Off-stoichiometric silver antimony telluride: An experimental study of transport properties with intrinsic and extrinsic doping

Journal Article · Fri May 15 00:00:00 EDT 2015 · AIP Advances

DOI:https://doi.org/10.1063/1.4916217· OSTI ID:22488563

Nielsen, Michele D.; Jaworski, Christopher M. ^[1]

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1. Department of Mechanical and Aerospace Engineering, The Ohio State University, Columbus, Ohio 43210 (United States)

AgSbTe{sub 2} is a thermoelectric semiconductor with an intrinsically low thermal conductivity and a valence band structure that is favorable to obtaining a high thermoelectric figure of merit zT. It also has a very small energy gap Eg ∼ 7.6 ± 3 meV. As this gap is less than the thermal excitation energy at room temperature, near-intrinsic AgSbTe{sub 2} is a two carrier system having both holes (concentration p) and electrons (n). Good thermoelectric performance requires heavy p-type doping (p > > n). This can be achieved with native defects or with extrinsic doping, e.g. with transition metal element. The use of defect doping is complicated by the fact that many of the ternary Ag-Sb-Te and pseudo-binary Sb{sub 2}Te{sub 3}-Ag{sub 2}Te phase diagrams are contradictory. This paper determines the compositional region most favorable to creating a single phase material. Through a combination of intrinsic and extrinsic doping, values of zT > 1 are achieved, though not on single-phased material. Additionally, we show that thermal conductivity is not affected by defects, further demonstrating that the low lattice thermal conductivity of I-V-VI{sub 2} materials is due to an intrinsic mechanism, insensitive to changes in defect structure.

• OSTI ID: 22488563
• Journal Information: AIP Advances, Vol. 5, Issue 5; Other Information: (c) 2015 Author(s); Country of input: International Atomic Energy Agency (IAEA); ISSN 2158-3226
• Country of Publication: United States
• Language: English

Related Subjects

36 MATERIALS SCIENCE
ANTIMONY TELLURIDES
DEFECTS
ELECTRONS
ENERGY GAP
EXCITATION
PHASE DIAGRAMS
SEMICONDUCTOR MATERIALS
SILVER
SILVER TELLURIDES
TEMPERATURE RANGE 0273-0400 K
THERMAL CONDUCTIVITY