Three-dimensional imaging of buried heterointerfaces

TL;DR

This paper demonstrates 3D imaging of buried heterointerfaces in twisted hexagonal boron nitride using multislice ptychography, achieving high lateral and depth resolution from a single data set, surpassing traditional methods.

Contribution

The study introduces a novel application of multislice ptychography for 3D imaging of buried heterointerfaces with significantly improved depth resolution over conventional incoherent imaging techniques.

Findings

Achieved 0.57 Å lateral resolution

Attained 2.5 nm depth resolution

Improved depth resolution by ~2.7 times

Abstract

We report three-dimensional (3D) structure determination of a twisted hexagonal boron nitride (h-BN) heterointerface from a single-view data set using multislice ptychography. We identify the buried heterointerface between two twisted h-BN flakes with a lateral resolution of 0.57 {\AA} and a depth resolution of 2.5 nm. The latter is a significant improvement (~2.7 times) over the aperture-limited depth resolution of incoherent imaging modes such as annular-dark-field scanning transmission electron microscopy. This is attributed to the diffraction signal extending beyond the aperture edge with the depth resolution set by the curvature of the Ewald sphere. Future advances to this approach could improve the depth resolution to the sub-nanometer level and enable the identification of individual dopants, defects and color centers in twisted heterointerfaces and other materials.