And when you put a whole bunch on top of each other, these layers can make. Direct production of graphene on substrates without transfer is highly desirable for simplified device processing. Evolution of raman spectra in nitrogen doped graphene zainab zafar a, zhen hua ni a, xing wu b, zhi xiang shi a, hai yan nan a, jing bai a, li tao sun b a department of physics, seu research center of converging technology, southeast university, nanjing 211189, china b seufei nanopico center, key laboratory of mems of ministry of education, school of electrical science and. Aksayc and yuehe lina received 21st march 2010, accepted 4th june 2010 doi. Synthesis of large area and high quality graphene has been demonstrated by this method 6,7. The currentvoltage iv characteristic curves of graphene contacts on pgan are nonlinear and a contact resistance of 5. Contact resistivity and current flow path at metalgraphene. Amine, nh 2, is of interest as a linker between organic molecules and graphene in novel biotechnologies. Graphene is a singleatomiclayer material with excellent mechanical properties and has the potential to enhance the strength of composites. The electronic, thermal, and optical properties of graphenebased materials depend strongly on the fabrication method used and can be further manipulated through the use of metal nanoparticles deposited on the graphene surface. Reducing contact resistance in graphene devices through.
Layers of graphene stacked on top of each other form graphite, with an interplanar spacing of 0. It is an allotrope of carbon in the form of a plane of sp2bonded atoms with a molecular bond length of 0. Tunable magnetic moment and potential halfmetal behavior of fenanostructureembedded graphene perforation huizhen zhang a,1, jiatao sun a, b,1, haifang yang a, lin li a, huixia fu a, sheng meng a, b, changzhi gu a, b, a beijing national laboratory for condensed matter physics, institute of physics, chinese academy of science, beijing 100190, china b. This wonder material is composed from a single layer of carbon atoms arranged in a honeycomblike structure. The analysis of the c kedge reveals that the interface states previously observed for graphene ni111 are suppressed in graphene ni110. Among them, nitrogendoping has been demonstrated to be most effective to improve the orr electrocatalytic activities of carbon nanomaterials. Graphenemetal composites, made simple materials today. Thermal contact resistance between graphene and silicon dioxide. A singlesheet graphene pn junction with two top gates. Here, we examine this assumption by undertaking a systematic study to understand mechanisms that lead to the contact. The analysis of the c kedge reveals that the interface states previously observed for grapheneni111 are suppressed in grapheneni110. Realization of low contact resistance close to theoretical. Synthesis of graphenetransition metal oxide hybrid.
Dames1,a 1department of mechanical engineering, university of california, riverside, california 92521, usa 2department of physics and astronomy, university of california, riverside, california 92521, usa received 19 august 2009. One common approach involves exploitation of workfunction engineering, using contact metals witha large workfunction di. Metals that strongly interact with graphene such as co and ni can form strong chemical bonds which may significantly alter the band structure of graphene near the dirac. So, in such a mess of electrical behaviors of metalgraphene contacts, with this work we report on experimental insights on the currentvoltage iv response of metalgraphene contacts on the nanoscale. Whoa, graphene can make other metals 500 times stronger. We will summarize the specific properties of graphenemetal contacts with particular attention to the nature of metals, impact of fabrication process, fermi level. Recently, one succeeded in obtaining stable multilayers and even single layers of graphene. Graphene consists of a single layer of carbon in a twodimensional 2d lattice.
For first time graphene and metal make super strong composite. Graphene thin films and graphene decorated with metal. Transferfree synthesis of doped and patterned graphene films. Electrical properties of graphenemetal contacts scientific. The c 1s core level shows a splitting typical of periodically rippled interfaces. For the pristine graphene, the d peak does not show, indicating the high. We herein describe an attempt to make use of the insulating properties of graphene oxide. Highquality and waferscale graphene on insulating gate dielectrics is a prerequisite for graphene electronic applications. Since the first report in 2004, graphene has attracted great interest in the scientific community due to its unique properties such as superior charge carrier mobility, high. Adsorption of nh2 on graphene in the presence of defects and adsorbates chad e. Apr 12, 2012 graphene is truly the material of the moment. An architecture with metal on the bottom of graphene is found to yield resistivities that are lower, by a factor of four, and most consistent as compared to metal.
