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Abstract: (Bi1−xSnx)2Te2.7Se0.3 thermoelectric thin films with thickness of 800nm have been deposited on glass substrates by flash evaporation method at 473K. The structures, morphology of the thin films were analyzed by X-ray diffraction and field emission scanning electron microscopy respectively. Effects of Sn-doping concentration on thermoelectric properties of the annealed thin films were investigated by room-temperature measurement of Seebeck coefficient and electrical resistivity. The thermoelectric power factor was enhanced to 12.8μW/cmK2 (x=0.003). From x=0.004 to 0.01 Sn doping concentration, the Seebeck coefficients are positive and show p-type conduction. The Seebeck coefficient and electrical resistivity gradually decrease with increasing Sn doping concentration. [Copyright &y& Elsevier]

Abstract: Taking elemental antimony and tellurium as source materials, Sb2Te3 nanopowders were prepared by vacuum arc plasma evaporation technique. Microstructure and morphology of the samples were characterized via X-ray diffraction and field emission scanning electron microscope. Compositional analysis was carried out by energy dispersive analysis of X-rays. Lattice constants (a = 4.267 Å, c = 30.469 Å) of Sb2Te3 nanopowders are calculated by (015) and (110) diffraction peaks of X-ray diffraction patterns. Field emission scanning electron microscope surface morphology of the nanopowders shows the irregular polyhedron and rhombohedral structure. Atoms percentage of the nanopowders is calculated by quantitative analysis using energy dispersive analysis of X-rays spectrum. The experimental results show that the percentages of Sb and Te atoms are 41.3% and 58.7% respectively. [Copyright &y& Elsevier]

Abstract: The p-type Bi0.4Sb1.6Te3 system compounds with fine microstructure were prepared by mechanical alloying (MA) and equal channel angular extrusion (ECAE) in the present work. A preferentially orientated microstructure that the (110) plane preferentially orientated along the perpendicular direction to extrusion and the basal planes (00 l) preferentially orientated along the extrusion direction was formed in the ECAE process, and the orientation factors F of the basal planes (00 l) of the extruded alloys was about 0.36. The electrical and thermal transmission performances were strongly affected by the preferential orientation and the thermoelectric properties in the extrusion direction were obviously improved by the ECAE process. The maximum dimensionless figure of merit of the 4wt.% Te-doped Bi0.4Sb1.6Te3 alloys was obtained in the extrusion direction at testing temperature 343K, ZT=0.979. [Copyright &y& Elsevier]

Abstract: Deposition of Sb2Te3 thin films on polycrystalline Au substrates by electrochemical atomic layer epitaxy (ECALE) is described in this paper. Electrochemical aspects were characterized by means of cyclic voltammetry, anodic potentiodynamic scanning and coulometry. A steady ECALE deposition for Sb2Te3 compound could be attained after negatively adjusting the underpotential deposition (UPD) potentials of Sb and Te on Au in steps over the initial 40 cycles, and the potentials could be kept constant for the following deposition. A 400 cycle deposit, which was grown with the steady deposition potentials, was proved to be a single phase Sb2Te3 compound by X-ray diffraction analysis and SEM observation shows the deposit consisted of nanoscale particles with average size about 100nm. The 2:3 stoichiometric ratio of the deposit was further verified by energy dispersive X-ray (EDX) quantitative analysis. [Copyright &y& Elsevier]

Abstract: Starting from elemental bismuth, tellurium and selenium powders, n-type Bi2Te2.85Se0.15 solid solution with fine microstructure was prepared by mechanical alloying (MA) and plasma activated sintering (PAS) in the present work. The effect of PAS process on microstructure and thermoelectric properties of the sintered samples was investigated. The sintering temperature of PAS process (683K) was 80–100K lower than that of conventional hot pressing and the whole PAS process was also greatly shortened to about 30min. A preferentially orientated microstructure with the basal planes (00 l) perpendicular to pressing direction was formed in the PASed sample and the maximum figure of merit (Z) at room temperature was 1.80×10−3 K−1. [Copyright &y& Elsevier]