Preparation and characterization of nanostructured Bi_2Se_3 and Sn_(0.5)-Bi_2Se_3

Nanostructured Bi2Se3 and Sn0.5-Bi2Se3 were successfully synthesized by hydrothermal coreduction from SnCl2?H2O and the oxides of Bi and Se. The products were characterized by X-ray diffraction (XRD),transmission electron microscopy (TEM),and field emission scanning electron microscope (FESEM). Bi2Se3 powders obtained at 180°C and 150°C consist of hexagonal flakes of 50-150 nm in side length and nanorods of 30-100 nm in diameter and more than 1 μm in length. The product obtained at 120°C is composed of thin irregular nanosheets with a size of 100-200 nm and several nanometers in thickness. The major phase of Sn0.5-Bi2Se3 synthesized at 180°C is similar to that of Bi2Se3. Sn0.5-Bi2Se3 powders are primarily nanorod structures,but small amount of powders demonstrate irregular morphologies.