Electron-Beam-Induced Substitutional Carbon Doping of Boron Nitride Nanosheets, Nanoribbons, and Nanotubes

Wei, Xianlong; Wang, Mingsheng; Bando, Yoshio; Golberg, Dmitri

doi:10.1021/nn103548r

Cited by 261 publications

(199 citation statements)

References 29 publications

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“…Interestingly, recent experiments have shown that carbon substitution (doping) in BN nanostructures is favored at the edges. 9 Note that C N and B C (defects of set N ) are energetically favorable in a nitrogen-poor environment (B rich), and the same is true for N C and C B (set B) in a N-rich situation, so that the localization of defects at each edge of the heterojunction could be chemically controlled. Furthermore, when neutral C N and B C defects are formed, one hole is added to the system, so that these defects can act as electron traps.…”

Section: Resultsmentioning

confidence: 99%

“…Following the advances in experimental growth of hybrid C-BN nanostructures, [7][8][9] the stability of domain-separated C and BN nanosheets and nanotubes has been studied by first-principles simulations in the last few years. [10][11][12][13][14] There is general agreement that segregation is energetically advantageous, because B-N and C-C bonds are more stable than C-N and C-B bonds and the former are favored by the formation of C and BN domains.…”

Section: Introductionmentioning

confidence: 99%

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Native defects in hybrid C/BN nanostructures by density functional theory calculations

Pruneda

2012

Phys. Rev. B

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First-principles calculations of substitutional defects and vacancies are performed for zigzag-edged hybrid C/BN nanosheets and nanotubes which recently have been proposed to exhibit half-metallic properties. The formation energies show that defects form preferentially at the interfaces between graphene and BN domains rather than in the middle of these domains, and that substitutional defects dominate over vacancies. Chemical control can be used to favor localization of defects at C-B interfaces (nitrogen-rich environment) or C-N interfaces (nitrogen-poor environment). Although large defect concentrations have been considered here (10 6 cm −1 ), halfmetallic properties can subsist when defects are localized at the C-B interface and for negatively charged defects localized at the C-N interface; hence the promising magnetic properties theoretically predicted for these zigzag-edged nanointerfaces might not be destroyed by point defects if these are conveniently engineered during synthesis.

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Section: Resultsmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Native defects in hybrid C/BN nanostructures by density functional theory calculations

Pruneda

2012

Phys. Rev. B

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“…In the case of MoS 2 , we also carry out HR-TEM experiments and provide evidence of electron-irradiation-induced production of vacancies in this material. In addition -inspired by the recent advances in introducing impurities in h-BN monolayers [24,25] -we discuss irradiation-mediated doping of TMD materials.…”

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confidence: 99%

Two-Dimensional Transition Metal Dichalcogenides under Electron Irradiation: Defect Production and Doping

et al. 2012

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Using first-principles atomistic simulations, we study the response of atomically-thin layers of transition metal dichalcogenides (TMDs) -a new class of two-dimensional inorganic materials with unique electronic properties -to electron irradiation. We calculate displacement threshold energies for atoms in 21 different compounds and estimate the corresponding electron energies required to produce defects. For a representative structure of MoS2, we carry out high-resolution transmission electron microscopy experiments and validate our theoretical predictions via observations of vacancy formation under exposure to a 80 keV electron beam. We further show that TMDs can be doped by filling the vacancies created by the electron beam with impurity atoms. Thereby, our results not only shed light on the radiation response of a system with reduced dimensionality, but also suggest new ways for engineering the electronic structure of TMDs. [6,7]. Recently, TMDs with a common structural formula MeX 2 , where Me stands for transition metals (Mo, W, Ti, etc.) and X for chalcogens (S, Se, Te), have received considerable attention. These 2D materials are expected to have electronic properties varying from metals to wide-gap semiconductors, similar to their bulk counterparts [8,9], and excellent mechanical characteristics [10]. The monolayer TMD materials have already shown a good potential in nanoelectronic [3,11,12] and photonic [4,13,14] applications.Characterization of the h-BN [15-17] and TMD [5,6,18] samples has extensively been carried out using high-resolution transmission electron microscopy (HR-TEM). During imaging, however, energetic electrons in the TEM can give rise to production of defects due to ballistic displacements of atoms from the sample and beam-stimulated chemical etching [19], as studies on h-BN membranes also indicate [15][16][17]20].Contrary to h-BN, very little is known about the effects of electron irradiation on TMDs. So far, atomic defects have been observed via HR-TEM in WS 2 nanoribbons encapsulated inside carbon nanotubes at electron acceleration voltage of 60 kV [21] as well as at the edges of MoS 2 clusters under 80 kV irradiation [22], while no significant damage or amorphization was reported for MoS 2 sheets at 200 kV [18] -a surprising result taking into account the relatively low atomic mass of the S atom. Clearly, precise microscopic knowledge of defect production in TMDs under electron irradiation is highly desirable for assessing the effects of the beam on the samples. This knowledge would allow designing experimental conditions required to minimize damage, as well as developing beam-mediated post-synthesis doping techniques. Moreover, information on the displacement thresholds is important in the context of fundamental aspects of the interaction of beams of energetic particles with solids, as the reduced dimensionality may give rise to an irradiation response different from that in the bulk counterpart of the 2D material [23].Here, by employing first-principles simulations, we study the ...

