Graphene production techniques

A rapidly increasing list of graphene production techniques have been developed to enable graphene's use in commercial applications [1].

Isolated 2D crystals cannot be grown via chemical synthesis beyond small sizes even in principle, because the rapid growth of phonon density with increasing lateral size forces 2D crystallites to bend into the third dimension.[2] However, other routes to 2d materials exist:

Fundamental forces place seemingly insurmountable barriers in the way of creating [2D crystals]... The nascent 2D crystallites try to minimize their surface energy and inevitably morph into one of the rich variety of stable 3D structures that occur in soot. But there is a way around the problem. Interactions with 3D structures stabilize 2D crystals during growth. So one can make 2D crystals sandwiched between or placed on top of the atomic planes of a bulk crystal. In that respect, graphene already exists within graphite... One can then hope to fool Nature and extract single-atom-thick crystallites at a low enough temperature that they remain in the quenched state prescribed by the original higher-temperature 3D growth.[3]

The early approaches of cleaving multi-layer graphite into single layers or growing it epitaxially by depositing a layer of carbon onto another material have been supplemented by numerous alternatives. In all cases, the graphite must bond to some substrate to retain its 2d shape.[2]

Exfoliation

As of 2014 exfoliation produced graphene with the lowest number of defects and highest electron mobility.[4]

Adhesive tape

Andre Geim and Konstantin Novoselov initially used adhesive tape to split graphite into graphene. Achieving single layers typically requires multiple exfoliation steps, each producing a slice with fewer layers, until only one remains. After exfoliation the flakes are deposited on a silicon wafer. Crystallites larger than 1 mm and visible to the naked eye can be obtained.[3]

Wedge-based

In this method, a sharp single-crystal diamond wedge penetrates onto the graphite source to exfoliate layers.[5] This method uses highly ordered pyrolytic graphite (HOPG) as the starting material. The experiments were supported by molecular dynamic simulations.[6]

Graphite oxide reduction

P. Boehm reported producing monolayer flakes of reduced graphene oxide in 1962.[7][8] Rapid heating of graphite oxide and exfoliation yields highly dispersed carbon powder with a few percent of graphene flakes. Reduction of graphite oxide monolayer films, e.g. by hydrazine with annealing in argon/hydrogen also yielded graphene films. Later the oxidation protocol was enhanced to yield graphene oxide with an almost intact carbon framework that allows efficient removal of functional groups, neither of which was originally possible. The measured charge carrier mobility exceeded 1,000 centimetres (393.70 in)/Vs.[9] Spectroscopic analysis of reduced graphene oxide has been conducted.[10][11]

Shearing

In 2014 defect-free, unoxidized graphene-containing liquids were made from graphite using mixers that produce local shear rates greater than 10×104. The method was claimed to be applicable to other 2D materials, including boron nitride, Molybdenum disulfide and other layered crystals.[12][13]

Sonication

Solvent-aided

Dispersing graphite in a proper liquid medium can produce graphene by sonication. Graphene is separated from graphite by centrifugation,[14] producing graphene concentrations initially up to 0.01 mg/ml in N-methylpyrrolidone (NMP) and later to 2.1 mg/ml in NMP,.[15] Using a suitable ionic liquid as the dispersing liquid medium produced concentrations of 5.33 mg/ml.[16] Graphene concentration produced by this method is very low, because nothing prevents the sheets from restacking due to van der Waals forces. The maximum concentrations achieved are the points at which the van der Waals forces overcome the interactive forces between the graphene sheets and the solvent molecules.

Adding a surfactant to a solvent prior to sonication prevents restacking by adsorbing to the graphene's surface. This produces a higher graphene concentration, but removing the surfactant requires chemical treatments.

Immiscible liquids

Sonicating graphite at the interface of two immiscible liquids, most notably heptane and water, produced macro-scale graphene films. The graphene sheets are adsorbed to the high energy interface between the heptane and the water, where they are kept from restacking. The graphene remained at the interface even when exposed to force in excess of 300,000 g. The solvents may then be evaporated. The sheets are up to ~95% transparent and conductive.[17]

Molten salts

Graphite particles can be corroded in molten salts to form a variety of carbon nanostructures including graphene.[18] Hydrogen cations, dissolved in molten Lithium chloride, can be discharged on cathodically polarized graphite rods, which then intercalate into the graphite structure, peeling graphite to produce graphene. The graphene nanosheets produced displayed a single-crystalline structure with a lateral size of several hundred nanometers and a high degree of crystallinity and thermal stability.[19]

Electrochemical synthesis

Electrochemical synthesis can exfoliate graphene. Varying a pulsed voltage controls thickness, flake area, number of defects and affects its properties. The process begins by bathing the graphite in a solvent for intercalation. The process can be tracked by monitoring the solution’s transparency with an LED and photodiode.[20][21]

Hydrothermal self-assembly

Graphene has been prepared by using a sugar (e.g. glucose, fructose, etc.) This substrate-free "bottom-up" synthesis is safer, simpler and more environmentally friendly than exfoliation. The method can control thickness, ranging from monolayer to multilayers.[22]

Epitaxy

Epitaxy refers to the deposition of a crystalline overlayer on a crystalline substrate, where there is registry between the two. In some cases epitaxial graphene layers are coupled to surfaces weakly enough (by Van der Waals forces) to retain the two dimensional electronic band structure of isolated graphene.[23][24] An example of this weak coupling is epitaxial graphene on SiC[25] and on Pt(111).[26] On the other hand, the epitaxial graphene layer on some metals can be strongly bonded to the surface with covalent bonds. The properties of the covalently bonded graphene can differ from the ones of free-standing graphene.[27] An example of this strong coupling is epitaxial graphene on Ru(0001).[28] However, the coupling is strong only for the first graphene layer on Ru(0001): the second layer is more weakly coupled to the first layer and has already properties very close to the free standing graphene.

Chemical vapor deposition

Chemical vapor deposition (CVD) is a common form of epitaxy. The process of deposition of solid material onto a heated substrate through decomposition or chemical reaction of compounds contained in the gas passing over the substrate is called chemical vapor deposition. The reactants, generally in the gaseous or vapor phase, react on or near the surface of the substrates, which are at some elevated temperature. The subsequent reaction results in the deposition of atoms or molecules on the entire substrate surface. CVD processes are also widely used for growing epitaxial layers such as a silicon epitaxial layer on a single-crystal silicon substrate (homoepitaxy or commonly referred to as epitaxy) or epitaxial layer deposition on a sapphire (Heteroepitaxy).[29][30] A special method in CVD, called Epitaxy or Epitaxial Layer Deposition or Vapor-Phase Epitaxy (VPE), has only a single-crystal form as the deposited layer. This process is usually carried out for certain combinations of substrate and layer materials and under special deposition conditions.

Epitaxy of graphene

Epitaxial graphene films can be grown on various crystalline surfaces. The atomic lattice of the substrate facilitate in orientationally registering the carbon atoms of the graphene layer. The chemical interaction of the graphene with the substrate can vary from weak to strong. This also modifies the properties of the graphene layer. The need for epitaxial graphene arises from the challenges of incorporating carbon nanotubes in large-scale integrated electronic architectures. Research on 2D graphene was thus initiated by experiments on epitaxially grown graphene on single crystal silicon carbide. While significant control has been in growing and characterizing epitaxial graphene, challenges remain in being able to fully exploit the potential of these structures. The promise lies in the hope that charge carriers on these graphene structures, like carbon nanotubes, remain ballistic. If so, it could revolutionize the world of electronics.[31]

Silicon carbide

Heating silicon carbide (SiC) to high temperatures (>1100 °C) under low pressures (~10−6 torr) reduces it to graphene.[32] This process produces epitaxial graphene with dimensions dependent upon the size of the wafer. The polarity of the SiC used for graphene formation, silicon- or carbon-polar, highly influences the thickness, mobility and carrier density.

