Regensburg 2002 – wissenschaftliches Programm
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HL: Halbleiterphysik
HL 11: Poster 1
HL 11.30: Poster
Montag, 11. März 2002, 17:00–19:30, Poster A
The semiconducting silicides ReSi1.75 and Ru2Si3: crystal growth, doping, electrical and thermoelectric behaviour — •Dmitri Souptel1, Ludmila Ivanenko2, Jochen Werner1, Guenter Behr1, Hartmut Vinzelberg1, and Joachim Schumann1 — 1IFW Dresden, PF 270016, D-01171 Dresden — 2Belarusian State University of Informatics and Radioelectronics, Minsk, Belarus
The semiconducting silicides ReSi1.75 and Ru2Si3 are known as promising candidates for efficient thermoelectric materials. For Ru2Si3 the Figure of merit ZT has been estimated theoretically and experimentally to be greater than unity, however, due to difficulties of the sample preparation a reliable verification of these data could not be performed yet. Therefore, single crystals of ReSi1.75 and Ru2Si3 have been grown by FZ technique with radiation heating. For optimising the thermoelectric performance the crystals were doped (Ru2Si3 by 1 % Mn, ReSi1.75 by 1 % Rh or Al). Ru2Si3 has orthorhombic structure (Pbcn), ReSi1.75 has a triclinic cell (P1). Transport measurements have been carried out in the temperature range 100K <T<900 K and resulted in the determination of resistivity ρ, Seebeck and Hall coefficient S and RH, respectively. On the base of these experimental data the crystals are characterised concerning the type of conductivity, band gap, activation energy of dopants, carrier density and mobility. The electrical behaviour of undoped and doped samples is compared and the thermoelectric power factor is calculated. Based on room temperature measurements of the thermal conductivity κ and on the transport properties S and ρ the thermoelectric Figure of merit T2S/ρ κ for doped crystals has been determined.