scholarly journals Effect of a Balanced Concentration of Hydrogen on Graphene CVD Growth

2016 ◽  
Vol 2016 ◽  
pp. 1-10 ◽  
Author(s):  
S. Chaitoglou ◽  
E. Pascual ◽  
E. Bertran ◽  
J. L. Andujar
Keyword(s):  
Copper Substrate ◽  
Single Layer ◽  
Chemical Vapor ◽  
Experimental System ◽  
Single Layer Graphene ◽  
Growth Time ◽  
Monolayer Graphene ◽  
Flow Ratio ◽  
Large Area ◽  
Hydrogen Flow

The extraordinary properties of graphene make it one of the most interesting materials for future applications. Chemical vapor deposition (CVD) is the synthetic method that permits obtaining large areas of monolayer graphene. To achieve this, it is important to find the appropriate conditions for each experimental system. In our CVD reactor working at low pressure, important factors appear to be the pretreatment of the copper substrate, considering both its cleaning and its annealing before the growing process. The carbon precursor/hydrogen flow ratio and its modification during the growth are significant in order to obtain large area graphene crystals with few defects. In this work, we have focused on the study of the methane and the hydrogen flows to control the production of single layer graphene (SLG) and its growth time. In particular, we observe that hydrogen concentration increases during a usual growing process (keeping stable the methane/hydrogen flow ratio) resulting in etched domains. In order to balance this increase, a modification of the hydrogen flow results in the growth of smooth hexagonal SLG domains. This is a result of the etching effect that hydrogen performs on the growing graphene. It is essential, therefore, to study the moderated presence of hydrogen.

scholarly journals Ultrathin Functional Polymer Modified Graphene for Enhanced Enzymatic Electrochemical Sensing

Biosensors ◽  
2019 ◽  
Vol 9 (1) ◽  
pp. 16 ◽  
Author(s):  
Anitha Devadoss ◽  
Rhiannan Forsyth ◽  
Ryan Bigham ◽  
Hina Abbasi ◽  
Muhammad Ali ◽  
...  
Keyword(s):  
Single Layer ◽  
Chemical Vapor ◽  
Electrochemical Analysis ◽  
Electrochemical Sensing ◽  
Single Layer Graphene ◽  
Monolayer Graphene ◽  
Polymer Layers ◽  
Thin Polymer ◽  
Amine Groups ◽  
Modified Graphene

Grafting thin polymer layers on graphene enables coupling target biomolecules to graphene surfaces, especially through amide and aldehyde linkages with carboxylic acid and primary amine derivatives, respectively. However, functionalizing monolayer graphene with thin polymer layers without affecting their exceptional electrical properties remains challenging. Herein, we demonstrate the controlled modification of chemical vapor deposition (CVD) grown single layer graphene with ultrathin polymer 1,5-diaminonaphthalene (DAN) layers using the electropolymerization technique. It is observed that the controlled electropolymerization of DAN monomer offers continuous polymer layers with thickness ranging between 5–25 nm. The surface characteristics of pure and polymer modified graphene was examined. As anticipated, the number of surface amine groups increases with increases in the layer thickness. The effects of polymer thickness on the electron transfer rates were studied in detail and a simple route for the estimation of surface coverage of amine groups was demonstrated using the electrochemical analysis. The implications of grafting ultrathin polymer layers on graphene towards horseradish peroxidase (HRP) enzyme immobilization and enzymatic electrochemical sensing of H2O2 were discussed elaborately.

