  Hexagonal boron nitride (h-BN) has long been recognized as an ideal substrate
for electronic devices due to its dangling-bond-free surface, insulating nature
and thermal/chemical stability. Therefore, to analyse the lattice structure and
orientation of h-BN crystals becomes important. Here, the stacking order and
wrinkles of h-BN are investigated by transmission electron microscopy (TEM). It
is experimentally confirmed that the layers in the h-BN flakes are arranged in
the AA' stacking. The wrinkles in a form of threefold network throughout the
h-BN crystal are oriented along the armchair direction, and their formation
mechanism was further explored by molecular dynamics simulations. Our findings
provide a deep insight about the microstructure of h-BN and shed light on the
structural design/electronic modulations of two-dimensional crystals.
