Triggering the atomic layers control of hexagonal boron nitride films

Yang, Xuejin; Zhang, Changrui; Li, Bin; Jiang, Ding‐Sheng; Ding, Guqiao; Wang, Haomin; Xie, Xiaoming

doi:10.1016/j.apsusc.2014.06.040

Cited by 23 publications

(13 citation statements)

References 37 publications

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“…Thus, low pressure, ammonia-borane derived h-BN syntheses proceed by both bulk precipitation and surface catalysis. Further, these findings are consistent the recent observation of bulk precipitation for CVD h-BN growth on Ni and Co foils. , …”

Section: Resultssupporting

confidence: 92%

“…Further, these findings are consistent the recent observation of bulk precipitation for CVD h-BN growth on Ni and Co foils. 73,75 Figure 4a shows FTIR spectra for h-BN films grown under a variety of conditions; a spectrum of the bare Cu foil is also presented. The h-BN samples all have a peak near ∼824 cm −1 for the A 2u out-of-plane h-BN vibration.…”

Section: ■ Resultsmentioning

confidence: 99%

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Role of Pressure in the Growth of Hexagonal Boron Nitride Thin Films from Ammonia-Borane

et al. 2016

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We analyze the optical, chemical, and electrical properties of chemical vapor deposition (CVD) grown hexagonal boron nitride (h-BN) using the precursor ammonia-borane (H3N-BH3) as a function of Ar/H2 background pressure (PTOT). Films grown at PTOT ≤ 2.0 Torr are uniform in thickness, highly crystalline, and consist solely of h-BN. At larger PTOT, with constant precursor flow, the growth rate increases, but the resulting h-BN is more amorphous, disordered, and sp 3 bonded. We attribute these changes in h-BN grown at high pressure to incomplete thermolysis of the H3N-BH3 precursor from a passivated Cu catalyst. A similar increase in h-BN growth rate and amorphization is observed even at low PTOT if the H3N-BH3 partial pressure is initially greater than the background pressure PTOT at the beginning of growth. h-BN growth using the H3N-BH3 precursor reproducibly can give large-area, crystalline h-BN thin films, provided that the total pressure is under 2.0 Torr and the precursor flux is well-controlled.* Correspondence should be addressed to lyding@illinois.edu, jkoepkeuiuc@gmail.com, and joshua.wood@northwestern.edu. Films of h-BN have been used as insulating spacers, 1 encapsulants, 2 substrates for electronic devices, 3, 4 corrosion and oxidation-resistant coatings, 5, 6 and surfaces for growth of other 2D nanomaterials such as graphene 7 and WS2. 8 Most of these studies employed small-area (~100 µm 2 ) h-BN pieces exfoliated from sintered h-BN crystals, 9 limiting technological use of h-BN films. Additionally, unlike graphene, h-BN is difficult to prepare in monolayer form by exfoliation. The electronegativity difference between B and N and the reduced resonance stabilization relative to graphene results in electrostatic attractions between layers and in-plane. Consequently, it is more challenging to control h-BN grain size and layer number. Furthermore, partially ionic B-N bonds can form between neighboring BN layers, serving to "spot weld" such layers together. 10 Several groups have sought to overcome these limitations by using chemical vapor deposition (CVD) to grow large-area, monolayer h-BN films. [11][12][13][14][15][16][17][18][19][20][21][22] CVD growth of h-BN has been accomplished using various precursors (e.g., ammonia borane, borazine, and diborane) on transition metal substrates (e.g., Cu, Ni, 23 Fe, 24 Ru, 25, 26 etc.). Of these h-BN growth substrates, we focus on Cu, as Cu has a high catalytic activity, 27 is inexpensive, and is the typical growth substrate 28 for conventional graphene CVD.Regarding h-BN growth precursors, volatile borazine-B3N3H6, isoelectronic with benzene-is far from an ideal choice, as borazine is hazardous and decomposes quickly even at room temperature. While borazine can pyrolyze and dehydrogenate 23, 25,29,30 to generate h-BN films, 13,17,19,20,22,31 partial dehydrogenation is common, [30] resulting in oligomeric BN compounds and aperiodic h-BN grain boundaries. 13,17 Finally, thin films of h-BN can also be grown from mixtures of diborane (B2H6) and ammonia (NH3...

