T. Plecháček

Defect structure of Pb-doped Bi2Te3 single crystals

Pb-doped Bi2Te3 single crystals with a Pb concentration of c Pb = 0−9.4 ×  1025 m−3 were prepared from the elements Bi, Pb and Te of 99.999% purity by means of the Bridgman method. Samples of these crystals were characterized by measurements of the Hall coefficient R H(B∥c), electrical conductivity σ⊥c and Seebeck coefficient α(c⊥ΔT) over the temperature range 90–420 K. It was found that Pb impurities in Bi2Te3 behave as acceptors; some (40%) of the incorporated Pb atoms are electrically inactive. This effect is explained by the model of crystal lattice defects based on the assumption that the Pb atoms interact with native defects in the crystal lattice of undoped Bi2Te3, that is with antisite defects and vacancies in the Te sublattice.

Thermoelectric Properties of Cu2HgSnSe4-Cu2HgSnTe4 Solid Solution

Copper-based semiconductors from the family Cu2-II-IV-VI4 have recently attracted a great deal of attention because of their promising thermoelectric (TE) properties. Polycrystalline samples from the Cu2HgSnSexTe4−x (x = 0, 0.8, 2, 3.2, 4) solid solution were prepared and structurally characterized by powder x-ray diffraction. The samples from this solid solution crystallize in the stannite structure (space group

High-temperature thermoelectric properties of Hg-doped CuInTe2

I\bar{4}2m

Thermoelectric properties of the Ru{sub 2}Ni{sub 2}Sb{sub 12} ternary skutterudite

I4¯2m). Transport, TE, and thermal properties of hot-pressed samples are reported. About a 20 % reduction in calculated lattice thermal conductivities, compared to the lattice thermal conductivities of pure components of the alloys (i.e. Cu2HgSnSe4 and Cu2HgSnTe4), was observed for Cu2HgSnSe2Te2 alloy. The maximum ZT of the Cu2HgSnSe2Te2 sample reaches 0.6 at 575 K.

Thermoelectric properties of Ru2Ni2Sb12 ternary skutterudite

The properties of thin thermoelectric layers (about 60 nm in thickness) prepared by pulsed laser deposition are presented. Hot pressed targets were made from “middle” temperature range thermoelectric bulk materials with the potential high figure of merit ZT. P-type and N-type layers were prepared from Yb0.19Co4Sb12 and Ce0.1Fe0.7Co3.3Sb12 targets, respectively. The thin films were deposited on quartz glass substrates using KrF excimer laser. The individual layers were prepared by applying different laser beam energy densities (2 or 3 J cm−2) at several substrate temperatures (200, 250, or 300 °C). Crystallinity and composition of the layers were examined by x-ray diffraction and wavelength dispersive analysis, respectively. Homogeneity of Yb across a surface of the Yb filled film was explored by secondary ion mass spectrometry. The thermoelectric properties, the Seebeck coefficient, the electrical resistivity, and the power factor, for the best prepared P and N layer are presented in the temperature range...

Some physical properties of Hf-doped Sb/sub 2/Te/sub 3/ single crystals

Polycrystalline samples of composition CuIn1−xHgxTe2 (x = 0–0.21) were synthesized from elements of 5N purity using a solid state reaction. The phase purity of the products was verified by X-ray diffraction. Samples for transport property measurements were prepared using hot-pressing. The samples were characterized by measurement of the electrical conductivity, Hall coefficient, Seebeck coefficient, and thermal conductivity over a temperature range of 300–675 K. All samples show p-type conductivity. We discuss the influence of Hg substitution on the free carrier concentration and thermoelectric performance. The investigation of the thermoelectric properties shows up to a 40% improvement of ZT in the temperature range of 300–600 K.

Conduction band splitting and transport properties of Bi2Se3.

Polycrystalline samples of the RuSb2Te ternary skutterudite compound were prepared by the powder metallurgy method, and the influence of various types of doping on its thermoelectric properties was studied. The phase purity of the prepared samples was checked by means of powder x-ray diffraction, and their compositions were checked by electron probe x-ray microanalysis. Hot-pressed p-type samples were characterized by measurements of electrical conductivity, Hall coefficient, Seebeck coefficient, and thermal conductivity. Various doping strategies, i.e., cation substitution (Ru0.95Fe0.05Sb2Te), anion substitution (RuSb2Sn0.1Te0.9) or partial filling of voids of the ternary skutterudite structure (Yb0.05RuSb2Te), were investigated, and the influence of the dopants on the changes of the resulting transport, thermoelectric, and thermal properties is described.

Thermoelectric properties of Ni-doped CuInTe2

The synthesis of the Ru{sub 2-x}Ni{sub 2-x}Sb{sub 12} compounds (0{<=}x{<=}0.2), their structural characterization and temperature dependencies of selected transport and thermal properties are reported. At x=0, Ru{sub 2-x}Ni{sub 2-x}Sb{sub 12} displays cubic symmetry, space group Im3{sup Macron} with lattice parameter a=9.1767(1) A. From increasing electrical conductivity above 600 K the band gap (E{sub g}{approx}0.06 eV) was estimated using an Arrhenius plot. Different signs of the Seebeck coefficient (negative) and the Hall coefficient (positive) have been explained as a consequence of a multicarrier transport. The substitution on a cation site, i.e., formation of the Ru{sub 2-x}Ni{sub 2-x}Sb{sub 12} ternary skutterudites proved to be effective way in suppressing of the thermal conductivity. - Graphical abstract: Polyhedral representation of the Ru{sub 2}Ni{sub 2}Sb{sub 12} skutterudite crystal structure emphasizing the [(Ru/Ni)Sb{sub 6}] corner-sharing octahedra. Highlights: Black-Right-Pointing-Pointer Skutterudite-type structure with space group Im3{sup Macron} of the Ru{sub 2}Ni{sub 2}Sb{sub 12} was confirmed. Black-Right-Pointing-Pointer The band gap of the studied compounds was estimated - E{sub g}{approx}0.06 eV. Black-Right-Pointing-Pointer Low lattice thermal conductivity of the Ru{sub 2}Ni{sub 2}Sb{sub 12} was observed.