Metal Boron Research Articles

Electroless Deposition of Cobalt-Tungsten-Boron Films from Glycine Containing Solutions As Barrier Layer Against Cu Diffusion

Electroless cobalt films have been demonstrated to produce high quality barrier and capping layers for Cu. The best barriers so far include, in addition to the cobalt, refractory metals ions (e.g., W, Mo, or Re), and either phosphorus or boron. Electroless cobalt and its alloys can be used in micro- and nano-technologies, e.g. for microelectro-mechanical systems (MEMS), as well as for ultra large-scale integration (ULSI) technology of integrated cicuits. In this work we present novel deposition solutions that is used to form cobalt-tungsten-boron films used morpholine borane as reducing agents. The films of cobalt that cointain small amounts of tungsten and boron were deposited by the electroless process. The cobalt-tungsten-boron coatings were deposited on the copper surface using a solutions containing (mol l-1): CoSO4 - 0.1, NH2CH2COOH (glycine) – 0.2, C4H8ONH·BH3 (morpholine borane) – 0.2, Na2WO4 – (0-0.02), C6H8O7 (citric acid) – 0.175. The bath operated at pH 7 and 60 ºC. The thickness of the compact cobalt-tungsten-boron coatings obtained under optimal operating conditions were ca. 0.5 µm. The morphology and strukture of the cobalt alloys were characterized by means of Field Emission Scanning Electron Microscopy. The composition of the cobalt-tungsten-boron films obtained was determined by means of X-ray Photoelectron Spectroscopy using an ESCALAB MKII spektrometer. To obtain depht profiles, the sample were etched in the preparation chamber by ionized argon at a vacuum of 5·10-4 Pa. The mikrostructure of the coatings changes with the intercorporation of tungsten into the coatings. The particles of cobalt-tungsten-boron films are larger and almost equilateral as compared with the cobalt-boron particles. XPS depth profile investigation does not show any significant diffusion of Cu atoms into cobalt after heat-treatment of the cobalt-tungsten-boron film. This fact confirms that the cobalt-tungsten-boron thin layer, deposited from glycine containing solutions, serves as a perfect diffucion barrier to prevent Cu diffusion. This research was funded by a Grant (No. TEC-06/2015) from the Research Council of Lithuania.