Graphene's electronic band-structure (so-called Dirac cone structure) was first visualized in this material.[33][34][35] Weak anti-localization is observed in this material, but not in exfoliated graphene produced by the drawing method.[36] Large, temperature-independent mobilities approach those in exfoliated graphene placed on silicon oxide, but lower than mobilities in suspended graphene produced by the drawing method. Even without transfer, graphene on SiC exhibits massless Dirac fermions.[37][38][39][40][41][42][43] The graphene–substrate interaction can be further passivated.[44]

The weak van der Waals force that coheres multilayer stacks does not always affect the individual layers' electronic properties. That is, while the electronic properties of certain multilayered epitaxial graphenes are identical to that of a single layer,[45] other properties are affected,[33][34] as they are in bulk graphite. This effect is well understood theoretically and is related to the symmetry of the interlayer interactions.[45]

Epitaxial graphene on SiC can be patterned using standard microelectronics methods. A band gap can be created and tuned by laser irradiation.[46]

Silicon/germanium/hydrogen

A normal silicon wafer coated with a layer of germanium (Ge) dipped in dilute hydrofluoric acid strips the naturally forming germanium oxide groups, creating hydrogen-terminated germanium. Chemical vapor deposition deposits a layer of graphene on top. The graphene can be peeled from the wafer using a dry process and is then ready for use. The wafer can be reused. The graphene is wrinkle-free, high quality and low in defects.[47][48]

Metal single crystal substrates

Metal single crystals are often used as substrates in graphene growth since they form a smooth and chemically uniform growth platform for graphene. Especially, the chemical uniformity is an important advantage of metal single crystal surfaces: for example in different oxide surfaces the oxidized component and the oxygen forms very different adsorption sites. A typical metal single crystal substrate surface is hexagonal close-packed surface since this geometry is also the geometry of carbon atoms in a graphene layer. Common surfaces that have hexagonal close packed geometry are for example FCC(111) and HCP(0001) surfaces. Of course, the similar surface geometries alone do not ensure perfect graphene adsorption on the surface since the distances between surface metal atoms and carbon atoms can be different, resulting in moiré patterns. Common metal surfaces for graphene growth are Pt(111), Ir(111), Ni(111), Ru(0001), Co(0001) and Cu(111)[29] but also at least Fe(110), Au(111), Pd(111), Re(101͊0) and Rh(111) have been used.[49]

Preparation methods of metal single crystal substrates

There are several methods how good quality metal single crystal substrates can be manufactured. Czochralski and Bridgman–Stockbarger methods are common industrial methods for bulk metal crystal manufacturing. In these methods, the metal is first melted, after which the metal is let to crystallize around a seed crystal. After crystallization, the crystal is cut into wafers. Other commonly used method especially in research is epitaxy, which enables the growth of numerous different metal single crystal surfaces on some commonly available single crystals like monocrystalline silicon.[50] The advantage of epitaxy over the industrial methods is its low material consumption: with epitaxy substrates with thickness in nanometer scale can be manufactured in comparison to complete self-supporting wafers. This is especially important with rare and expensive metals like rhenium and gold.

Ruthenium(0001)

Graphene can be grown on ruthenium(0001) surface with CVD, temperature programmed growth (TPG) or segregation.[49] In CVD, a hot ruthenium surface is exposed for some carbon containing molecule like methane or ethene. This results in graphene formation. It has been observed that the graphene can grow only “downhill” of the ruthenium surface steps, not uphill.[28] Graphene bonds strongly with covalent bonds to the surface and has only 1.45 Å separation to the surface.[28] This affects the electronic structure of the graphene layer, and the layer behaves differently than a free-standing graphene layer. However, the CVD graphene growth on ruthenium is not totally self-terminating and multilayer graphene formation is possible. The second and higher layers cannot bond to the existing graphene layers as strongly as the first layer bonds to the metal surface, which results in higher 3 Å separation between the graphene layers. The second layer thus has much weaker interaction with the substrate and has very similar electronic properties as free-standing graphene. Due to the strong bonding of graphene on the ruthenium surface, only R0 orientation is observed for graphene layer. Although, different studies have shown different lengths for the moiré repeat distance, varying around Graphene(11 x 11) and Ru(10 x 10).[49][51][52][53] The moiré pattern also causes strong corrugation for the graphene layer, peak height being as much as 1.5 Å.[54]

Iridium(111)

Graphene is commonly deposited on iridium(111) by CVD but also with temperature programmed growth (TPG) is possible.[55] In CVD, a hot iridium surface is exposed to ethylene. Ethylene decomposes on the surface due to pyrolysis, and the formed carbon adsorbs to the surface forming a graphene monolayer. Thus, only a monolayer growth is possible.[56] The formed graphene layer is weakly bounded to the iridium substrate and is located about 3.3 Å above the surface.[57] The graphene layer and the Ir(111) substrate also forms a moiré pattern with period around 25 Å,[49][57] depending on the orientation of the graphene on Ir(111). There are many different possibilities for the graphene layer orientation, the most common ones being R0 and R30.[49] The graphene layer has also corrugation due to the moiré pattern, with height varying from 0.04 Å to 0.3 Å.[49] Due to the long-range order of these ripples, minigaps in the electronic band-structure (Dirac cone) become visible.[58]

Platinum(111)

Graphene sheets have been reported to be grown by dosing ethylene onto the clean, single platinum(111) substrate at temperatures above 1000 °C in ultra-high vacuum (UHV).[26][29][59][60] Graphene monolayer interacts weakly with the Pt(111) surface below it confirmed by the local density of states which is a ‘V’ shape.[26] Kim et al., reported the electronic properties of the graphene nanoislands whose geometry is affected by varying the annealing temperatures and providing a fundamental understanding on graphene growth.[29] The effect of annealing on the average size and density of graphene islands grown on Pt(111) has been widely studied.[60][29] Sutter et al., reported a thermal-stress driven wrinkle propagation on the graphene sheet as observed from low-energy electron microscopy during cooling after growth.[59] The onset of lattice mismatch precedes the observation of moiré patterns with small (e.g., (3x3)G) and large unit cells (e.g., (8x8)G).[59]

Nickel(111)

High-quality sheets of few-layer graphene exceeding 1 cm2 (0.2 sq in) in area have been synthesized via CVD on thin nickel films using multiple techniques. First the film is exposed to argon gas at 900–1000 degrees Celsius. Methane is then mixed into the gas, and the methane's disassociated carbon is absorbed into the film. The solution is then cooled and the carbon diffuses out of the nickel to form graphene films.[37][61][62][63] CVD grown graphene on Ni(111) surface forms (1 x 1) structure, i.e. the lattice constants of Ni and graphene matches and no moiré pattern is formed. There are still different possible adsorption sites for carbon atoms on nickel, at least top, hcp hollow, fcc hollow and bridge sites have been reported [17].[64][65]

Another method used temperatures compatible with conventional CMOS processing, using a nickel-based alloy with a gold catalyst.[66] This process dissolves carbon atoms inside a transition metal melt at a certain temperature and then precipitates the dissolved carbon at lower temperatures as single layer graphene (SLG).

The metal is first melted in contact with a carbon source, possibly a graphite crucible inside which the melt is carried out or graphite powder/chunks that are placed in the melt. Keeping the melt in contact with the carbon at a specific temperature dissolves the carbon atoms, saturating the melt based on the metal–carbon binary phase diagram. Lowering the temperature decreases carbon's solubility and the excess carbon precipitates onto the melt. The floating layer can be either skimmed or frozen for later removal.

Using different morphology, including thick graphite, few layer graphene (FLG) and SLG were observed on metal substrate. Raman spectroscopy proved that SLG had grown on nickel substrate. The SLG Raman spectrum featured no D and D′ band, indicating its pristine nature. Since nickel is not Raman active, direct Raman spectroscopy of graphene layers on top of the nickel is achievable.[67]

Another approach covered a sheet of silicon dioxide glass (the substrate) on one side with a nickel film. Graphene deposited via chemical vapor deposition formed into layers on both sides of the film, one on the exposed top side, and one on the underside, sandwiched between nickel and glass. Peeling the nickel and the top layer of graphene left an intervening layer of graphene on the glass. While the top graphene layer could be harvested from the foil as in earlier methods, the bottom layer was already in place on the glass. The quality and purity of the attached layer was not assessed.[68]

Cobalt(0001)

Graphene on cobalt(0001) is grown similarly as on a Ni substrate.[69] A Co(0001) film is first grown on a wolfram(110) substrate, following which chemical vapor deposition of propylene at 450 °C enables graphene growth on Co(0001).[70] This results in a p(1x1) structure along with structures that indicated domains of graphene slightly rotated with respect to the Co lattice.[70] Graphene structures grown on Co(0001) are found to be identical to those grown on Ni(111) upon structural and electronic characterization.[70] Co(0001) is ferromagnetic but the graphene monolayer grown over was found to not diminish the spin polarization.[70] Unlike its Ni(111) counterpart, graphene grown on Co(0001) does not show the Rashba effect.