Strengthening effect of singleatomiclayer graphene in. Finally rc w values below 100xlm have been recently reported when using highly pure pd contacts. Strengthening effect of singleatomiclayer graphene in metal. Making devices with graphene necessarily involves making contacts with metals. Metalgraphene sheets as ptype transparent conducting. Raman mapping spectra of i g i d and i 2d i g patterned graphene figure s1 and raman spectra of n doped graphene synthesized by hatcn figure s2, xps spectra of graphene grown with different pahs figure s3, luminance as a function of voltage for graphene and ito devices figure s4, and comparison of measured parameters of graphene prepared through different carbon sources table s1. Experimentally, one way to improve the graphenemetal contact is thorough high temperature annealing, but the detailed mechanisms behind. Tunable magnetic moment and potential halfmetal behavior. Adsorption of nh on graphene in the presence of defects. We use density functional theory to study how graphene is.
Low contact resistance metals for graphene based devices. Properties of metalgraphene contacts joachim knoch, zhihong chen, and joerg appenzeller abstractwe present a study on the metalgraphene contact properties. Realization of low contact resistance close to theoretical limit in graphene transistors hua zhong, zhiyong zhang, bingyan chen, haitao xu, dangming yu, le huang and lianmao peng peking university, china high quality graphenemetal junction with contact resistance below 100. Stretchable graphenemetal nanowire electrode enables led fitted soft eye contact lenses nanowerk news a hybrid transparent and stretchable electrode could open the new way for flexible displays, solar cells, and even electronic devices fitted on a curvature substrate such as soft eye contact lenses, by the unistulsan national institute of. Rolltoroll encapsulation of metal nanowires between. Similar to graphene dispersion in water, our graphene dispersion in nmp boasts incredibly high electrical conductivity. Nitrogendoped graphene and its electrochemical applications. It was found that in contrast to conventional metalsemiconductor contacts, the graphene underneath a contact metal can still be in. A singlesheet graphene pn junction with two top gates 6 november 2014 the graphene layer has two gates to create local changes in charge carrier. Remarkably, a highly desirable lateral ptype ohmic contact is formed with graphene in both directions.
Contact resistivity and current flow path at metal. It is a densely packed, atomically thin layer of sp 2 hybridised carbon atoms arranged in a honeycomb network. Thermal contact resistance between graphene and silicon. Graphene is already being used in optoelectronics, solar panels, batteries and capacitors. Evolution of raman spectra in nitrogen doped graphene. In graphite every other layer of graphene is shifted in the horizontal plane, leading to the wellknown ab stacking. Atomistic insight into the formation of metalgraphene. Metals that strongly interact with graphene such as co and ni can form strong chemical bonds which may significantly alter the band. Annealing is a postprocessing treatment commonly used to improve metalgraphene contacts with the assumption that resist residues sandwiched at the metalgraphene contacts are removed during annealing. We report an alternative approach to lower contact resistance and extend charge transfer length by forming graphene antidot arrays under metal electrode to introduce edge contact of graphene. To obtain the precise r c value, we fabricate a defined rectangular graphene channel and a tlm. Nanoscale electrical characteristics of metal au, pd. Graphene oxide, which is an intermediate product to form graphene, is insulating, and it should be thermally reduced to be electrically conductive.
Reduced graphene oxide rgo, a graphenelike material, can be easily prepared by reduction of graphene oxide go and therefore offers the possibility to fabricate a large variety of graphenetransition metal oxide tmo np hybrids. Its twodimensional geometry, high intrinsic strength. The electronic, thermal, and optical properties of graphene based materials depend strongly on the fabrication method used and can be further manipulated through the use of metal nanoparticles deposited on the graphene surface. Design, synthesis, and characterization of graphene. Currently the growth and development of high quality, largearea cvd graphene on catalytic metal. Monolayer graphene is obtained by mechanical exfoliation using scotch tapes. Metalgraphene sheets as ptype transparent conducting electrodes in gan light emitting diodes jung min lee,1 hae yong jeong,1 kyoung jin choi,2 and won il park1,a 1division of materials science engineering, hanyang university, seoul 3791, korea 2nanophotonics center, korea institute of science and technology, seoul, 650, korea received 12 april 2011. Jun 09, 2014 comparison of the graphene surface between the residuefree and resistpatterned metalgraphene contacts prior to metallization, characterization of material composition of annealed nickelongraphene sample, verification of carbon dissolved from graphene into nickel, comparison study of the annealing effect on both ni and aucontacted fewlayer graphene, impact of annealing on aucontacted. To facilitate the differential 3 measurements, on a electronic mail. If the direct growth of semiconductor is possible on them, the application. Low and reproducible metalgraphene contact resistance r c i. Thermal contact resistance between graphene and silicon dioxide z.
