Semiconducting icosahedral boron arsenide crystal growth for neutron detection

Whiteley, Clinton; Zhang, Y.; Gong, Yinyan; Bakalova, S.; Mayo, Ashley; Edgar, James H.; Kuball, Martin

doi:10.1016/j.jcrysgro.2010.10.057

Cited by 14 publications

(13 citation statements)

References 27 publications

(33 reference statements)

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“…Otherwise, the difference in the coefficient of thermal expansion between the crystals and the nickel solvent (13.4x10 -6 K -1 ) will cause the crystals to be compressed and possibly crack. Additionally, the coefficient of thermal expansion for B 12 As 2 was proposed as one reason for cracking of the heteroepitaxially grown layers [5]. The average coefficients of thermal expansion for Si and 6H-SiC over this same temperature range are α Si =3.8x10 -6 K -1 and α a =3.6x10 -6 K -1 , and α c =5.1x10 -6 K -1 respectively [17,18].…”

Section: Resultsmentioning

confidence: 97%

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The coefficients of thermal expansion of boron arsenide (B12As2) between 25°C and 850°C

Whiteley

Kirkham

Edgar

2013

Journal of Physics and Chemistry of Solids

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Section: Resultsmentioning

confidence: 97%

“…Knowing the coefficients of thermal expansion (CTE) for B 12 As 2 is important for understanding its properties when produced by both the solution growth method [5] and as thin films deposited by chemical vapor deposition (CVD) [6][7]. The B 12 As 2 can be strained on cooling from its synthesis temperature.…”

Section: Introductionmentioning

confidence: 99%

The coefficients of thermal expansion of boron arsenide (B12As2) between 25°C and 850°C

Whiteley

Kirkham

Edgar

2013

Journal of Physics and Chemistry of Solids

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“…As for the three-dimensional bulk crystals, in particular icosahedral boron-rich solids, governed by the three-center two-electron chemical bonds, they exhibit several outstanding properties, such as high chemical stability, high hardness, high melting point, and low wear coefficient [6][7][8][9][10][11][12][13]. Together with the small atomic mass of boron and low density of the compounds, they are thus promising materials for a wide range of technological applications [6,[13][14][15][16][17][18][19][20][21]. For this reason, icosahedral boron-rich solids have become attractive to researchers and have been extensively studied both experimentally and theoretically over the past decades.…”

Section: Introductionmentioning

confidence: 99%

Thermodynamic stability and properties of boron subnitrides from first principles

2017

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We use the first-principles approach to clarify the thermodynamic stability as a function of pressure and temperature of three different α-rhombohedral-boron-like boron subnitrides, with the compositions of B 6 N, B 13 N 2 , and B 38 N 6 , proposed in the literature. We find that, out of these subnitrides with the structural units of B 12 (N-N), B 12 (NBN), and [B 12 (N − N)] 0.33 [B 12 (NBN)] 0.67 , respectively, only B 38 N 6 , represented by [B 12 (N − N)] 0.33 [B 12 (NBN)] 0.67 , is thermodynamically stable. Beyond a pressure of about 7.5 GPa depending on the temperature, also B 38 N 6 becomes unstable, and decomposes into cubic boron nitride and α-tetragonalboron-like boron subnitride B 50 N 2 . The thermodynamic stability of boron subnitrides and relevant competing phases is determined by the Gibbs free energy, in which the contributions from the lattice vibrations and the configurational disorder are obtained within the quasiharmonic and the mean-field approximations, respectively. We calculate lattice parameters, elastic constants, phonon and electronic density of states, and demonstrate that [B 12 (N − N)] 0.33 [B 12 (NBN)] 0.67 is both mechanically and dynamically stable, and is an electrical semiconductor. The simulated x-ray powder-diffraction pattern as well as the calculated lattice parameters of [B 12 (N − N)] 0.33 [B 12 (NBN)] 0.67 are found to be in good agreement with those of the experimentally synthesized boron subnitrides reported in the literature, verifying that B 38 N 6 is the stable composition of α-rhombohedral-boron-like boron subnitride.

