Characterization of Epitaxial Films of Layered Materials Using Moiré Images of Scanning Tunneling Microscope

Abstract
Moiré-type modulated patterns have been observed in scanning tunneling microscope (STM) images of ultrathin epitaxial films of MoSe2 grown on MoS2 substrates, which arise from the existence of a very abrupt interface between two lattice-mismatched materials. Some distortions have been observed in the moiré patterns, reflecting the local lattice distortions in epitaxial films. It has been proven from a simple analysis that the moiré patterns enhance the distortions in the epitaxial films by a factor of 10 to 20, which enables the precise characterization of local lattice distortions in the epitaxial films.