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Transport Properties of Ag‐doped ZnSb
Author(s) -
Eklöf Daniel,
Fischer Andreas,
Grins Jekabs,
Scherer Wolfgang,
Häussermann Ulrich
Publication year - 2021
Publication title -
zeitschrift für anorganische und allgemeine chemie
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.354
H-Index - 66
eISSN - 1521-3749
pISSN - 0044-2313
DOI - 10.1002/zaac.202000314
Subject(s) - spark plasma sintering , seebeck coefficient , materials science , doping , thermoelectric effect , electrical resistivity and conductivity , hall effect , condensed matter physics , figure of merit , thermoelectric materials , thermal conductivity , impurity , intermetallic , grain boundary , band gap , grain size , analytical chemistry (journal) , sintering , metallurgy , optoelectronics , composite material , chemistry , microstructure , thermodynamics , electrical engineering , physics , organic chemistry , alloy , chromatography , engineering
The intermetallic compound ZnSb is a (II‐V) narrow gap semiconductor with interesting thermoelectric properties. Electrical resistivity, Hall coefficient, thermopower and thermal conductivity were measured up to 400 K on Ag‐doped samples with concentrations 0.2, 0.5, 1, 2, and 3 at.%, which were consolidated to densities in excess of 99.5 % by spark plasma sintering. The work confirms a huge improvement of the thermoelectric Figure‐of‐merit, ZT , upon Ag doping. The optimum doping level is near 0.5 at.% Ag and results in ZT values around 1.05 at 390 K. The improvement stems from a largely decreased resistivity, which in turn relates to an increase of the hole charge carrier concentration by two orders of magnitude. It is argued that Ag can replace minute concentrations of Zn (on the order of 0.2 at.%) in the crystal structure which enhances the intrinsic impurity band of ZnSb. Excess Ag was found to segregate in grain boundaries. So the best performing material may be considered as a composite Zn ~0.998 Ag ~0.002 Sb/Ag ~0.003 .