Copper

Copper foil, at room temperature and very low pressure and in the presence of small amounts of methane produces high quality graphene. The growth automatically stops after a single layer forms. Arbitrarily large films can be created.[62][71] The single layer growth is due to the low concentration of carbon in methane. The process is surface-based rather than relying on absorption into the metal and then diffusion of carbon into graphene layers on the surface.[72] The room temperature process eliminates the need for postproduction steps and reduces production from a ten-hour/nine- to ten-step procedure to a single step that takes five minutes. A chemical reaction between the hydrogen plasma formed from the methane and ordinary air molecules in the chamber generates cyano radicals—carbon–nitrogen molecules without electrons. These charged molecules scour away surface imperfections, providing a pristine substrate. The graphene deposits form lines that merge into each other, forming a seamless sheet that contributes to mechanical and electrical integrity.[73]

Larger hydrocarbons such as ethane and propane produce bilayer coatings.[74] Atmospheric pressure CVD growth produces multilayer graphene on copper (similar to nickel).[75]

The material has fewer defects, which in higher temperature processes result from thermal expansion/contraction.[73] Ballistic transport was observed in the resulting material.[76]

Tin

Tin has been recently used for synthesis of graphene at 250°C. Low-temperature as well as the transfer free graphene growth on substrates is the major concern of graphene research for its practical applications. The transfer free graphene growth on SiO2 covered Si (SiO2/Si) substrate at 250 °C based on a solid-liquid-solid reaction has been achieved by tin.[77]

Sodium ethoxide pyrolysis

Gram-quantities were produced by the reduction of ethanol by sodium metal, followed by pyrolysis of the ethoxide product and washing with water to remove sodium salts.[78]

Roll-to-roll

Large scale roll-to-roll production of graphene based on chemical vapor deposition, was first demonstrated in 2010.[79] In 2014 a two-step roll-to-roll manufacturing process was announced. The first roll-to-roll step produces the graphene via chemical vapor deposition, and the second step binds the graphene to a substrate.[80][81] In 2018, researchers at MIT refined the roll-to-roll process, creating a promising way to produce large amounts of graphene.[82]

Cold wall

Growing graphene in an industrial resistive-heating cold wall CVD system was claimed to produce graphene 100 times faster than conventional CVD systems, cuts costs by 99 percent and produce material with enhanced electronic qualities.[83][84]

Cold wall CVD technique can be used to study the underlying surface science involved in graphene nucleation and growth as it allows unprecedented control of process parameters like gas flow rates, temperature and pressure as demonstrated in a recent study. The study was carried out in a home-built vertical cold wall system utilizing resistive heating by passing direct current through the substrate. It provided conclusive insight into a typical surface-mediated nucleation and growth mechanism involved in two-dimensional materials grown using catalytic CVD under conditions sought out in the semiconductor industry.[85][86]

Nanotube slicing

Graphene can be created by cutting open carbon nanotubes.[87] In one such method multi-walled carbon nanotubes are cut open in solution by action of potassium permanganate and sulfuric acid.[88] In another method graphene nanoribbons were produced by plasma etching of nanotubes partly embedded in a polymer film.[89]

Langmuir-Blodgett (LB)

In applications where the thickness and packing density of graphene layer needs to carefully controlled, the Langmuir-Blodgett method has been used.[90] In addition to forming directly a layer of graphene, another approach that has been widely studied is forming a graphene oxide layer which can then be reduced further into graphene.[91][92][93]

Some of the benefits of LB deposition include an accurate control over the layered architecture of the graphene, the layer-by-layer deposition process is amenable to assembling any combination of thin carbon layers on a substrates, the assembly process operates at room temperature and produces high throughputs while it is amenable to automation and mass production.[94]

Carbon dioxide reduction

A highly exothermic reaction combusts magnesium in an oxidation–reduction reaction with carbon dioxide, producing a variety of carbon nanoparticles including graphene and fullerenes. The carbon dioxide reactant may be either solid (dry-ice) or gaseous. The products of this reaction are carbon and magnesium oxide. US patent 8377408 was issued for this process.[95]

Spin coating

In 2014, carbon nanotube-reinforced graphene was made via spin coating and annealing functionalized carbon nanotubes. The resulting material was stronger, flexible and more conductive than conventional graphene.[96]

Supersonic spray

Supersonic acceleration of droplets through a Laval nozzle was used to deposit small droplets of reduced graphene-oxide in suspension on a substrate. The droplets disperse evenly, evaporate rapidly and display reduced flake aggregations. In addition, the topological defects (Stone-Wales defect and C
2 vacancies) originally in the flakes disappeared. The result was a higher quality graphene layer. The energy of the impact stretches the graphene and rearranges its carbon atoms into flawless hexagonal graphene with no need for post-treatment.[97][98] The high amount of energy also allows the graphene droplets to heal any defects in the graphene layer that occur during this process.[99]

Another approach sprays buckyballs at supersonic speeds onto a substrate. The balls cracked open upon impact, and the resulting unzipped cages then bond together to form a graphene film. The buckyballs are released into a helium or hydrogen gas, which expands at supersonic speeds, carrying the carbon balls with it. The buckyballs achieve energies of around 40 keV without changing their internal dynamics. This material contains hexagons and pentagons that come from the original structures. The pentagons could introduce a band gap.[100]

Intercalation

Producing graphene via intercalation splits graphite into single layer graphene by inserting guest molecules/ions between the graphite layers. Graphite was first intercalated in 1841 using a strong oxidizing or reducing agent that damaged the material's desirable properties. Kovtyukhova developed a widely used oxidative intercalation method in 1999. In 2014, she was able to achieve intercalation using non-oxidizing Brønsted acids (phosphoric, sulfuric, dichloroacetic and alkylsulfonic acids), but without oxidizing agents. The new method has yet to achieve output sufficient for commercialization.[101][102]

Laser

In 2014 a laser-based single-step, scalable approach to graphene production was announced. The technique produced and patterned porous three-dimensional graphene film networks from commercial polymer films. The system used a CO2 infrared laser. The sp3-carbon atoms were photothermally converted to sp2-carbon atoms by pulsed laser irradiation. The result exhibits high electrical conductivity. The material can produce interdigitated electrodes for in-plane microsupercapacitors with specific capacitances of >4 mF cm−2 and power densities of ~9 mW cm−2. Laser-induced production appeared to allow roll-to-roll manufacturing processes and provides a route to electronic and energy storage devices.[103]

Applying a layer of graphite oxide film to a DVD and burning it in a DVD writer produced a thin graphene film with high electrical conductivity (1738 siemens per meter) and specific surface area (1520 square meters per gram) that was highly resistant and malleable.[104]

Microwave-assisted oxidation

In 2012, a microwave-assisted, scalable approach was reported to directly synthesize graphene with different size from graphite in one step.[105][106][107] The resulting graphene does not need any post reduction treatment as it contains very little oxygen. This approach avoids use of potassium permanganate in the reaction mixture. It was also reported that by microwave radiation assistance, graphene oxide with or without holes can be synthesized by controlling microwave time.[108] This method uses a recipe similar to Hummer's method, but uses microwave heating instead of traditional heating. Microwave heating can dramatically shorten the reaction time from days to seconds.

Ion implantation

Accelerating carbon ions under an electrical field into a semiconductor made of thin Ni films on a substrate of SiO2/Si, creates a wafer-scale (4 inches (100 mm)) wrinkle/tear/residue-free graphene layer that changes the semiconductor's physical, chemical and electrical properties. The process uses 20 keV and a dose of 1 × 1015 cm−2 at a relatively low temperature of 500 °C. This was followed by high-temperature activation annealing (600–900 °C) to form an sp2-bonded structure.[109][110]

Heated vegetable oil

Researchers heated soybean oil in a furnace for ≈30 minutes. The heat decomposed the oil into elemental carbon that deposited on nickel foil as single/few-layer graphene.[111]

Bacteria processing of graphene oxide

Graphene oxide can be converted to graphene using the bacteria Shewanella oneidensis[112][113]

Flash joule heating

(Waste) food, plastics, wood, paper, clothes and other carbon materialscan be converted to graphene by rapidly heating it to 3,000 K (2,730 °C; 4,940 °F) for 10 milliseconds.[114]

Graphene characterization techniques

Low-energy and photoemission electron microscopy

Low-energy electron microscopy (LEEM) and photoemission electron microscopy (PEEM) are techniques suited to performing dynamic observations of surfaces with nanometer resolution in a vacuum. With LEEM, it is possible to carry out low-energy electron diffraction (LEED) and micro-LEED experiments. LEED is the standard method for studying the surface structure of a crystalline material. Low-energy electrons (20–200 eV) impact the surface and elastically backscattered electrons illuminate a diffraction pattern on a fluorescent screen. The LEED method is a surface-sensitive technique as electrons have low energy and are not able to penetrate deep into the sample. For example, a micro-sized LEED revealed the presence of rotational variations of graphene on SiC substrate.[115]

Raman spectroscopy and microscopy

Raman spectroscopy can provide information about the number of layers on graphene stacks, the atomic structure of graphene edges, disorder and defects, the stacking order between different layers, the effect of strain, and charge transfer. Graphene has three main features in its Raman spectrum, called the D, G, and 2D (also called G’) modes that appear at about 1350, 1583 and 2700 cm-1.[115][116]

Scanning tunneling microscopy

In scanning tunneling microscopy (STM), a sharp tip scans the surface of a sample in a regime of such tip-sample distances that electrons can quantum tunneling from the tip to the sample surface or vice versa. STM can be performed in a constant current or a constant height mode. The low temperature STM measurements provide thermal stability, which is a requirement for high resolution imaging and spectroscopic analysis. The first atomically resolved images of graphene grown on a platinum substrate were obtained using STM in the 1990s.[115][117]

