Regensburg 2013 – wissenschaftliches Programm
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DS: Fachverband Dünne Schichten
DS 12: Poster Session II: Functionalized semiconductor nanowires (jointly with HL); Resistive switching (jointly with DF, KR, HL); Thermoelectric materials
DS 12.20: Poster
Montag, 11. März 2013, 17:00–20:00, Poster B1
Structural and electrical properties of thermoelectric FexCo1−xSb3 thin films — Ayham Dalla, •Marcus Daniel, Andreas Liebig, Fabian Ganss, Gunter Beddies, and Manfred Albrecht — Chemnitz University of Technology, Institute of Physics
Increasing interest in efficiency enhancement of existing energy sources led to an extended research in the field of thermoelectricity. A suitable thermoelectric material like CoSb3 is characterised by a high power factor and a low thermal conductivity. To control and improve the power factor a targeted electrical doping is necessary to achieve charge carrier densities up to 1020 cm−3. In case of CoSb3 controlled doping can be obtained by a partially substitution of Co by Fe atoms. In this study, 30 nm thick FexCo1−xSby films have been deposited via MBE onto thermally oxidized Si(100) substrates at room temperature. The samples were post-annealed in ultra-high vacuum for one hour at 450∘C. Two sample series with varying Fe content (0<x<0.5) were fabricated, a Sb rich (y = 3.3) and a Sb deficient series (y = 2.5). The composition was verified by RBS and the XRD analysis confirmed CoSb3 as major phase. A systematic decrease of the extracted lattice parameter with increasing Fe content indicated the substitution of Co by Fe atoms. The electrical characterization was performed in a temperature range between 4 K and 300 K. Both series show an increase in charge carrier concentration with increasing Fe content, and thus a decrease in resistivity. The temperature dependence of the resistivity revealed for both sample series a change from semiconducting to metallic behaviour at a critical charge carrier concentration.