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THE EFFECT OF DOPING WITH ARSENIC ON THE THERMOELECTRIC PROPERTIES OF POLYCRYSTALLINE SnSe

Authors: Šraitrová Kateřina | Kucek Vladimír | Ruleová Pavlína | Plecháček Tomáš | Drašar Čestmír

Year: 2017

Type of publication: ostatní - přednáška nebo poster

Page from-to: nestránkováno

Titles:

Language	Name	Abstract	Keywords
eng	THE EFFECT OF DOPING WITH ARSENIC ON THE THERMOELECTRIC PROPERTIES OF POLYCRYSTALLINE SnSe	Recently, high thermoelectric performance (ZT = 2.6 at 923 K) has been reported in single crystalline SnSe [1]. Primary aim of this work was to investigate the influence of doping with arsenic on the thermoelectric properties of SnSe in terms of enhancement of ZT in mid temperature region. Polycrystalline SnSe1-xAsx samples, where x = 0, 0.005, 0.0075, 0.01, 0.02 and 0.04 were prepared utilizing solid-state reactions and hot-pressing. The samples were characterized by X-ray diffraction and electrical conductivity, thermal conductivity and Seebeck coefficient. These parameters were measured over the temperature range of 300 – 725 K. Figure of merit ZT was calculated from the obtained data. In search for an effective and stable p-dopant we have chosen As in place of Se atoms. We assumed arsenic would increase hole concentration and electrical conductivity in our material. X-ray analysis results show the solubility limit around x = 0.01. For samples with x higher than 0.02 we observe presence of secondary phase SnAs. Arsenic seems to substitute not only for Se atoms, but also for Sn atoms in the structure. Presumably, Sn sublattice is the prefered place of substitution. In contradiction with our assumption, arsenic in place of Se atoms does not increase hole concentration in SnSe markedly. The values of the electrical conductivity increased only in temperature range 450 – 550 K. On the other hand, the values of Seebeck coefficient show decrease in this temperature range, which is in agreement with the electrical conductivity results. Arsenic doping causes a decrease of the thermal conductivity in the whole temperature range. We observe a small increase of ZT parameter in the temperature range 450 – 550 K from the value 0.05 (undoped sample) to the 0.1 for the sample with x = 0.005 at 525 K.	thermoelectric materials, figure of merit, SnSe