Low-Temperature Transport Properties of Bi-Substituted β-As₂Te₃ Compounds

Jean-Baptiste Vaney (1, 2) , Julie Carreaud (2) , Gaëlle Delaizir (2) , Cédric Morin (3) , Judith Monnier (3) , Eric Alleno (3) , Andrea Piarristeguy (4) , Annie Pradel (4) , Antonio P. Goncalves (5) , Elsa B. Lopes (5) , Christophe Candolfi (1) , Anne Dauscher (1) , Bertrand Lenoir (1)

1 IJL - Institut Jean Lamour
2 SPCTS-AXE3 - Axe 3 : organisation structurale multiéchelle des matériaux
3 ICMPE - Institut de Chimie et des Matériaux Paris-Est
4 ICGM - Institut Charles Gerhardt Montpellier - Institut de Chimie Moléculaire et des Matériaux de Montpellier
5 Instituto Superior Técnico

β-As₂Te₃ belongs to the family of Bi₂Te₃-based alloys, a well-known class of efficient thermoelectric materials around room temperature. As₂Te₃ exists in two allotropic configurations: α- and β-As₂Te₃, of which only the latter crystallizes in the same rhombohedral structure as Bi₂Te₃. Herein, we report on substitution of Bi for As in the As_2−xBi_xTe₃ system with x = 0.0, 0.015, 0.025, and 0.035. These samples have been characterized by x-ray diffraction and scanning electron microscopy. The transport properties have been measured at low temperatures (5 K to 300 K) in both directions, parallel and perpendicular to the pressing direction. The results are compared with those obtained in previous study on samples substituted by Sn. Compared with Sn, Bi allows for a clear decrease in electrical resistivity while maintaining the thermal conductivity below 1 W m^-1 K^-1 over the whole temperature range. As a result, a comparable peak ZT value near 0.2 was obtained at room temperature.

Mots clés: Thermoelectric materials; Arsenic telluride; Metastable thermoelectric phase

Domaines: Science des matériaux [cond-mat.mtrl-sci]; Matériaux

Jean-Baptiste Vaney, Julie Carreaud, Gaëlle Delaizir, Cédric Morin, Judith Monnier, et al.. Low-Temperature Transport Properties of Bi-Substituted β-As₂Te₃ Compounds. Journal of Electronic Materials, 2016, 45 (3), pp.1786-1791. ⟨10.1007/s11664-015-4227-1⟩. ⟨hal-01279971⟩