Moiré Fringe Method via Scanning Transmission Electron Microscopy.

Moiré fringe, originated from the beating of two sets of lattices, is a commonly observed phenomenon in physics, optics, and materials science. Recently, a new method of creating moiré fringe via scanning transmission electron microscopy (STEM) has been developed to image materials' structures at a large field of view. Moreover, this method shows great advantages in studying atomic structures of beam sensitive materials by significantly reduced electron dose. Here, the development of the STEM moiré fringe (STEM-MF) method is reviewed. The authors first introduce the theory of STEM-MF and then discuss the advances of this technique in combination with geometric phase analysis, annular bright field imaging, energy dispersive X-ray spectroscopy, and electron energy loss spectroscopy. Applications of STEM-MF on strain, defects, 2D materials, and beam-sensitive materials are further summarized. Finally, the authors' perspectives on the future directions of STEM-MF are presented.