Regensburg 2010 – wissenschaftliches Programm
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DS: Fachverband Dünne Schichten
DS 13: Thermoelectric Thin Films and Nanostructures I
DS 13.4: Vortrag
Dienstag, 23. März 2010, 11:15–11:30, H8
Evidence of Multiphase Nature of β-Zn4Sb3 by means of Surface Scanning Techniques — •Titas Dasgupta1, Christian Stiewe1, Ralf Hassdorf1, Lothar Böttcher1, Hao Yin2, Bo Iversen2, and Eckhard Müller1 — 1German Aerospace Center (DLR), Institute of Materials Research, Linder Höhe, 51147, Cologne, Germany — 2University of Aarhus, Department of Chemistry, Langelandsgade 140, DK-8000, Aarhus, Denmark
β-Zn4Sb3 has been considered as a promising candidate for thermogenerator applications for long due to its high thermoelectric figure of merit (ZT) reaching up to ∼1.3 at intermediate temperatures. The high ZT is a result of the unusually low thermal conductivity (κ) observed in this material. The cause of this low κ is still under debate. Reports on structural analyses reveal a disordered structure with presence of interstitial Zn atoms to be the likely cause of the low κ. Also, soft phonon modes have been observed in this material due to the presence of Sb dimers which can also lead to the observed low κ. Thus the present work investigates the surface homogeneity and microstructure of β-Zn4Sb3 based on Seebeck Microprobe (PSM) and Scanning Electron Microscopy (SEM) studies. PSM measurements indicate the presence of local structures with slightly varying but distinct Seebeck (S) values. SEM studies also reveal the presence of local structures arising due to dopant contrast.Based on these observations, the possibility of the presence of multiple phases within β-Zn4Sb3 is discussed.