Synthesis of Large-Area and Monolayer of Graphene: Role of Transition Metal Support and Growth Time by CVD Method

2011 ◽  
Vol 306-307 ◽  
pp. 331-335
Author(s):  
Hui Gao ◽  
Yun Fei Wang ◽  
Yan Xia Liu ◽  
Er Qing Xie ◽  
Pulickel M. Ajayan
Keyword(s):  
Graphene Sheet ◽  
Chemical Vapor ◽  
Liquid Hydrocarbon ◽  
Growth Time ◽  
Monolayer Graphene ◽  
Large Area ◽  
Cvd Method ◽  
Graphene Synthesis ◽  
Transmission Electron ◽  
Metal Support

Continuous monolayer graphene sheet with large area has been synthesized via chemical vapor deposition (CVD) method using liquid hydrocarbon as precursor. Synthesis parameters including growth substrate and growth time have been investigated to assess their influence on monolayer graphene synthesis. Raman spectroscopy and high resolution transmission electron microscopy (HRTEM) reveal that the number of layers and quality of graphene sheet depend greatly on the varied synthesis parameter. The study could be used to improve understanding the growth of graphene by CVD method in order to meet the needs of graphene in various electronic applications.

scholarly journals Scattering Theory of Graphene Grain Boundaries

Materials ◽  
2018 ◽  
Vol 11 (9) ◽  
pp. 1660 ◽  
Author(s):  
Francesco Romeo ◽  
Antonio Di Bartolomeo
Keyword(s):  
Grain Boundary ◽  
Grain Boundaries ◽  
Scattering Theory ◽  
Carrier Transport ◽  
Single Layer ◽  
Chemical Vapor ◽  
Industrial Applications ◽  
Single Layer Graphene ◽  
Large Area ◽  
Current Conservation

The implementation of graphene-based electronics requires fabrication processes that are able to cover large device areas, since the exfoliation method is not compatible with industrial applications. The chemical vapor deposition of large-area graphene represents a suitable solution; however, it has an important drawback of producing polycrystalline graphene with the formation of grain boundaries, which are responsible for the limitation of the device’s performance. With these motivations, we formulate a theoretical model of a single-layer graphene grain boundary by generalizing the graphene Dirac Hamiltonian model. The model only includes the long-wavelength regime of the charge carrier transport, which provides the main contribution to the device conductance. Using symmetry-based arguments deduced from the current conservation law, we derive unconventional boundary conditions characterizing the grain boundary physics and analyze their implications on the transport properties of the system. Angle resolved quantities, such as the transmission probability, are studied within the scattering matrix approach. The conditions for the existence of preferential transmission directions are studied in relation with the grain boundary properties. The proposed theory provides a phenomenological model to study grain boundary physics within the scattering approach, and represents per se an important enrichment of the scattering theory of polycrystalline graphene. Moreover, the outcomes of the theory can contribute to understanding and limiting the detrimental effects of graphene grain boundaries, while also providing a benchmark for more elaborate techniques.

scholarly journals Unveiling the Direct Correlation between the CVD-Grown Graphene and the Growth Template

2018 ◽  
Vol 2018 ◽  
pp. 1-6 ◽  
Author(s):  
Junghyun Lee ◽  
Jihyung Seo ◽  
Sungchul Jung ◽  
Kibog Park ◽  
Hyesung Park
Keyword(s):  
Graphene Sheet ◽  
Copper Substrate ◽  
Chemical Vapor ◽  
Industrial Applications ◽  
Monolayer Graphene ◽  
Low Carbon ◽  
Large Area ◽  
High Quality ◽  
Carbon Solubility ◽  
Grown Graphene

Chemical vapor deposition (CVD) is known to produce continuous, large-area graphene sheet with decent physical properties. In the CVD process, catalytic metal substrates are typically used as the growth template, and copper has been adopted as the representative material platform due to its low carbon solubility and resulting monolayer graphene growth capability. For the widespread industrial applications of graphene, achieving the high-quality is essential. Several factors affect the qualities of CVD-grown graphene, such as pressure, temperature, carbon precursors, or growth template. In this work, we provide detailed analysis on the direct relation between the metallic growth substrate (copper) and overall properties of the resulting CVD-grown graphene. The surface morphology of copper substrate was modulated via simple chemical treatments, and its effect on physical, optical, and electrical properties of graphene was analyzed. Based on these results, we propose a simple synthesis route to produce high-quality, continuous, monolayer graphene sheet, which can facilitate the commercialization of CVD graphene into reality.

