Solvothermal Synthesis of Bi<sub>2</sub>Se<sub>3</sub> Hexagonal Nanosheet Crystals

Bismuth selenide (Bi 2 Se 3 ) hexagonal nanosheet crystals with uniform size were successfully prepared via a solvothermal method at 160°C for 22 h using bismuth trichloride(BiCl 3 ) and selenium powder(Se) as raw materials, sodium bisulfite(NaHSO 3 ) as a reducing agent, diethylene glycol(DEG) as solvent, and ammonia as pH regulator. Various techniques such as X-ray diffraction (XRD), field-emission scanning electron microscope (FESEM), high-resolution transmission electron microscope (HRTEM), and selected area electron diffraction (SAED) were used to characterize the obtained products. Results show that the as-synthesized samples are pure Bi 2 Se 3 hexagonal nanosheet crystals. A possible growth mechanism for Bi 2 Se 3 hexagonal nanosheet crystals is also discussed based on the experiment.