High Thermoelectric Performance and Enhanced Mechanical Stability of p-type Ge1–xSbxTe

Perumal, Suresh; Roychowdhury, Subhajit; Negi, Devendra Singh; Datta, Ranjan; Biswas, Kanishka

doi:10.1021/acs.chemmater.5b03434

Cited by 306 publications

(397 citation statements)

References 59 publications

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“…The negative Seebeck coefficients confirms the n-type charge carriers in the samples. The linear increase of the absolute Seebeck coefficient and the monotonic decrease in electrical conductivity with increasing temperature suggests degenerate semiconducting behavior for most of the samples [29][30][31]. These tendencies, expected due to a slight loss of degeneracy at elevated temperatures [13], allow the assumption of single band conduction behavior for these samples within the values of carrier density and temperature ranges studied.…”

Section: Resultsmentioning

confidence: 77%

Enhancement in thermoelectric performance of n-type Pb-deficit Pb-Sb-Te alloys

Srinivasan

Gucci

Boussard‐Plédel

et al. 2017

Journal of Alloys and Compounds

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PbTe based materials are well known for their high performance thermoelectric properties. Here, a systematic study of thermoelectric transport properties of n-type Pb-deficit Pb0.98-xSbxTe alloys with carrier concentrations in the range of 10 -19 cm -3 is presented from room temperature to 623 K. A maximum thermoelectric figure of merit (zT) of 0.81 was achieved at 623 K for 4 mol% Sb containing Pb-deficit composition, by the cumulative integration of enhanced power factor and significant reduction in thermal conductivity. The scattering of phonons at Pb vacancies, contributed to the reduction of lattice thermal conductivity, and thereby strikingly boosted the zT of the Pb-deficit samples when compared with the pristine Pb1-xSbxTe.

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Section: Resultsmentioning

confidence: 77%

Enhancement in thermoelectric performance of n-type Pb-deficit Pb-Sb-Te alloys

Srinivasan

Gucci

Boussard‐Plédel

et al. 2017

Journal of Alloys and Compounds

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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: 96%

“…In pristine materials with optimized carrier concentrations, the lower-energy offset between these two bands in PbTe (0.17 eV 29,30,35 at 300 K) compared with that in SnTe (0.3-0.4 eV 32,34 at 300 K) leads to a much higher-power factor (30 μW cm − 1 K − 2 36 ) for PbTe than that for SnTe (20 μW cm − 1 K − 2 37 ). For GeTe, the available literature shows a power factor of ∼ 40 μW cm − 1 K − 2 , [38][39][40][41] which is the highest among the three compounds. The underlying origin of this phenomenon, however, is ambiguous, to our best knowledge.…”

Section: Introductionmentioning

confidence: 98%

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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“…40 Sb x Ge 1 − x Te compounds showed a similar ZT of~1.85 and high mechanical stability. 41 Therefore, GeTe can provide a versatile lead-free base material for thermoelectric applications. 34 However, the influence of resonant levels on the thermoelectric response of GeTe warrants further exploration.…”

Section: Introductionmentioning

confidence: 99%

Resonant level-induced high thermoelectric response in indium-doped GeTe

et al. 2017

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Resonant levels are promising for high-performance single-phase thermoelectric materials. Recently, phase-change materials have attracted much attention for energy conversion applications. As the energetic position of resonant levels could be temperature dependent, searching for dopants in phase-change materials, which can introduce resonant levels in both low and high temperature phases, remains challenging. In this study, possible distortions of the electronic density of states due to group IIIA elements (Ga, In, Tl) in GeTe are theoretically investigated. Resonant levels induced by indium dopants in both rhombohedral and cubic phase GeTe have been demonstrated. The experimental Seebeck coefficients of In x Ge 1 − x Te exhibit a large enhancement compared with those observed for other prior dopants. Indium dopants reduce the defect concentrations in GeTe, and thus, they lower the carrier concentrations and suppress the electronic component of the total thermal conductivity. The enhanced Seebeck coefficient, together with the suppressed thermal conductivity, leads to a reasonably high ZT of 1.3 at a temperature near 355°C in In 0.02 Ge 0.98 Te. The corresponding average ZT is enhanced by~70% across the entire temperature range of the rhombohedral and cubic phases. These observations indicate that indium-doped GeTe is a promising base material for achieving an even higher thermoelectric performance.

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High Thermoelectric Performance and Enhanced Mechanical Stability of p-type Ge_1–xSb_xTe

Cited by 306 publications

References 59 publications

Enhancement in thermoelectric performance of n-type Pb-deficit Pb-Sb-Te alloys

Enhancement in thermoelectric performance of n-type Pb-deficit Pb-Sb-Te alloys

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

Resonant level-induced high thermoelectric response in indium-doped GeTe

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