Atomic and electrostatic force microscopy

Atomic force microscopy (AFM) is mostly used to measure the force between atoms located at the sharp point of the tip (located on the cantilever) and atoms at the sample surface.[115] The bending of the cantilever as a result of the interaction between the tip and the sample is detected and converted to an electrical signal. The electrostatic force microscopy mode of AFM has been used to detect the surface potential of graphene layers as a function of thickness variation allowing for quantification of potential difference maps showing distinction between graphene layers of different thicknesses.[115][118]

Transmission electron microscopy

Transmission electron microscopy (TEM) uses electrons to generate high-resolution images as using electrons allows to overcome limitations of visible light wavelengths. TEM on graphene should be done with electron energy less than 80 keV to induce a smaller amount of defects, because this energy is the threshold electron energy for damaging a single-wall carbon nano-tube.[115][119] There are some other difficulties in the study of graphene by TEM, e.g., in a plane-view geometry (top-view graphene) the substrate causes strong electron scattering, and a thick substrate makes it impossible to detect the graphene layer. For a cross-section view, detecting a monolayer graphene is a difficult task as it needs simulation of the TEM images.[115]

Scanning electron microscopy

In scanning electron microscopy (SEM), a high-energy electron beam (ranging a few 100 eVs to a few keVs) is used to generate a variety of signals at the surface of a sample. These signals which come from the electron-sample interactions expose information about the sample, including surface morphology, crystalline structure, and chemical composition. SEM is also used for characterizations of the growth of graphene on SiC.[115][120] Because of its atomic thickness, graphene is usually detected with secondary electrons that probe only a sample surface. With SEM imaging, different contrast can be observed, such as thickness, roughness, and edge contrast; the brighter area shows the thinner part of the graphene layers.[120] The roughness contrast of a graphene layer is due to the different numbers of secondary electrons detected. The defects such as wrinkles, ruptures, and folds can be studied by different contrast in SEM images.[115]

gollark: Ah, palaiologos, ¬🐝 programming language recommendations?
gollark: It's hard to tell.
gollark: Of course, they may also get horrible and worse.
gollark: Anyway, hopefully as time goes on software development tools will get better and more expressive, we may get a non🐝 programming language, and I may actually be able to implement minoteaur!
gollark: Essentially.

