Half-metallic graphene nanoribbons

Son, Young‐Woo; Cohen, Marvin L.; Louie, Steven G.

doi:10.1038/nature05180

Cited by 3,999 publications

(3,710 citation statements)

References 30 publications

(48 reference statements)

Supporting

145

Mentioning

3,531

Contrasting

Unclassified

Order By: Relevance

“…124 On the basis of calculations, the observed magnetic behavior in all these systems was explained in terms of defects in the graphitic network (either native or produced by ion irradiation) such as under-coordinated carbon atoms, for example, vacancies, 125 interstitials, 126 carbon adatoms, 47 and atoms at the edges of graphitic nanofragments with dangling bonds either passivated with hydrogen atoms or free. 127 Such defects have local magnetic moments and may give rise to flat bands and eventually to the development of magnetic ordering. Magnetism may also originate from impurity atoms which are nonmagnetic by themselves (such as hydrogen or nitrogen), but because of the specific chemical environment give rise to local magnetic moments.…”

Section: Properties Of Defective Graphenementioning

confidence: 99%

Structural Defects in Graphene

2010

View full text Add to dashboard Cite

Graphene is one of the most promising materials in nanotechnology. The electronic and mechanical properties of graphene samples with high perfection of the atomic lattice are outstanding, but structural defects, which may appear during growth or processing, deteriorate the performance of graphenebased devices. However, deviations from perfection can be useful in some applications, as they make it possible to tailor the local properties of graphene and to achieve new functionalities. In this article, the present knowledge about point and line defects in graphene are reviewed. Particular emphasis is put on the unique ability of graphene to reconstruct its lattice around intrinsic defects, leading to interesting effects and potential applications. Extrinsic defects such as foreign atoms which are of equally high importance for designing graphene-based devices with dedicated properties are also discussed.

show abstract

Section: Properties Of Defective Graphenementioning

confidence: 99%

Structural Defects in Graphene

2010

View full text Add to dashboard Cite

show abstract

“…Theoretical and experimental studies indicate that B-or N-doped graphenes reveal p-or n-type semiconductor characteristics [15][16][17] accompanied by a band gap opening [18][19][20] and thus doped 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 graphene and structurally related graphene nanoribbons are considered as promising materials with tunable electronic properties. 21,22 N-Doped graphene, and particularly B-doped graphene are still scarcely investigated experimentally as compared to graphene 23 and graphene oxide. 24 So far, few methods for generating N-doped graphene are described.…”

Section: Thermally Induced Chemical Vapor Deposition (Cvd) Was Used Tmentioning

confidence: 99%

“…21,22 N-Doped graphene, and particularly B-doped graphene are still scarcely investigated experimentally as compared to graphene 23 and graphene oxide. 24 So far, few methods for generating N-doped graphene are described.…”

mentioning

confidence: 99%

Chemical Vapor Deposition of N-Doped Graphene and Carbon Films: The Role of Precursors and Gas Phase

et al. 2014

View full text Add to dashboard Cite

Thermally induced chemical vapor deposition (CVD) was used to study the formation of nitrogen doped graphene and carbon films on copper from aliphatic nitrogen containingprecursors consisting of C 1 -and C 2 -units and (hetero) The deposition of carbon films from the gas phase leads to materials of widely different structure and composition. The films can be i) crystalline, e.g. like graphene, graphite or diamond and consist ideally of a single type of either sp 2 or sp 3 -hybridized carbon atoms, ii) can contain domains of any of these phases in more or less ordered arrangements, or iii) can even incorporate a considerable amount of hydrogen or other heteroatoms. Within this manifold of carbon films, graphene, a two-dimensional allotrope of carbon has recently attained high interest due to its electronic and optical properties and chemical inertness. [1][2][3] Graphene with controllable electronic properties is expected to be a promising material for the development of new electronic devices, 4,5 such as e.g. field-effect transistors 6 or electrochemical sensors, 7,8 as well as for applications in energy storage 9,10 and conversion systems like super capacitors, 11 lithium batteries, 12 and fuel cells. 13 Furthermore, transparent conducting graphene films are considered for organic electronic devices such as OLED's and organic solar cells. 14 Graphene itself does not reveal a band gap and therefore has no intrinsic semiconducting properties. Thus, doping of graphene with heteroelements like boron (B) or nitrogen (N), which fit into the carbon lattice, is an important issue. Theoretical and experimental studies indicate that B-or N-doped graphenes reveal p-or n-type semiconductor characteristics [15][16][17] accompanied by a band gap opening [18][19][20] and thus doped 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 graphene and structurally related graphene nanoribbons are considered as promising materials with tunable electronic properties. 21,22 N-Doped graphene, and particularly B-doped graphene are still scarcely investigated experimentally as compared to graphene 23 and graphene oxide. 24 So far, few methods for generating N-doped graphene are described. Among these are thermal CVD of methane and ammonia gas, 25 CVD of molecular precursors like pyridine 26 or acetonitrile 27 on a Cu substrate or exposure of graphene to a nitrogen 28 or ammonia 29 containing plasma discharge.In these reactions, the presence of nitrogen was identified by XPS, whereas the mechanism for nitrogen incorporation at specific positions of the graphene lattice is still not understood. 15,16,30 Recently, the formation mechanism of graphene from molecular precursors has been investigated. From the decay it was reasoned that dicarbon (C 2 -) species, formed as reaction intermediates, can contribute significantly to the built-up of graphene. 31 Sin...