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Section: Resultssupporting

confidence: 92%

Section: ■ Resultsmentioning

confidence: 99%

Role of Pressure in the Growth of Hexagonal Boron Nitride Thin Films from Ammonia-Borane

et al. 2016

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“…The thicknesses of the flakes were measured to be around 0.45 nm, which corresponds to one atomic layer. This phenomenon is also reported by other workers . The crystalline h‐BN flakes adopt a triangular shape due to the asymmetric edge energy of the B‐rich and N‐rich sides, where all three sides should be N‐terminated as it is energetically more favorable .…”

Section: Resultssupporting

confidence: 85%

Seven‐inch large‐size synthesis of monolayer hexagonal BN film by low‐pressure CVD

Soomro

Sun

et al. 2015

Physica Status Solidi (b)

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We report the large-size synthesis of atomic monolayer hexagonal boron nitride (h-BN) film on flexible Cu foil by a low-pressure chemical vapor deposition (CVD) method. The borazane powder was used as the precursor carried by mixed hydrogen/argon gases. By rolling the Cu foil substrate into a cylindrical shape, wafer-scale monolayer h-BN film has been achieved at a size over 7 in. With the aid of PMMA, the h-BN monolayer was transferred onto a 4 00 Si wafer for characterization and further electrical applications. This technique could be transferred to thin-film growth on any flexible substrates.

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“…The majority of wrinkle junctions (>90%) are 3-fold and form oriented honeycomb pattern indicating that it is under isotropic biaxial compression strain . This wrinkle pattern is a ubiquitous phenomenon for deformed graphene due to its low bending rigidity − and was also observed in h-BN monolayer or a few layer flakes. ,,,, It is characteristic of graphene and h-BN due to their negative thermal expansion coefficient. − Hexagonal BN has an in-plane thermal expansion coefficient of −2.7 × 10 –6 K –1 , while sapphire has a positive coefficient of 5.0 × 10 –6 K –1 . Consequently, during the cooling process from the growth temperature of 1280 °C, the induced compressive strain in the layer leads to the wrinkling instability to release the energy.…”

Section: Resultsmentioning

confidence: 99%

Large-Area Two-Dimensional Layered Hexagonal Boron Nitride Grown on Sapphire by Metalorganic Vapor Phase Epitaxy

Sundaram

Gmili

et al. 2016

Crystal Growth & Design

121

118

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This article reports on two-dimensional (2D) layered hexagonal BN (h-BN) grown on sapphire by metalorganic vapor phase epitaxy (MOVPE). The highly oriented lattice and hexagonal phase of the epitaxial layers were confirmed by X-ray diffraction, Raman spectrum, and cross-section scanning transmission electron microscopy. The surface of BN over a 2-in. wafer exhibits specific 2D material morphology features for different BN thicknesses, from an atomically flat surface to a honeycomb wrinkle network. The grown epitaxial layers demonstrate a large absorption coefficient (∼10 6 cm −1 ) above the bandgap energy of 5.87 eV with direct band transition behavior. Near-bandgap luminescence at 216.5 nm (5.73 eV) and characteristic defect band recombination at longer wavelengths were observed by cathodoluminescence at 77 K. This wafer-scale MOVPE-grown layered h-BN with different 2D morphology and with near bandgap emission can facilitate applications such as graphene-based electronics, advanced van der Waals heterostructures, and deep UV photonics.

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Triggering the atomic layers control of hexagonal boron nitride films

Cited by 23 publications

References 37 publications

Role of Pressure in the Growth of Hexagonal Boron Nitride Thin Films from Ammonia-Borane

Role of Pressure in the Growth of Hexagonal Boron Nitride Thin Films from Ammonia-Borane

Seven‐inch large‐size synthesis of monolayer hexagonal BN film by low‐pressure CVD

Large-Area Two-Dimensional Layered Hexagonal Boron Nitride Grown on Sapphire by Metalorganic Vapor Phase Epitaxy

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