See also

References
  1. Backes, Claudia; et al. (2020). "Production and processing of graphene and related materials". 2D Materials. 7 (2): 022001. Bibcode:2020TDM.....7b2001B. doi:10.1088/2053-1583/ab1e0a.
  2. Geim, A. (2009). "Graphene: Status and Prospects". Science. 324 (5934): 1530–4. arXiv:0906.3799. Bibcode:2009Sci...324.1530G. doi:10.1126/science.1158877. PMID 19541989.
  3. Geim, A. K.; MacDonald, A. H. (2007). "Graphene: Exploring carbon flatland". Physics Today. 60 (8): 35–41. Bibcode:2007PhT....60h..35G. doi:10.1063/1.2774096.
  4. Kusmartsev, F. V.; Wu, W. M.; Pierpoint, M. P.; Yung, K. C. (2014). "Application of Graphene within Optoelectronic Devices and Transistors". arXiv:1406.0809 [cond-mat.mtrl-sci].
  5. Jayasena, Buddhika; Subbiah Sathyan (2011). "A novel mechanical cleavage method for synthesizing few-layer graphenes". Nanoscale Research Letters. 6 (95): 95. Bibcode:2011NRL.....6...95J. doi:10.1186/1556-276X-6-95. PMC 3212245. PMID 21711598.
  6. Jayasena, B.; Reddy C.D; Subbiah. S (2013). "Separation, folding and shearing of graphene layers during wedge-based mechanical exfoliation". Nanotechnology. 24 (20): 205301. Bibcode:2013Nanot..24t5301J. doi:10.1088/0957-4484/24/20/205301. PMID 23598423.
  7. "Boehm's 1961 isolation of graphene". Graphene Times. 7 December 2009. Archived from the original on October 8, 2010.
  8. "Many Pioneers in Graphene Discovery". Letters to the Editor. Aps.org. January 2010.
  9. Eigler, S.; Enzelberger-Heim, M.; Grimm, S.; Hofmann, P.; Kroener, W.; Geworski, A.; Dotzer, C.; Röckert, M.; Xiao, J.; Papp, C.; Lytken, O.; Steinrück, H.-P.; Müller, P.; Hirsch, A. (2013). "Wet Chemical Synthesis of Graphene". Advanced Materials. 25 (26): 3583–3587. doi:10.1002/adma.201300155. PMID 23703794.
  10. Yamada, Y.; Yasuda, H.; Murota, K.; Nakamura, M.; Sodesawa, T.; Sato, S. (2013). "Analysis of heat-treated graphite oxide by X-ray photoelectron spectroscopy". Journal of Materials Science. 48 (23): 8171–8198. Bibcode:2013JMatS..48.8171Y. doi:10.1007/s10853-013-7630-0.
  11. Ji, L.; Xin, H. L.; Kuykendall, T. R.; Wu, S. L.; Zheng, H.; Rao, M.; Cairns, E. J.; Battaglia, V.; Zhang, Y. (2012). "SnS2 nanoparticle loaded graphene nanocomposites for superior energy storage". Physical Chemistry Chemical Physics. 14 (19): 6981–6. Bibcode:2012PCCP...14.6981J. doi:10.1039/C2CP40790F. PMID 22495542.
  12. "A new method of producing large volumes of high-quality graphene". KurzweilAI. 2 May 2014. Retrieved 3 August 2014.
  13. Paton, Keith R. (2014). "Scalable production of large quantities of defect-free few-layer graphene by shear exfoliation in liquids" (PDF). Nature Materials. 13 (6): 624–630. Bibcode:2014NatMa..13..624P. doi:10.1038/nmat3944. hdl:2262/73941. PMID 24747780.
  14. Hernandez, Y.; Nicolosi, V.; Lotya, M.; Blighe, F. M.; Sun, Z.; De, S.; McGovern, I. T.; Holland, B.; Byrne, M.; Gun'Ko, Y. K.; Boland, J. J.; Niraj, P.; Duesberg, G.; Krishnamurthy, S.; Goodhue, R.; Hutchison, J.; Scardaci, V.; Ferrari, A. C.; Coleman, J. N. (2008). "High-yield production of graphene by liquid-phase exfoliation of graphite". Nature Nanotechnology. 3 (9): 563–568. arXiv:0805.2850. Bibcode:2008NatNa...3..563H. doi:10.1038/nnano.2008.215. PMID 18772919.
  15. Alzari, V.; Nuvoli, D.; Scognamillo, S.; Piccinini, M.; Gioffredi, E.; Malucelli, G.; Marceddu, S.; Sechi, M.; Sanna, V.; Mariani, A. (2011). "Graphene-containing thermoresponsive nanocomposite hydrogels of poly(N-isopropylacrylamide) prepared by frontal polymerization". Journal of Materials Chemistry. 21 (24): 8727. doi:10.1039/C1JM11076D. S2CID 27531863.
  16. Nuvoli, D.; Valentini, L.; Alzari, V.; Scognamillo, S.; Bon, S. B.; Piccinini, M.; Illescas, J.; Mariani, A. (2011). "High concentration few-layer graphene sheets obtained by liquid phase exfoliation of graphite in ionic liquid". Journal of Materials Chemistry. 21 (10): 3428–3431. arXiv:1010.2859. doi:10.1039/C0JM02461A.
  17. Woltornist, Steven J.; Oyer, Andrew J.; Carrillo, Jan-Michael Y.; Dobrynin, Andrey V.; Adamson, Douglas H. (2013-08-27). "Conductive Thin Films of Pristine Graphene by Solvent Interface Trapping". ACS Nano. 7 (8): 7062–7066. doi:10.1021/nn402371c. ISSN 1936-0851. PMID 23879536.
  18. Kamali, A.R.; Fray, D.J. (2013). "Molten salt corrosion of graphite as a possible way to make carbon nanostructures". Carbon. 56: 121–131. doi:10.1016/j.carbon.2012.12.076.
  19. Kamali, A.R.; Fray, D.J. (2015). "Large-scale preparation of graphene by high temperature insertion of hydrogen into graphite". Nanoscale. 7 (26): 11310–11320. doi:10.1039/C5NR01132A. PMID 26053881.
  20. "How to tune graphene properties by introducing defects | KurzweilAI". www.kurzweilai.net. July 30, 2015. Retrieved 2015-10-11.
  21. Hofmann, Mario; Chiang, Wan-Yu; Nguyễn, Tuân D; Hsieh, Ya-Ping (2015-08-21). "Controlling the properties of graphene produced by electrochemical exfoliation - IOPscience". Nanotechnology. 26 (33): 335607. Bibcode:2015Nanot..26G5607H. doi:10.1088/0957-4484/26/33/335607. PMID 26221914. S2CID 206072084.
  22. Tang, L.; Li, X.; Ji, R.; Teng, K. S.; Tai, G.; Ye, J.; Wei, C.; Lau, S. P. (2012). "Bottom-up synthesis of large-scale graphene oxide nanosheets". Journal of Materials Chemistry. 22 (12): 5676. doi:10.1039/C2JM15944A. hdl:10397/15682.
  23. Gall, N. R.; Rut'Kov, E. V.; Tontegode, A. Ya. (1997). "Two Dimensional Graphite Films on Metals and Their Intercalation". International Journal of Modern Physics B. 11 (16): 1865–1911. Bibcode:1997IJMPB..11.1865G. doi:10.1142/S0217979297000976.
  24. Gall, N. R.; Rut'Kov, E. V.; Tontegode, A. Ya. (1995). "Influence of surface carbon on the formation of silicon-refractory metal interfaces". Thin Solid Films. 266 (2): 229–233. Bibcode:1995TSF...266..229G. doi:10.1016/0040-6090(95)06572-5.
  25. Novoselov, K. S.; Geim, A. K.; Morozov, S. V.; Jiang, D.; Zhang, Y.; Dubonos, S. V.; Grigorieva, I. V.; Firsov, A. A. (2004). "Electric Field Effect in Atomically Thin Carbon Films" (PDF). Science. 306 (5696): 666–669. arXiv:cond-mat/0410550. Bibcode:2004Sci...306..666N. doi:10.1126/science.1102896. PMID 15499015. Archived from the original (PDF) on October 13, 2006.
  26. Gao, M.; Pan, Y.; Huang, L.; Hu, H.; Zhang, L. Z.; Guo, H. M.; Du, S. X.; Gao, H.-J. (2011). "Epitaxial growth and structural property of graphene on Pt(111)". Applied Physics Letters. 98 (3): 033101–033104. Bibcode:2011ApPhL..98c3101G. doi:10.1063/1.3543624. S2CID 119932696.
  27. Gao, M.; Pan, Y.; Zhang, C.; Hu, H.; Yang, R.; Lu, H.; Cai, J.; Du, S.; Liu, F.; Gao, H.-J. (2010). "Tunable interfacial properties of epitaxial graphene on metal substrates". Applied Physics Letters. 96 (5): 053109–053112. Bibcode:2010ApPhL..96e3109G. doi:10.1063/1.3309671. S2CID 55445794.
  28. Sutter, P. W.; Flege, J.-I.; Sutter, E. A. (2008). "Epitaxial graphene on ruthenium". Nature Materials. 7 (5): 406–411. Bibcode:2008NatMa...7..406S. doi:10.1038/nmat2166. PMID 18391956.
  29. Batzill, M. (2012). "The surface science of graphene: Metal interfaces, CVD synthesis, nanoribbons, chemical modifications, and defects". Surface Science Reports. 67 (3–4): 83–115. Bibcode:2012SurSR..67...83B. doi:10.1016/j.surfrep.2011.12.001.
  30. Bianco, G. V.; Losurdo, M.; Giangregorio, M. M.; Sacchetti, A.; Prete, P.; Lovergine, N.; Capezzuto, P.; Bruno, G. (2015). "Direct epitaxial CVD synthesis of tungsten disulfide on epitaxial and CVD graphene". RSC Advances. 5 (119): 98700–98708. doi:10.1039/C5RA19698A.
  31. de Heer, W. A.; Berger, C. (2012). "Epitaxial graphene". Journal of Physics D: Applied Physics. 45 (15): 150301–150302. doi:10.1088/0022-3727/45/15/150301.
  32. Sutter, P. (2009). "Epitaxial graphene: How silicon leaves the scene". Nature Materials. 8 (3): 171–2. Bibcode:2009NatMa...8..171S. doi:10.1038/nmat2392. PMID 19229263.
