scholarly journals Mechanical removal of surface residues on graphene for TEM characterizations

2020 ◽  
Vol 50 (1) ◽  
Author(s):  
Dong-Gyu Kim ◽  
Sol Lee ◽  
Kwanpyo Kim
Keyword(s):  
Cleaning Process ◽  
Contact Mode ◽  
Graphene Layers ◽  
Force Microscopy ◽  
Mechanical Removal ◽  
Carrier Scattering ◽  
Transmission Electron ◽  
Charge Carrier Scattering ◽  
2D Crystals ◽  
Mechanical Cleaning

AbstractContamination on two-dimensional (2D) crystal surfaces poses serious limitations on fundamental studies and applications of 2D crystals. Surface residues induce uncontrolled doping and charge carrier scattering in 2D crystals, and trapped residues in mechanically assembled 2D vertical heterostructures often hinder coupling between stacked layers. Developing a process that can reduce the surface residues on 2D crystals is important. In this study, we explored the use of atomic force microscopy (AFM) to remove surface residues from 2D crystals. Using various transmission electron microscopy (TEM) investigations, we confirmed that surface residues on graphene samples can be effectively removed via contact-mode AFM scanning. The mechanical cleaning process dramatically increases the residue-free areas, where high-resolution imaging of graphene layers can be obtained. We believe that our mechanical cleaning process can be utilized to prepare high-quality 2D crystal samples with minimum surface residues.

scholarly journals Mechanical Removal of Surface Residues on Graphene for TEM Characterizations

2020 ◽  
Author(s):  
Dong-Gyu KIM ◽  
Sol Lee ◽  
Kwanpyo Kim
Keyword(s):  
Cleaning Process ◽  
Contact Mode ◽  
Graphene Layers ◽  
Force Microscopy ◽  
Mechanical Removal ◽  
Carrier Scattering ◽  
Transmission Electron ◽  
Charge Carrier Scattering ◽  
2D Crystals ◽  
Mechanical Cleaning

Abstract Contamination on two-dimensional (2D) crystal surfaces poses serious limitations on fundamental studies and applications of 2D crystals. Surface residues induce uncontrolled doping and charge carrier scattering in 2D crystals, and trapped residues in mechanically assembled 2D vertical heterostructures often hinder coupling between stacked layers. Developing a process that can reduce the surface residues on 2D crystals is important. In this study, we explored the use of atomic force microscopy (AFM) to remove surface residues from 2D crystals. Using various transmission electron microscopy (TEM) investigations, we confirmed that surface residues on graphene samples can be effectively removed via contact-mode AFM scanning. The mechanical cleaning process dramatically increases the residue-free areas, where high-resolution imaging of graphene layers can be obtained. We believe that our mechanical cleaning process can be utilized to prepare high-quality 2D crystal samples with minimum surface residues.

Temperature Dependent Structural Evolution of Graphene Layers on 4H-SiC(0001)

2011 ◽  
Vol 679-680 ◽  
pp. 797-800 ◽  
Author(s):  
Sushant Sonde ◽  
Carmelo Vecchio ◽  
Filippo Giannazzo ◽  
Corrado Bongiorno ◽  
Salvatore di Franco ◽  
...  
Keyword(s):  
Electron Microscopy ◽  
Structural Evolution ◽  
Morphological Transformation ◽  
Temperature Dependent ◽  
Microscopy Imaging ◽  
Graphene Layers ◽  
Force Microscopy ◽  
Atomic Force ◽  
Transmission Electron ◽  
Mode Atomic Force Microscopy

In this study we examined the structural evolution of graphene grown on 8° off-axis 4H-SiC(0001) substrates at temperatures from 1600°C to 1700°C in Ar ambient. Morphological transformation of SiC substrate after annealing was examined by Tapping Mode Atomic Force Microscopy. Moreover, by etching-out graphene layers from graphitized SiC substrates in selective trenches we determined the number of graphene layers. Numbers of graphene layers were then independently confirmed by Transmission Electron Microscopy imaging.

scholarly journals Estimation of Number of Graphene Layers Using Different Methods: A Focused Review

Materials ◽  
2021 ◽  
Vol 14 (16) ◽  
pp. 4590
Author(s):  
Vineet Kumar ◽  
Anuj Kumar ◽  
Dong-Joo Lee ◽  
Sang-Shin Park
Keyword(s):  
Electron Microscopy ◽  
Raman Spectra ◽  
Monolayer Graphene ◽  
Multilayer Graphene ◽  
Characterization Methods ◽  
Graphene Layers ◽  
Force Microscopy ◽  
Stacking Order ◽  
Transmission Electron ◽  
Few Layer Graphene

