Thermoelectric properties of Tl-doped Bi2Se3 single crystals

✍ Scribed by P. Janíček; Č. Drašar; L. Beneš; P. Lošťák

• Publisher: John Wiley and Sons
• Year: 2009
• Tongue: English
• Weight: 213 KB
• Volume: 44
• Category: Article
• ISSN: 0232-1300
• DOI: 10.1002/crat.200800615

✦ Synopsis

The single crystals of the ternary system based on Bi 2-x Tl x Se 3 (nominaly x = 0.0-0.1) were prepared using the Bridgman technique. Samples with varying content of Tl were characterized by the measurement of lattice parameters, electrical conductivity σ ⊥c , Hall coefficient R H (B||c), and Seebeck coefficient S(ΔT⊥c). The measurements indicate that by incorporating Tl in Bi 2 Se 3 one lowers the concentration of free electrons and enhances their mobility. This effect is explained in terms of the point defects in the crystal lattice -formation of substitutional defects thallium on the site of bismuth Tl Bi and the decrease of concentration of selenium vacancies +2 Se V . We also discuss the temperature dependence of the power factor σS 2 of the samples. Upon the thallium doping we observe a significant increase of the power factor compare to the parental Bi 2 Se 3 .