Preparation of High-Quality Graphene by Sodium Borohydride Reducing Stage-1 FeCl3-GIC via In Situ Hydrogen Exfoliation

2017 ◽  
Vol 744 ◽  
pp. 458-462
Author(s):  
Xu Qiao ◽  
Zhi Lin ◽  
Yuan Yuan Si ◽  
Xiao Dan Lin ◽  
Shao Wei Cui ◽  
...  
Keyword(s):  
Sodium Borohydride ◽  
Single Layer ◽  
Single Layer Graphene ◽  
High Quality ◽  
Force Microscopy ◽  
Sem Image ◽  
Exfoliated Graphene ◽  
Atomic Force ◽  
Stage 1

High-quality graphene is prepared via In Situ hydrogen exfoliation of the reaction of stage-1 FeCl3-GIC with sodium borohydride solution, followed by washings and sonication. The hydrogen evolved from the borohydride exfoliates the GIC and reduces defect structure in the graphene simultaneously, make it more conjugated. Raman spectrum results show the intensity ratio of the D and G peak is about 0.09, even smaller than that of the original graphite, which is 0.17. The only C1s peak locating at 284.9 eV in another way supports the only one structure in the graphene. SEM image of exfoliated graphene Fig. 2(f) shows that the graphene obtained has curly morphology, which is significantly different from graphite flakes. TEM of the graphene shows a single layer graphene and its overlap with other graphene. Atomic force microscopy (AFM) measure shows that the average thickness of graphene sheets is about 0.530 nm. Proving that the high quality graphene prepared is chiefly single layer. After compression molded into graphene mat, its conductivity reaches 2.85×105S/m, which is about one third of the theoretical value of graphene. This method is promising for mass production of high-quality graphene.

scholarly journals Graphene on SiC(0001) inspected by dynamic atomic force microscopy at room temperature

2015 ◽  
Vol 6 ◽  
pp. 901-906 ◽  
Author(s):  
Mykola Telychko ◽  
Jan Berger ◽  
Zsolt Majzik ◽  
Pavel Jelínek ◽  
Martin Švec
Keyword(s):  
Electron Scattering ◽  
Room Temperature ◽  
Single Layer ◽  
Tunneling Current ◽  
Single Layer Graphene ◽  
Force Microscopy ◽  
Atomic Force ◽  
Scattering Effects ◽  
Out Of Plane ◽  
Theoretical Simulations

We investigated single-layer graphene on SiC(0001) by atomic force and tunneling current microscopy, to separate the topographic and electronic contributions from the overall landscape. The analysis revealed that the roughness evaluated from the atomic force maps is very low, in accord with theoretical simulations. We also observed that characteristic electron scattering effects on graphene edges and defects are not accompanied by any out-of-plane relaxations of carbon atoms.

Single layer growth of sub-micron metal–organic framework crystals observed by in situ atomic force microscopy

2009 ◽  
pp. 6294 ◽  
Author(s):  
Neena S. John ◽  
Camilla Scherb ◽  
Maryiam Shöâeè ◽  
Michael W. Anderson ◽  
Martin P. Attfield ◽  
...  
Keyword(s):  
Atomic Force Microscopy ◽  
Metal Organic Framework ◽  
Single Layer ◽  
Layer Growth ◽  
Force Microscopy ◽  
Atomic Force ◽  
Metal Organic ◽  
Organic Framework

Structural Strain in Single Layer Graphene Fabricated on SiC

2019 ◽  
Vol 963 ◽  
pp. 161-165
Author(s):  
Wan Cheng Yu ◽  
Xiu Fang Chen ◽  
Xiao Bo Hu ◽  
Xian Gang Xu ◽  
Peng Jin ◽  
...  
Keyword(s):  
Thermal Decomposition ◽  
Single Layer ◽  
Ex Situ ◽  
Single Layer Graphene ◽  
Growth Time ◽  
Kelvin Probe ◽  
Force Microscopy ◽  
Layer Graphene ◽  
Atomic Force ◽  
Structural Strain

Single layer graphene is fabricated on the Si face of silicon carbide through thermal decomposition. The thickness of graphene was checked by a combination of ex situ Kelvin probe force microscopy together with Raman spectroscopy and atomic force microscopy. The amount of residual strain induced is calculated to between 1.3% and 0.7%. Results also show that the magnitude of strain increased with growth time while the uniformity of strain improved.

scholarly journals Mica as an Ultra-Flat Substrate for Studying Mechanically Exfoliated Graphene

2021 ◽  
Author(s):  
◽  
Mashael M. Alshaikh
Keyword(s):  
Electron Microscopy ◽  
Raman Spectroscopy ◽  
Single Layer ◽  
Force Microscopy ◽  
Flat Substrate ◽  
Exfoliated Graphene ◽  
Atomic Force ◽  
Common Support ◽  
Two Dimensional Materials ◽  
Free Graphene