(Invited) Mixed Dimensional Nanoelectronic Heterostructures

Layered two-dimensional (2D) nanomaterials interact primarily via van der Waals bonding, which has created new opportunities for nanoelectronic heterostructures that are not constrained by epitaxial growth [1]. However, it is important to acknowledge that van der Waals interactions are not limited to interplanar interactions in 2D materials. In principle, any passivated, dangling bond-free surface interacts with another via non-covalent forces. Consequently, the emerging layered 2D nanomaterials can be integrated with a diverse range of other materials [2-4], including those of different dimensionality, to form van der Waals heterostructures. This talk will explore mixed dimensional combinations of 2D + n-D (n = 0, 1 and 3) materials, thus significantly expanding the van der Waals heterostructure concept. In order to efficiently explore the vast phase space for mixed dimensional heterostructures, our laboratory employs solution-based additive assembly. In particular, constituent nanomaterials (e.g., carbon nanotubes, graphene, transition metal dichalcogenides, black phosphorus, and boron nitride) are isolated in solution [5-9], and then deposited into thin films with scalable additive manufacturing methods (e.g., inkjet [10], gravure [11], and screen printing [12]). By achieving high levels of nanomaterial monodispersity and printing fidelity, large-area device arrays can realize complex electronic signal conditioning such as frequency and phase shift keying [4]. Furthermore, by integrating multiple nanomaterial inks into heterostructures, unprecedented device function has been demonstrated including anti-ambipolar p-n heterojunctions [2-4] and gate-tunable memristors [13]. In addition to technological implications for nanoelectronics and optoelectronics, this work allows the exploration of several fundamental issues including band alignment, doping, trap states, and charge/energy transfer across previously unexplored mixed dimensional heterointerfaces. [1] D. Jariwala, V. K. Sangwan, L. J. Lauhon, T. J. Marks, and M. C. Hersam, “Emerging device applications for semiconducting two-dimensional transition metal dichalcogenides,” ACS Nano, 8, 1102 (2014). [2] D. Jariwala, S. L. Howell, K.-S. Chen, J. Kang, V. K. Sangwan, S. A. Filippone, R. Turrisi, T. J. Marks, L. J. Lauhon, and M. C. Hersam, “Hybrid, gate-tunable, van der Waals p-n heterojunctions from pentacene and MoS2,” Nano Lett., DOI: 10.1021/acs.nanolett.5b04141 (2015). [3] D. Jariwala, V. K. Sangwan, C.-C. Wu, P. L. Prabhumirashi, M. L. Geier, T. J. Marks, L. J. Lauhon, and M. C. Hersam, “Gate-tunable carbon nanotube-MoS2 heterojunction p-n diode,” Proc. Nat. Acad. Sci. USA, 110, 18076 (2013). [4] D. Jariwala, V. K. Sangwan, J.-W. T. Seo, W. Xu, J. Smith, C. H. Kim, L. J. Lauhon, T. J. Marks, and M. C. Hersam, “Large-area, low-voltage, antiambipolar heterojunctions from solution-processed semiconductors,” Nano Lett., 15, 416 (2015). [5] N. D. Mansukhani, L. M. Guiney, P. J. Kim, Y. Zhao, D. Alducin, A. Ponce, E. Larios, M. J. Yacaman, and M. C. Hersam, “High-concentration aqueous dispersions of nanoscale two-dimensional materials using nonionic, biocompatible block copolymers,” Small, DOI: 10.1002/smll.201503082 (2015). [6] J. Zhu, X. Liu, M. L. Geier, J. J. McMorrow, D. Jariwala, M. E. Beck, W. Huang, T. J. Marks, and M. C. Hersam, “Layer-by-layer assembled two-dimensional montmorillonite dielectrics for solution-processed electronics,” Adv. Mater., DOI: 10.1002/adma.201504501 (2015). [7] J. Zhu, J. Kang, J. Kang, D. Jariwala, J. D. Wood, J.-W. T. Seo, K.-S. Chen, T. J. Marks, and M. C. Hersam, “Solution-processed dielectrics based on thickness-sorted two-dimensional hexagonal boron nitride nanosheets,” Nano Lett., 15, 7029 (2015). [8] J. Kang, J. D. Wood, S. A. Wells, J.-H. Lee, X. Liu, K.-S. Chen, and M. C. Hersam, “Solvent exfoliation of electronic-grade, two-dimensional black phosphorus,” ACS Nano, 9, 3596 (2015). [9] J. Kang, J.-W. T. Seo, D. Alducin, A. Ponce, M. J. Yacaman, and M. C. Hersam, “Thickness sorting of two-dimensional transition metal dichalcogenides via copolymer-assisted density gradient ultracentrifugation,” Nature Communications, 5, 5478 (2014). [10] E. B. Secor, P. L. Prabhumirashi, K. Puntambekar, M. L. Geier, and M. C. Hersam, “Inkjet printing of high conductivity, flexible graphene patterns,” J. Phys. Chem. Lett., 4, 1347 (2013). [11] E. B. Secor, S. Lim, H. Zhang, C. D. Frisbie, L. F. Francis, and M. C. Hersam, “Gravure printing of graphene for large-area flexible electronics,” Adv. Mater., 26, 4533 (2014). [12] W. J. Hyun, E. B. Secor, M. C. Hersam, C. D. Frisbie, and L. F. Francis, “High-resolution patterning of graphene by screen printing with a silicon stencil for highly flexible printed electronics,” Adv. Mater., 27, 109 (2015). [13] V. K. Sangwan, D. Jariwala, I. S. Kim, K.-S. Chen, T. J. Marks, L. J. Lauhon, and M. C. Hersam, “Gate-tunable memristive phenomena mediated by grain boundaries in single-layer MoS2,” Nature Nanotechnology, 10, 403 (2015).

New route toward nanosized crystalline metal borides with tuneable stoichiometry and variable morphologies.

