Graphene nanoribbons gnrs, also called nanographene ribbons or nanographite ribbons are strips of graphene with width less than 50 nm. Wafer scale graphene transfer kim et al nature 2010 mechanical peeling off in water supportgraphene nior cusio 2 ni or cu sio 2 rapid etching with fecl 3 aq graphene on polymer support graphene on arbitrary substrate transfer patterning patterned graphene on ni patterned graphene on arbtirary substrate postpatterning prepatterning. To provide answers to some of these questions, here, we report our work on the characterization of go and fgss by raman spectroscopy and scanning tunneling microscopy stm. Because of continuous arcing of graphitemetal electrodes, the graphene sheets were observed in water with uniformity and little damage. Subsequently reduced graphene oxide rgo having few layer graphene is extracted from go by the thermal reduction of go. Electron states of mono and bilayer graphene on sic probed by stm p. These nanosheets were subjected to various purification steps. As exemplified by the stm image of a go monolayer shown in figure 1d, the hexagonal lattice of the sheets turns out to be partially preserved.
First stm spectroscopy of graphene flakes yields new surprises under the stm tip a flake of graphene 50 microns millionths of a meter long rests on a substrate of silicon with a thin layer of. Synthesis, characterization, chemical reduction and. Scanning tunneling microscopy stm of graphene sciencedirect. The graphene sheet is approximately 60% smoother than the oxide surface. Probing the catalytic activity of porous graphene oxide. These structural insights demonstrate that go is not a defined material and it is important to.
Graphene has received so much attention due to its exceptional electronic, thermal, mechanical, and optical properties in addition to its large surface area and singleatom thickness. The mechanical properties of this graphene oxide paper. The observed random corrugations with lateral dimensions of several nanometers and vertical dimensions of around 0. From fundamentals to applications article pdf available in journal of physics condensed matter 271. Jul 21, 2008 first stm spectroscopy of graphene flakes yields new surprises under the stm tip a flake of graphene 50 microns millionths of a meter long rests on a substrate of silicon with a thin layer of. Graphene edges and nanographene electronic structure and. Chemical reduction of individual graphene oxide sheets as.
Highresolution scanning tunneling microscopy imaging of mesoscopic graphene sheets on an insulating surface elena stolyarova, kwang taeg rim, sunmin ryu, janina maultzsch, philip kim, louis e. We report on a means to tune the topographical and electrical properties of reduced go rgo with nanoscopic resolution by local thermal reduction of go with a heated atomic force microscope tip. Preparation and characterization graphene potential application of graphene conclusions 3. Nano letters electronic transport properties of individual. Graphene nanoribbons with controlled edge orientation have been fabricated by scanning tunneling microscope stm lithography. In none of these early works was freestanding graphene or grapheneoxide files isolated or identified as such. Chemical functionalization and characterization of graphene. Graphenepva nanocomposite formation through mixing of graphene oxide suspension and pva solution is reported in ref. Graphene, a single layer of graphite, has attracted great inter est in recent years. Internalization and cytotoxicity of graphene oxide and. Intrinsic structure and friction properties of graphene and graphene. The reduced form of graphene oxide go is an attractive alternative to graphene for producing largescale flexible conductors and for creating devices that require an electronic gap. Dec 18, 2012 graphene oxide, a twodimensional aromatic scaffold decorated by oxygencontaining functional groups, possesses rich chemical properties and may present a green alternative to precious metal.