  33. Ohta, T.; Bostwick, Aaron; McChesney, J.; Seyller, Thomas; Horn, Karsten; Rotenberg, Eli (2007). "Interlayer Interaction and Electronic Screening in Multilayer Graphene Investigated with Angle-Resolved Photoemission Spectroscopy". Physical Review Letters. 98 (20): 206802. Bibcode:2007PhRvL..98t6802O. doi:10.1103/PhysRevLett.98.206802. hdl:11858/00-001M-0000-0011-00DC-C. PMID 17677726.
  34. Bostwick, A.; Ohta, Taisuke; McChesney, Jessica L; Emtsev, Konstantin V; Seyller, Thomas; Horn, Karsten; Rotenberg, Eli (2007). "Symmetry breaking in few layer graphene films". New Journal of Physics. 9 (10): 385. arXiv:0705.3705. Bibcode:2007NJPh....9..385B. doi:10.1088/1367-2630/9/10/385.
  35. Zhou, S.Y.; Gweon, G.-H.; Graf, J.; Fedorov, A. V.; Spataru, C. D.; Diehl, R. D.; Kopelevich, Y.; Lee, D.-H.; Louie, Steven G.; Lanzara, A. (2006). "First direct observation of Dirac fermions in graphite". Nature Physics. 2 (9): 595–599. arXiv:cond-mat/0608069. Bibcode:2006NatPh...2..595Z. doi:10.1038/nphys393.
  36. Morozov, S.V.; Novoselov, K. S.; Katsnelson, M. I.; Schedin, F.; Ponomarenko, L. A.; Jiang, D.; Geim, A. K. (2006). "Strong Suppression of Weak Localization in Graphene". Physical Review Letters. 97 (1): 016801. arXiv:cond-mat/0603826. Bibcode:2006PhRvL..97a6801M. doi:10.1103/PhysRevLett.97.016801. PMID 16907394.
  37. Kim, Kuen Soo; Zhao, Y; Jang, Houk; Lee, Sang Yoon; Kim, Jong Min; Kim, Kwang S.; Ahn, Jong-Hyun; Kim, Philip; Choi, Jae-Young; Hong, Byung Hee; et al. (2009). "Large-scale pattern growth of graphene films for stretchable transparent electrodes". Nature. 457 (7230): 706–10. Bibcode:2009Natur.457..706K. doi:10.1038/nature07719. PMID 19145232.
  38. Jobst, Johannes; Waldmann, Daniel; Speck, Florian; Hirner, Roland; Maude, Duncan K.; Seyller, Thomas; Weber, Heiko B. (2009). "How Graphene-like is Epitaxial Graphene? Quantum Oscillations and Quantum Hall Effect". Physical Review B. 81 (19): 195434. arXiv:0908.1900. Bibcode:2010PhRvB..81s5434J. doi:10.1103/PhysRevB.81.195434.
  39. Shen, T.; Gu, J.J.; Xu, M; Wu, Y.Q.; Bolen, M.L.; Capano, M.A.; Engel, L.W.; Ye, P.D. (2009). "Observation of quantum-Hall effect in gated epitaxial graphene grown on SiC (0001)". Applied Physics Letters. 95 (17): 172105. arXiv:0908.3822. Bibcode:2009ApPhL..95q2105S. doi:10.1063/1.3254329.
  40. Wu, Xiaosong; Hu, Yike; Ruan, Ming; Madiomanana, Nerasoa K; Hankinson, John; Sprinkle, Mike; Berger, Claire; de Heer, Walt A. (2009). "Half integer quantum Hall effect in high mobility single layer epitaxial graphene". Applied Physics Letters. 95 (22): 223108. arXiv:0909.2903. Bibcode:2009ApPhL..95v3108W. doi:10.1063/1.3266524.
  41. Lara-Avila, Samuel; Kalaboukhov, Alexei; Paolillo, Sara; Syväjärvi, Mikael; Yakimova, Rositza; Fal'ko, Vladimir; Tzalenchuk, Alexander; Kubatkin, Sergey (7 July 2009). "SiC Graphene Suitable For Quantum Hall Resistance Metrology". Science Brevia. arXiv:0909.1193. Bibcode:2009arXiv0909.1193L.
  42. Alexander-Webber, J.A.; Baker, A.M.R.; Janssen, T.J.B.M.; Tzalenchuk, A.; Lara-Avila, S.; Kubatkin, S.; Yakimova, R.; Piot, B. A.; Maude, D. K.; Nicholas, R.J. (2013). "Phase Space for the Breakdown of the Quantum Hall Effect in Epitaxial Graphene". Physical Review Letters. 111 (9): 096601. arXiv:1304.4897. Bibcode:2013PhRvL.111i6601A. doi:10.1103/PhysRevLett.111.096601. PMID 24033057.
  43. Tzalenchuk, Alexander; Lara-Avila, Samuel; Kalaboukhov, Alexei; Paolillo, Sara; Syväjärvi, Mikael; Yakimova, Rositza; Kazakova, Olga; Janssen, T. J. B. M.; Fal'Ko, Vladimir; Kubatkin, Sergey (2010). "Towards a quantum resistance standard based on epitaxial graphene". Nature Nanotechnology. 5 (3): 186–9. arXiv:0909.1220. Bibcode:2010NatNa...5..186T. doi:10.1038/nnano.2009.474. PMID 20081845.
  44. Riedl, C.; Coletti, C.; Iwasaki, T.; Zakharov, A.A.; Starke, U. (2009). "Quasi-Free-Standing Epitaxial Graphene on SiC Obtained by Hydrogen Intercalation". Physical Review Letters. 103 (24): 246804. arXiv:0911.1953. Bibcode:2009PhRvL.103x6804R. doi:10.1103/PhysRevLett.103.246804. PMID 20366220.
  45. Hass, J.; Varchon, F.; Millán-Otoya, J.; Sprinkle, M.; Sharma, N.; De Heer, W.; Berger, C.; First, P.; Magaud, L.; Conrad, E. (2008). "Why multilayer graphene on 4H-SiC(000(1)over-bar) behaves like a single sheet of graphene". Physical Review Letters. 100 (12): 125504. Bibcode:2008PhRvL.100l5504H. doi:10.1103/PhysRevLett.100.125504. PMID 18517883.
  46. Singh, Ram Sevak; Nalla, Venkatram; Chen, Wei; Wee, Andrew Thye Shen; Ji, Wei (2011). "Laser Patterning of Epitaxial Graphene for Schottky Junction Photodetectors". ACS Nano. 5 (7): 5969–75. doi:10.1021/nn201757j. PMID 21702443.
  47. "Samsung's graphene breakthrough could finally put the wonder material into real-world devices". ExtremeTech. 7 April 2014. Retrieved 13 April 2014.
  48. Lee, J. -H.; Lee, E. K.; Joo, W. -J.; Jang, Y.; Kim, B. -S.; Lim, J. Y.; Choi, S. -H.; Ahn, S. J.; Ahn, J. R.; Park, M. -H.; Yang, C. -W.; Choi, B. L.; Hwang, S. -W.; Whang, D. (2014). "Wafer-Scale Growth of Single-Crystal Monolayer Graphene on Reusable Hydrogen-Terminated Germanium". Science. 344 (6181): 286–9. Bibcode:2014Sci...344..286L. doi:10.1126/science.1252268. PMID 24700471.
  49. Tetlow, H.; Posthuma de Boer, J.; Ford, I. J.; Vvedensky, D.D.; Coraux, J.; Kantorovich, L. (2014). "growth of epitaxial graphene: Theory and experiment". Physics Reports. 542 (3): 195–295. arXiv:1602.06707. Bibcode:2014PhR...542..195T. doi:10.1016/j.physrep.2014.03.003.
  50. Brückner, F.-U.; Schwerdtfeger, K. (1994). "Single crystal growth with the Czochralski method involving rotational electromagnetic stirring of the melt". Journal of Crystal Growth. 139 (3–4): 351–356. Bibcode:1994JCrGr.139..351B. doi:10.1016/0022-0248(94)90187-2.
  51. Vasquez de Parga, A. L.; Calleja, F.; Borca, B.; Passeggi, M. C. G.; Hinarejos, J. J.; Guinea, F.; Miranda, R. (2008). "Periodically Rippled Graphene: Growth and Spatially Resolved Electronic Structure". Physical Review Letters. 100 (5): 056807–056811. arXiv:0709.0360. doi:10.1103/PhysRevLett.100.056807. PMID 18352412.
  52. Zhang, H.; Fu, Q.; Cui, Y.; Tan, D.; Bao, X. (2009). "Growth Mechanism of Graphene on Ru(0001) and O_2 Adsorption on the Graphene/Ru(0001) Surface". The Journal of Physical Chemistry C. 113 (19): 8296–8301. doi:10.1021/jp810514u.
  53. Marchini, S.; G\"unther, S.; Wintterlin, J. (2007). "Scanning tunneling microscopy of graphene on Ru(0001)". Physical Review B. 76 (7): 075429–075438. Bibcode:2007PhRvB..76g5429M. doi:10.1103/PhysRevB.76.075429.
  54. Moritz, W.; Wang, B.; Bocquet, M.-L.; Brugger, T.; Greber, T.; Wintterlin, J.; G\”unther, S. (2010). "Structure Determination of the Coincidence Phase of Graphene on Ru(0001)". Physical Review Letters. 104 (13): 136102–136106. Bibcode:2010PhRvL.104m6102M. doi:10.1103/PhysRevLett.104.136102. PMID 20481896. S2CID 16308799.
  55. Coraux, J.; N’Diaye, A. T.; Engler, M.; Busse, C.; Wall, D.; Buckanie, N.; Meyer zu Heringdorf, F.-J.; van Gastel, R.; Poelsema, B.; Michely, T. (2009). "Growth of graphene on Ir(111)". New Journal of Physics. 11 (2): 023006–023028. Bibcode:2009NJPh...11b3006C. doi:10.1088/1367-2630/11/2/023006.
  56. N’Diaye, A. T.; Coraux, J.; Plasa, T. N.; Busse, C.; Michely, T. (2008). "Structure of epitaxial graphene on Ir(111)". New Journal of Physics. 10 (4): 043033–043049. doi:10.1088/1367-2630/10/4/043033.
  57. Hämäläinen, S. K.; Boneschanscher, M.P.; Jacobse, P. H.; Swart, I.; Pussi, K.; Moritz, W.; Lahtinen, J.; Liljeroth, P.; Sainio, J. (2013). "Structure and local variations of the graphene moir\'e on Ir(111)". Physical Review B. 88 (20): 201406–201412. arXiv:1310.7772. doi:10.1103/PhysRevB.88.201406.
  58. Pletikosić, I.; Kralj, M.; Pervan, P.; Brako, R.; Coraux, J.; n’Diaye, A.; Busse, C.; Michely, T. (2009). "Dirac Cones and Minigaps for Graphene on Ir(111)". Physical Review Letters. 102 (5): 056808. arXiv:0807.2770. Bibcode:2009PhRvL.102e6808P. doi:10.1103/PhysRevLett.102.056808. PMID 19257540.
  59. Sutter, P.; Sadowski, J. T.; Sutter, E. (2009). "Graphene on Pt(111): Growth and substrate interaction". Physical Review B. 80 (24): 245411–245421. Bibcode:2009PhRvB..80x5411S. doi:10.1103/PhysRevB.80.245411.