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“…It has been shown that strain-engineering could shrink the band gap [27,32] but so far not enough to make h-BN useful for field-effect transistors (FETs). Motivated in part by the recent experimental observation of IMTs in h-BN nanostructures [8] and related materials [33], we explore the possibility to obtain conduction in h-BN through a disorder-induced IMT. Our calculations reveal an IMT requiring the presence of both electron interactions and disorder with the transition following a monotonic curve [see Fig.…”

Section: (A)mentioning

confidence: 99%

“…, and a combination of both [3][4][5] have been shown to lead to diverse emerging phenomena in a wide range of physical systems, one of which is the insulator-metal transition (IMT) [6,7]. Though disorder and electron interactions can independently lead to an IMT, transport and scanning probe measurements have shown that both are needed for a proper characterization of real materials [4,6,8]. Computational approaches for studying correlated, disordered materials generally rely on either density functional theory (DFT) [9] using supercells or the dynamical meanfield approximation (DMFA) [10], including cluster extensions [2,12].…”

mentioning

confidence: 99%

First-Principles-Based Method for Electron Localization: Application to Monolayer Hexagonal Boron Nitride

2017

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We present a first-principles-based many-body typical medium dynamical cluster approximation method for characterizing electron localization in disordered structures. This method applied to monolayer hexagonal boron nitride shows that the presence of a boron vacancies could turn this wide-gap insulator into a correlated metal. Depending on the strength of the electron interactions, these calculations suggest that conduction could be obtained at a boron vacancy concentration as low as 1.0%. We also explore the distribution of the local density of states, a fingerprint of spatial variations, which allows localized and delocalized states to be distinguished. The presented method enables the study of disorder-driven insulator-metal transitions not only in h-BN but also in other physical materials. , and a combination of both [3][4][5] have been shown to lead to diverse emerging phenomena in a wide range of physical systems, one of which is the insulator-metal transition (IMT) [6,7]. Though disorder and electron interactions can independently lead to an IMT, transport and scanning probe measurements have shown that both are needed for a proper characterization of real materials [4,6,8]. Computational approaches for studying correlated, disordered materials generally rely on either density functional theory (DFT) [9] using supercells or the dynamical meanfield approximation (DMFA) [10], including cluster extensions [2,12]. While the DFT supercell approach can only describe ordered defect structures, DMFA deals explicitly with statistical disorder distributions [13], as does the coherent potential approximation (CPA). Traditional DMFA/CPA methods use arithmetic averages in their self-consistent-field (SCF) routines, and therefore lose essential information about the distribution of the local density of states ρ. Moreover, these methods use arithmetically averaged density of states, ρ a ≡ ρ arit , which cannot distinguish between extended and localized states [4,14]. Therefore, we will instead adopt the typical medium dynamical cluster approximation (TMDCA) [3,4,14], which is built around a geometrically averaged density of states ρ g ≡ ρ geom . This latter average is sensitive to skewness in the local density of states distribution P[ρ] [see Fig. 1(B)], making ρ g a suitable order parameter for characterizing localization transitions [4,14,17,18]. The TMDCA approach has both experimental and theoretical support [3-6, 14, 19, 20] and has been successfully used to describe disordered and/or interacting model systems [3,4].In this letter, we extend the TMDCA approach to physical materials with electronic properties computed from density-functional theory (TMDCA@DFT). See schematic in Fig. 1(A). This first-principles-based manybody approach is expected to provide further insight

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Electron-Beam-Induced Substitutional Carbon Doping of Boron Nitride Nanosheets, Nanoribbons, and Nanotubes

Cited by 261 publications

References 29 publications

Native defects in hybrid C/BN nanostructures by density functional theory calculations

Native defects in hybrid C/BN nanostructures by density functional theory calculations

Two-Dimensional Transition Metal Dichalcogenides under Electron Irradiation: Defect Production and Doping

First-Principles-Based Method for Electron Localization: Application to Monolayer Hexagonal Boron Nitride

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