Influence of Vanadium on the Defect Structure and Thermoelectric Properties of GeTe

Nashchekina, O. N.; Рогачева, Е. И.; Водорез, О. С.

doi:10.1007/s11664-012-2423-9

Cited by 10 publications

(4 citation statements)

References 5 publications

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“…It is worth noting that Sn atoms were previously reported to exclusively substitute Pb atoms in Pb 1– y Sn y Se ( y > 0.2) alloys. The significantly different defect chemistry of Sn in lightly and heavily SnSe-alloyed PbSe might originate from the percolation effect, which has been investigated for several decades in the fields of semiconductor, metallurgy, polymer physics, and so on. − In dilute solid solutions of hole-doped PbSe–SnSe, Sn atoms are well separated from each other, and the interactions between Sn dopants can be ignored. Under this circumstance, the introduction of Sn atoms gradually increases the configuration entropy of the system, which facilitates the formation of diverse defects (Sn i 4+ , Sn Pb , and V Pb ) as demonstrated by our microscopy study and positron annihilation measurements.…”

Section: Resultsmentioning

confidence: 99%

Percolation Process-Mediated Rich Defects in Hole-Doped PbSe with Enhanced Thermoelectric Performance

et al. 2022

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PbSe–SnSe solid solutions have been extensively investigated in the fields of topological physics, optoelectronic conversion, and thermoelectric technology. In this study, we show that minute Sn-doped Pb0.98Na0.02Se behaves quite differently from conventional solid solutions. A dilute amount of Sn dopants induces rich defects (substitutional Sn atoms, interstitial Sn atoms, and cation vacancies) in hole-doped PbSe. Moreover, with growing concentration of Sn, the dominated defect type varies accordingly due to the percolation process of dopants, leading to anomalies in the dependences of thermoelectric properties on compositions. These rich defects increase the thermoelectric performance of p-type PbSe by (i) enhancement of Seebeck coefficient through increased density of states by interstitial Sn atoms; (ii) reduction of lattice thermal conductivity through strong point defect scattering mostly contributed by interstitial Sn atoms and cation vacancies. Moreover, the dynamic migrations of Sn atoms from the interstitial sites to regular lattice sites at elevated temperatures (>623 K) give rise to diffusion-like atomic vibrations that frustrate heat conduction further. Consequently, 1 mol % Sn doping in Pb0.98Na0.02Se yields 20% improvement of thermoelectric performance. This work demonstrates that dilute doping-induced percolation phenomena should be taken into consideration when developing efficient thermoelectric materials.

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Section: Resultsmentioning

confidence: 99%

Percolation Process-Mediated Rich Defects in Hole-Doped PbSe with Enhanced Thermoelectric Performance

et al. 2022

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“…In the high-temperature cubic phase (β), the smallest effective masses for both the L and Σ bands are responsible for the high power factor Figure 1 Room-temperature Hall carrier concentration-dependent power factor (PF = S 2 σ) for SnTe 1 − x I x , 37 Na x Pb 1 − x Te 36 and GeTe in comparison with literature data for p-GeTe. [38][39][40]88 The optimal carrier concentration for GeTe is found to be 1-3 × 10 20 cm − 3 (shadow area). Thermoelectric performance of p-type GeTe J Li et al in GeTe.…”

Section: Introductionmentioning

confidence: 97%

Electronic origin of the high thermoelectric performance of GeTe among the p-type group IV monotellurides

et al. 2017

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PbTe and SnTe in their p-type forms have long been considered high-performance thermoelectrics, and both of them largely rely on two valence bands (the first band at L point and the second one along the Σ line) participating in the transport properties. This work focuses on the thermoelectric transport properties inherent to p-type GeTe, a member of the group IV monotellurides that is relatively less studied. Approximately 50 GeTe samples have been synthesized with different carrier concentrations spanning from 1 to 20 × 10 20 cm − 3 , enabling an insightful understanding of the electronic transport and a full carrier concentration optimization for the thermoelectric performance. When all of these three monotellurides (PbTe, SnTe and GeTe) are fully optimized in their p-type forms, GeTe shows the highest thermoelectric figure of merit (zT up to 1.8). This is due to its superior electronic performance, originating from the highly degenerated Σ band at the band edge in the low-temperature rhombohedral phase and the smallest effective masses for both the L and Σ bands in the high-temperature cubic phase. The high thermoelectric performance of GeTe that is induced by its unique electronic structure not only provides a reference substance for understanding existing research on GeTe but also opens new possibilities for the further improvement of the thermoelectric performance of this material.

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“…Unfortunately, this is the case for p -type thermoelectric GeTe and its related alloys and composites. Although many literatures have reported a zT of 1.5 or even higher, the carrier concentration may not be fully optimized since GeTe by nature comes with a significantly high carrier concentration − and the challenge on measuring the carrier concentration at high temperatures (300–800 K). These high zT materials are typified by GeTe-AgSbTe 2 (TAGS), − GeTe-Sb 2 Te 3 , − GeTe-Bi 2 Te 3 , − and GeTe-PbTe ,− alloys.…”

Section: Introductionmentioning

confidence: 99%

Realizing the High Thermoelectric Performance of GeTe by Sb-Doping and Se-Alloying

et al. 2016

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GeTe-based alloys have been intensively considered as p-type thermoelectrics for about 50 years, yet existing literature barely discussed the thermoelectric properties of pristine GeTe at high temperatures (300−800 K). This work first backs to a fundamental understanding on the thermoelectric transport properties inherent to p-type GeTe, based on more than 50 samples synthesized with expected carrier concentrations ranging from 1 × 10 20 to 3 × 10 21 cm −3 . A thermoelectric figure of merit zT as high as ∼1.7 is found inherent to this compound when it is optimally doped with a Hall carrier concentration of 2.2 ± 10% × 10 20 cm −3 , offering a reference substance to expose the origins for the high zT in historical GeTe-based alloys. Guided by the above knowledge, further alloying Te with Se in samples with an optimal carrier concentration enables a reduction on the lattice thermal conductivity by ∼40% and eventually leads to a further enhancement on zT (up to 2.0) by ∼20%. This work demonstrates not only GeTe as an inherently high performance thermoelectric matrix compound but also its availability for further improvements by additional strategies.

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Influence of Vanadium on the Defect Structure and Thermoelectric Properties of GeTe

Cited by 10 publications

References 5 publications

Percolation Process-Mediated Rich Defects in Hole-Doped PbSe with Enhanced Thermoelectric Performance

Percolation Process-Mediated Rich Defects in Hole-Doped PbSe with Enhanced Thermoelectric Performance

Electronic origin of the high thermoelectric performance of GeTe among the p-type group IV monotellurides

Realizing the High Thermoelectric Performance of GeTe by Sb-Doping and Se-Alloying

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