Real time growth of bismuth teluride thin films investigated by LEEM

Narrow gap semiconductors such as Bi$_{2}$Te$_{3}$ and Bi$_{2}$Se$_{3}$ have long been considered traditional thermoelectric materials. The very recent discovery of gapless metallic states at their surface characterizes them as a new class of quantum matter, the so-called topological insulators (TIs). To date, the TI materials have mainly been prepared in the form of crystals using melt-growth and suffer from unwanted bulk carriers or extrinsic dopants. In order to overcome this problem, efforts have been made to grow TI thin films. In this work, we use a low energy electron microscope (LEEM), which can reveal film growth processes in real time, to investigate the growth dynamics of Bi$_{2}$Te$_{3}$ films Combined with atomic force microscopy and Raman spectroscopy, we discuss the optimal conditions to obtain high quality Bi$_{2}$Te$_{3}$ films on several substrates.