Understanding the Intrinsic P-Type Behavior and Phase Stability of Thermoelectric α-Mg 3 Sb 2

Xiaoyu Chong, Pin Wen Guan, Yi Wang, Shunli Shang, Jorge Paz Soldan Palma, Fivos Drymiotis, Vilupanur A. Ravi, Kurt E. Star, Jean Pierre Fleurial, Zi-kui Liu

Research output: Contribution to journalArticle

5 Citations (Scopus)

Abstract

α-Mg 3 Sb 2 is an excellent thermoelectric material through excess-Mg addition and n-type impurity doping to overcome its persistent p-type behavior. It is generally believed that the role of excess-Mg is to compensate the single Mg vacancy to realize n-type carrier conduction. In contrary to this belief, the present work indicates that the role of excess-Mg is to compensate the electronic charge of defect complex (V Mg(2) + Mg I ) 1- . The Mg solubility in α-Mg 3+x Sb 2 is quite small when only considering a single defect, but it enlarged up to x = 0.011 with the defect complex (V Mg(2) + Mg I ) 1- , which is more reasonable as supported by experiments. Under Mg-poor conditions, V Mg(1) 2- and V Mg(2) 2- are the dominant defects, and their concentrations can reach (1.05-1.18) × 10 19 cm -3 at 1200 K. Under Mg-rich conditions, (V Mg(2) + Mg I ) 1- is found to be the dominant reason for strong p-type behavior, and their concentrations can reach as high as 3.5 × 10 20 cm -3 , which shifts the Fermi level closer to the valence band maximum. The predicted carrier concentrations in the range 10 17 -10 20 cm -3 are in the same range found experimentally for pure p-type α-Mg 3 Sb 2 .

Original languageEnglish (US)
Pages (from-to)6600-6608
Number of pages9
JournalACS Applied Energy Materials
Volume1
Issue number11
DOIs
StatePublished - Nov 26 2018

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Phase stability
Defects
Valence bands
Fermi level
Vacancies
Carrier concentration
Solubility
Doping (additives)
Impurities
Experiments
oligomycin sensitivity-conferring protein

All Science Journal Classification (ASJC) codes

  • Energy Engineering and Power Technology
  • Chemical Engineering (miscellaneous)
  • Electrochemistry
  • Materials Chemistry
  • Electrical and Electronic Engineering

Cite this

Chong, Xiaoyu ; Guan, Pin Wen ; Wang, Yi ; Shang, Shunli ; Paz Soldan Palma, Jorge ; Drymiotis, Fivos ; Ravi, Vilupanur A. ; Star, Kurt E. ; Fleurial, Jean Pierre ; Liu, Zi-kui. / Understanding the Intrinsic P-Type Behavior and Phase Stability of Thermoelectric α-Mg 3 Sb 2 In: ACS Applied Energy Materials. 2018 ; Vol. 1, No. 11. pp. 6600-6608.
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title = "Understanding the Intrinsic P-Type Behavior and Phase Stability of Thermoelectric α-Mg 3 Sb 2",
abstract = "α-Mg 3 Sb 2 is an excellent thermoelectric material through excess-Mg addition and n-type impurity doping to overcome its persistent p-type behavior. It is generally believed that the role of excess-Mg is to compensate the single Mg vacancy to realize n-type carrier conduction. In contrary to this belief, the present work indicates that the role of excess-Mg is to compensate the electronic charge of defect complex (V Mg(2) + Mg I ) 1- . The Mg solubility in α-Mg 3+x Sb 2 is quite small when only considering a single defect, but it enlarged up to x = 0.011 with the defect complex (V Mg(2) + Mg I ) 1- , which is more reasonable as supported by experiments. Under Mg-poor conditions, V Mg(1) 2- and V Mg(2) 2- are the dominant defects, and their concentrations can reach (1.05-1.18) × 10 19 cm -3 at 1200 K. Under Mg-rich conditions, (V Mg(2) + Mg I ) 1- is found to be the dominant reason for strong p-type behavior, and their concentrations can reach as high as 3.5 × 10 20 cm -3 , which shifts the Fermi level closer to the valence band maximum. The predicted carrier concentrations in the range 10 17 -10 20 cm -3 are in the same range found experimentally for pure p-type α-Mg 3 Sb 2 .",
author = "Xiaoyu Chong and Guan, {Pin Wen} and Yi Wang and Shunli Shang and {Paz Soldan Palma}, Jorge and Fivos Drymiotis and Ravi, {Vilupanur A.} and Star, {Kurt E.} and Fleurial, {Jean Pierre} and Zi-kui Liu",
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Chong, X, Guan, PW, Wang, Y, Shang, S, Paz Soldan Palma, J, Drymiotis, F, Ravi, VA, Star, KE, Fleurial, JP & Liu, Z 2018, ' Understanding the Intrinsic P-Type Behavior and Phase Stability of Thermoelectric α-Mg 3 Sb 2 ', ACS Applied Energy Materials, vol. 1, no. 11, pp. 6600-6608. https://doi.org/10.1021/acsaem.8b01520

