transfer-free method to synthesize graphene directly on insulating substrates (SiO2/Si, quartz) by using a Cu layer, graphene oxide and Poly (vinyl alcohol) as the catalyst, seeds and carbon sources, respectively. Atomic force microscope (AFM), scanning electronic microscope (SEM) and Raman spectroscopy are used to characterize the interface of insulating substrate and graphene. The graphene films directly grown on quartz glass can attain a high transmittance of 92.8% and a low sheet resistance of 620 Ω/square. The growth mechanism is also revealed. This approach provides a highly efficient method for the direct production of graphene on insulating substrates.

scholarly journals Distinct Protofilament-scale Dynamics Define the Differential Remodeling of Microtubule Arrays

2020 ◽  
Author(s):  
S. S. Wijeratne ◽  
M. Marchan ◽  
J. S. Tresback ◽  
R. Subramanian
Keyword(s):  
Electron Microscopy ◽  
Large Scale ◽  
Dynamic Instability ◽  
Lattice Defect ◽  
Nanometer Scale ◽  
Force Microscopy ◽  
Atomic Force ◽  
Length Regulation ◽  
Intrinsic Dynamic ◽  
Powerful Strategy

SUMMARYThe intrinsic dynamic instability of microtubules and their control by associated enzymes, such as depolymerases, are essential for the organization of complex multi-microtubule arrays like spindle and axoneme. However, existing optical or electron-microscopy methods lack the spatial-temporal resolution to observe the dynamics of individual microtubules within arrays. We use Atomic Force Microscopy (AFM) to image depolymerizing arrays at single microtubule and protofilament resolution. We discover previously unseen modes of microtubule destabilization by conserved depolymerases. The kinesin-13 MCAK mediates asynchronous protofilament depolymerization and lattice-defect propagation, whereas the kinesin-8 Kip3p promotes synchronous protofilament depolymerization. Unexpectedly, MCAK can depolymerize axonemal doublets but Kip3p cannot. We propose that distinct protofilament-level activities underlie the functional dichotomy of depolymerases, resulting in either large-scale destabilization or length regulation of microtubule arrays. Our work establishes AFM as a powerful strategy to visualize microtubule dynamics and reveals how nanometer-scale substrate specificity leads to differential remodeling of micron-sized cytoskeletal structures.

scholarly journals Polystyrene as Graphene Film and 3D Graphene Sponge Precursor

2018 ◽  
Author(s):  
Alejandra Rendón-Patiño ◽  
Jinan Niu ◽  
Antonio Doménech-Carbó ◽  
Hermenegildo García ◽  
Ana Primo
Keyword(s):  
Thin Film ◽  
Photoelectron Spectroscopy ◽  
Graphene Film ◽  
Visible Absorption ◽  
X Ray ◽  
3D Graphene ◽  
Force Microscopy ◽  
Atomic Force ◽  
Graphene Films ◽  
Graphene Sponge

Polystyrene as a thin film on arbitrary substrates or pellets form defective graphene films or powders that can be dispersed in water and organic solvents. The materials were characterized by visible absorption, Raman and X-ray photoelectron spectroscopy, electron and atomic force microscopy and electrochemistry. Raman spectra of these materials show the presence of the expected 2D, G and D peaks at 2750, 1590 and 1350 cm-1, respectively. The relative intensity of the G vs. the D peak is taken as a quantitative indicator of the density of defects in the G layer.

scholarly journals SYNTHETIC GRAPHENE GROWN BY CHEMICAL VAPOR DEPOSITION ON COPPER FOILS

2013 ◽  
Vol 27 (10) ◽  
pp. 1341002 ◽  
Author(s):  
TING FUNG CHUNG ◽  
TIAN SHEN ◽  
HELIN CAO ◽  
LUIS A. JAUREGUI ◽  
WEI WU ◽  
...  
Keyword(s):  
Chemical Vapor Deposition ◽  
Vapor Deposition ◽  
Large Scale ◽  
Rapid Development ◽  
Graphene Film ◽  
Single Layer ◽  
Chemical Vapor ◽  
Mechanical And Thermal Properties ◽  
Large Area ◽  
Exfoliated Graphene

The discovery of graphene, a single layer of covalently bonded carbon atoms, has attracted intense interest. Initial studies using mechanically exfoliated graphene unveiled its remarkable electronic, mechanical and thermal properties. There has been a growing need and rapid development in large-area deposition of graphene film and its applications. Chemical vapor deposition on copper has emerged as one of the most promising methods in obtaining large-scale graphene films with quality comparable to exfoliated graphene. In this paper, we review the synthesis and characterizations of graphene grown on copper foil substrates by atmospheric pressure chemical vapor deposition. We also discuss potential applications of such large-scale synthetic graphene.