Silicon dioxide (SiO2) is a common support for studying two-dimensional materials and creating devices from them. However, graphene conformation to SiO2 roughness worsens the electronic properties, whereas graphene deposited on flat terraces of insulating mica is free of ripples. This thesis solves key challenges in the use of mica to support mechanically exfoliated graphene. Methods of mica cleavage and graphene exfoliation, and settings for electron microscopy, atomic force microscopy (AFM) and Raman spectroscopy were developed. Vacuum annealing was compared for graphene samples of different thicknesses, down to a single layer. Pre- and post-annealing, graphene on mica provided defect-free graphene and no observable strain or doping. In contrast, graphene on SiO2 showed disorder before annealing. Annealing up to 300°C reduced the Raman defect peak but did not remove it. Above 300°C, the defect peak increased. Graphene on SiO2 appeared to become ‘invisible’ with AFM after annealing at 500°C, in line with previous observations with scanning electron microscopy. Other studies attributed this to the graphene being removed, but, here, using substrate markers, Raman spectroscopy and line-averaged AFM showed that the graphene was still present but had conformed to the underlying roughness of the SiO2 so well as to appear nearly invisible. Mica annealed at 400°C showed the formation of potassium carbonate particles following dehydroxylation of the mica surface at a temperature lower than previously reported. In addition, the graphene appeared to act as a mask, protecting the mica underneath it while the surrounding surface was removed at 500°C. Patterning and etching mica are essential to create location grids and etch trenches to suspend deposited materials. The first patterning lithography recipe for mica was established herein using electron-beam lithography. Finally, mechanically exfoliated graphene was successfully transferred to the patterned mica and studied.

scholarly journals Configurational Effects on Strain and Doping at Graphene-Silver Nanowire Interfaces

2020 ◽  
Vol 10 (15) ◽  
pp. 5157
Author(s):  
Frank Lee ◽  
Manoj Tripathi ◽  
Peter Lynch ◽  
Alan B. Dalton
Keyword(s):  
Atomic Force Microscopy ◽  
Adhesion Force ◽  
Single Layer ◽  
Silver Nanowire ◽  
Single Layer Graphene ◽  
Fermi Energy Level ◽  
Essential Information ◽  
Force Microscopy ◽  
Layer Graphene ◽  
Atomic Force

Graphene shows substrate-dependent physical and electronic properties. Here, we presented the interaction between single-layer graphene and silver nanowire (AgNW) in terms of physical straining and doping. We observed a snap-through event for single-layer graphene/AgNW at a separation of AgNWs of 55 nm, beyond the graphene suspended over the nanowires. The adhesion force between the Atomic Force Microscopy (AFM) tip apex and the suspended graphene was measured as higher than the conformed one by 1.8 nN. The presence of AgNW modulates the Fermi energy level of graphene and reduces the work function by 0.25 eV, which results in n-type doping. Consequently, a lateral p-n-p junction is formed with single AgNW. The correlation Raman plot between G-2D modes reveals the increment of strain in graphene of 0.05% due to the curvature around AgNW, and 0.01% when AgNW lies on the top of graphene. These results provide essential information in inspecting the physical and electronic influences from AgNW.

Nanolithography of Single-Layer Graphene Oxide Films by Atomic Force Microscopy

Langmuir ◽  
2010 ◽  
Vol 26 (9) ◽  
pp. 6164-6166 ◽  
Author(s):  
Gang Lu ◽  
Xiaozhu Zhou ◽  
Hai Li ◽  
Zongyou Yin ◽  
Bing Li ◽  
...  
Keyword(s):  
Atomic Force Microscopy ◽  
Graphene Oxide ◽  
Oxide Films ◽  
Single Layer ◽  
Single Layer Graphene ◽  
Force Microscopy ◽  
Layer Graphene ◽  
Atomic Force

Dynamics of InAs Quantum Dots Formation on AlAs and GaAs

2000 ◽  
Vol 648 ◽  
Author(s):  
M. Yakimov ◽  
V. Tokranov ◽  
S. Oktyabrsky
Keyword(s):  
Quantum Dots ◽  
Self Assembly ◽  
Single Layer ◽  
High Energy ◽  
Ex Situ ◽  
Inas Quantum Dots ◽  
Force Microscopy ◽  
Atomic Force ◽  
Kinetics Of

AbstractWe have studied the formation of InAs quantum dots (QDs) grown by molecular beam epitaxy on top of GaAs and 2 ML-thick AlAs layers in the temperature range from 350 to 500°C. In-situ reflection high energy electron diffraction (RHEED) patterns were recorded in real time during the growth and analyzed to characterize the 2D-to-3D transition on the surface, including QD formation, and ripening process. The kinetics of QD formation was studied using the InAs growth rates ranging from 0.01 to 1 ML/s and different ratios of As2/In fluxes. RHEED patterns and ex-situ atomic force microscopy images were analyzed to reveal the development of sizes and shapes of the single-layer and stacked QD ensembles. The critical InAs coverage for QD formation was shown to be consistently higher for dots grown on the AlAs overlayer than for those grown on GaAs surface. Self-assembly of multilayer QD stacks revealed the reduction of the critical thickness for dots formed in the upper layers.

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