Herein we highlight for the first time the ability to tune the stoichiometry of metal boride nanocrystals through nanoparticle synthesis in thermally stable inorganic molten salts. Two metal-boron systems are chosen as case studies: boron-poor nickel borides and boron-rich yttrium borides. We show that NiB, Ni4B3, Ni2B, Ni3B, and YB6 particles can be obtained as crystalline phases with good selectivity. Anisotropic crystallization is observed in two cases: the first boron-rich YB4 nanorods are reported, while boron-poor NiB nanoparticles show a peculiar crystal habit, as they are obtained as spheres with uniaxial defects related to the crystal structure. Crystallization mechanisms are proposed to account for the appearance of these two kinds of anisotropy at the nanoscale.

Controllable Synthesis of Ultrathin Transition‐Metal Hydroxide Nanosheets and their Extended Composite Nanostructures for Enhanced Catalytic Activity in the Heck Reaction

AbstractWe report an effective and universal approach for the preparation of ultrathin single‐ or multiple‐component transition‐metal hydroxide (TMH) nanosheets with thickness below 5 nm. The unique synthesis benefits from the gradual decomposition of the preformed metal–boron (M‐B, M=Fe, Co, Ni, NiCo) composite nanospheres which facilitates the formation of ultrathin nanosheets by the oxidation of the metal and the simultaneous release of boron species. The high specific surface area of the sheets associated with their ultrathin nature promises a wide range of applications. For example, we demonstrate the remarkable adsorption ability of PbII and AsV in waste water by the ultrathin FeOOH nanosheets. More interestingly, the process can be extended simply to the synthesis of composite structures of metal alloy hollow shells encapsulated by TMH nanosheets, which show excellent catalytic activity in the Heck reaction.

Graphene and graphene-like 2D materials for optical biosensing and bioimaging: a review

The increasing demands of bioassay and biomedical applications have significantly promoted the rational design and fabrication of a wide range of functional nanomaterials. Coupling these advanced nanomaterials with biomolecule recognition events leads to novel sensing and diagnostic platforms. Because of their unique structures and multifunctionalities, two-dimensional nanomaterials, such as graphene and graphene-like materials (e.g., graphitic carbon nitride, transition metal dichalcogenides, boron nitride, and transition metal oxides), have stimulated great interest in the field of optical biosensors and imaging because of their innovative mechanical, physicochemical and optical properties. Depending on the different applications, the graphene and graphene-like nanomaterials can be tailored to form either fluorescent emitters or efficient fluorescence quenchers, making them powerful platforms for fabricating a series of optical biosensors to sensitively detect various targets including ions, small biomolecules, DNA/RNA and proteins. This review highlights the recent progress in optical biosensors based on graphene and graphene-like 2D materials and their imaging applications. Finally, the opportunities and some critical challenges in this field are also addressed.

Solubility of Boron, Carbon, and Nitrogen in Transition Metals: Getting Insight into Trends from First-Principles Calculations

Efficient chemical vapor deposition synthesis of two-dimensional (2D) materials such as graphene, boron nitride, and mixed BCN systems with tunable band gaps requires precise knowledge of the solubility and mobility of B/C/N atoms in the transition metals (TMs) used as substrates for the growth. Yet, surprisingly little is known about these quantities either from experiments or simulations. Using first-principles calculations, we systematically study the behavior of B/C/N impurity atoms in a wide range of TMs. We compute formation energies of B/C/N interstitials and demonstrate that they exhibit a peculiar but common behavior for TMs in different rows of the periodic table, as experimentally observed for C. Our simulations indicate that this behavior originates from an interplay between the unit cell volume and filling of the d-shell electronic states of the metals. We further assess the vibrational and electronic entropic contributions to the solubility, as well as the role of anharmonic effects. Finally...

Inorganic Graphene Analogs

In the last four to five years, there has been a great resurgence of research on two-dimensional inorganic materials, partly because of the impetus received from graphene research. Unlike graphene, which is a gap-less material, most inorganic layered materials are semiconductors or insulators. Some of them, as exemplified by MoS2, exhibit unexpected properties, not unlike graphene, with possible applications. Thus, layered metal chalcogenides are being explored intensely, and MoS2is emerging as a wonder material. In this article, we present the synthesis and properties of nanosheets composing single or few layers of these fascinating materials. Besides metal chalcogenides, boron nitride, borocarbonitrides (BxCyNz), metal oxides, and metal-organic frameworks are also discussed.

