Non‐stoichiometry and properties of SnTe〈Cd〉 semiconducting phase of variable composition

Рогачева, Е. И.; Nashchekina, O. N.

doi:10.1002/pssa.200669654

Cited by 7 publications

(6 citation statements)

References 4 publications

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“…The smallest lattice parameter of $6.29 Å suggests a solution limit of 4% Cd in SnTe according to Vegard's law, which is consistent with previous studies. 31 The EDXS results also conrm the Cd amount in SnTe (Table S2, ESI †).…”

Section: Resultsmentioning

confidence: 97%

Enhanced thermopower in rock-salt SnTe–CdTe from band convergence

Liu

et al. 2016

RSC Adv.

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SnCdxTe materials were synthesized by the zone-melting method for the thermoelectric performance study. The X-ray diffraction results show that the lattice parameter decreases with increasing x, following the Vegard's law of rock-salt structure SnTe and CdTe. Besides, the room temperature Seebeck coefficients of the SnCdxTe system enhance to > 60 μV/K, larger than those of Cd-doped SnTe synthesized by spark plasma sintering. A large power factor of ~ 25 μW/cmK is achieved in SnCd0.12Te at 820 K, which rivals those of high performance PbTe-based materials. As a result, the highest ZT of ~1.03 at 820 K was achieved for SnCd0.12Te.

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Section: Resultsmentioning

confidence: 97%

Enhanced thermopower in rock-salt SnTe–CdTe from band convergence

Liu

et al. 2016

RSC Adv.

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“…Dopant solubility in SnTe has been thoroughly studied by Rogacheva et al, they investigated the complexities involved with doping phases which are intrinsically nonstoichiometric. 33 Gd with normal valence Gd 3+ might be expected to substitute for Sn 2+ and be an electron donor, but instead Gd is observed to cause an increase in the p-type, hole carrier concentration. Similar results were reported by Story et al who suggest that Gd is a resonant dopant.…”

Section: Resultsmentioning

confidence: 99%

Optimization of thermoelectric efficiency in SnTe: the case for the light band

Zhou

Gibbs

Wang

et al. 2014

Phys. Chem. Chem. Phys.

244

262

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bd p-Type PbTe is an outstanding high temperature thermoelectric material with zT of 2 at high temperatures due to its complex band structure which leads to high valley degeneracy. Lead-free SnTe has a similar electronic band structure, which suggests that it may also be a good thermoelectric material. However, stoichiometric SnTe is a strongly p-type semiconductor with a carrier concentration of about 1 Â 10 20 cm À3 , which corresponds to a minimum Seebeck coefficient and zT. While in the case of p-PbTe (and n-type La 3 Te 4 ) one would normally achieve higher zT by using high carrier density in order to populate the secondary band with higher valley degeneracy, SnTe behaves differently. It has a very light, upper valence band which is shown in this work to provide higher zT than doping towards the heavier second band. Therefore, decreasing the hole concentration to maximize the performance of the light band results in higher zT than doping into the high degeneracy heavy band. Here we tune the electrical transport properties of SnTe by decreasing the carrier concentration with iodine doping, and increasing the carrier concentration with Gd doping or by making the samples Te deficient. A peak zT value of 0.6 at 700 K was obtained for SnTe 0.985 I 0.015 which optimizes the light, upper valence band, which is about 50% higher than the other peak zT value of 0.4 for Gd z Sn 1ÀzT e and SnTe 1+y which utilize the high valley degeneracy secondary valence band.

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“…This results in a higher Seebeck coefficient that increases the ZT value of Sn 1.03 Te by 60% to 0.96 for SnCd 0.03 Te (at 550 °C) . In the same way, doping with Cd improves the power factor of nonstoichiometric Sn 0.984 Te . As this system is comparable to SST and GST compounds, Cd might be a promising dopant for improving the performance of GST and SST compounds.…”

Section: Introductionmentioning

confidence: 92%

“…[ 22 ] In the same way, doping with Cd improves the power factor of nonstoichiometric Sn 0.984 Te. [ 24 ] As this system is comparable to SST and GST compounds, Cd might be a promising dopant for improving the performance of GST and SST compounds. Cd 2+ should signifi cantly infl uence the band structure as it has no lone electron pair.…”

Section: Introductionmentioning

confidence: 99%

Increasing Seebeck Coefficients and Thermoelectric Performance of Sn/Sb/Te and Ge/Sb/Te Materials by Cd Doping

Welzmiller

Fahrnbauer

Hennersdorf

et al. 2015

Adv Elect Materials

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Ge and Sn in (GeTe)nSb2Te3 (GST) and (SnTe)nSb2Te3 compounds, respectively, are partially substituted by Cd. These layered compounds (n = 1) consist of NaCl‐type slabs that are separated by van der Waals gaps. Resonant X‐ray diffraction yields different Cd‐atom distributions in Cd0.2Ge0.8Sb2Te4 and Cd0.2Sn0.8Sb2Te4, which indicate how van der Waals gaps in metastable cubic GeTe‐rich or SnTe‐rich compounds (n ≥ 7) are surrounded. The latter exhibit promising thermoelectric properties with figures of merit ZT ≈ 0.8 at 450 °C. Alloying with Sb2Te3 increases the ZT value of SnTe by a factor of up to two because of an increased Seebeck coefficient and a reduced thermal conductivity; the hole concentration is significantly reduced. A further improvement in ZT by ≈20% is possible by Cd‐doping, most likely due to a more covalent bonding character, yielding a ZT of ≈1.1 at 450 °C for Cd1.2Sn10.8Sb2Te15. In order to understand the electronic transport properties of these p‐type semiconductors, the single parabolic band model is applied. By contrast, Cd doping in GST materials reduces the Hall mobility and therefore decreases the power factor compared to undoped GST materials.

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Non‐stoichiometry and properties of SnTe〈Cd〉 semiconducting phase of variable composition

Cited by 7 publications

References 4 publications

Enhanced thermopower in rock-salt SnTe–CdTe from band convergence

Enhanced thermopower in rock-salt SnTe–CdTe from band convergence

Optimization of thermoelectric efficiency in SnTe: the case for the light band

Increasing Seebeck Coefficients and Thermoelectric Performance of Sn/Sb/Te and Ge/Sb/Te Materials by Cd Doping

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