Direct observation of layer-stacking and oriented wrinkles in multilayer hexagonal boron nitride

TL;DR

This study uses TEM and molecular dynamics to reveal the stacking order and wrinkle orientation in multilayer hexagonal boron nitride, providing insights into its microstructure and potential for electronic applications.

Contribution

It is the first to experimentally confirm AA' stacking and analyze wrinkle formation mechanisms in multilayer h-BN using combined TEM and simulations.

Findings

Layers are arranged in AA' stacking.

Wrinkles form a threefold network oriented along the armchair direction.

Mechanism of wrinkle formation was elucidated through molecular dynamics simulations.

Abstract

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.