Graphene, a two-dimensional nanosheet, is composed of carbon species (sp2 hybridized carbon atoms) and is the center of attention for researchers due to its extraordinary physicochemical (e.g., optical transparency, electrical, thermal conductivity, and mechanical) properties. Graphene can be synthesized using top-down or bottom-up approaches and is used in the electronics and medical (e.g., drug delivery, tissue engineering, biosensors) fields as well as in photovoltaic systems. However, the mass production of graphene and the means of transferring monolayer graphene for commercial purposes are still under investigation. When graphene layers are stacked as flakes, they have substantial impacts on the properties of graphene-based materials, and the layering of graphene obtained using different approaches varies. The determination of number of graphene layers is very important since the properties exhibited by monolayer graphene decrease as the number of graphene layer per flake increases to 5 as few-layer graphene, 10 as multilayer graphene, and more than 10 layers, when it behaves like bulk graphite. Thus, this review summarizes graphene developments and production. In addition, the efficacies of determining the number of graphene layers using various characterization methods (e.g., transmission electron microscopy (TEM), atomic force microscopy (AFM), scanning electron microscopy (SEM), X-ray diffraction (XRD), Raman spectra and mapping, and spin hall effect-based methods) are compared. Among these methods, TEM and Raman spectra were found to be most promising to determine number of graphene layers and their stacking order.

Preparation of a P(FcA-co-ANI)/graphene composite for application in supercapacitors

2016 ◽  
Vol 29 (5) ◽  
pp. 524-532 ◽  
Author(s):  
Yunlong Li ◽  
Yuying Zheng
Keyword(s):  
Electron Microscopy ◽  
Electrochemical Impedance ◽  
Proton Nuclear Magnetic Resonance ◽  
Diffusion Resistance ◽  
X Ray Diffraction ◽  
Graphene Layers ◽  
Force Microscopy ◽  
Atomic Force ◽  
Transmission Electron ◽  
Surface Morphologies

A conducting copolymer of 1,1′-ferrocenediacyl anilide and aniline (P(FcA-co-ANI)) was synthesized, which had a conjugated structure and ferrocene moieties in the main chain. The monomer and copolymer were characterized using proton nuclear magnetic resonance and Fourier-transform infrared (FTIR) spectroscopies. A P(FcA-co-ANI)/reduced graphene oxide (rGO) composite was synthesized by oxidation polymerization, using rGO as a substrate. The characteristic peaks of P(FcA-co-ANI) and rGO were observed in the FTIR spectrum of P(FcA-co-ANI)/rGO. The X-ray diffraction pattern of P(FcA-co-ANI)/rGO exhibited similar peaks to the pattern of P(FcA-co-ANI), except for the absence of the weak broad peak at 9.0° owing to rGO. The surface morphologies of the materials were characterized by atomic force microscopy, transmission electron microscopy and scanning electron microscopy. The interlayer distances of rGO and P(FcA-co-ANI)/rGO were 0.96 and 1.38 nm, respectively. The morphology of the copolymer was spherical, and it contained island structures covering the surface of the graphene layers. The electrochemical properties of the composite were measured by cyclic voltammetry, galvanostatic charge–discharge measurements and electrochemical impedance spectroscopy. The maximum specific capacitance of the composite was 722.5 F/g at 0.5 A/g. The diffusion resistance was very small, and the composites durability was sufficient for subjecting to prolonged oxidation and reduction.

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.

Structural Characterization of Graphene Grown by Thermal Decomposition of Off-Axis 4H-SiC (0001)

2012 ◽  
Vol 711 ◽  
pp. 141-148 ◽  
Author(s):  
Filippo Giannazzo ◽  
Martin Rambach ◽  
Wielfried Lerch ◽  
Corrado Bongiorno ◽  
Salvatore di Franco ◽  
...  
Keyword(s):  
Electron Microscopy ◽  
Thermal Decomposition ◽  
Cross Section ◽  
Structural Characterization ◽  
Plan View ◽  
Graphene Layers ◽  
Force Microscopy ◽  
Atomic Force ◽  
Transmission Electron

We present a nanoscale morphological and structural characterization of few layers of graphene grown by thermal decomposition of off-axis 4H-SiC (0001). A comparison between transmission electron microscopy (TEM) in cross-section and in plan view allows to fully exploit the potentialities of TEM. Such a comparison was used to get information on the number of graphene layers as well as on the rotational order between the layers and with respect to the substrate. Some peculiar structures observed by TEM (wrinkles) could only be systematically measured by atomic force microscopy (AFM). In particular, the density and the height of the wrinkles in the few layers of graphene was investigated.