Self-Assembly of Metal Boron Imidazolate Cages

To study the synthetic strategy from cages to extended frameworks is very important to elucidate and mimic cage-based self-assembly behavior in zeolites and other open frameworks. Here, two dodecahedral cages are rationally designed by using tridentate boron imidazolate ligands to link tetrahedral or square metal centers. The self-assembly of metal boron imidazolate cages is successfully realized. The cage-based materials display good properties on gas adsorption and reducing noble metals. This work may help us to understand the formation mechanism of extended metal–organic frameworks.

Peranan Sedimen Perairan Outlet DAS Sumber Brantas Terhadap Ketersediaan Ca2+, Mg2+, Na+, K+, dan Boron dalam Badan Air Sebagai Sumber Air Irigasi

The role of aquatic sediment of outlet DAS Sumber Brantas for the availability of Ca 2+ , Mg 2+ , Na + , K + , and boron in water body has been investigated from July-September 2014. Sediment and water samples were collected from the outlet of Sumber Brantas watershed in Arboretum Sumber Brantas village, Batu. This research aim was to investigate the distribution and sediment role for availability of Ca, Mg, Na, K, and boron in water body. The research results show that Ca was the dominant metal ion that was found in water body, while in sediment metal ions that dominant were Ca and Mg. The concentration of metal ion Ca was highest in August with average of concentration 1105.51 ppm and concentration of metal ion Mg was highest in July with average of concentration 1038.94 ppm. Comparison for metal ions concentration in water and sediment shows that sediment had a greater role as a sink for metal ion Ca and boron, while the sediment was a source for metal ions Mg, Na, and K in water body.

Ferro- and antiferro-magnetism in (Np, Pu)BC

Two new transuranium metal boron carbides, NpBC and PuBC, have been synthesized. Rietveld refinements of powder XRD patterns of {Np,Pu}BC confirmed in both cases isotypism with the structure type of UBC. Temperature dependent magnetic susceptibility data reveal antiferromagnetic ordering for PuBC below TN = 44 K, whereas ferromagnetic ordering was found for NpBC below TC = 61 K. Heat capacity measurements prove the bulk character of the observed magnetic transition for both compounds. The total energy electronic band structure calculations support formation of the ferromagnetic ground state for NpBC and the antiferromagnetic ground state for PuBC.

Unusual behaviour of (Np,Pu)B2C

Two transuranium metal boron carbides, NpB2C and PuB2C have been synthesized by argon arc melting. The crystal structures of the {Np,Pu}B2C compounds were determined from single-crystal X-ray data to be isotypic with the ThB2C-type (space group , a = 0.6532(2) nm; c = 1.0769(3) nm for NpB2C and a = 0.6509(2) nm; c = 1.0818(3) nm for PuB2C; Z = 9). Physical properties have been derived from polycrystalline bulk material in the temperature range from 2 to 300 K and in magnetic fields up to 9 T. Magnetic susceptibility and heat capacity data indicate the occurrence of antiferromagnetic ordering for NpB2C with a Neel temperature TN = 68 K. PuB2C is a Pauli paramagnet most likely due to a strong hybridization of s(p,d) electrons with the Pu-5f states. A pseudo-gap, as concluded from the Sommerfeld value and the electronic transport, is thought to be a consequence of the hybridization. The magnetic behaviour of {Np,Pu}B2C is consistent with the criterion of Hill.

X-ray absorption spectroscopy determination of the products of manganese borohydride decomposition upon heating

Manganese borohydride Mn(BH4)2 powder is heated in a hydrogen atmosphere in vacuum. The long-range order in the structure is monitored in situ by means of X-ray absorption spectroscopy and X-ray diffraction; short-range order, via Mg K-edge X-ray absorption near-edge structure spectroscopy. Above 120°C, the X-ray diffraction pattern disappears and an irreversible phase transition occurs, accompanied by sample amorphization and profuse hydrogen desorption. In the hydrogen atmosphere, the phase transition occurs at a temperature of ∼110°C. The standard scheme of borohydride decomposition suggests hydrogen desorption and the formation of metallic manganese and boron. However, a theoretical analysis of X-ray absorption spectra shows that the most likely products of Mn(BH4)2 decomposition are manganese borides.

