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BeH is Boron Nitride structured and crystallizes in the hexagonal P6_3mc space group. The structure is three-dimensional. Be is bonded in a rectangular see-saw-like geometry to four equivalent H atoms. All Be–H bond lengths are 1.67 Å. H is bonded in a rectangular see-saw-like geometry to four equivalent Be atoms.
RhBr is Boron Nitride structured and crystallizes in the hexagonal P6_3mc space group. The structure is three-dimensional. Rh is bonded in a rectangular see-saw-like geometry to four equivalent Br atoms. There are one shorter (2.43 Å) and three longer (2.53 Å) Rh–Br bond lengths. Br is bonded in a rectangular see-saw-like geometry to four equivalent Rh atoms.
CaBr is Boron Nitride structured and crystallizes in the hexagonal P6_3mc space group. The structure is three-dimensional. Ca is bonded in a rectangular see-saw-like geometry to four equivalent Br atoms. There are one shorter (2.96 Å) and three longer (3.01 Å) Ca–Br bond lengths. Br is bonded in a rectangular see-saw-like geometry to four equivalent Ca atoms.
CuBr is Boron Nitride-like structured and crystallizes in the hexagonal P6_3/mmc space group. The structure is two-dimensional and consists of two CuBr sheets oriented in the (0, 0, 1) direction. Cu1+ is bonded in a trigonal planar geometry to three equivalent Br1- atoms. All Cu–Br bond lengths are 2.39 Å. Br1- is bonded in a trigonal planar geometry to three equivalent Cu1+ atoms.
BN is Boron Nitride-like structured and crystallizes in the hexagonal P6_3/mmc space group. The structure is two-dimensional and consists of two BN sheets oriented in the (0, 0, 1) direction. B3+ is bonded in a trigonal planar geometry to three equivalent N3- atoms. All B–N bond lengths are 1.45 Å. N3- is bonded in a trigonal planar geometry to three equivalent B3+ atoms.
NaC64 is Boron Nitride-like structured and crystallizes in the hexagonal P6_3/mmc space group. The structure is two-dimensional and consists of two natrium molecules and sixteen C sheets oriented in the (0, 0, 1) direction. In each C sheet, C+0.02- is bonded in a trigonal planar geometry to three equivalent C+0.02- atoms. There is one shorter (1.42 Å) and two longer (1.43 Å) C–C bond length.
BN is Boron Nitride-like structured and crystallizes in the hexagonal P-6m2 space group. The structure is two-dimensional and consists of two BN sheets oriented in the (0, 0, 1) direction. B3+ is bonded in a trigonal planar geometry to three equivalent N3- atoms. All B–N bond lengths are 1.45 Å. N3- is bonded in a trigonal planar geometry to three equivalent B3+ atoms.
BN is Boron Nitride-like structured and crystallizes in the hexagonal P6_3mc space group. The structure is two-dimensional and consists of two BN sheets oriented in the (0, 0, 1) direction. B3+ is bonded in a trigonal planar geometry to three equivalent N3- atoms. All B–N bond lengths are 1.45 Å. N3- is bonded in a trigonal planar geometry to three equivalent B3+ atoms.
GaN is Boron Nitride-like structured and crystallizes in the hexagonal P6_3/mmc space group. The structure is two-dimensional and consists of two GaN sheets oriented in the (0, 0, 1) direction. Ga3+ is bonded in a trigonal planar geometry to three equivalent N3- atoms. All Ga–N bond lengths are 1.85 Å. N3- is bonded in a trigonal planar geometry to three equivalent Ga3+ atoms.
CaGa2 is Boron Nitride-like structured and crystallizes in the hexagonal P6_3/mmc space group. The structure is zero-dimensional and consists of two calcium molecules and two digallane molecules.
BC1 is Boron Nitride-like structured and crystallizes in the hexagonal P-6m2 space group. The structure is two-dimensional and consists of one BC1 sheet oriented in the (0, 0, 1) direction. B3+ is bonded in a trigonal planar geometry to three equivalent C3- atoms. All B–C bond lengths are 1.55 Å. C3- is bonded in a trigonal planar geometry to three equivalent B3+ atoms.
A low energy ion beam deposition technique was used to grow boron nitride films on quartz, germanium, silicon, gallium arsenide, and indium phosphate. The film structure was amorphous with evidence of a hexagonal phase. The peak boron concentration was 82 at %. The carbon and oxygen impurities were in the 5 to 8 at % range. Boron-nitrogen and boron-boron bonds were revealed by X-ray photoelectron spectroscopy. The index of refraction varied from 1.65 to 1.67 for films deposited on III-V compound semiconductors. The coefficient of friction for boron nitride in sliding contact with diamond was less than 0.1. The substrate was silicon.
