Solid Phase Growth of Graphene on Silicon Carbide by Nickel Silicidation: Graphene Formation Mechanisms

2014 ◽  
Vol 778-780 ◽  
pp. 1162-1165
Author(s):  
Enrique Escobedo-Cousin ◽  
Konstantin Vassilevski ◽  
Toby Hopf ◽  
Nicholas Wright ◽  
Anthony G. O'Neill ◽  
...  
Keyword(s):  
Raman Spectroscopy ◽  
Solid Phase ◽  
Formation Mechanisms ◽  
Layer By Layer ◽  
Phase Growth ◽  
Force Microscopy ◽  
Layer Graphene ◽  
Atomic Force ◽  
High Temperature Stage ◽  
Few Layer Graphene

This work presents experimental evidence of the formation mechanisms of few-layer graphene (FLG) films on SiC by nickel silicidation. FLG is formed by annealing of a 40 nm thick Ni layer on 6H-SiC at 1035ºC for 60 s, resulting in a Ni2Si layer which may be capped by any Ni that did not react during annealing. It has been proposed that FLG forms on top of the Ni during the high temperature stage. In contrast, during cooling, carbon atoms which were released during the silicidation reaction may diffuse back towards the Ni2Si/SiC interface to form a second FLG film. After annealing, layer-by-layer de-processing was carried out in order to unequivocally identify the FLG at each location using Atomic force microscopy (AFM) and Raman spectroscopy.

Local Solid Phase Epitaxy of Few-Layer Graphene on Silicon Carbide

2012 ◽  
Vol 717-720 ◽  
pp. 629-632 ◽  
Author(s):  
Enrique Escobedo-Cousin ◽  
Konstantin Vassilevski ◽  
Irina P. Nikitina ◽  
Nicolas G. Wright ◽  
Anthony G. O'Neill ◽  
...  
Keyword(s):  
Raman Spectroscopy ◽  
Solid Phase ◽  
Nickel Silicide ◽  
Surface Roughening ◽  
Solid Phase Epitaxy ◽  
Force Microscopy ◽  
Atomic Force ◽  
Wet Processing ◽  
20 Nm ◽  
Few Layer Graphene

Patterned Few Layers Graphene (FLG) films were grown by local solid phase epitaxy from nickel silicide supersaturated with carbon. The process was realised by annealing of thin Ni films deposited on the carbon-terminated surface of 6H-SiC semi-insulating wafer followed by wet processing to remove the resulting nickel silicide. Raman spectroscopy was used to investigate both the formation and subsequent removal of nickel silicide during processing. Characterisation of the resulting FLG films was carried out by Raman spectroscopy and Atomic Force Microscopy (AFM). The thickness of the final FLG film estimated from the Raman spectra varied from 1 to 3 monolayers for initial Ni layers varying from 3 to 20 nm thick. AFM observations revealed process-induced surface roughening in FLG films, however, electrical conductivity measurements by Transmission Line Model (TLM) structures confirmed that roughness does not compromise the film sheet resistance.

scholarly journals Growth of Ordered Graphene Ribbons by Sublimation Epitaxy

Crystals ◽  
2018 ◽  
Vol 8 (12) ◽  
pp. 449
Author(s):  
Shuxian Cai ◽  
Xingfang Liu ◽  
Xin Zheng ◽  
Zhonghua Liu
Keyword(s):  
Substrate Surface ◽  
Graphene Film ◽  
Graphene Ribbon ◽  
High Quality ◽  
Graphene Layers ◽  
Force Microscopy ◽  
Layer Graphene ◽  
Micro Raman Spectroscopy ◽  
Atomic Force ◽  
Few Layer Graphene

Ordered graphene ribbons were grown on the surface of 4° off-axis 4H-SiC wafers by sublimation epitaxy, and characterized by using scanning electron microscopy (SEM), atomic force microscopy (AFM) and micro-Raman spectroscopy (μ-Raman). SEM showed that there were gray and dark ribbons on the substrate surface, and AFM further revealed that these ordered graphene ribbons had clear stepped morphologies due to surface step-bunching. It was shown by μ-Raman that the numbers of graphene layers of these two types of regions were different. The gray region was composed of mono- or bilayer ordered graphene ribbon, while the dark region was of tri- or few-layer ribbon. Meanwhile, ribbons were all homogeneous and had a width up to 40 μm and a length up to 1000 μm, without micro defects such as grain boundaries, ridges, or mono- and few-layer graphene mixtures. The results of this study are useful for optimized growth of high-quality graphene film on silicon carbide crystal.

scholarly journals Preparation of Colloidal Dispersions of Graphene Sheets in Organic Solvents by Using Ball Milling

2010 ◽  
Vol 2010 ◽  
pp. 1-5 ◽  
Author(s):  
Weifeng Zhao ◽  
Furong Wu ◽  
Hang Wu ◽  
Guohua Chen
Keyword(s):  
Organic Solvents ◽  
Colloidal Suspension ◽  
Colloidal Dispersions ◽  
Graphene Sheets ◽  
Graphite Nanosheets ◽  
Force Microscopy ◽  
Layer Graphene ◽  
Atomic Force ◽  
Transmission Electron ◽  
Few Layer Graphene

