Structural and electrical properties of Bi2(Te0.4Se0.6)3 thin films
TL;DR: In this article, thin films of Bi2(Te0.4Se0.6)3 alloy have been flash evaporated on to clean glass plates held at room temperature in a vacuum of 2.5 × 10−5 −5 torr.
About: This article is published in Materials Chemistry and Physics.The article was published on 2000-01-14. It has received 3 citations till now. The article focuses on the topics: Grain growth & Grain size.
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TL;DR: In this paper, an attempt to prepare Fe2VAl deposited film and the thermoelectric module using RF sputtering has been made, where the material composition was controlled by controlling the aluminum content of the starting material.
Abstract: An attempt to prepare Fe2VAl deposited film and the thermoelectric module using RF sputtering has been made. Sputtering target has been prepared using mechanical alloying of metallic powders and the subsequent pulse current sintering process. The obtained deposited film has had a lack of aluminum content compared to the composition of the starting material. Controlling of aluminum content for the preparation of Fe2VAl sputtering target has made it possible to obtain the desired material composition. The film has had the experimental thermoelectric force being similar to the one estimated from the measured thermoelectric data of the materials. Fe2VAl thermoelectric module of eight pairs with a film thickness of 4 μm has had an electric force of 31mV and 5.6μW.
3 citations
TL;DR: In this article, a p-type thermoelectric film of (Bi2Te3)0.25(Sb 2Te3 )0.75 was fabricated on a polyimide substrate by RF sputtering.
Abstract: A p-type thermoelectric film of (Bi2Te3)0.25(Sb2Te3)0.75 was fabricated by radio frequency sputtering. The target for the sputtering was prepared by mechanical alloying (MA) and pulsed current sintering (PCS) process. The single phase of Bi0.5Sb1.5Te3 was obtained by planetary ball milling Bi powder, Te powder and Sb powder for 36ks. The obtained powder was consolidated by PCS into the cylindrical target of 50 mm in diameter and 4mm in thickness at 643 K under a pressure of 13 MPa. The sintered body consisted of Bi0.5Sb1.5Te3 without cracks. The sintered Bi0.5Sb1.5Te3 was joined to Cu backing plate with In for an insertion by PCS process. The thin film of (Bi2Te3)0.25(Sb2Te3)0.75 was fabricated on a polyimide substrate by RF sputtering. The thickness of this thin film was about 15-20μm. This film was amorphous state and crystallized at about 520 K. The performance of this p-type thermoelectric film after the crystallization were 2.0mV in voltage and 2.9μA in current at 20 K of the difference between heating side temperature 353 K and cooling side temperature 333 K.
2 citations
TL;DR: A number of articles have been devoted to the thermoelectric properties of materials as discussed by the authors, where the type-I clathrates have attracted much attention because they would possess a low kL value as the theoretical minimum one, which results from rattling of atoms filled in their cages.
Abstract: Thermoelectric (TE) devices are increasingly being seen as having the potential to make important contributions to reducing greenhouse gas emissions and providing cleaner forms of energy. A number of articles have been devoted to the thermoelectric properties of materials. From the search for novel and effective thermoelectric materials the clathrate structures has emerged as one of the most promising candidates for achieving very high thermoelectric figure of merit: ZT= α2σT/κ, where α, T, σ and κ are the Seebeck coefficient, absolute temperature, electrical conductivity, and total thermal conductivity, respectively [1]. For the past decade, caged clathrate compounds of group IV elements have attracted much attention because they would possess a low kL value as the theoretical minimum one, which results from rattling of atoms filled in their cages [2-3]. There are the type-I, type-III, and type-VIII structures in thermoelectric clathrates, but most compounds adopt type-I structure (space group No.223; Pm-3n). A large number of the type-I clathrates with the chemical formula of II8III16IV30 (II=Ba, Sr, Eu, III=Al, Ga, In, and IV= Si, Ge, Sn) have been synthesized and studied intensively [5-11], which results in relatively high ZT values such as 0.7 at 700 K for Ba8Ga16Ge30 and 0.87 at 870 K for Ba8Ga16Si30 [3]. Among type-I clathrates, a single-crystal n-type Ba8Ga16Ge30 grown using the Czochralski method with a ZT of 1.35 at 900 K is one of the most promising results [12].
References
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TL;DR: In this article, Boron doses of 1×1012-5×1015/cm2 were implanted at 60 keV into 1-μm-thick polysilicon films and Hall and resistivity measurements were made over a temperature range −50-250 °C.
Abstract: Boron doses of 1×1012–5×1015/cm2 were implanted at 60 keV into 1‐μm‐thick polysilicon films. After annealing at 1100 °C for 30 min, Hall and resistivity measurements were made over a temperature range −50–250 °C. It was found that as a function of doping concentration, the Hall mobility showed a minimum at about 2×1018/cm3 doping. The electrical activation energy was found to be about half the energy gap value of single‐crystalline silicon for lightly doped samples and decreased to less than 0.025 eV at a doping of 1×1019/cm3. The carrier concentration was very small at doping levels below 5×1017/cm3 and increased rapidly as the doping concentration was increased. At 1×1019/cm3 doping, the carrier concentration was about 90% of the doping concentration. A grain‐boundary model including the trapping states was proposed. Carrier concentration and mobility as a function of doping concentration and the mobility and resistivity as a function of temperature were calculated from the model. The theoretical and ex...
2,657 citations
TL;DR: The mean free path of electrons in metals has been studied in this paper, where the authors show that electrons follow a straight line along the path of the electron in the metal atom.
Abstract: (2001). The mean free path of electrons in metals. Advances in Physics: Vol. 50, No. 6, pp. 499-537.
2,273 citations
IBM1
TL;DR: In this paper, the total resistivity of a thin metal film is calculated from a model in which three types of electron scattering mechanisms are simultaneously operative: an isotropic background scattering (due to the combined effects of phonons and point defects), scattering due to a distribution of planar potentials (grain boundaries), and scattering by the external surfaces.
Abstract: In this paper, the total resistivity of a thin metal film is calculated from a model in which three types of electron scattering mechanisms are simultaneously operative: an isotropic background scattering (due to the combined effects of phonons and point defects), scattering due to a distribution of planar potentials (grain boundaries), and scattering due to the external surfaces. The intrinsic or bulk resistivity is obtained by solving a Boltzmann equation in which both grain-boundary and background scattering are accounted for. The total resistivity is obtained by imposing boundary conditions due to the external surfaces (as in the Fuchs theory) on this Boltzmann equation. Interpretation of published data on grain-boundary scattering in bulk materials in terms of the calculated intrinsic resistivity, and of thin-film data in terms of the calculated total resistivity suggests that (i) the grain-boundary reflection coefficient in Al is \ensuremath{\approx} 0.15, while it is somewhat higher in Cu; (ii) the observed thickness dependence of the resistivity in thin films is due to grain-boundary scattering as well as to the Fuchs size effect; and (iii) the common observation that single-crystal films possess lower resistivities than polycrystalline films may be accounted for by grain-boundary effects rather than by differences in the nature of surface scattering.
1,842 citations
TL;DR: The field of thermoelectric energy conversion is reviewed from both a theoretical and an experimental standpoint in this paper, with particular emphasis being placed on the most recent developments in high-temperature semiconductors.
Abstract: The field of thermoelectric energy conversion is reviewed from both a theoretical and an experimental standpoint. The basic theory is introduced and the thermodynamic and solid state views are compared. An overview of the development of thermoelectric materials is presented with particular emphasis being placed on the most recent developments in high-temperature semiconductors. A number of possible device applications are discussed and the successful use and suitability of these devices for space power is manifest.
940 citations