GeAs: Highly Anisotropic van der Waals Thermoelectric Material
2016 (English)In: Chemistry of Materials, ISSN 0897-4756, E-ISSN 1520-5002, Vol. 28, no 8, 2776-2785 p.Article in journal (Refereed) PublishedText
GeAs and Sn-doped GeAs were synthesized from elements. Both crystallize in a layered crystal structure in the C2/m space group (No. 12) in the GaTe structure type. The crystal structure consists of As-terminated layers separated by van der Waals gaps. Sn-119 Mossbauer spectroscopy reveals that in the doped compound, Sn atoms are situated in a symmetric and homogeneous environment, most probably in the form of Sn-2 dumbbells. The anisotropic crystal structure of GeAs leads to highly anisotropic transport properties. High electrical and thermal conductivities were determined along the crystallographic layers. For the perpendicular direction across the layers, a sharp drop of more than an order of magnitude was observed for the transport properties of the GeAs single crystal. As a result, an order of magnitude difference in the figure of merit, ZT, was achieved: High-temperature thermoelectric characterization of the Sn-doped compound reveals a remarkable ZT with a maximum of 0.35 at 660 K.
Place, publisher, year, edition, pages
2016. Vol. 28, no 8, 2776-2785 p.
IdentifiersURN: urn:nbn:se:uu:diva-297353DOI: 10.1021/acs.chemmater.6b00567ISI: 000375244500035OAI: oai:DiVA.org:uu-297353DiVA: diva2:941902