A systematic study of the atmospheric pressure growth of large-area hexagonal crystalline boron nitride film

Tay, Roland Yingjie; Wang, Xingli; Tsang, Siu Hon; Loh, G. C.; Singh, Ram Sevak; Li, Hong; Mallick, Govind; Teo, Edwin Hang Tong

doi:10.1039/c3tc32011a

Cited by 76 publications

(95 citation statements)

References 38 publications

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“…Methods describes the growth by atmospheric-pressure chemical vapor deposition (APCVD) (20) on cold-rolled copper foils. Except for the precursor, the conditions were the same as we previously used to grow graphene crystallites (19).…”

Section: Resultsmentioning

confidence: 99%

Unusual role of epilayer–substrate interactions in determining orientational relations in van der Waals epitaxy

Liu

Siegel

Chen

et al. 2014

Proc. Natl. Acad. Sci. U.S.A.

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Using selected-area low-energy electron diffraction analysis, we showed strict orientational alignment of monolayer hexagonal boron nitride (h-BN) crystallites with Cu(100) surface lattices of Cu foil substrates during atmospheric pressure chemical vapor deposition. In sharp contrast, the graphene-Cu(100) system is well-known to assume a wide range of rotations despite graphene's crystallographic similarity to h-BN. Our density functional theory calculations uncovered the origin of this surprising difference: The crystallite orientation is determined during nucleation by interactions between the cluster's edges and the substrate. Unlike the weaker B-and N-Cu interactions, strong C-Cu interactions rearrange surface Cu atoms, resulting in the aligned geometry not being a distinct minimum in total energy. The discovery made in this specific case runs counter to the conventional wisdom that strong epilayer-substrate interactions enhance orientational alignment in epitaxy and sheds light on the factors that determine orientational relation in van der Waals epitaxy of 2D materials.two-dimensional materials | van der Waals epitaxy | hexagonal boron nitride | graphene | orientational relation R esearch on van der Waals (vdW) heterostructures formed by stacking up various 2D crystals is an emerging field (1) because the numerous possible interfaces may lead to new physics not necessarily associated with the constituent 2D materials and, therefore, to novel applications. Most pioneering works on vdW heterostructures are based on mechanical placement of exfoliated 2D crystal flakes (2-4), where uncertainty in the orientational relation between layers is inevitable. For some purposes, e.g., to enhance graphene's transport by placing it on hexagonal boron nitride (3) (h-BN, or simply BN hereafter), the orientational relation is not important. In other cases, however, a definitive orientational relation is necessary for certain physical properties to arise. Examples include the tunneling behavior of a graphene-insulator-graphene junction (5) and the band structure of graphene placed on top of BN (2).The only practical way to achieve certainty in orientational relation, or azimuthal order, in vdW heterostructures is epitaxial growth. Actually, vdW epitaxy has been studied for decades as a method to overcome lattice mismatch (6, 7) enabled by the relatively weak and flexible vdW interactions between the epilayer and the substrate. Although vdW epitaxy [or quasiepitaxy (8)] is typically incommensurate, there can be a well-defined orientational relation (8), which has been observed in many examples of vdW epitaxy (6, 7, 9-11). In some cases, however, a definitive epilayer-substrate orientational relation is lacking (12, 13). At the moment when vdW epitaxy is shaping into a new thrust area in 2D crystal research, it is imperative to uncover the mechanisms that determine the orientational relation.Epilayer-substrate interactions lead to registry in commensurate epitaxy, which naturally guarantees orientational alignment between the...

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Section: Resultsmentioning

confidence: 99%

Unusual role of epilayer–substrate interactions in determining orientational relations in van der Waals epitaxy

Liu

Siegel

Chen

et al. 2014

Proc. Natl. Acad. Sci. U.S.A.

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“…For example, for their thin films, Tay et al [26] reported a typical hBN domain size that was less than 1.0 square microns. Using transmission electron microscopy, Levendorf et al [27] established their hBN grain size was on the order of 1 to 10 microns.…”

Section: Discussionmentioning

confidence: 99%

Characterization of bulk hexagonal boron nitride single crystals grown by the metal flux technique

Edgar

Hoffman

Clubine

et al. 2014

Journal of Crystal Growth

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“…However, the flakes are obtained through a highly skilled manual process-mechanical exfoliation and transferring, which is not a scalable method for practical applications. So far, many efforts have been taken on various substrates such as Ni [16][17][18][19][20][21] , Cu 3,[21][22][23][24][25][26][27] , Pt 28,29 , Ru 30,31 and Co 32 to obtain large h-BN crystals via the chemical vapour deposition (CVD) process. However, those grains in h-BN films are very small (usually o50 mm 2 ) because of high nucleation density at the early growth stages 10,11,[15][16][17]19,22 .…”

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confidence: 99%

Synthesis of large single-crystal hexagonal boron nitride grains on Cu–Ni alloy

et al. 2015

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Hexagonal boron nitride (h-BN) has attracted significant attention because of its superior properties as well as its potential as an ideal dielectric layer for graphene-based devices. The h-BN films obtained via chemical vapour deposition in earlier reports are always polycrystalline with small grains because of high nucleation density on substrates. Here we report the successful synthesis of large single-crystal h-BN grains on rational designed Cu-Ni alloy foils. It is found that the nucleation density can be greatly reduced to 60 per mm 2 by optimizing Ni ratio in substrates. The strategy enables the growth of single-crystal h-BN grains up to 7,500 mm 2 , approximately two orders larger than that in previous reports. This work not only provides valuable information for understanding h-BN nucleation and growth mechanisms, but also gives an effective alternative to exfoliated h-BN as a high-quality dielectric layer for large-scale nanoelectronic applications.

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A systematic study of the atmospheric pressure growth of large-area hexagonal crystalline boron nitride film

Cited by 76 publications

References 38 publications

Unusual role of epilayer–substrate interactions in determining orientational relations in van der Waals epitaxy

Unusual role of epilayer–substrate interactions in determining orientational relations in van der Waals epitaxy

Characterization of bulk hexagonal boron nitride single crystals grown by the metal flux technique

Synthesis of large single-crystal hexagonal boron nitride grains on Cu–Ni alloy

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