Novel surface chemical synthesis route for large area graphene-on-insulator films

Raghavan, S.; Denig, Tobias; Nelson, Timothy C.; Stinespring, C. D.

doi:10.1116/1.4710997

Cited by 13 publications

(19 citation statements)

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“…[13] Members of our research team have recently reported an ovel methodf or synthesis of epitaxial graphene films that involves halogen-based plasma etchingo fS iC followed by ultrahigh vacuum annealing. [14] This produces single and multilayer graphene films with ah alogenated defect whose concentration can be controlled by the annealing temperature. Using nuclear magnetic resonance( NMR) and X-ray photoelectron spectroscopy (XPS), Ito and co-workers [15] have identified asimilar defecti nf luorine-graphite intercalation compounds (F-GICs).…”

Section: Introductionmentioning

confidence: 99%

Electronic Structures, Bonding Configurations, and Band‐Gap‐Opening Properties of Graphene Binding with Low‐Concentration Fluorine

2015

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To better understand the effects of low-level fluorine in graphene-based sensors, first-principles density functional theory (DFT) with van der Waals dispersion interactions has been employed to investigate the structure and impact of fluorine defects on the electrical properties of single-layer graphene films. The results show that both graphite-2 H and graphene have zero band gaps. When fluorine bonds to a carbon atom, the carbon atom is pulled slightly above the graphene plane, creating what is referred to as a CF defect. The lowest-binding energy state is found to correspond to two CF defects on nearest neighbor sites, with one fluorine above the carbon plane and the other below the plane. Overall this has the effect of buckling the graphene. The results further show that the addition of fluorine to graphene leads to the formation of an energy band (BF) near the Fermi level, contributed mainly from the 2p orbitals of fluorine with a small contribution from the p orbitals of the carbon. Among the 11 binding configurations studied, our results show that only in two cases does the BF serve as a conduction band and open a band gap of 0.37 eV and 0.24 eV respectively. The binding energy decreases with decreasing fluorine concentration due to the interaction between neighboring fluorine atoms. The obtained results are useful for sensor development and nanoelectronics.

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Section: Introductionmentioning

confidence: 99%

Electronic Structures, Bonding Configurations, and Band‐Gap‐Opening Properties of Graphene Binding with Low‐Concentration Fluorine

2015

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“…High temperature processes are required to remove the residues. 4 Epitaxial growth on SiC 5 by the sublimation of Si atoms at high temperatures and high vacuum or by etching 6 on the other hand leads to better quality of graphene, but involves high costs in synthesis and subsequent transferring 7 of graphene to desired substrates. 8 Uniform epitaxial graphene layers can be deposited over large areas covered with catalytic metal layers, such as Ni, Pt, Ru, Ir, Cu, and Co, or metal carbides by chemical vapor deposition 9,10 of hydrocarbons as well as pulsed laser deposition 11 (PLD) using suitable targets, such as highly ordered pyrolytic graphite (HOPG).…”

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confidence: 99%

Ultraviolet laser deposition of graphene thin films without catalytic layers

Kumar

Alshareef

2013

Applied Physics Letters

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In this letter, the formation of nanostructured graphene by ultraviolet laser ablation of a highly ordered pyrolytic graphite target under optimized conditions is demonstrated, without a catalytic layer, and a model for the growth process is proposed. Previously, graphene film deposition by low-energy laser (2.3 eV) was explained by photo-thermal models, which implied that graphene films cannot be deposited by laser energies higher than the C-C bond energy in highly ordered pyrolytic graphite (3.7 eV). Here, we show that nanostructured graphene films can in fact be deposited using ultraviolet laser (5 eV) directly over different substrates, without a catalytic layer. The formation of graphene is explained by bond-breaking assisted by photoelectronic excitation leading to formation of carbon clusters at the target and annealing out of defects at the substrate.

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“…Following this approach, single, bi and trilayer films produced here were observed to have electrical resistivity values in the range of 1.6-6.4 µΩ-cm. The conductivity values for samples produced using Cl2-based plasma were in the same range [46]. Overall, these values are comparable to those reported by Murali and coworkers for exfoliated graphene nanoribbons [111].…”

Section: Electrical Characterizationsupporting

confidence: 87%

“…Raghavan et al studied graphene synthesis by using inductively coupled plasma-reactive ion etching (ICP-RIE) with the halogen based gases like Cl2 and CF4 [46]. Silicon was selectively removed from 6H-SiC substrate using halogen gases to produce a carbon rich layer on the substrate.…”

Section: Reactive Ion Etchingmentioning

confidence: 99%

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Development of Graphene and Graphene-Nanoparticle Composites for Sensor Applications

Chaudhari¹

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Development of Graphene and Graphene-Nanoparticle Composites for Sensor Applications Saurabh Chaudhari The goal of this research was the synthesis of graphene and graphene nanocomposite for use as sensor materials. This dissertation describes the optimization of a novel approach to the synthesis of few layer graphene films on SiC, the modification of the graphene surface by wet chemical methods, the nucleation of nanoparticles to form graphene-nanoparticle composites, the fabrication of chemoresistive sensor structures from these materials, and the characterization of these surfaces and films. In this work, the basic graphene synthesis method which uses halogen based plasma etching and ultra-high vacuum annealing (UHVA), has been optimized to reliably produce one, two, and three layer graphene on SiC films. The process has also been extended by replacing the UHVA step with rapid thermal annealing (RTA) in atmospheric pressure argon. Graphene films produced by both methods have been characterized using x-ray photoelectron spectroscopy (XPS), Raman microscopy, and atomic force microscopy (AFM). The UHVA process produces films with halogen-based and possibly some oxygenbased defects, whereas the RTA processes produces exclusively oxygen-based defects which include epoxide, hydroxyl, and carbonyl groups similar to, but at much lower levels, than that observed for graphene oxide (GO). As in the case for GO, the defect density was further reduced by wet chemical surface modification. Nanoparticles (Ag, Au, Pt, Ir) were attached to these surfaces using solution based methods. The particle diameter and height distributions along with surface coverage were characterized using AFM methods. Key parameters in these studies included solution composition and incubation time. For electrical characterization and sensor testing, two structures were then fabricated using lithography free methods and electron beam evaporation. The first of these structures, referred to as the transmission line method (TLM) structure, was used in the present work for electrical characterization. Using the TLM structure, the electrical properties were characterized using two and four point probe methods. The films exhibited semiconducting behavior which is believed to be due to the opening of a band gap by the halogen-and oxygen-based defects. Using the two and four pint methods, the Schottky barrier height, the carrier density, electrical resistivity, and the carrier mobility were determined. The electrical resistivity was found to have an inverse relationship with number of graphene layers for one, two, and three layer films. The second device structure was a simple interdigitated sensor structure which was passed on to

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Novel surface chemical synthesis route for large area graphene-on-insulator films

Abstract: Articles you may be interested inLocal solid phase growth of few-layer graphene on silicon carbide from nickel silicide supersaturated with carbon

Cited by 13 publications

References 28 publications

Electronic Structures, Bonding Configurations, and Band‐Gap‐Opening Properties of Graphene Binding with Low‐Concentration Fluorine

Electronic Structures, Bonding Configurations, and Band‐Gap‐Opening Properties of Graphene Binding with Low‐Concentration Fluorine

Ultraviolet laser deposition of graphene thin films without catalytic layers

Development of Graphene and Graphene-Nanoparticle Composites for Sensor Applications

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