Determination of Heavy Metals in Low Value Food Fish from Commercial Landing Centers (India) by Inductively Coupled Plasma Optical Emission Spectrometer

A bio-monitoring study was performed to investigate certain metals (cadmium, cobalt, copper, iron, magnesium, manganese, nickel, lead, zinc, aluminium and boron), using Inductively Coupled Plasma Optical Emission Spectrometer (ICP-OES) for the assessment of the present status in the two coastal ecosystems and compiling the baseline data for future monitoring. Tissue samples of fishes have different level of accumulation viz, Cd = 0.07-0.40, Co = 0-0.32, Cu = 0.53–0.39, Fe = 1.42–8.12, Mg = 9.74–33.1, Mn = 0.08–0.84, Ni = 0.01–0.97, Pb = 0.12–2.05, Zn = 0.81–2.11, Al = 1.26-3.98, Cr = 0.25-1.76 and B = 0.17-1.87 µg g -1 dry wt. respectively. The rate of metal accumulation higher in species ( Thalassoma trilobatum and Saurida tumbil) . Concentration of toxic metals such as Cd and Pb were well above the permissible limits proposed by the World Health Organization and Food and Agricultural Organizations.

Synthesis and characterisation of curcumin–M (M = B, Fe and Cu) films grown on p-Si substrate for dielectric applications

Metal-coordinated yellow curcumin was extracted from green natural sources and sublimated in vacuum to prepare thin films on p-Si and glass substrates for dielectric and optical investigations. The synthesised curcumin complexed with the metals boron, iron, and copper powders were crystalline while the prepared films were amorphous. The optical absorption spectrum of the prepared films showed similar two absorption band structure in the visible range. The onset energy of the main optical absorption band of the film was determined using the Tauc technique. The dielectric properties of this material were systematically studied for future applications in metal–insulator–semiconductor MIS field of applications. The complex dielectric properties were studied in the frequency range of 1–1000kHz and was analysed. The important find is a large optoelectronic sensitivity so that the integral optical responsivity (S∗) reaches ∼1.0A/W and the electrical conductivity increases under light illumination by ∼400–1000%. Generally, Curcumin metal complex can be used in small-k environmentally friendly production of microelectronic and optoelectronic devices.

New hybrid materials for organic light-emitting diode devices

The regularities of polymorphism in high-purity crystalline tris(8-hydroxyquinoline) aluminum, gallium, and indium (Meq3) have been studied in the temperature range of 300–712 K. From the results of an analysis of photoluminescence and Raman spectra and X-ray diffraction data, a generalized picture has been produced, according to which, for all the studied compounds, a series of polymorphic transitions is the same: β → α → δ → γ → ɛ. Based on high-purity single-phase specimens of the investigated metal complexes and boron oxide, new hybrid materials have been synthesized: bulk samples (alloying technique) and thin films (vacuum thermal evaporation). The photo- and electroluminescent properties of the hybrid materials at room temperature have been investigated. It has been established that, as the synthesis duration of the bulk hybrid materials increases from 5 to 60 min, a photoluminescence maximum shifts to a short-wavelength domain from the value typical of pure δ(γ)-Meq3 by 40, 15, and 10 nm for Alq3, Gaq3, and Inq3, respectively.

Unexpected Synergy between Magnetic Iron Chains and Stacked B6 Rings in Nb6Fe1−xIr6+xB8

AbstractThe synergistic combination of experiment and density functional theory has led to the discovery of the first ferromagnetic material, Nb6Fe1−xIr6+xB8, containing in its crystal structure iron chains embedded in stacked B6 rings. The strong ferromagnetic Fe–Fe interactions found in the iron chains induce an unexpected strengthening of the B–B interactions in the B6 rings. Beside these strong B–B interactions, strong interlayer metal–boron bonds (Ir–B and Nb–B) ensure the overall structural stability of this phase, while the magnetic Fe–Fe interactions are mainly responsible for the observed ferromagnetic ordering below TC=350 K.