A low energy ion beam deposition technique was used to grow boron nitride films on quartz, germanium, silicon, gallium arsenide, and indium phosphate. The film structure was amorphous with evidence of a hexagonal phase. The peak boron concentration was 82 at. percent. The carbon and oxygen impurities were in the 5 to 8 at. percent range. Boron-nitrogen and boron-boron bonds were revealed by X-ray photoelectron spectroscopy. The index of refraction varied from 1.65 to 1.67 for films deposited on III-V compound semiconductors. The coefficient of friction for boron nitride in sliding contact with diamond was less than 0.1. The substrate was silicon.
A simple cluster model is proposed to describe zigzag and armchair contacts of graphene to a hexagonal two-dimensional binary compound adsorbed on a metal substrate. A graphene–boron nitride heterostructure (HS) is studied in detail. Analytical expressions are obtained for the local densities of states and the occupation numbers of contact atoms. The charge transfer for quasi-free HSs is analyzed. The energy of binding of a HS to a metal substrate is estimated.
Cubic boron nitride (c-BN), with a small 1.4% lattice mismatch with diamond, presents a heterostructure with multiple opportunities for electronic device applications. However, the formation of c-BN/diamond heterostructures has been limited by the tendency to form hexagonal BN at the interface. In this study, c-BN has been deposited on free standing polycrystalline and single crystal boron-doped diamond substrates via electron cyclotron resonance plasma enhanced chemical vapor deposition (ECR-PECVD), employing fluorine chemistry. In situ x-ray photoelectron spectroscopy (XPS) is used to characterize the nucleation and growth of boron nitride (BN) films as a function of hydrogen gas flow rates during deposition. The PECVD growth rate of BN was found to increase with increased hydrogen gas flow. In the absence of hydrogen gas flow, the BN layer was reduced in thickness or etched. The XPS results show that an excess of hydrogen gas significantly increases the percent of sp2 bonding, characteristic of hexagonal BN (h-BN), particularly during initial layer growth. Reducing the hydrogen flow, such that hydrogen gas is the limiting reactant, minimizes the sp2 bonding during the nucleation of BN. TEM results indicate the partial coverage of the diamond with thin epitaxial islands of c-BN. The limited hydrogen reaction is found to be a favorable growth environment for c-BN on boron-doped diamond.
Phonon polaritons (PhPs) enable a variety of applications, yet it requires PhPs supported in the desired frequency range. The two BN allotropes (cubic and hexagonal, cBN and hBN) are of particular interest, as their optic phonons fall within the so-called molecular-fingerprint region (~ 1000–1610 cm -1 ). However, there remains a spectral gap between PhPs covered by these two, limiting applications. Thus, we isotopically engineered hBN and cBN and examined the optic phonons. Furthermore, for hBN, enhancement of the optic phonon lifetimes and shifted frequencies are observed. However, lifetimes are observed to decrease with the enrichment of cBN by 10 B, 11 B, and 15 N. We propose that the reduced lifetimes are not due to intrinsic loss, but rather increased defect concentrations resulting from the modified growth, supported by first-principles calculations. Thus, reducing the extrinsic defects in isotopically engineered cBN may present a path toward overcoming these restrictions for applications in the molecular-fingerprint region.
Here, in the field of van der Waals heterostructures, the twist angle between stacked two-dimensional layers has been identified to be of utmost importance for the properties of the heterostructures. In this context, we previously reported the growth of a single layer of unconventionally oriented epitaxial graphene that forms in a surfactant atmosphere [F. C. Bocquet et al., Phys. Rev. Lett. 125, 106102 (2020)]. The resulting G-R0° layer is aligned with the SiC lattice, and hence represents an important milestone towards high-quality twisted bilayer graphene, a frequently investigated model system in this field. Here, we focus on the surface structures obtained in the same surfactant atmosphere, but at lower preparation temperatures at which a boron nitride template layer forms on SiC(0001). In a comprehensive study based on complementary experimental and theoretical techniques, we find—in contrast to the literature—that this template layer is a hexagonal B x N y layer, but not high-quality hBN. It is aligned with the SiC lattice and gradually replaced by low-quality graphene in the 0° orientation of the B x N y template layer upon annealing.
The unique multifunctional properties of boron nitride (BN) nanomaterials are identified as a parameter that would revolutionize electric propulsion in Aeronautics due to the lightweight ceramic with chemical inertness, high strength, high electrical resistivity and high thermal conductivity. Hexagonal BN (h-BN) nanofibers will enable new high-performance fibers that can be used in ceramic or polymer matrix composites, or thin films to provide revolutionary multifunctional ceramics for extreme environments and structures. Polymer derived h-BN materials have been previously demonstrated, providing an avenue to tailor properties of the ceramic end product. This effort also uses forcespinning (FS) technology that produces continuous non-woven nanofibers in a range of diameters depending on the processing parameters with a large production rate of 1 g/min allowing for manufacturing scale production. FTIR, SEM, TGA and XRD were used to characterize the materials in each processing steps.