Atomic-scale information
is essential for understanding and designing
unique structures and properties of two-dimensional (2D) materials.
Recent developments in in situ transmission electron microscopy (TEM)
and scanning transmission electron microscopy (STEM) enable research
to provide abundant insights into the growth of nanomaterials. In
this study, 2D MoS
2
is synthesized on a suspended graphene
substrate inside a TEM column through thermolysis of the ammonium
tetrathiomolybdate (NH
4
)
2
MoS
4
precursor
at 500 °C. To avoid misinterpretation of the in situ STEM images,
a deep-learning framework, DeepSTEM, is developed. The DeepSTEM framework
successfully reconstructs an object function in atomic-resolution
STEM imaging for accurate determination of the atomic structure and
dynamic analysis. In situ STEM imaging with DeepSTEM enables observation
of the edge configuration, formation, and reknitting progress of MoS
2
clusters with the formation of a mirror twin boundary. The
synthesized MoS
2
/graphene heterostructure shows various
twist angles, as revealed by atomic-resolution TEM. This deep-learning
framework-assisted in situ STEM imaging provides atomic information
for in-depth studies on the growth and structure of 2D materials and
shows the potential use of deep-learning techniques in 2D material
research.