Highresolution scanning tunneling microscopy imaging of. Synthesis of graphene oxide go by modified hummers. Jun 24, 2011 the first scanning tunneling microscopy stm images of graphene synthesized on copper foil. Graphene nanosheets produced in the form of stable aqueous dispersions by chemical reduction of graphene oxide and deposited onto graphite substrates have been investigated by atomic force and scanning tunneling microscopy afm stm. The first scanning tunneling microscopy stm images of graphene synthesized on copper foil. Eg layer grown on a 4hsic0001 substrate strupinski, w. Graphene is an allotrop of carbon, which consists of a twodimensional 2d crystalline lattice of hexagonally arranged, sp 2hybridized carbon atoms. We present a scanning tunneling microscopy stm study of native defects in graphene islands grown by ultrahigh vacuum decomposition of ethylene on cu1 1 1. Graphene oxide is the oxidized form of graphene produced by oxidizing crystal graphite with a mixture of sulfuric acid, sodium nitrate, and potassium permanganate the hummers method. However, the synthesis of go in an economical and efficient way remains a great. Synthesis and fabrication of graphene and graphene oxide. Cvd, exfoliation, graphene, graphene oxide, synthesis. Graphene nanosheets produced in the form of stable aqueous dispersions by chemical reduction of graphene oxide and deposited onto graphite substrates have been investigated by atomic force and scanning tunneling microscopy afmstm.
Adsorption of sodium dodecyl sulfate on functionalized. Highefficient synthesis of graphene oxide based on improved. Structurally, graphene oxide can be visualized as a graphene sheet with its basal plane decorated by oxygencontaining. Jun 11, 2010 the reduced form of graphene oxide go is an attractive alternative to graphene for producing largescale flexible conductors and for creating devices that require an electronic gap. The stm images of the go sheets are distinguishable from pristine graphene by the appearance of bright spotsregions lacking. Conductance images between two stm probes in graphene. Netzer, vassilikialexandra glezakou, roger rousseau, and zdenek dohnale. Localized resistance measurements of wrinkled reduced. Reaction schemes and stm images of graphene nanoribbons. Hashmi, in reference module in materials science and materials engineering, 2018. Local defects under high vacuum are observed with transmission electron microscopy tem and scanning tunneling microscopy stm.
Supplementary information oxidation of cu111 coming. A noticeable degree of charge inhomogeneities ascribed to impurities is also observed. Chemistry with graphene and graphene oxide challenges. Evolution of the raman spectrum of graphene grown on. Graphene papers show elastic modulus of 3040 gpa, strength of 120 mpa, and toughness of 0. Electronic transport properties of individual chemically reduced graphene oxide sheets cristina go. First stm spectroscopy of graphene flakes yields new surprises. Because graphene is twodimensional, 1,2 scanning tunneling microscopy stm is ideal for its characterization. The field of nanotechnology has advanced following the discovery of a twodimensional material of sp2 hybridized carbon atoms, graphene in 2004 by geim and novoselov. Localized resistance measurements of wrinkled reduced graphene oxide using insitu transmission electron microscopy hanna m. The chemically reduced graphene oxide nanosheets were hardly distinguishable from their unreduced counterparts in the topographic afm images. Graphene components can be incorporated into polymeric matrices by in situ reduction of graphene oxide.
The reduction of graphene oxide songfeng pei, huiming cheng shenyang national laboratory for materials science, institute of metal research, chinese academy of sciences, 72 wenhua road. Individual graphene oxide sheets subjected to chemical reduction were electrically characterized as. Nanoscale tunable reduction of graphene oxide for graphene. From fundamental to future applications aman gupta b. This work represents a stateoftheart technique developed for the preparation of graphene from graphitemetal electrodes by the arcdischarge method carried out in a continuous flow of water.
