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Single crystalline SnSe doped with As and its interaction with native defects

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

Year: 2018

Type of publication: ostatní - přednáška nebo poster

Page from-to: nestránkováno

Titles:

Language	Name	Abstract	Keywords
eng	Single crystalline SnSe doped with As and its interaction with native defects	SnSe has been recently studied as a promising thermoelectric material, especially for its high values of figure of merit (ZT = 2.6 at 923 K) and very low values of thermal conductivity [1]. These initial conditions opened space for enhancement of figure of merit via doping. Large number of new doping studies appears every year. Based on our previous experience with polycrystalline SnSe doped with As, in this work we present results of single crystalline doped SnSe. Two series SnSe1-xAsx and Sn1-xAsxSe, where x = 0.0025, 0.005 and 0.01 were prepared. Phase purity of samples was confirmed by X-ray diffraction. Samples were characterized by Hall coefficient and Seebeck coefficient. These parameters were measured over a temperature range 93 – 473 K. Electrical conductivity was measured over a temperature range 93 – 723 K. From our results it follows that SnSe prefers substitution of As for Sn rather than for Se. Arsenic does not improve thermoelectric properties of SnSe. However, it seems it could contribute to the discussion of native defects in SnSe. Arsenic suppresses formation of native defects in low temperatures. On the other hand it seems to support formation of native defects around 450 K. In stoichiometric SnSe these native defects form at temperatures around 600 K and they are considered to be Sn vacancies [2]. Thus, arsenic doping seems to shift their formation temperature towards lower temperatures.