A top-down method was developed for producing colloidal dispersions of graphene sheets. Graphite nanosheets comprising hundreds of carbon layers were dispersed and gently ball-milled to exfoliate into graphene in a variety of organic solvents. After 30 hours of the shear-force-dominated grinding and a subsequent 4000 r.p.m. of centrifugation, single- and few-layer graphene sheets were readily prepared and homogeneously and stably suspended in the good solvent medium which possesses a surface tension value close to 40 mJm−2, such as inN,N-dimethylformamide, at a concentration up to 0.08 mg ml−1, achieving a yield higher than 32.0 wt%. The graphene materials in the colloidal suspension were characterized using scanning and transmission electron microscopy and atomic force microscopy.

Synthesis of Few-Layer Graphene on Copper Using a Low-Cost Atmospheric Thermal Chemical Vapour Deposition System with Methane and Forming Gas

Nano Hybrids ◽  
2016 ◽  
Vol 10 ◽  
pp. 1-13
Author(s):  
M.S. Shamsudin ◽  
S.J. Fishlock ◽  
M. Rusop ◽  
S.M. Sanip ◽  
Suan Hui Pu
Keyword(s):  
Chemical Vapour Deposition ◽  
Vapour Deposition ◽  
Low Cost ◽  
Graphene Film ◽  
Chemical Vapour ◽  
Force Microscopy ◽  
Layer Graphene ◽  
Atomic Force ◽  
Temperature Deposition ◽  
Few Layer Graphene

Graphene has attracted wide interest across a range of applications due to its electrical, mechanical and optical properties. The use of a low-cost, table-top chemical vapour deposition system to deposit few-layer graphene onto copper is reported in this work. Characterisation of the graphene is performed using Raman spectroscopy and atomic force microscopy. The results show that few-layer graphene can be deposited at 1000 °C using CH4 as a carbon precursor, and 5% H2, 95% N2 forming gas as a diluent. The effects of deposition temperature, deposition time, and forming gas addition on graphene film quality was studied experimentally. An increase in graphene quality was observed when forming gas was added during deposition.

scholarly journals Local solid phase growth of few-layer graphene on silicon carbide from nickel silicide supersaturated with carbon

2013 ◽  
Vol 113 (11) ◽  
pp. 114309 ◽  
Author(s):  
Enrique Escobedo-Cousin ◽  
Konstantin Vassilevski ◽  
Toby Hopf ◽  
Nick Wright ◽  
Anthony O'Neill ◽  
...  
Keyword(s):  
Silicon Carbide ◽  
Solid Phase ◽  
Nickel Silicide ◽  
Phase Growth ◽  
Layer Graphene ◽  
Few Layer Graphene

FORMATION OF HOLLOW CAVITIES ON {100} FACES OF LAP CRYSTALS INVESTIGATED BY AFM

2007 ◽  
Vol 14 (05) ◽  
pp. 985-989
Author(s):  
Y. L. GENG ◽  
ZH. H. SUN ◽  
D. XU
Keyword(s):  
Atomic Force Microscopy ◽  
Formation Mechanisms ◽  
Layer By Layer ◽  
Cavity Formation ◽  
Force Microscopy ◽  
Elementary Steps ◽  
Atomic Force ◽  
Hollow Cavity ◽  
Dislocation Sources ◽  
Nucleation Growth

Atomic force microscopy (AFM) has been used to study the hollow cavity formation mechanisms of the L-arginine phosphate monohydrate (LAP) crystals. Hollow cavities are formed through three modes. During 2D nucleation growth, initially formed 2D cavity prevents the growth around it layer-by-layer and causes the formation of 3D cavity with stepped-walls inside. Interaction of the steps advancing along different directions generated by different dislocation sources is also responsible for the appearance of hollow cavities. When the steps overrun impurities incorporated into the kinks, triangular pits among regular elementary steps come into being.

scholarly journals Exploring Intramolecular Methyl–Methyl Coupling on a Metal Surface for Edge-Extended Graphene Nanoribbons

2021 ◽  
Vol 03 (02) ◽  
pp. 128-133
Author(s):  
Zijie Qiu ◽  
Qiang Sun ◽  
Shiyong Wang ◽  
Gabriela Borin Barin ◽  
Bastian Dumslaff ◽  
...  
Keyword(s):  
Raman Spectroscopy ◽  
Atomic Force Microscopy ◽  
High Resolution ◽  
Graphene Nanoribbons ◽  
Scanning Tunneling ◽  
Tunneling Microscopy ◽  
Force Microscopy ◽  
Methyl Methyl ◽  
Atomic Force ◽  
Edge Extension

Intramolecular methyl–methyl coupling on Au (111) is explored as a new on-surface protocol for edge extension in graphene nanoribbons (GNRs). Characterized by high-resolution scanning tunneling microscopy, noncontact atomic force microscopy, and Raman spectroscopy, the methyl–methyl coupling is proven to indeed proceed at the armchair edges of the GNRs, forming six-membered rings with sp3- or sp2-hybridized carbons.

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