  Topological insulator surface properties are strongly correlated to
structural properties, requiring high-resolution techniques capable of probing
both surface and bulk structures at once. In this work, high flux of
synchrotron source, recursive equations for fast X-ray dynamical diffraction
simulation, and genetic algorithm for data fitting are combined to reveal the
detailed structure of bismuth telluride epitaxic films with thickness ranging
from 8 to 168 nm. It includes stacking sequences, thickness and composition of
layers in model structures, interface coherence, surface termination and
morphology. These results are in agreement with the surface morphology
determined by atomic force microscopy. Moreover, by using X-ray data from zero
noise area detector to construct three-dimensional reciprocal space maps,
insights into the nanostructure of domains and stacking faults in Bi2Te3 films
are given.
