The preparation process and feature of the topological insulator Bi2Te3

Topological insulators are insulating in the bulk but have metallic surface states. Its unique physicochemical properties can find numerous applications in electronics, spintronics, photonics, the energy sciences, and the signal control of transportation. We report an experimental approach to synthesize the high-quality single crystal of topological insulator Bi2Te3 by using self-flux method. We obtained the optimal preparation conditions by adjusting the parameters of heat treatment, and successfully prepared the single-crystal Bi2Te3 sample. The as-grown samples have a surface with bright metallic luster and are soft and fragile. Furthermore, Bi2Te3 has the obvious layer structure from SEM results. The data of X-ray diffraction and scanning electron microscope show that Bi2Te3 single crystal grows along the c-axis with the order of Te(1)–Bi–Te(2)–Bi–Te(1) and crystallizes in the hexagonal system with space group of R/3 m. The ρ–T curve shows that ρ decreases with temperature, showing metallic behavior over the whole temperature range.