Atomic force and scanning tunneling microscopy imaging of. Copper and nickel were used as catalysts in the cvd graphene synthesis, ch4 and h2being used as precursor gases. Although graphenelike structures have been studied since the middle of the 20thcentury 24 and freestanding ultrathin graphene sheets have been already imaged in 1962 by boehm et al. Scanning tunneling microscopy topographic scans of fewlayered water con. Stm scanning tunneling microscopy, afm atomic force microscopy, etc. The maximally oxidized bulk product is a yellow solid with c. During the formation of graphite oxide the graphene layers in graphite become intercalated by an acid to form a stage 1 intercalation compound with all layers being intercalated. Experimental evidence of edge state scanning tunneling microscopyspectroscopy stm sts near edge xray absorption fine structure nexafs electron spin resonance esr. Cvd graphene transportqhe ramanoptical stmafmspm thermal deviceapplications number refers to paper id in full publication list chemical vapor deposited cvd graphene 120 rui he, tingfung chung, conor delaney, courtney keiser, luis a. Such a study may also help us understand the graphene growth mechanism and improve the quality of the cvd graphene. The stm topography of a gated graphene flake device is shown in fig. Graphite oxide, formerly called graphitic oxide or graphitic acid, is a compound of carbon, oxygen, and hydrogen in variable ratios, obtained by treating graphite with strong oxidizers. Functionalized graphene sheets fgss, which can be produced in large quantities by thermal exfoliation and reduction of graphite oxide go1,2 or by chemical reduction of graphene oxide,3 have been used to improve performance in many applications, including graphene metal oxide nanocomposites for liion battery electrodes,4,5 graphene polymer. Probing the catalytic activity of porous graphene oxide and.
In 1948, g ruess and f vogt used transmission electron microscopy tem and, after drying a droplet of a grapheneoxide suspension on a tem grid, they observed creased. Natural flake graphite nfg was procured from loba chemie india having a mean size of 60 mesh and purity of 98%. Use of graphite oxide and graphene oxide as catalysts in the synthesis of dipyrromethane and calix4pyrrole. Electron states of mono and bilayer graphene on sic probed. The chemically reduced graphene oxide nanosheets were hardly distinguishable. Chen, graphene induced surface reconstruction of cu, nano letters 12, 3893 2012 pdf. Stm has been widely used to probe the atomicscale structure and electronic properties such as local density of. Graphene ribbons were introduced as a theoretical model by mitsutaka fujita and coauthors to examine the edge and nanoscale size effect in graphene. Chemically derived graphene oxide go possesses a unique set of properties arising from oxygen functional groups that are introduced during chemical exfoliation of graphite.
As an important precursor and derivate of graphene, graphene oxide go has received wide attention in recent years. Direct evidence of structural disorder was provided by atomicscale stm imaging, which revealed an absence of. Andrei1, guohong li1 and xu du2 1department of physics and astronomy, rutgers university, piscataway, nj 08855, usa. On the other hand, several earlier scanning tunneling microscopy stm studies of graphitized surfaces, suchasir1119,pt11110,11,andsic6,alsohavebeen performed. Chemistry with graphene and graphene oxide challenges for. Ultimate stress and ultimate strain of the nanocomposite is reported as 120 mpa and 1. Pdf synthesis and fabrication of graphene and graphene oxide. Scanning tunneling microscopy study and nanomanipulation of. To understand the origin of these effects, we further characterized the samples by scanning tunneling microscopy stm, scanning tunneling spectroscopy sts, and atomic force microscopy afm. Graphite oxide method most common and high yield method. Graphene oxide go has been initially prepared by a modified hummersmethod.
We characterize these defects through a survey of their apparent heights, atomicresolution imaging, and detailed tunneling spectroscopy. Basic characters of stm imaging on graphitic materials. Graphene oxide sheets can be fabricated by a vacuumassisted assembly technique 126129. Synthesis variables were optimized according to a thickness value, calculated using a homemade excelvba.
Bittner, matteo scolari, alf mews, marko burghard, and klaus kern, maxplanckinstitut fuer festkoerperforschung, heisenbergstrasse 1, 70569 stuttgart. Wafer scale graphene transfer kim et al nature 2010 mechanical peeling off in water support graphene nior cusio 2 ni or cu sio 2 rapid etching with fecl 3 aq graphene on polymer support graphene on arbitrary substrate transfer patterning patterned graphene on ni patterned graphene on arbtirary substrate postpatterning prepatterning. Pdf the field of nanotechnology has advanced following the discovery of a. The average composition and chemical structure of graphene oxide materials can be veri. Clearer information can be obtained, regardless on the.