Author
S. Ariponnammal
Bio: S. Ariponnammal is an academic researcher from Anna University. The author has contributed to research in topics: Electrical resistivity and conductivity. The author has an hindex of 1, co-authored 1 publications receiving 7 citations.
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8 citations
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TL;DR: The lattice parameters of the grown crystals have been determined by the Energy dispersive x-ray diffraction technique (EDXRD) and the structure has been confirmed as discussed by the authors.
Abstract: The Tris Zinc Thiourea Sulphate (ZTS) crystals have been crystallized by slow evaporation technique. The lattice parameters of the grown crystals have been determined by the Energy dispersive x-ray diffraction technique (EDXRD) and the structure has been confirmed. And, the high pressure electrical resistivity study have been carried out on this crystal and the results have been reported here. (© 2005 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim)
54 citations
TL;DR: In this paper, the authors measured the thermoelectric power (seebeck coefficient) and electrical resistivity of undoped single tin telluride (SnTe) crystals under applied high pressure up to 9 GPa, i.e., across the above phase transition.
Abstract: At normal conditions, tin telluride (SnTe) adopts a cubic NaCl-type structure, but under applied pressure above 1.5–2 GPa, it transforms to a distorted crystal structure with an orthorhombic symmetry. Electronic properties of this high-pressure phase, including potential thermoelectricity, remain unexplored to date. Here, we measure the thermoelectric power (the Seebeck coefficient) and electrical resistivity of undoped single crystals of SnTe under applied high pressure up to 9 GPa, i.e., across the above phase transition. We establish that the high-pressure polymorph of SnTe is a p-type semiconductor and estimate its bandgap value at 3 GPa as Eg ∼ 65 meV. In contrast to the NaCl-type phase, the orthorhombic phase is stable in a much wider pressure range up to about 20 GPa, and its energy gap only insignificantly decreases with pressure with a coefficient of dEg/dP ∼ −4 meV/GPa. We find that the thermoelectric power factor of SnTe can be significantly improved in its orthorhombic phase due to the enhancement of the Seebeck coefficient. Furthermore, we show that the high-pressure phase preserves on the pressure releasing down to 0.3 GPa, and its thermopower grows progressively up to about 100 μV/K due to the bandgap expansion to Eg ∼ 105 meV. This results in a colossal rising of the thermoelectric power factor to about 8 mW/(K2m). Probably, this enhancement is contributed by structural distortions in the orthorhombic phase. We discuss how one could fabricate and optimize the orthorhombic polymorph of SnTe for potential use in various technologies, including thermoelectric applications.
7 citations
TL;DR: In this paper, the Bis Thiourea Cadmium Chloride (BTCC) crystals have been crystallized by slow evaporation technique and the lattice parameters of the grown crystals were determined by the Energy dispersive x-ray diffraction technique (EDXRD) and the structure has been confirmed.
Abstract: The Bis Thiourea Cadmium Chloride (BTCC) crystals have been crystallized by slow evaporation technique. The lattice parameters of the grown crystals have been determined by the Energy dispersive x-ray diffraction technique (EDXRD) and the structure has been confirmed. The high pressure electrical resistivity study have been carried out on this crystal and the results have been reported here. (© 2005 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim)
5 citations
TL;DR: In this paper, a mixture of hexagonal Te and orthorhombic SnSe was found to have better properties than SnSe, and the absorption coefficient of SnTexSe1−x films was shown to reach a value of 0.93 eV.
Abstract: As prepared by fusion, SnTexSe1−x (x = 0.68) alloy is found to possess mixed phases of hexagonal Te and orthorhombic SnSe. The deposited films of this alloy demonstrate incongruent evaporation of the constituents. Reductions in c-parameter and strain along the z-axis in lattices of SnSe and Te constituents have been observed in these films at 353 K. These deviations in the structure of SnTexSe1−x films make it superior to SnSe for various optoelectronic applications. The absorption coefficient of SnTexSe1−x films is higher than SnSe, and its bandgap attains a value of 0.93 eV. Further, resistivity value of SnTexSe1−x (∼ 6.12 × 10−2 Ω cm) is lower and carrier concentration (∼ 1.31 × 1019 cm−3) is higher than SnSe, whereas its mobility value (∼ 25.8 cm2/V s) matches SnSe and similar materials. The surface quality of SnTexSe1−x improves and number of crystallites increases. The interface of p-SnTexSe1−x with Ag metal forms a Schottky diode. The current–voltage (I–V) behaviour of Ag/p-SnTexSe1−x Schottky diodes is analysed and diode parameters are determined by using thermionic emission and diffusion (TED) current transport mechanism.
3 citations
TL;DR: In this paper, the lattice parameters of the grown ZTC crystals were determined by angle dispersive X-ray powder diffraction technique (XRD) and the structure was confirmed by high pressure electrical resistivity study.
Abstract: Zinc thiourea chloride (ZTC) crystals were crystallized by slow evaporation technique. The lattice parameters of the grown crystals were determined by angle dispersive X-ray powder diffraction technique (XRD) and the structure was confirmed. High pressure electrical resistivity study was carried out on this crystal and the results are reported here.
3 citations