Controlled Radiation Damage and Edge Structures in Boron Nitride Membranes

Kim, Judy; Borisenko, Konstantin B.; Nicolosi, Valeria; Kirkland, Angus I.

doi:10.1021/nn2005443

Cited by 37 publications

(35 citation statements)

References 47 publications

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“…It was suggested that B atoms were knocked out to form such a kind of defects since the operating electron energy (80 keV) was close to the threshold energy (79.5 keV) to knock the B atoms out but far below that (118.6 keV) to knock the N atoms out . After 45 min (Figure c), some “nanoscrolls” appeared on the surface of the nanotube and more came out after 60 min (Figure d). Such “nanoscrolls” formed when the dangling part of the damaged walls peeled off during the irradiation.…”

Section: Resultsmentioning

confidence: 99%

Evolution of Irradiation‐Induced Vacancy Defects in Boron Nitride Nanotubes

Cheng

Yao

Sang

et al. 2015

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Irradiation-induced vacancy defects in multiwalled (MW) boron nitride nanotubes (BNNTs) are investigated via in situ high-resolution transmission electron microscope operated at 80 kV, with a homogeneous distribution of electron beam intensity. During the irradiation triangle-shaped vacancy defects are gradually generated in MW BNNTs under a mediate electron current density (30 A cm(-2)), by knocking the B atoms out. The vacancy defects grow along a well-defined direction within a wall at the early stage as a result of the curvature induced lattice strain, and then develop wall by wall. The orientation or the growth direction of the vacancy defects can be used to identify the chirality of an individual wall. With increasing electron current density, the shape of the irradiation-induced vacancy defects changes from regular triangle to irregular polygon.

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Section: Resultsmentioning

confidence: 99%

Evolution of Irradiation‐Induced Vacancy Defects in Boron Nitride Nanotubes

Cheng

Yao

Sang

et al. 2015

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“…To-date, the majority of structural studies on 2D h-BN have focused on the edge structures, topological, point, and substitutional defects, [15][16][17][18][19][20] largely ignoring stacking sequence and their local variations. In this paper we have investigated the stacking sequences present in sheets of h-BN produced by liquid-phase exfoliation of bulk h-BN in common organic solvents.…”

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confidence: 99%

Impurity induced non-bulk stacking in chemically exfoliated h-BN nanosheets

et al. 2013

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Structural characterization of 2D nanomaterials is an important step towards their future applications. In this work we carried out imaging and structural analysis of 2D h-BN produced by chemicalexfoliation, emphasizing the stacking order in few-layer sheets. Our analysis, for the first time has shown conclusively that non-bulk stacking can exist in 2D h-BN.Compounds with layered crystal structure are an emergent and diverse source of two-dimensional nanomaterials with high specic surface areas that are important for applications in sensing, 1 catalysis, 2 energy harvesting 3 and storage. 4 Whilst graphene is the most renowned, there is considerable interest in other layered materials such as 2D hexagonal boron nitride (h-BN). Electronically, h-BN is a dielectric with direct bandgap of approximately 5.8 eV 5 making it a candidate for applications as a substrate in graphene-based eld effect transistors 6,7 and a top-gate dielectric.8 Chemical exfoliation methods of bulk h-BN has been shown to produce useful quantities of monolayer and stacked bi-and few-layer 9 and a rapid growth in the technological applications of these is expected to follow. For these applications the structural properties of the material as synthesised will play an important role in determining the intrinsic properties and subsequent performance in devices.As we examine the structure and stacking of h-BN, it is important to note the possible high-symmetry structural models projected along the [001] and [110] directions based on variations of both "simple" and "Bernal" stacking oen reported in the literature for h-BN 10-12 (Scheme 1). These include: AA 0 stacking, usually found in the bulk h-BN material, where atomic columns projected along the [001] direction consist of alternating B and N atoms (Scheme 1a); AA stacking where monolayer structure repeats itself; and two other high symmetry congurations AB and ABC (Scheme 1c and d respectively) formed by shiing the h-BN layers by 1/3 and 1/3, 2/3 a unit cell as compared to the AA, respectively. Theoretical calculations indicate similar cohesive energies for all these models 10-12 where the AA type (which has not been observed experimentally in pure h-BN) is calculated as least energetically favourable.12 Moreover, AB stacking was shown to be the most stable for h-BN bilayers.11 Van der Waals forces have been predicted to determine the interlayer distance and electrostatic forces have been shown to dictate the optimal stacking sequence.13 This suggests that modications of stacking arrangements may occur through intercalation of ionic species between the layers and at the edges. In fact, a theoretical calculations of h-BN intercalated with neutral potassium suggest the AA stacking between the h-BN layers.

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“…A subsequent study highlighted an instance where a hexagonal defect formed in multilayer h-BN, under similar electron irradiation conditions (Warner et al, 2010). Another report showed, through EWF studies, that the edges of the flakes had an equal probability of displaying B or N terminations, for both monolayer and multilayered areas (Kim et al, 2011). A recent study has shown that the polarity of the defects which are created in h-BN depends on the temperature (Cretu et al, 2015); here it was found that at high-temperature N atoms are preferentially removed, creating N vacancies and B-terminated tetravacancies.…”

Section: Discussionmentioning

confidence: 94%

Inelastic electron irradiation damage in hexagonal boron nitride

Cretu

Lin

Suenaga

2015

Micron

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We present a study of the inelastic effects caused by electron irradiation in monolayer hexagonal boron nitride (h-BN). The data was obtained through in situ experiments performed inside a low-voltage aberration-corrected transmission electron microscope (TEM). By using various specialized sample holders, we study defect formation and evolution with sub-nanometer resolution over a wide range of temperatures, between -196 and 1200 °C, highlighting significant differences in the geometry of the structures that form. The data is then quantified, allowing insight into the defect formation mechanism, which is discussed in comparison with the potential candidate damage processes. We show that the defect shapes are determined by an interplay between electron damage, which we assign to charging, and thermal effects. We additionally show that this damage can be avoided altogether by overlapping the samples with a monolayer of graphene, confirming this for h-BN and providing a way to overcome the well-known fragility of h-BN under the electron beam.

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Controlled Radiation Damage and Edge Structures in Boron Nitride Membranes

Cited by 37 publications

References 47 publications

Evolution of Irradiation‐Induced Vacancy Defects in Boron Nitride Nanotubes

Evolution of Irradiation‐Induced Vacancy Defects in Boron Nitride Nanotubes

Impurity induced non-bulk stacking in chemically exfoliated h-BN nanosheets

Inelastic electron irradiation damage in hexagonal boron nitride

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