  60. Kim, H. W.; Ko, W.; Ku, J.-Y.; Kim, Y.; Park, S.; Hwang, S. (2017). "Evolution of Graphene Growth on Pt(111): From Carbon Clusters to Nanoislands". The Journal of Physical Chemistry C. 121 (45): 25074–25078. doi:10.1021/acs.jpcc.7b06540.
  61. Zhou, Chongwu (2013). "Review of Chemical Vapor Deposition of Graphene and Related Applications". Accounts of Chemical Research. 46 (10): 2329–2339. doi:10.1021/ar300203n. PMID 23480816.
  62. Bae, S.; et al. (2010). "Roll-to-roll production of 30-inch graphene films for transparent electrodes". Nature Nanotechnology. 5 (8): 574–578. Bibcode:2010NatNa...5..574B. CiteSeerX 10.1.1.176.439. doi:10.1038/nnano.2010.132. PMID 20562870.
  63. Rafiee, J.; Mi, X.; Gullapalli, H.; Thomas, A.V.; Yavari, F.; Shi, Y.; Ajayan, P.M.; Koratkar, N.A. (2012). "Wetting transparency of graphene". Nature Materials. 11 (3): 217–222. Bibcode:2012NatMa..11..217R. doi:10.1038/nmat3228. PMID 22266468.
  64. Zhao, W.; Kozlov, S.M.; Höfert, O.; Gotterbarm, K.; Lorenz, M.P.A.; Viñes, F.; Papp, C.; Görling, A.; Steinrück, H.-P. (2011). "Graphene on Ni(111): Coexistence of Different Surface Structures". The Journal of Physical Chemistry Letters. 2 (7): 759–764. doi:10.1021/jz200043p.
  65. Gamo, Y.; Nagashima, A.; Wakabayashi, M.; Terai, M.; Oshima, C. (1997). "Atomic structure of monolayer graphite formed on Ni(111)". Surface Science. 374 (1–3): 61–64. Bibcode:1997SurSc.374...61G. doi:10.1016/S0039-6028(96)00785-6.
  66. Weatherup, R.S.; Bayer, Bernhard C.; Blume, Raoul; Ducati, Caterina; Baehtz, Carsten; Schlögl, Robert; Hofmann, Stephan (2011). "In Situ Characterization of Alloy Catalysts for Low-Temperature Graphene Growth". Nano Letters. 11 (10): 4154–60. Bibcode:2011NanoL..11.4154W. doi:10.1021/nl202036y. PMID 21905732.
  67. Amini, Shaahin; Garay, Javier; Liu, Guanxiong; Balandin, Alexander A.; Abbaschian, Reza (2010). "Growth of Large-Area Graphene Films from Metal–Carbon Melts". Journal of Applied Physics. 108 (9): 094321–094321–7. arXiv:1011.4081. Bibcode:2010JAP...108i4321A. doi:10.1063/1.3498815.
  68. "New process could lead to more widespread use of graphene". Gizmag.com. 2014-05-28. Retrieved 14 June 2014.
  69. Varykhalov, A.; S\’anchez-Barriga, J.; Shikin, A.M.; Biswas, C.; Vescovo, E.; Rybkin, A.; Marchenko, D.; Rader, O. (2008). "Electronic and Magnetic Properties of Quasifreestanding Graphene on Ni". Physical Review Letters. 101 (15): 157601–157605. Bibcode:2008PhRvL.101o7601V. doi:10.1103/PhysRevLett.101.157601. PMID 18999644.
  70. Varykhalov, A.; Rader, O. (2009). "Graphene grown on Co(0001) films and islands: Electronic structure and its precise magnetization dependence". Physical Review B. 80 (3): 035437–035443. Bibcode:2009PhRvB..80c5437V. doi:10.1103/PhysRevB.80.035437.
  71. Li, Xuesong; Cai, W; An, Jinho; Kim, Seyoung; Nah, Junghyo; Yang, Dongxing; Piner, Richard; Velamakanni, Aruna; Jung, Inhwa; Tutuc, Emanuel; Banerjee, Sanjay K.; Colombo, Luigi; Ruoff, Rodney S.; et al. (2009). "Large-Area Synthesis of High-Quality and Uniform Graphene Films on Copper Foils". Science. 324 (5932): 1312–4. arXiv:0905.1712. Bibcode:2009Sci...324.1312L. doi:10.1126/science.1171245. PMID 19423775.
  72. Mattevi, Cecilia; Kim, Hokwon; Chhowalla, Manish (2011). "A review of chemical vapour deposition of graphene on copper". Journal of Materials Chemistry. 21 (10): 3324–3334. doi:10.1039/C0JM02126A. S2CID 213144.
  73. Than, Ker (2015-03-18). "Cool process to make better graphene". R&D. Retrieved April 2015. Check date values in: |access-date= (help)
  74. Wassei, Jonathan K.; Mecklenburg, Matthew; Torres, Jaime A.; Fowler, Jesse D.; Regan, B. C.; Kaner, Richard B.; Weiller, Bruce H. (12 May 2012). "Chemical Vapor Deposition of Graphene on Copper from Methane, Ethane and Propane: Evidence for Bilayer Selectivity". Small. 8 (9): 1415–1422. doi:10.1002/smll.201102276. PMID 22351509.
  75. Lenski, Daniel R.; Fuhrer, Michael S. (2011). "Raman and optical characterization of multilayer turbostratic graphene grown via chemical vapor deposition". Journal of Applied Physics. 110 (1): 013720–013720–4. arXiv:1011.1683. Bibcode:2011JAP...110a3720L. doi:10.1063/1.3605545.
  76. Calado, V. E.; Zhu, Shou-En; Goswami, S.; Xu, Q.; Watanabe, K.; Taniguchi, T.; Janssen, G. C. A. M.; Vandersypen, L. M. K. (13 January 2014). "Ballistic transport in graphene grown by chemical vapor deposition". Applied Physics Letters. 104 (2): 023103. arXiv:1401.6771. Bibcode:2014ApPhL.104b3103C. doi:10.1063/1.4861627.
  77. Vishwakarma, R.; et al. (2017). "Transfer free graphene growth on SiO2 substrate at 250 °C". Sci. Rep. 7: 43756. doi:10.1038/srep43756. PMC 5333118. PMID 28251997.
  78. Choucair, M.; Thordarson, P; Stride, JA (2008). "Gram-scale production of graphene based on solvothermal synthesis and sonication". Nature Nanotechnology. 4 (1): 30–3. Bibcode:2009NatNa...4...30C. doi:10.1038/nnano.2008.365. PMID 19119279.
  79. Bae, Sukang; Kim, Hyeongkeun; Lee, Youngbin; Xu, Xiangfan; Park, Jae-Sung; Zheng, Yi; Balakrishnan, Jayakumar; Lei, Tian; Kim, Hye Ri (August 2010). "Roll-to-roll production of 30-inch graphene films for transparent electrodes". Nature Nanotechnology. 5 (8): 574–578. Bibcode:2010NatNa...5..574B. CiteSeerX 10.1.1.176.439. doi:10.1038/nnano.2010.132. PMID 20562870.
  80. Martin, Steve (18 September 2014). "Purdue-based startup scales up graphene production, develops biosensors and supercapacitors". Purdue University. Retrieved 4 October 2014.
  81. "Startup scales up graphene production, develops biosensors and supercapacitors". R&D Magazine. 19 September 2014. Retrieved 4 October 2014.
  82. "A graphene roll-out". MIT News. Retrieved 2018-09-04.
  83. Quick, Darren (June 26, 2015). "New process could usher in "graphene-driven industrial revolution"". www.gizmag.com. Retrieved 2015-10-05.
  84. Bointon, Thomas H.; Barnes, Matthew D.; Russo, Saverio; Craciun, Monica F. (2015-07-01). "High Quality Monolayer Graphene Synthesized by Resistive Heating Cold Wall Chemical Vapor Deposition". Advanced Materials. 27 (28): 4200–4206. arXiv:1506.08569. Bibcode:2015arXiv150608569B. doi:10.1002/adma.201501600. ISSN 1521-4095. PMC 4744682. PMID 26053564.
  85. Das, Shantanu; Drucker, Jeff (10 March 2017). "Nucleation and growth of single layer graphene on electrodeposited Cu by cold wall chemical vapor deposition". Nanotechnology. 28 (10): 105601. Bibcode:2017Nanot..28j5601D. doi:10.1088/1361-6528/aa593b. PMID 28084218.
  86. Das, Shantanu; Drucker, Jeff (28 May 2018). "Pre-coalescence scaling of graphene island sizes". Journal of Applied Physics. 123 (20): 205306. Bibcode:2018JAP...123t5306D. doi:10.1063/1.5021341.
  87. Brumfiel, G. (2009). "Nanotubes cut to ribbons New techniques open up carbon tubes to create ribbons". Nature. doi:10.1038/news.2009.367.
  88. Kosynkin, D. V.; Higginbotham, Amanda L.; Sinitskii, Alexander; Lomeda, Jay R.; Dimiev, Ayrat; Price, B. Katherine; Tour, James M. (2009). "Longitudinal unzipping of carbon nanotubes to form graphene nanoribbons". Nature. 458 (7240): 872–6. Bibcode:2009Natur.458..872K. doi:10.1038/nature07872. hdl:10044/1/4321. PMID 19370030.
  89. Liying, Jiao; Zhang, Li; Wang, Xinran; Diankov, Georgi; Dai, Hongjie (2009). "Narrow graphene nanoribbons from carbon nanotubes". Nature. 458 (7240): 877–80. Bibcode:2009Natur.458..877J. doi:10.1038/nature07919. PMID 19370031.
  90. Li, Xiaolin; Zhang, Guangyu; Bai, Xuedong; Sun, Xiaoming; Wang, Xinran; Wang, Enge; Dai, Hongjie (2008). "Highly conducting graphene sheets and Langmuir–Blodgett films". Nature Nanotechnology. 3 (9): 538–542. arXiv:0808.0502. Bibcode:2008NatNa...3..538L. doi:10.1038/nnano.2008.210. ISSN 1748-3395. PMID 18772914.
  91. Zheng, Qingbin; Ip, Wai Hing; Lin, Xiuyi; Yousefi, Nariman; Yeung, Kan Kan; Li, Zhigang; Kim, Jang-Kyo (2011-07-26). "Transparent Conductive Films Consisting of Ultralarge Graphene Sheets Produced by Langmuir–Blodgett Assembly". ACS Nano. 5 (7): 6039–6051. doi:10.1021/nn2018683. ISSN 1936-0851. PMID 21692470.
