Defect Density and Atomic Defect Recognition in the Middle Layer of a Trilayer MoS<sub>2</sub> Stack.

Quincke, Moritz; Mundszinger, Manuel; Biskupek, Johannes; Kaiser, Ute · Nano Lett · 2024

basic_science · Level V

Where this comes from

Abstract

Molybdenum disulfide (MoS<sub>2</sub>) is one of the most intriguing two-dimensional materials, and moreover, its single atomic defects can significantly alter the properties. These defects can be both imaged and engineered using spherical and chromatic aberration-corrected high-resolution transmission electron microscopy (C<sub>C</sub>/C<sub>S</sub>-corrected HRTEM). In a few-layer stack, several atoms are vertically aligned in one atomic column. Therefore, it is challenging to determine the positions of missing atoms and the damage cross-section, particularly in the not directly accessible middle layers. In this study, we introduce a technique for extracting subtle intensity differences in C<sub>C</sub>/C<sub>S</sub>-corrected HRTEM images. By exploiting the crystal structure of the material, our method discerns chalcogen vacancies even in the middle layer of trilayer MoS<sub>2</sub>. We found that in trilayer MoS<sub>2</sub> the middle layer's damage cross-section is about ten times lower than that in the monolayer. Our findings could be essential for the application of few-layer MoS<sub>2</sub> in nanodevices.