Real-Time Observation of Morphological Transformations in II–VI Semiconducting Nanobelts via Environmental Transmission Electron Microscopy

It has been observed that wurtzite
II–VI semiconducting nanobelts transform into single-crystal,
periodically branched nanostructures upon heating. The mechanism of
this novel transformation has been elucidated by heating II–VI
nanobelts in an environmental transmission electron microscope (ETEM)
in oxidizing, reducing, and inert atmospheres while observing their
structural changes with high spatial resolution. The interplay of
surface reconstruction of high-energy surfaces of the wurtzite phase
and environment-dependent anisotropic chemical etching of certain
crystal surfaces in the branching mechanism of nanobelts has been
observed. Understanding of structural and chemical transformations
of materials via in situ microscopy techniques and their role in designing
new nanostructured materials is discussed.