Topological insulator thin films starting from the amorphous phase-Bi2Se3 as example

We present a new method to obtain topological insulator Bi2Se3 thin films with a centimeter large lateral length. To produce amorphous Bi2Se3 thin films, we have used a sequential flash-evaporation method at room temperature. Transmission electron microscopy has been used to verify that the prepared samples are in a pure amorphous state. During annealing, the samples transform into the rhombohedral Bi2Se3 crystalline structure which was confirmed using X-ray diffraction and Raman spectroscopy. Resistance measurements of the amorphous films show the expected Mott variable range hopping conduction process with a high specific resistance compared to the one obtained in the crystalline phase (metallic behavior). We have measured the magnetoresistance and the Hall effect at different temperatures between 2K and 275 K. At temperatures T less than or similar to 50K and fields B less than or similar to 1 T, we observe weak anti-localization in the MR; the Hall measurements confirm the n-type character of the samples. All experimental results of our films are in quantitative agreement with results from samples prepared using more sophisticated methods. (C) 2015 AIP Publishing LLC.