Phases and thermoelectric properties of SnTe with (Ge, Mn) co-doping. Issue 42 (19th October 2017)

• Record Type: Journal Article
• Authors: Li, J. Q.; Huang, S.; Chen, Z. P.; Li, Y.; Song, S. H.; Liu, F. S.; Ao, W. Q.
• Is Part Of: Physical chemistry chemical physics. Volume 19:Issue 42(2017)
• Page Start: 28749
• Page End: 28755
• Publication Date: 2017-10-19
• Subjects: Chemistry, Physical and theoretical -- Periodicals; 541.3
• DOI: 10.1039/c7cp04931e
• Languages: English
• ISSNs: 1463-9076

Abstract

Abstract : Solute Ge/Mn atoms and a minor Ge phase in a SnTe-based system synergistically enhance the thermoelectric properties. Abstract : A lead-free SnTe compound shows good electrical properties but also high thermal conductivity, resulting in a low figure of merit ZT . We demonstrate a significant enhancement of the thermoelectric properties of SnTe by (Ge, Mn) co-doping. (Ge, Mn) co-doped samples (Sn0.8 Ge0.2 )1− x Mn x Te with x = 0, 0.03, 0.06, 0.09, 0.12, 0.15, 0.18 and 0.2 were prepared for this investigation. The substitution of Ge for Sn in SnTe promotes the solubility of Mn in a SnTe-based phase up to 20 at%, which further enlarges the band gap and gives rise to enhanced valence band convergence as compared with Mn doping, leading to a notably increased Seebeck coefficient and a power factor. All alloys retain p-type conduction and hole carrier concentration increases with increasing Mn content. The solute Ge and Mn atoms as well as the second phase of Ge in a SnTe-based system enhance phonon scattering and thus reduce thermal conductivity. The synergistic role that Ge and Mn play in regulating the electron and phonon transport of SnTe yields a maximum figure of merit ZT of 1.22 at 873 K for the sample (Sn0.8 Ge0.2 )0.85 Mn0.15 Te.