Schottky barriers at hexagonal boron nitride/metal interfaces: A first-principles study

The formation of a Schottky barrier at the interface between a metal and hexagonal boron nitride (h-BN) is studied using density functional theory. For metals whose work functions range from 4.2 to 6.0 eV, we find Schottky barrier heights for holes between 1.2 and 2.3 eV. A central role in determining the Schottky barrier height is played by a potential step of between 0.4 and 1.8 eV that is formed at the metal|h-BN interface and effectively lowers the metal work function. If h-BN is physisorbed, as is the case on fcc Cu, Al, Au, Ag and Pt(111) substrates, the interface potential step is described well by a universal function that depends only on the distance separating h-BN from the metal surface. The interface potential step is largest when h-BN is chemisorbed, which is the case for hcp Co and Ti (0001) and for fcc Ni and Pd (111) substrates.

Existence form of boron in dissimilar weld metals of low-alloy steel with boron-bearing high-chromium steel during post-weld heat treatment†

Recently, higher steam inlet temperature and pressure has been required for fossil power plants in order to increase the power generation efficiency. Therefore, boron-bearing high-chromium (high-Cr) steels with higher long-term creep strength are applied to structure materials in these plants. Dissimilar (metal) weld joints between a boron-bearing high-Cr steel and a low-alloy steel are applied for various parts of boilers and other equipment in the plants. Caution has to be paid to maintain the quality of these weld joints because boron is diffused to the low-alloy steel weld deposits by dilution from the boron-bearing high-Cr base metal. However, the existing form of boron and the effect of boron on reheat cracking susceptibility during post-weld heat treatment (PWHT) have not been surveyed in the previous literature. Therefore, using Cr–Mo low-alloy steels with varied contents of B and Cr, reheat cracking susceptibility of the weld metal was evaluated, and the precipitation behaviour of the carbides during PWHT was observed. From these results, the existing form of boron in boron-bearing Cr–Mo steel weld metals is discussed in this study. Reheat cracking susceptibility clearly increased with boron addition, whereas it decreased with increasing chromium content. It was shown by thermo-dynamic calculation that possible existing forms of boron were of four types, namely BN, M2B, M23(C, B)6 and dissolved boron. The amount of M23C6-type carbides was increased with increasing chromium content. On the basis of these results, it was presumed that the amount of dissolved boron in boron-bearing low-chromium steel weld metals was larger than in those with high-Cr. It was suggested that the larger amount of dissolved boron enhanced the strength difference between the matrix and the grain boundary in low-chromium steels, hence it led to higher susceptibility to reheat cracking.

High pressure synthesis and properties studies on spherical bulk ϵ-Fe3N

Spherical iron nitride (ϵ-Fe3N) of 4 mm in diameter was synthesized by a high pressure solid-state metathesis reaction between alkaline or alkaline-earth metal ferrite (NaFeO2, MgFe2O4, and Ca2Fe2O5) and boron nitride. The Fe/N atomic ratio of the obtained crystals is close to 3:1 by means of energy-dispersive X-ray analysis, X-ray photoelectron spectroscopy, and chemical reaction analysis. Bulk modulus B0 = 154(2) GPa with a fixed pressure derivative is determined by high pressure synchrotron axial X-ray diffraction measurement. ϵ-Fe3N is thermally stable in the air below 500°C by in situ high-temperature Raman spectroscopy. Vickers hardness tests show that the Hv is 5.9 GPa with a load of 5 N, and vibrating sample magnetometer measurements show that saturation magnetization (σs) is 88.53 emu/g and coercivity value (Hc) is 466.67 Oe.

Complete and partial 1,2-additions across transition metal-boron double bonds.

The first 1,2-additions across a metal-boron double bond are reported, one a definitive chlorogallation of a Fe═B bond, the other a partial chlorogallation of a Mo═B bond that leads to a highly unusual, planar Mo-B-Ga-Cl rhombus. The two reactions occur with opposite regiochemistry, with the Ga atom bound to the Fe atom in the former and to both the Mo and B atoms in the latter. The bonding in the Mo adduct and the reasons for the differing regiochemistry of the reaction are explored computationally.