show abstract

“…5 One of the attractive features of free-standing graphene, a semimetal, is its semiconducting behavior 6,7 at length scales below 500 Å with a size-dependent band gap. [8][9][10] Previous reports [11][12][13] have shown that a band gap can also be opened in graphene grown on insulating SiC(0001) and BN(0001) via interactions with the substrate.…”

mentioning

confidence: 99%

Growth of Semiconducting Graphene on Palladium

et al. 2009

View full text Add to dashboard Cite

We report in situ scanning tunneling microscopy studies of graphene growth on Pd(111) during ethylene deposition at temperatures between 723 and 1023 K. We observe the formation of monolayer graphene islands, 200-2000 Å in size, bounded by Pd surface steps. Surprisingly, the topographic image contrast from graphene islands reverses with tunneling bias, suggesting a semiconducting behavior. Scanning tunneling spectroscopy measurements confirm that the graphene islands are semiconducting, with a band gap of 0.3 ( 0.1 eV. On the basis of density functional theory calculations, we suggest that the opening of a band gap is due to the strong interaction between graphene and the Pd substrate. Our findings point to the possibility of preparing semiconducting graphene layers for future carbon-based nanoelectronic devices via direct deposition onto strongly interacting substrates.Graphene 1,2 sa two-dimensional crystalline sheet of carbon atoms arranged in a honeycomb latticesgenerated enormous interest in the research community owing to its ultrathin geometry and properties such as high carrier mobility, 3 excellent thermal conductivity, 4 and high mechanical strength. 5 One of the attractive features of free-standing graphene, a semimetal, is its semiconducting behavior 6,7 at length scales below 500 Å with a size-dependent band gap. [8][9][10] Previous reports [11][12][13] have shown that a band gap can also be opened in graphene grown on insulating SiC(0001) and BN(0001) via interactions with the substrate. Here, we report the formation of semiconducting graphene layers with a band gap of 0.3 ( 0.1 eV on Pd(111), a metallic substrate. Using in situ scanning tunneling microscopy (STM) and spectroscopy (STS), we determine the electronic structure of graphene islands grown in situ via chemical vapor deposition on Pd(111). In contrast to recent reports on nanoribbons, where the band gap originates from size/ edge effects, 8-10 the band gap in epitaxial graphene on palladium is caused by a strong interaction with the Pd substrate and the ensuing breaking of translational symmetry between the two hexagonal close-packed sublattices of graphene. Our experiments illustrate the control over the electronic properties of graphene through interactions with substrates in well-defined epitaxial configurations. This approach opens up the possibility of preparing metal-semiconducting graphene structures and metal-doped graphenebased devices with potentially new applications.Using STM, we followed the formation and growth of graphene on Pd(111) during ethylene deposition over a range of pressures, substrate temperatures, and times. Panels A and B of Figure 1 are representative STM images of graphene islands acquired from a Pd(111) surface in situ during ethylene deposition at 968 K. In our experiments, island sizes vary between 200 and 2000 Å and are commonly observed at or near the Pd step edges as in Figure 1A, or spanning across multiple terraces as in Figure 1B. During ethylene deposition, we observe graphene islands on the...

show abstract

Half-metallic graphene nanoribbons

Cited by 3,999 publications

References 30 publications

Structural Defects in Graphene

Structural Defects in Graphene

Chemical Vapor Deposition of N-Doped Graphene and Carbon Films: The Role of Precursors and Gas Phase

Growth of Semiconducting Graphene on Palladium

Contact Info

Product

Resources

About