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“…Apart from being synthesized, using the chemical vapor deposition (CVD) technique for instance [27,[94][95][96][97][98], B 12 As 2 and B 12 P 2 can also be obtained from the irreversible thermal decompositions of zinc-blende boron arsenide (BAs) and boron phosphide (BP) at high temperature (T 1200 K), respectively [99][100][101]. BAs, in itself, is also of interest, as it has been predicted to have a remarkably high value of thermal conductivity (κ) at room temperature (2240 W·m…”

Section: Boron Subarsenide and Subphosphidementioning

confidence: 99%

“…Compared to the other icosahedral boron-rich solids, in particular boron carbide, having been frequently addressed in the literature [1,6,17,20,25,27,28,30,35,36,84,91,[94][95][96][108][109][110][111][112][113][114], relatively few studies have so far been made on boron subnitride [19,[115][116][117][118][119][120]. For this reason, several issues about boron subnitride, for example its stable compositions, properties, as well as the correct representation of its basic structural unit, are still inconclusive.…”

Section: Boron Subnitridementioning

confidence: 99%

Disordered Icosahedral Boron-Rich Solids: A Theoretical Study of Thermodynamic Stability and Properties

Ektarawong¹

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The cover page illustrates the crystal structure of disordered boron carbide (B 4 C), projected on the (100) r crystal plane in rhombohedral symmetry.The cover image is visualized by the VESTA package. Red and white spheres represent boron and carbon atoms, respectively.During the course of research underlying this thesis, Annop Ektarawong was enrolled in Agora Materiae, a multidisciplinary doctoral program at Linköping University, Sweden.c Annop Ektarawong Printed by LiU-Tryck 2017 AbstractThis thesis is a theoretical study of configurational disorder in icosahedral boronrich solids, in particular boron carbide, including also the development of a methodological framework for treating configurational disorder in such materials, namely superatom-special quasirandom structure (SA-SQS). In terms of its practical implementations, the SA-SQS method is demonstrated to be capable of efficiently modeling configurational disorder in icosahedral boron-rich solids, whiles the thermodynamic stability as well as the properties of the configurationally disordered icosahedral boron-rich solids, modeled from the SA-SQS method, can be directly investigated, using the density functional theory (DFT).In case of boron carbide, especially B 4 C and B 13 C 2 compositions, the SA-SQS method is used for modeling configurational disorder, arising from a high concentration of low-energy B/C substitutional defects. The results, obtained from the DFT-based calculations, demonstrate that configurational disorder of B and C atoms in boron carbide is not only thermodynamically favored at high temperature, but it also plays an important role in altering the properties of boron carbide − for example, restoration of higher rhombohedral symmetry of B 4 C, a metal-tononmetal transition and a drastic increase in the elastic moduli of B 13 C 2 . The configurational disorder can also explain large discrepancies, regarding the properties of boron carbide, between experiments and previous theoretical calculations, having been a long standing controversial issue in the field of icosahedral boronrich solids, as the calculated properties of the disordered boron carbides are found to be in qualitatively good agreement with those, observed in experiments. In order to investigate the configurational evolution of B 4 C as a function of temperature, beyond the SA-SQS level, a brute-force cluster-expansion method in combination with Monte Carlo simulations is implemented. The results demonstrate that configurational disorder in B 4 C indeed essentially takes place within the icosahedra in a way that justifies the focus on low-energy defect patterns of the superatom picture.The investigation of the thermodynamic stability of icosahedral carbon-rich iii iv boron carbides beyond the believed solubility limit of carbon (20 at.% C) demonstrates that, apart from B 4 C generally addressed in the literature, B 2.5 C represented by B 10 C p 2 (CC) is predicted to be thermodynamically stable with respect to B 4 C as well as pure boron and carbon under high pressure...

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Semiconducting icosahedral boron arsenide crystal growth for neutron detection

Cited by 14 publications

References 27 publications

The coefficients of thermal expansion of boron arsenide (B12As2) between 25°C and 850°C

The coefficients of thermal expansion of boron arsenide (B12As2) between 25°C and 850°C

Thermodynamic stability and properties of boron subnitrides from first principles

Disordered Icosahedral Boron-Rich Solids: A Theoretical Study of Thermodynamic Stability and Properties

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