Review of Chemical Vapor Deposition of Graphene and Related Applications
Department of Electrical Engineering, ‡Department of Chemistry, and §Department of Chemical Engineering and Materials Science, University of Southern California , Los Angeles, California 90089, United States.Accounts of Chemical Research (Impact Factor: 22.32). 03/2013; 46(10). DOI: 10.1021/ar300203n
Since its debut in 2004, graphene has attracted enormous interest because of its unique properties. Chemical vapor deposition (CVD) has emerged as an important method for the preparation and production of graphene for various applications since the method was first reported in 2008/2009. In this Account, we review graphene CVD on various metal substrates with an emphasis on Ni and Cu. In addition, we discuss important and representative applications of graphene formed by CVD, including as flexible transparent conductors for organic photovoltaic cells and in field effect transistors. Growth on polycrystalline Ni films leads to both monolayer and few-layer graphene with multiple layers because of the grain boundaries on Ni films. We can greatly increase the percentage of monolayer graphene by using single-crystalline Ni(111) substrates, which have smooth surface and no grain boundaries. Due to the extremely low solubility of carbon in Cu, Cu has emerged as an even better catalyst for the growth of monolayer graphene with a high percentage of single layers. The growth of graphene on Cu is a surface reaction. As a result, only one layer of graphene can form on a Cu surface, in contrast with Ni, where more than one layer can form through carbon segregation and precipitation. We also describe a method for transferring graphene sheets from the metal using polymethyl methacrylate (PMMA). CVD graphene has electronic properties that are potentially valuable in a number of applications. For example, few-layer graphene grown on Ni can function as flexible transparent conductive electrodes for organic photovoltaic cells. In addition, because we can synthesize large-grain graphene on Cu foil, such large-grain graphene has electronic properties suitable for use in field effect transistors.
[Show abstract] [Hide abstract]
- "Graphene is being used in electronics, graphene-based transistors, graphene photonics and optoelectronics, energy production and storage, and biosensors. Various production methods have also been developed to accommodate the need for graphene synthesis with fine-tuned properties for such diverse applications, including mechanical exfoliation, epitaxial growth on silicon carbide (SiC), chemical exfoliation, and chemical vapor deposition (CVD) (Zhang et al., 2013). "
ABSTRACT: Graphene, a two dimensional engineered nanomaterial, is now being used in many applications, such as electronics, biological engineering, filtration, lightweight and strong nanocomposite materials, and energy storage. However, there is a lack of information on the potential health effects of graphene in humans based on inhalation, the primary ENM exposure pathway in workplaces. Thus, an inhalation toxicology study of graphene was conducted using a nose-only inhalation system for 28 days (6 hrs/day and 5 days/week) with male Sprague-Dawley (SD) rats that were then allowed to recover for 1, 28, and 90 days post-exposure period. Animals were separated into 4 groups (control, low, moderate, and high) with 15 male rats (5 rats per time point) in each group. The measured mass concentrations for the low, moderate, and high exposure groups were 0.12, 0.47, and 1.88 mg/m(3), respectively, very close to target concentrations of 0.125, 0.5, and 2 mg/m(3). Airborne graphene exposure was monitored using several real-time instrumentation over 10 nm to 20µm for size distribution and number concentration. The total and respirable elemental carbon (EC) concentrations were also measured using filter sampling. Graphene in the air and biological media was traced using transmission electron microscopy. In addition to mortality and clinical observations, the body weights and food consumption were recorded weekly. At the end of the study, the rats were subjected to a full necropsy, blood samples were collected for blood biochemical tests, and the organ weights were measured. No dose-dependent effects were recorded for the body weights, organ weights, BAL fluid inflammatory markers, and blood biochemical parameters at 1-day post-exposure and 28-days post-exposure. The inhaled graphenes were mostly ingested by macrophages. No distinct lung pathology was observed at the 1-, 28- and 90-days post-exposure. The inhaled graphene was translocated to lung lymph nodes. The results of this 28-day graphene inhalation study suggest low toxicity and a NOAEL of no less than 1.88 mg/m(3).
[Show abstract] [Hide abstract]
- "The polymer/graphene film is then washed and transferred to the desired substrate followed by thermal annealing for better adhesion of graphene to the new substrate. At the end, the polymer is dissolved using different organic solvents such as acetone leaving the graphene clinging to the desired substrate  . However, the chemical etching transfer methods suffer from process-specific drawbacks, as the method itself is sensitive to the adhesion forces between different interfaces, chemical etchants http://dx.doi.org/10.1016/j.apsusc.2015.11.265 0169-4332/© 2015 Elsevier B.V. All rights reserved. "
ABSTRACT: Graphene transfer is a procedure of paramount importance for the production of graphene-based electronic devices. The transfer procedure can affect the electronic properties of the transferred graphene and can be detrimental for possible applications both due to procedure induced defects which can appear and due to scalability of the method. Hence, it is important to investigate new transfer methods for graphene that are less time consuming and show great promise. In the present study we propose an efficient, etching-free transfer method that consists in applying a thin polyvinyl alcohol layer on top of the CVD grown graphene on Cu and then peeling-off the graphene onto the polyvinyl alcohol film. We investigate the quality of the transferred graphene before and after the transfer, using Raman spectroscopy and imaging as well as optical and atomic force microscopy techniques. This simple transfer method is scalable and can lead to complete transfer of graphene onto flexible and transparent polymer support films without affecting the quality of the graphene during the transfer procedure.
- "The thickness and quality of graphene films can be determined by Raman spectroscopy that is a very convenient tool to probe the electron-phonon and phonon-phonon couplings in graphene samples  . Raman characterization of CVD graphene can be performed directly on Cu but due to detrimental background effect from a Cu substrate and grapheneesubstrate interaction, the measurements are more often performed after the transfer of graphene to the Si/SiO 2 substrate    . Compared to Cu, the Ni substrates show higher catalytic activity and more efficiently contribute to dissociation of the carbon precursors and formation of the graphitic crystal lattice at high temperatures (review in Ref. ). "
Data provided are for informational purposes only. Although carefully collected, accuracy cannot be guaranteed. The impact factor represents a rough estimation of the journal's impact factor and does not reflect the actual current impact factor. Publisher conditions are provided by RoMEO. Differing provisions from the publisher's actual policy or licence agreement may be applicable.