scholarly journals Correction: Direct chemical vapor deposition synthesis of large area single-layer brominated graphene

RSC Advances ◽  
2019 ◽  
Vol 9 (28) ◽  
pp. 16057-16057
Author(s):  
Maria Hasan ◽  
Wang Meiou ◽  
Liu Yulian ◽  
Sami Ullah ◽  
Huy Q. Ta ◽  
...  
Keyword(s):  
Chemical Vapor Deposition ◽  
Vapor Deposition ◽  
Single Layer ◽  
Chemical Vapor ◽  
Large Area

Correction for ‘Direct chemical vapor deposition synthesis of large area single-layer brominated graphene’ by Maria Hasan et al., RSC Adv., 2019, 9, 13527–13532.

Epitaxial Chemical Vapor Deposition Growth of Single-Layer Graphene over Cobalt Film Crystallized on Sapphire

ACS Nano ◽  
2010 ◽  
Vol 4 (12) ◽  
pp. 7407-7414 ◽  
Author(s):  
Hiroki Ago ◽  
Yoshito Ito ◽  
Noriaki Mizuta ◽  
Kazuma Yoshida ◽  
Baoshan Hu ◽  
...  
Keyword(s):  
Chemical Vapor Deposition ◽  
Vapor Deposition ◽  
Single Layer ◽  
Chemical Vapor ◽  
Single Layer Graphene ◽  
Chemical Vapor Deposition Growth ◽  
Cobalt Film ◽  
Layer Graphene

Photoelectron Spectroscopic Imaging and Device Applications of Large-Area Patternable Single-Layer MoS2Synthesized by Chemical Vapor Deposition

ACS Nano ◽  
2014 ◽  
Vol 8 (5) ◽  
pp. 4961-4968 ◽  
Author(s):  
Woanseo Park ◽  
Jaeyoon Baik ◽  
Tae-Young Kim ◽  
Kyungjune Cho ◽  
Woong-Ki Hong ◽  
...  
Keyword(s):  
Chemical Vapor Deposition ◽  
Vapor Deposition ◽  
Single Layer ◽  
Chemical Vapor ◽  
Spectroscopic Imaging ◽  
Large Area ◽  
Device Applications

scholarly journals Atmospheric Pressure Catalytic Vapor Deposition of Graphene on Liquid Sn and Cu–Sn Alloy Substrates

Nanomaterials ◽  
2020 ◽  
Vol 10 (11) ◽  
pp. 2150
Author(s):  
Maryam A. Saeed ◽  
Ian A. Kinloch ◽  
Brian Derby
Keyword(s):  
Vapor Deposition ◽  
Atmospheric Pressure ◽  
Defect Density ◽  
Chemical Vapor ◽  
Hydrogen Solubility ◽  
Monolayer Graphene ◽  
High Catalytic Activity ◽  
Graphene Growth ◽  
Hydrogen Flow

The chemical vapor deposition (CVD) of graphene on liquid substrates produces high quality graphene films due to the defect-free and atomically flat surfaces of the liquids. Through the detailed study of graphene growth on liquid Sn using atmospheric pressure CVD (APCVD), the quality of graphene has been found to have a close relationship with hydrogen flow rate that reflects on hydrogen partial pressure inside the reactor (PH2) and hydrogen solubility of the growth substrates. The role of PH2 was found to be crucial, with a low defect density monolayer graphene being obtained in low PH2 (90.4 mbar), while partial graphene coverage occurred at high PH2 (137.3 mbar). To further understand the role of substrate’s composition, binary alloy with compositions of 20, 30, 50, 60 and 80 wt.% tin in copper were made by arc-melting. Graphene quality was found to decrease with increasing the content of copper in the Cu–Sn alloys when grown using the conditions optimised for Sn substrates and this was related to the change in hydrogen solubility and the high catalytic activity of Cu compared to Sn. This shall provide a tool to help optimising CVD conditions for graphene growth based on the properties of the used catalytic substrate.

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