In recent years, graphene studies have increased rapidly. But comparing cvd graphene properties to exfoliated graphene, the latter goes on exhibiting better quality so far. Au edge contacts,18 showing that the fabrication of edge contacts can be promising for the rc decrease. Investigation on nanotubemetal contacts under different. Stretchable graphene metal nanowire electrode enables led fitted soft eye contact lenses nanowerk news a hybrid transparent and stretchable electrode could open the new way for flexible displays, solar cells, and even electronic devices fitted on a curvature substrate such as soft eye contact lenses, by the unistulsan national institute of science and technology research team. The effects of thermal annealing on the tape residues and edges of graphene are researched. According to the researchers, this work represents the first time a metalgraphene multilayer composite material has been successfully produced that. Performance of graphene electronics is limited by contact resistance associated with the metal graphene mg interface, where unique transport challenges arise as carriers are injected from a 3d. Contact resistivity and current flow path at metalgraphene contact k. Starting from single layer graphene sheets on cu substrate, we deposited au or pd films with increasing thickness h 5, 25, 50 nm on the. Stretchable graphenemetal nanowire electrode enables led. Nov 01, 20 graphene s unique flexibility and strength properties make it attractive for use in flexible touch screens and. Graphenes unique flexibility and strength properties make it attractive for use in flexible touch screens and.
Monolayer tellurenemetal contacts journal of materials chemistry. Graphene layers can be formed on many kinds of metals, which are. Apr 19, 2016 graphene ni110 has been studied by timeresolved xray photoelectron spectroscopy and nearedge xray absorption fine structure. According to the researchers, this work represents the first time a metal graphene multilayer composite material has been successfully produced that exploits graphene s extraordinary strength. Schematic and structure of graphene and metal nanowire hybrid.
Examples include ndoped carbon nanotubes 2,3,ndoped graphene ng 4, bcn graphene 5, and n, p codoped vacnts 6. The properties of graphene are altered by the metal contact. This investigation gives insight into the interfacial. For such applications, graphene is typically synthesized and then transferred to a desirable substrate for subsequent device processing. Doping graphene with metal contacts university of twente. Thermal induced polishing volume 3 issue 12 eliezer fernando oliveira, ricardo paupitz santos, pedro alves da silva autreto, stanislav moshkalev, douglas soares galvao. The effects of contact architecture, graphene defect density and metalsemiconductor work function difference on the resistivity of metalgraphene contacts have been investigated. The role of contact resistance in graphene fieldeffect devices. Apr 11, 2016 the effects of contact architecture, graphene defect density and metalsemiconductor work function difference on the resistivity of metalgraphene contacts have been investigated. Engelhard,a guosheng li,a guocheng shao,a yong wang,ab jun liu,a ilhan a. The kvector conservation is considered to be a fundamental factor to in. Reinecke naval research laboratory, washington, dc 20375, united states abstract. Controllable ndoping of graphene beidou guo, qian liu, erdan chen, hewei zhu, liang fang, and jian ru gong, laboratory for nanodevices, national center for nanoscience and technology, china, 11 zhongguancun beiyitiao, beijing 100190, peoples republic of china, and department of applied physics, chongqing university, chongqing 400044, peoples republic. Thong, department of electrical and computer engineering, national university of singapore, singapore, singapore 117583 department of chemistry, national university of singapore, singapore, singapore 117543 s supporting information abstract.
Raman spectra of the annealed graphene show both the 2d. Note that there are also ohmic contacts between graphene and other metals in our samples, e. Graphene nanoparticle hybrids exist in two forms, as graphene. Knoch j, chen z, appenzeller j 2012 properties of metalgraphene contacts. Contact resistivity and current flow path at metal graphene contact k.
Graphene is a single layer monolayer of carbon atoms, tightly bound in a hexagonal honeycomb lattice. Adsorption of nh on graphene in the presence of defects and. The contact resistivity of metal on graphene and related 2d materials deserves special attention, while the schottky junctions formed between. In order to search a guideline to prepare lowresistance ohmic contacts to graphene by depositing a single metal element, the contact resistance r c is measured by a transmission line method tlm for a variety of metals ti, ag, co, cr, fe, ni, and pd contacting to the graphene channel. Graphene dispersion in nmp graphene oxide dispersions. Grapheneni110 has been studied by timeresolved xray photoelectron spectroscopy and nearedge xray absorption fine structure. Jul 11, 2017 low and reproducible metalgraphene contact resistance r c i. Improvement of graphenemetal contact resistance by. Nitrogendoped graphene and its electrochemical applications yuyan shao,a sheng zhang,a mark h. Nano res 1 graphenegan schottky diodes seongjun kim 1, tae hoon seo2, eunkyung suh, keun man song3, myung jong kim2, and hyunsoo kim1 nano res. The spectra show three main features in the 3000 cm1 region.
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