Scanning tunneling microscopy and atomic force microscopy: New tools for biology

1989 ◽  
Vol 47 ◽  
pp. 778-779
Author(s):  
CE Bracker ◽  
P. K. Hansma
Keyword(s):  
Physical Property ◽  
Scanning Probe ◽  
Scanning Tunneling ◽  
Small Scale ◽  
Tunneling Microscopy ◽  
Force Microscopy ◽  
New Family ◽  
Small Probe ◽  
Atomic Force ◽  
Transmission Electron

A new family of scanning probe microscopes has emerged that is opening new horizons for investigating the fine structure of matter. The earliest and best known of these instruments is the scanning tunneling microscope (STM). First published in 1982, the STM earned the 1986 Nobel Prize in Physics for two of its inventors, G. Binnig and H. Rohrer. They shared the prize with E. Ruska for his work that had led to the development of the transmission electron microscope half a century earlier. It seems appropriate that the award embodied this particular blend of the old and the new because it demonstrated to the world a long overdue respect for the enormous contributions electron microscopy has made to the understanding of matter, and at the same time it signalled the dawn of a new age in microscopy. What we are seeing is a revolution in microscopy and a redefinition of the concept of a microscope.Several kinds of scanning probe microscopes now exist, and the number is increasing. What they share in common is a small probe that is scanned over the surface of a specimen and measures a physical property on a very small scale, at or near the surface. Scanning probes can measure temperature, magnetic fields, tunneling currents, voltage, force, and ion currents, among others.

Surface roughness measurements of vanadium-contaminated fluidized cracking catalysts by atomic force microscopy

1996 ◽  
Vol 54 ◽  
pp. 866-867
Author(s):  
H. Kinney ◽  
M.L. Occelli ◽  
S.A.C. Gould
Keyword(s):  
Surface Roughness ◽  
Zeolite Y ◽  
Atomic Level ◽  
Microporous Structure ◽  
Contact Mode ◽  
Force Microscopy ◽  
Atomic Force ◽  
Before And After ◽  
Roughness Measurements ◽  
Cracking Catalysts

For this study we have used a contact mode atomic force microscope (AFM) to study to topography of fluidized cracking catalysts (FCC), before and after contamination with 5% vanadium. We selected the AFM because of its ability to well characterize the surface roughness of materials down to the atomic level. It is believed that the cracking in the FCCs occurs mainly on the catalysts top 10-15 μm suggesting that the surface corrugation could play a key role in the FCCs microactivity properties. To test this hypothesis, we chose vanadium as a contaminate because this metal is capable of irreversibly destroying the FCC crystallinity as well as it microporous structure. In addition, we wanted to examine the extent to which steaming affects the vanadium contaminated FCC. Using the AFM, we measured the surface roughness of FCCs, before and after contamination and after steaming.We obtained our FCC (GRZ-1) from Davison. The FCC is generated so that it contains and estimated 35% rare earth exchaged zeolite Y, 50% kaolin and 15% binder.

Charge Carrier Scattering Mechanisms in Thermoelectric PbTe:Sb

2014 ◽  
Vol 59 (7) ◽  
pp. 706-711 ◽  
Author(s):  
D.M. Freik ◽  
◽  
S.I. Mudryi ◽  
I.V. Gorichok ◽  
R.O Dzumedze ◽  
...  
Keyword(s):  
Charge Carrier ◽  
Scattering Mechanisms ◽  
Carrier Scattering ◽  
Charge Carrier Scattering

Liquid-Phase Peak Force Infrared Microscopy

2020 ◽  
Author(s):  
Haomin Wang ◽  
Joseph M. González-Fialkowski ◽  
Wenqian Li ◽  
Yan Yu ◽  
Xiaoji Xu
Keyword(s):  
Liquid Phase ◽  
Spatial Resolution ◽  
Shear Force ◽  
Polymer Surface ◽  
Surface Damage ◽  
Peak Force ◽  
Infrared Microscopy ◽  
Contact Mode ◽  
Force Microscopy ◽  
Hydrogen Deuterium

Atomic force microscopy-infrared microscopy (AFM-IR) provides a route to bypass Abbe’s diffraction limit through photothermal detections of infrared absorption. With the combination of total internal reflection, AFM-IR can operate in the aqueous phase. However, AFM-IR in contact mode suffers from surface damage from the lateral shear force between the tip and sample, and can only achieve 20~25-nm spatial resolution. Here, we develop the liquid-phase peak force infrared (LiPFIR) microscopy that avoids the detrimental shear force and delivers an 8-nm spatial resolution. The non-destructiveness of the LiPFIR microscopy enables <i>in situ</i> chemical measurement of heterogeneous materials and investigations on a range of chemical and physical transformations, including polymer surface reorganization, hydrogen-deuterium isotope exchange, and ethanol-induced denaturation of proteins. We also perform LiPFIR imaging of the budding site of yeast cell wall in the fluid as a demonstration of biological applications. LiPFIR unleashes the potential of in liquid AFM-IR for chemical nanoscopy.

Sign in / Sign up

Export Citation Format

Share Document