Improved electrical conductivity and power factor in Sn and Se co-doped melt-grown Bi2Te3 single crystal

Abstract In the current work, growth and thermoelectric characterization of tin and selenium co-doped single crystal bismuth telluride have been carried out in the range of temperature 10–400 K. The crystals show hexagonal crystal structure with R $$\overline{3 }$$ 3 ¯ m space group . The direction of growth, quality of the single crystals, the density of dislocation, and dopants effect on the inner plane structure of the crystals have been analyzed through high-resolution X-ray diffraction study. Energy dispersive analysis of X-rays approves the elemental composition, and field emission scanning electron microscopy shows uniform growth with micro precipitates on the surface of the crystals. Quasi degenerate and non-degenerate electrical resistivity is observed in the pristine and doped samples, respectively. Temperature-dependent Seebeck coefficient measurements confirm the n -type semiconducting nature of the pristine as well as doped samples. Temperature-dependent power factor of (Bi 0.96 Sn 0.04 ) 2 Te 2.7 Se 0.3 is found to increase by 1.1 times, and electrical resistivity reduced by 3.3 times as compared to pristine Bi 2 Te 3 .