The Synthesis And Transport Observation Of Several Topological Insulator Microstructure Materials

In this work, with vapor-solid method, the author have synthesized Bi2Te3 and Bi2Se3 trigonal and hexagonal nanoflakes which can reach 20μm in the lateral and 6nm in the height and Bi2Te3-Bi2Se3 heterostructure which is still trigonal and hexagonal and in which Bi2Se3 nanoflakes is embedded in the Bi2Te3 ones. Using the same method, the author made the ternary topological insulators BTS with the mixture of Bi2Te3 and Bi2Se3 as the source materials. By the electro-magnetic induction furnace, the author can evaporate Cr which can be the source to produce the Cr-doping BTS.The author fabricated four-probe nano-devices and measured the transport of them in the low temperature. WAL feature is found in the transport measurement. HLN formula is used to fit the WAL. The channel indicator α and phase coherent length L(?) are extracted from the WAL. The author find that α increases with temperature increasing,which means there happens the decoupling. The decoupling in the Bi2Se3 can be elucidated by the competition between the surface-bulk scattering time and phase coherence time. A bulk-mediated intersurface coupling model interprets the decoupling in the BTS.