A Study of the Photoelectric Effect Caused by a Laser Beam Used in a Beam Bounce Technique in a C-AFM System

2008 ◽  
Author(s):  
Hung-Sung Lin ◽  
Mong-Sheng Wu
Keyword(s):  
Laser Beam ◽  
Failure Analysis ◽  
Atomic Force Microscope ◽  
Photoelectric Effect ◽  
Scanning Probe ◽  
Nanometer Scale ◽  
Electrical Characteristics ◽  
Atomic Force ◽  
Probe Microscope ◽  
Probe Head

Abstract The use of a scanning probe microscope (SPM), such as a conductive atomic force microscope (C-AFM) has been widely reported as a method of failure analysis in nanometer scale science and technology [1-6]. A beam bounce technique is usually used to enable the probe head to measure extremely small movements of the cantilever as it is moved across the surface of the sample. However, the laser beam used for a beam bounce also gives rise to the photoelectric effect while we are measuring the electrical characteristics of a device, such as a pn junction. In this paper, the photocurrent for a device caused by photon illumination was quantitatively evaluated. In addition, this paper also presents an example of an application of the C-AFM as a tool for the failure analysis of trap defects by taking advantage of the photoelectric effect.

scholarly journals Vertical monolithic integration of wide- and narrow-bandgap semiconductor nanostructures on graphene films

2021 ◽  
Vol 13 (1) ◽  
Author(s):  
Youngbin Tchoe ◽  
Janghyun Jo ◽  
HoSung Kim ◽  
Heehun Kim ◽  
Hyeonjun Baek ◽  
...  
Keyword(s):  
Graphene Film ◽  
Monolithic Integration ◽  
Hybrid Nanostructures ◽  
Dual Wavelength ◽  
Multilayer Graphene ◽  
Graphene Films ◽  
Transmission Electron ◽  
Zno Nanotubes ◽  
Metal Organic ◽  
Hybrid Configuration

AbstractWe report monolithic integration of indium arsenide (InAs) nanorods and zinc oxide (ZnO) nanotubes using a multilayer graphene film as a suspended substrate, and the fabrication of dual-wavelength photodetectors with the hybrid configuration of these materials. For the hybrid nanostructures, ZnO nanotubes and InAs nanorods were grown vertically on the top and bottom surfaces of the graphene films by metal-organic vapor-phase epitaxy and molecular beam epitaxy, respectively. The structural, optical, and electrical characteristics of the hybrid nanostructures were investigated using transmission electron microscopy, spectral photoresponse analysis, and current–voltage measurements. Furthermore, the hybrid nanostructures were used to fabricate dual-wavelength photodetectors sensitive to both ultraviolet and mid-infrared wavelengths.

scholarly journals Additive-Enhanced Exfoliation for High-Yield 2D Materials Production

Nanomaterials ◽  
2021 ◽  
Vol 11 (3) ◽  
pp. 601
Author(s):  
Dinh-Tuan Nguyen ◽  
Hsiang-An Ting ◽  
Yen-Hsun Su ◽  
Mario Hofmann ◽  
Ya-Ping Hsieh
Keyword(s):  
Large Scale ◽  
2D Materials ◽  
Transition Metal Dichalcogenides ◽  
Spectroscopic Characterization ◽  
High Yield ◽  
Nanometer Scale ◽  
Efficient Production ◽  
Device Performance ◽  
Metal Dichalcogenides ◽  
Scale Deposition

The success of van-der-Waals electronics, which combine large-scale-deposition capabilities with high device performance, relies on the efficient production of suitable 2D materials. Shear exfoliation of 2D materials’ flakes from bulk sources can generate 2D materials with low amounts of defects, but the production yield has been limited below industry requirements. Here, we introduce additive-assisted exfoliation (AAE) as an approach to significantly increase the efficiency of shear exfoliation and produce an exfoliation yield of 30%. By introducing micrometer-sized particles that do not exfoliate, the gap between rotor and stator was dynamically reduced to increase the achievable shear rate. This enhancement was applied to WS2 and MoS2 production, which represent two of the most promising 2D transition-metal dichalcogenides. Spectroscopic characterization and cascade centrifugation reveal a consistent and significant increase in 2D material concentrations across all thickness ranges. Thus, the produced WS2 films exhibit high thickness uniformity in the nanometer-scale and can open up new routes for 2D materials production towards future applications.

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