Thermoelectric properties of vapor-grown polycrystalline cubic SiC

Иванова, Л. Д.; Aleksandrov, P. A.; Demakov, K. D.

doi:10.1134/s0020168506110069

Cited by 20 publications

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“…The other experimental results are for the N-doped, and N-and-B-codoped n-type samples in Ref. 15. The case of N-only doping demonstrates the predictive power of the ab-initio approach.…”

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confidence: 80%

“…As we show here, by comparing predictive ab-initio calculations with experiments on defective samples, a richer physical picture emerges, unveiling the striking differences in the way different dopants affect κ. This also indirectly suggests that the intrinsic κ of defect-free 3C-SiC should be much higher than previously reported and surpass that of the 6H phase.In this paper, we compare our results to the κ(T ) curves for doped samples of 3C-SiC [15]. We use an abinitio approach to quantify the phonon scattering rates of N C substitutional defects.…”

mentioning

confidence: 99%

“…In this paper, we compare our results to the κ(T ) curves for doped samples of 3C-SiC [15]. We use an abinitio approach to quantify the phonon scattering rates of N C substitutional defects.…”

mentioning

confidence: 99%

“…Due to codoping, the carrier concentrations given in Ref. 15 correspond to the difference between the donor and acceptor concentrations, and thus they do not uniquely determine the defect densities. In this case, the ab-initio calculations are able to determine individual defect densities: by keeping the difference in concentrations equal to the experimental carrier concentration, the calculation matches the whole temperature dependent experimental curve only if the individual concentrations are 1.3% and 0.5% for N C and B C respectively ( Fig.…”

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confidence: 99%

“…The calculated κ for the defective structures of 3C-SiC are compared with experiments on polycrystalline samples from Ref. 15 in Fig. 1.…”

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confidence: 99%

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Exceptionally Strong Phonon Scattering by B Substitution in Cubic SiC

et al. 2017

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We use ab-initio calculations to predict the thermal conductivity of cubic SiC with different types of defects. An excellent quantitative agreement with previous experimental measurements is found. The results unveil that BC substitution has a much stronger effect than any of the other defect types in 3C-SiC, including vacancies. This finding contradicts the prediction of the classical massdifference model of impurity scattering, according to which the effects of BC and NC would be similar and much smaller than that of the C vacancy. The strikingly different behavior of the BC defect arises from a unique pattern of resonant phonon scattering caused by the broken structural symmetry around the B impurity.Silicon carbide (SiC) plays a fundamental role in many emerging technologies, ranging from biomedical sensors to optoelectronics, power electronics and photovoltaics [1][2][3][4][5][6][7][8][9]. Most notably, this material has been termed the "linchpin to green energy" that may replace Si-based technology in power electronics [1], owing partly to its large lattice thermal conductivity (κ). From the many stable polytypes of SiC [10], two of the hexagonal ones, 6H-SiC and 4H-SiC, have been extensively studied and widely used [10][11][12]. In contrast, the structurally less complex cubic polytype of SiC with zinc-blende structure (3C-SiC) is much less well understood, despite presumably having the best electronic properties [13], and, as we will see, possibly a higher κ than the other polytypes. This is partly due to the difficulty in synthesizing high quality crystals, although recent improvements in 3C-SiC growth techniques have prompted a renewed interest in it [13].Surprisingly, the reference measurements of κ on pure undoped 3C-SiC are over 20 years old and little detail is known about the quality of the samples [10,14]. The reference value of κ for 3C phase is perplexingly lower than that for the structurally more complex 6H phase, raising doubts about whether this is truly an intrinsic property or just a consequence of the defective, polycrystalline quality of the 3C-SiC samples. It is then clear that to understand the conduction properties of 3C-SiC, and to harness its full potential, one must first comprehend the way defects affect it. As we show here, by comparing predictive ab-initio calculations with experiments on defective samples, a richer physical picture emerges, unveiling the striking differences in the way different dopants affect κ. This also indirectly suggests that the intrinsic κ of defect-free 3C-SiC should be much higher than previously reported and surpass that of the 6H phase.In this paper, we compare our results to the κ(T ) curves for doped samples of 3C-SiC [15]. We use an abinitio approach to quantify the phonon scattering rates of N C substitutional defects. The predicted κ is in excellent agreement with the experimental results. This then allows us to explain the effect of codoping with N and B, and shows that B impurities scatter phonons two orders of magnitude more strongly overall...

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“…The other experimental results are for the N-doped, and N-and-B-codoped n-type samples in Ref. 15. The case of N-only doping demonstrates the predictive power of the ab-initio approach.…”

mentioning

confidence: 80%

mentioning

confidence: 99%

mentioning

confidence: 99%

mentioning

confidence: 99%

“…The calculated κ for the defective structures of 3C-SiC are compared with experiments on polycrystalline samples from Ref. 15 in Fig. 1.…”

mentioning

confidence: 99%

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