Doped Bi2Te3 nano-structured semiconductors obtained by ultrasonically assisted hydrothermal method

Nanocrystalline powders of doped Bi2Te3, with Ag (S1 sample), Sb (S2 sample), Sn (S3 sample) ions with different morphology and particle size 30-50 nm were prepared by a ultrasonically assisted hydrothermal method in alkaline aqueous solution with different concentration of NaBH4 as reducing agent at 200A degrees C for 3 hours and 80% fill degree of autoclave. The influence of dopants and hydrothermal treatment conditions on the formation features, phase composition, particle size, morphology and properties of the products were investigated by X-ray diffraction, scanning electron microscopy, energy dispersive spectroscopy, atomic force microscopy and electrical measurements. This paper reports a comparative study regarding the dopants influence to the shape and size of nano-structured thermoelectric materials. It was found that hydrothermal processing results in formation of low dimensional dispersion of doped Bi2Te3 nanostructures with desired shape and size and high degree of crystallinity with typical semiconductor behavior.