On the diffusion of free carriers in β-rhombohedral boron

Werheit, H.; Moldenhauer, Alexander

doi:10.1016/j.jssc.2005.11.039

Cited by 10 publications

(4 citation statements)

References 21 publications

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“…Indeed, correlations between specific defects and states in the band gap are largely missing. The band scheme in figure 19 is based on consistent experimental results like optical absorption [42,47,49], electrical conductivity [39,40], photo-absorption [64], photo-conductivity [65][66][67], drift experiments [68,69], luminescence [59,60], includes gap states evoked by carbon doping as well [41] and is advanced by electronic transitions gained in the present work (red arrows).…”

Section: Discussionsupporting

confidence: 57%

Influence of dopants, particularly carbon, onβ-rhombohedral boron

Werheit¹,

Flachbart²,

Pristáš³

et al. 2017

Semicond. Sci. Technol.

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Due to the high affinity of carbon to boron, the preparation of carbon-free boron is problematic. Even high-purity (6 N) β-rhombohedral boron contains 30-60 ppm of C. Hence, carbon affects the boron physical properties published so far more or less significantly. We studied well-defined carbon-doped boron samples based on pure starting material carefully annealed with up to about 1% C, thus assuring homogeneity. We present and discuss their electrical conductivity, optical absorption, luminescence and phonon spectra. Earlier attempts of other authors to determine the conductivity of C-doped boron are revised. Our results allow estimating the effects of oxygen and iron doping on the electrical conductivity using results taken from literature. Discontinuities at low T impair the electronic properties.

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Section: Discussionsupporting

confidence: 57%

Influence of dopants, particularly carbon, onβ-rhombohedral boron

Werheit¹,

Flachbart²,

Pristáš³

et al. 2017

Semicond. Sci. Technol.

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“…The idealized crystal structure of β-rhombohedral elemental boron, typically written as (B 12 ) 4 (B 28 ) 2 B or B 84 (B 10 ) 2 B with 105 atoms per unit cell, is based on icosahedral subunits. ,,− The X-ray diffraction spectra collected (independently) validated the elemental purity of each boron sample (Figure ). The crystalline boron spectrum contains the sharp, distinct peaks expected for a crystalline compound.…”

Section: Resultsmentioning

confidence: 99%

¹⁰B and ¹¹B NMR Study of Elemental Boron

2015

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Elemental boron typically exists in either of two states, crystalline or amorphous. In the synthesis of boron-based superhard materials, such as WB 4 , elemental boron is, in some instances, a side product that is difficult to separate from the desired superhard material. In the present study, both crystalline and amorphous boron are characterized by 10 B and 11 B nuclear magnetic resonance spectroscopy as a prelude for the study of boronbased superhard materials. The 11 B spectrum of a static sample reflects both bulk magnetic susceptibility and second-order quadrupolar lineshapes of quadrupolar frequencies ranging from zero to 680 kHz. The 10 B spectrum of a static sample shows quadrupolar frequencies ranging from zero to 142 kHz. In contrast to the previous literature indicating relaxation of quadrupolar origin, the variable temperature spin-lattice relaxation data indicate that the 11 B relaxation at 248 K and below is dominated by spindiffusion from paramagnetic centers. Above 248 K, relaxation is dominated by a thermally-activated interaction with the conduction charge carriers originating from the boron vacancies. Relaxation in amorphous elemental boron shows an additional insulating component with a comparatively long time constant of 44s.

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“…Recently, in β-rhombohedral boron the drift mobility of the very small concentration of optically generated untrapped electron-hole pairs was determined (μ ambipolar = 565(120) cm 2 V −1 s −1 ) [46]. This value corresponds to carrier mobilities known from typical classical semiconductors, e.g.…”

Section: β-Rhombohedral Boronmentioning

confidence: 87%

Are there bipolarons in icosahedral boron-rich solids?

Werheit

2007

J. Phys.: Condens. Matter

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The charge transport of boron carbide, often incorrectly denoted as B(4)C, has been controversially discussed. It is shown that the bipolaron hypothesis is not compatible with numerous experimental results. In particular, the determined real microstructure of boron carbide and its related electronic properties disprove several assumptions, which are fundamental to the bipolaron hypothesis. In contrast, the actual energy band scheme derived mainly from optical investigations is confirmed by careful evaluation of the high-temperature electrical conductivity, and allows a consistent description at most of the experimental results.

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On the diffusion of free carriers in β-rhombohedral boron

Cited by 10 publications

References 21 publications

Influence of dopants, particularly carbon, onβ-rhombohedral boron

Influence of dopants, particularly carbon, onβ-rhombohedral boron

¹⁰B and ¹¹B NMR Study of Elemental Boron

Are there bipolarons in icosahedral boron-rich solids?

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On the diffusion of free carriers in β-rhombohedral boron

Cited by 10 publications

References 21 publications

Influence of dopants, particularly carbon, onβ-rhombohedral boron

Influence of dopants, particularly carbon, onβ-rhombohedral boron

10B and 11B NMR Study of Elemental Boron

Are there bipolarons in icosahedral boron-rich solids?

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Product

Resources

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¹⁰B and ¹¹B NMR Study of Elemental Boron