  92. Cote, Laura J.; Kim, Franklin; Huang, Jiaxing (2009-01-28). "Langmuir−Blodgett Assembly of Graphite Oxide Single Layers". Journal of the American Chemical Society. 131 (3): 1043–1049. doi:10.1021/ja806262m. ISSN 0002-7863. PMID 18939796.
  93. Zheng, Qingbin; Shi, Lifang; Ma, Peng-Cheng; Xue, Qingzhong; Li, Jing; Tang, Zhihong; Yang, Junhe (2013-03-11). "Structure control of ultra-large graphene oxide sheets by the Langmuir–Blodgett method". RSC Advances. 3 (14): 4680. doi:10.1039/c3ra22367a. ISSN 2046-2069.
  94. Zheng, Qingbin; Zhang, Biao; Lin, Xiuyi; Shen, Xi; Yousefi, Nariman; Huang, Zhen-Dong; Li, Zhigang; Kim, Jang-Kyo (2012-11-20). "Highly transparent and conducting ultralarge graphene oxide/single-walled carbon nanotube hybrid films produced by Langmuir–Blodgett assembly". Journal of Materials Chemistry. 22 (48): 25072. doi:10.1039/c2jm34870e. ISSN 1364-5501. S2CID 95000859.
  95. Chakrabarti, A.; Lu, J.; Skrabutenas, J. C.; Xu, T.; Xiao, Z.; Maguire, J. A.; Hosmane, N. S. (2011). "Conversion of carbon dioxide to few-layer graphene". Journal of Materials Chemistry. 21 (26): 9491. doi:10.1039/C1JM11227A. S2CID 96850993.
  96. "Carbon nanotubes as reinforcing bars to strengthen graphene and increase conductivity". KurzweilAI. 9 April 2014. Retrieved 23 April 2014.
  97. Kim, D. Y.; Sinha-Ray, S.; Park, J. J.; Lee, J. G.; Cha, Y. H.; Bae, S. H.; Ahn, J. H.; Jung, Y. C.; Kim, S. M.; Yarin, A. L.; Yoon, S. S. (2014). "Self-Healing Reduced Graphene Oxide Films by Supersonic Kinetic Spraying". Advanced Functional Materials. 24 (31): 4986–4995. doi:10.1002/adfm.201400732.
  98. Kim, Do-Yeon; Sinha-Ray, Suman; Park, Jung-Jae; Lee, Jong-Gun; Cha, You-Hong; Bae, Sang-Hoon; Ahn, Jong-Hyun; Jung, Yong Chae; Kim, Soo Min; Yarin, Alexander L.; Yoon, Sam S. (2014). "Supersonic spray creates high-quality graphene layer". Advanced Functional Materials. 24 (31): 4986–4995. doi:10.1002/adfm.201400732. Retrieved 14 June 2014.
  99. Kim, Do-Yeon; Sinha-Ray, Suman; Park, Jung-Jae; Lee, Jong-Gun; Cha, You-Hong; Bae, Sang-Hoon; Ahn, Jong-Hyun; Jung, Yong Chae; Kim, Soo Min; Yarin, Alexander L.; Yoon, Sam S. (2014). "Self-Healing Reduced Graphene Oxide Films by Supersonic Kinetic Spraying". Advanced Functional Materials. 24 (31): 4986–4995. doi:10.1002/adfm.201400732.
  100. "How to Make Graphene Using Supersonic Buckyballs | MIT Technology Review". MIT Technology Review. August 13, 2015. Retrieved 2015-10-11.
  101. Kovtyukhova, Nina I.; et al. (7 September 2014). "Non-oxidative intercalation and exfoliation of graphite by Brønsted acids". Nature Chemistry. 6 (11): 957–963. Bibcode:2014NatCh...6..957K. doi:10.1038/nchem.2054. PMID 25343599.
  102. "Discovery shows route to industrial-scale production of graphene". KurzweilAI. 9 September 2014. Retrieved December 2014. Check date values in: |accessdate= (help)
  103. Lin, J.; Peng, Z.; Liu, Y.; Ruiz-Zepeda, F.; Ye, R.; Samuel, E. L. G.; Yacaman, M. J.; Yakobson, B. I.; Tour, J. M. (2014). "Laser-induced porous graphene films from commercial polymers". Nature Communications. 5: 5714. Bibcode:2014NatCo...5.5714L. doi:10.1038/ncomms6714. PMC 4264682. PMID 25493446.
  104. El-Kady, M. F.; Strong, V.; Dubin, S.; Kaner, R. B. (16 March 2012). "Laser Scribing of High-Performance and Flexible Graphene-Based Electrochemical Capacitors". Science. 335 (6074): 1326–1330. Bibcode:2012Sci...335.1326E. doi:10.1126/science.1216744. PMID 22422977. S2CID 18958488.
    Marcus, Jennifer (15 March 2012). "Researchers develop graphene supercapacitor holding promise for portable electronics / UCLA Newsroom". Newsroom.ucla.edu. Archived from the original on 16 June 2013. Retrieved 15 October 2015.
  105. Chiu, Pui Lam; Mastrogiovanni, Daniel D. T.; Wei, Dongguang; Louis, Cassandre; Jeong, Min; Yu, Guo; Saad, Peter; Flach, Carol R.; Mendelsohn, Richard (2012-04-04). "Microwave- and Nitronium Ion-Enabled Rapid and Direct Production of Highly Conductive Low-Oxygen Graphene". Journal of the American Chemical Society. 134 (13): 5850–5856. doi:10.1021/ja210725p. ISSN 0002-7863. PMID 22385480.
  106. Patel, Mehulkumar A.; Yang, Hao; Chiu, Pui Lam; Mastrogiovanni, Daniel D. T.; Flach, Carol R.; Savaram, Keerthi; Gomez, Lesly; Hemnarine, Ashley; Mendelsohn, Richard (2013-09-24). "Direct Production of Graphene Nanosheets for Near Infrared Photoacoustic Imaging". ACS Nano. 7 (9): 8147–8157. doi:10.1021/nn403429v. ISSN 1936-0851. PMID 24001023.
  107. Savaram, Keerthi; Kalyanikar, Malathi; Patel, Mehulkumar; Brukh, Roman; Flach, Carol R.; Huang, Ruiming; Khoshi, M. Reza; Mendelsohn, Richard; Wang, Andrew (2015-01-01). "Synergy of oxygen and a piranha solution for eco-friendly production of highly conductive graphene dispersions". Green Chem. 17 (2): 869–881. doi:10.1039/c4gc01752h. S2CID 9158541.
  108. Patel, M; Feng, W; Savaram, K; Khoshi, MR; Huang, R; Sun, J; Rabie, E; Flach, C; Mendelsohn, R; Garfunkel, E; He, H (2015). "Microwave Enabled One-Pot, One-Step Fabrication and Nitrogen Doping of Holey Graphene Oxide for Catalytic Applications". Small. 11 (27): 3358–3368. doi:10.1002/smll.201403402. PMID 25683019.
  109. "Korean researchers grow wafer-scale graphene on a silicon substrate | KurzweilAI". www.kurzweilai.net. July 21, 2015. Retrieved 2015-10-11.
  110. Kim, Janghyuk; Lee, Geonyeop; Kim, Jihyun (2015-07-20). "Wafer-scale synthesis of multi-layer graphene by high-temperature carbon ion implantation". Applied Physics Letters. 107 (3): 033104. Bibcode:2015ApPhL.107c3104K. doi:10.1063/1.4926605. ISSN 0003-6951.
  111. PUIU, TIBI (2017-02-01). "How to cook graphene using only soybean oil. Seriously, these scientists did it". ZME Science. Retrieved 2017-02-17.
  112. 3D Printed Bacteria Could Lead to 3D Printed Electronics in Space, Say TU Delft Researchers
  113. Lehner, Benjamin A. E.; Schmieden, Dominik T.; Meyer, Anne S. (2017). "A Straightforward Approach for 3D Bacterial Printing". ACS Synthetic Biology. 6 (7): 1124–1130. doi:10.1021/acssynbio.6b00395. PMC 5525104. PMID 28225616.
  114. Micu, Alexandru (2020-01-28). "Flash-baking waste could make for stronger concrete and protect the environment". ZME Science. Retrieved 2020-01-29.
  115. Yazdi, G. R.; Iakimov, T.; Yakimova, R. (2016). "Epitaxial Graphene on SiC: A Review of Growth and Characterization". Crystals. 6 (5): 53–98. doi:10.3390/cryst6050053. Material was copied from this source, which is available under a Creative Commons Attribution 4.0 International License.
  116. Malard, L. M.; Pimenta, M. A.; Dresselhaus, G.; Dresselhaus, M. S. (2009). "Raman spectroscopy in graphene". Physics Reports. 473 (5–6): 51–87. Bibcode:2009PhR...473...51M. doi:10.1016/j.physrep.2009.02.003.
  117. Land, T. A.; Michely, T.; Behm, R. J.; Hemminger, J. C.; Comsa, G. (1992). "STM investigation of single layer graphite structures produced on Pt(111) by hydrocarbon decomposition". Surface Science. 264 (3): 261–270. Bibcode:1992SurSc.264..261L. doi:10.1016/0039-6028(92)90183-7.
  118. Burnett, T.; Yakimova, R.; Kazakova, O. (2011). "Mapping of Local Electrical Properties in Epitaxial Graphene Using Electrostatic Force Microscopy". Nano Letters. 11 (6): 2324–2328. Bibcode:2011NanoL..11.2324B. doi:10.1021/nl200581g. PMID 21526826.
  119. Smith, B. W.; Luzzi, D. E. (2001). "Electron irradiation effects in single wall carbon nanotubes". Journal of Applied Physics. 90 (7): 3509–3515. Bibcode:2001JAP....90.3509S. doi:10.1063/1.1383020. S2CID 53054872.
  120. Grodecki, K.; Jozwik, I.; Baranowski, J. M.; Teklinska, D.; Strupinski, W. (2016). "SEM and Raman analysis of graphene on SiC(0001)". Micron. 80: 20–23. doi:10.1016/j.micron.2015.05.013. PMID 26409439.
This article is issued from Wikipedia. The text is licensed under Creative Commons - Attribution - Sharealike. Additional terms may apply for the media files.