Understanding the Intrinsic P-Type Behavior and Phase Stability of Thermoelectric α-Mg 3 Sb 2 . / Chong, Xiaoyu; Guan, Pin Wen; Wang, Yi; Shang, Shunli; Paz Soldan Palma, Jorge; Drymiotis, Fivos; Ravi, Vilupanur A.; Star, Kurt E.; Fleurial, Jean Pierre; Liu, Zi-kui.

In: ACS Applied Energy Materials, Vol. 1, No. 11, 26.11.2018, p. 6600-6608.

Research output: Contribution to journalArticle

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T1 - Understanding the Intrinsic P-Type Behavior and Phase Stability of Thermoelectric α-Mg 3 Sb 2

AU - Chong, Xiaoyu

AU - Guan, Pin Wen

AU - Wang, Yi

AU - Shang, Shunli

AU - Paz Soldan Palma, Jorge

AU - Drymiotis, Fivos

AU - Ravi, Vilupanur A.

AU - Star, Kurt E.

AU - Fleurial, Jean Pierre

AU - Liu, Zi-kui

PY - 2018/11/26

Y1 - 2018/11/26

N2 - α-Mg 3 Sb 2 is an excellent thermoelectric material through excess-Mg addition and n-type impurity doping to overcome its persistent p-type behavior. It is generally believed that the role of excess-Mg is to compensate the single Mg vacancy to realize n-type carrier conduction. In contrary to this belief, the present work indicates that the role of excess-Mg is to compensate the electronic charge of defect complex (V Mg(2) + Mg I ) 1- . The Mg solubility in α-Mg 3+x Sb 2 is quite small when only considering a single defect, but it enlarged up to x = 0.011 with the defect complex (V Mg(2) + Mg I ) 1- , which is more reasonable as supported by experiments. Under Mg-poor conditions, V Mg(1) 2- and V Mg(2) 2- are the dominant defects, and their concentrations can reach (1.05-1.18) × 10 19 cm -3 at 1200 K. Under Mg-rich conditions, (V Mg(2) + Mg I ) 1- is found to be the dominant reason for strong p-type behavior, and their concentrations can reach as high as 3.5 × 10 20 cm -3 , which shifts the Fermi level closer to the valence band maximum. The predicted carrier concentrations in the range 10 17 -10 20 cm -3 are in the same range found experimentally for pure p-type α-Mg 3 Sb 2 .

AB - α-Mg 3 Sb 2 is an excellent thermoelectric material through excess-Mg addition and n-type impurity doping to overcome its persistent p-type behavior. It is generally believed that the role of excess-Mg is to compensate the single Mg vacancy to realize n-type carrier conduction. In contrary to this belief, the present work indicates that the role of excess-Mg is to compensate the electronic charge of defect complex (V Mg(2) + Mg I ) 1- . The Mg solubility in α-Mg 3+x Sb 2 is quite small when only considering a single defect, but it enlarged up to x = 0.011 with the defect complex (V Mg(2) + Mg I ) 1- , which is more reasonable as supported by experiments. Under Mg-poor conditions, V Mg(1) 2- and V Mg(2) 2- are the dominant defects, and their concentrations can reach (1.05-1.18) × 10 19 cm -3 at 1200 K. Under Mg-rich conditions, (V Mg(2) + Mg I ) 1- is found to be the dominant reason for strong p-type behavior, and their concentrations can reach as high as 3.5 × 10 20 cm -3 , which shifts the Fermi level closer to the valence band maximum. The predicted carrier concentrations in the range 10 17 -10 20 cm -3 are in the same range found experimentally for pure p-type α-Mg 3 Sb 2 .

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