Impact of Copper Overpressure on the Synthesis of Hexagonal Boron Nitride Atomic Layers

Bresnehan, Michael S.; Bhimanapati, Ganesh R.; Wang, Ke; Snyder, David W.; Robinson, Joshua A.

doi:10.1021/am503844u

Cited by 21 publications

(18 citation statements)

References 34 publications

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“…In addition, it is worth to note that these smaller devices have similar leakage current at lower bias compared with those based on mechanically exfoliated BN films 41 . The hard breakdown phenomenon can be observed in the range of 3.0~3.3 MV/cm, which is comparable with the values from the devices based on h-BN films grown by CVD 8 11 42 and exfoliated h-BN films 43 . In addition to the vertical electrical characterizations, in-plane electrical characterizations were also carried out on a transferred h-BN thin film of Sample D on SiO 2 ( Figure S5 ).…”

Section: Resultssupporting

confidence: 84%

Large-area growth of multi-layer hexagonal boron nitride on polished cobalt foils by plasma-assisted molecular beam epitaxy

Tian

Khanaki

et al. 2017

Sci Rep

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Two-dimensional (2D) hexagonal boron nitride (h-BN), which has a similar honeycomb lattice structure to graphene, is promising as a dielectric material for a wide variety of potential applications based on 2D materials. Synthesis of high-quality, large-size and single-crystalline h-BN domains is of vital importance for fundamental research as well as practical applications. In this work, we report the growth of h-BN films on mechanically polished cobalt (Co) foils using plasma-assisted molecular beam epitaxy. Under appropriate growth conditions, the coverage of h-BN layers can be readily controlled by growth time. A large-area, multi-layer h-BN film with a thickness of 5~6 nm is confirmed by Raman spectroscopy, scanning electron microscopy, X-ray photoelectron spectroscopy and transmission electron microscopy. In addition, the size of h-BN single domains is 20~100 μm. Dielectric property of as-grown h-BN film is evaluated by characterization of Co(foil)/h-BN/Co(contact) capacitor devices. Breakdown electric field is in the range of 3.0~3.3 MV/cm, which indicates that the epitaxial h-BN film has good insulating characteristics. In addition, the effect of substrate morphology on h-BN growth is discussed regarding different domain density, lateral size, and thickness of the h-BN films grown on unpolished and polished Co foils.

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Section: Resultssupporting

confidence: 84%

Large-area growth of multi-layer hexagonal boron nitride on polished cobalt foils by plasma-assisted molecular beam epitaxy

Tian

Khanaki

et al. 2017

Sci Rep

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“…66 The faint striations running diagonally from upper right to lower left are attributed to thermally induced wrinkles in the h-BN overlayer. 13,16,32,36,67 Figure 1b Figure S3 and S4. Figure 2a shows an h-BN film grown at PTOT = 1.2 Torr (LPCVD regime); the film edge is indicated by the dashed, blue line.…”

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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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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“…It is possible to be viewed in Figure 2H for monolayer, drifts to higher wave number of 1370 cm −1 noticed due to the Raman peak broadens and when it compared with the bulk, which is 1366 eV. This study evidently flaunts BNNS formation through the red shift, which could be used later as standard to ensure BNNS presence [9].…”

Section: Structural Properties Of H-bnmentioning

confidence: 73%

Significance of Boron Nitride in Composites and Its Applications

Rathinasabapathy¹,

Sekar²,

Asokan³

2020

Recent Advances in Boron-Containing Materials

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Boron nitride (BN) exists in several polymorphic forms such as a-BN, h-BN, t-BN, r-BN, m-BN, o-BN, w-BN, and c-BN phases. Among them, c-BN and h-BN are the most common ceramic powders used in composites to ensure enhanced material properties. Cubic boron nitride (c-BN) has exceptional properties such as hardness, strength than relating with other ceramics so that are most commonly used as abrasives and in cutting tool applications. c-BN possesses the second highest thermal conductivity after diamond and relatively low dielectric constant. Hence pioneer preliminary research in AMCs proven substitute composites than virgin AA 6061 traditionally used for fins in heat sinks. Moreover, poly-crystalline c-BN (PCBN) tools are most suitable for various machining tasks due to their unmatchable mechanical properties. h-BN also finds its own unique applications where polymer composites for high temperature applications and sp 3 bonding in extreme temperature and compression conditions.

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Impact of Copper Overpressure on the Synthesis of Hexagonal Boron Nitride Atomic Layers

Cited by 21 publications

References 34 publications

Large-area growth of multi-layer hexagonal boron nitride on polished cobalt foils by plasma-assisted molecular beam epitaxy

Large-area growth of multi-layer hexagonal boron nitride on polished cobalt foils by plasma-assisted molecular beam epitaxy

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

Significance of Boron Nitride in Composites and Its Applications

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