Atomic-Resolution Imaging of 2D Electronic Materials under Ambient Conditions: Defects and Moiré Patterns

Thanks to their outstanding physical characteristics, two-dimensional (2D) materials have the potential to revolutionize next-generation electronics. To effectively utilize 2D materials in practical devices, a fundamental understanding of their electronic properties needs to be formed on the atomic scale. Although the great majority of applications utilizing 2D materials will take place under ambient conditions, conventional tools utilized to characterize materials with atomic resolution operate under strict environmental conditions imposed by ultrahigh vacuum (UHV). This critically limits the usefulness of the information provided by UHV-based methods such as scanning tunneling microscopy (STM) and noncontact atomic force microscopy (NC-AFM).

Our lab recently developed the capability of true atomic-resolution imaging via conductive atomic force microscopy (C-AFM) under ambient conditions [1]. Our approach delivers atomic-resolution maps of a variety of 2D materials. In this talk, we will focus on atomic-resolution imaging of various 2D electronic materials: (i) the prototypical transition metal dichalcogenide (TMD) molybdenum disulfide (MoS₂) [2], (ii) a 2D dielectric (indium oxide, InO₂) [3], and (iii) ultrathin crystals of tungsten carbide (WC), covered by monolayer graphene. In particular, we report the (i) imaging of defects down to individual atomic sites, as well as the (ii) detailed study of moiré patterns at heterostructure interfaces. Our findings herald the emergence of C-AFM as a powerful tool for atomic-resolution imaging of 2D electronic materials under ambient conditions.

[1] S.A. Sumaiya, J. Liu, M.Z. Baykara, ACS Nano 16, 20086 (2022).

[2] B. Kumral, et al. Nature Communications 16, 7105 (2025).

[3] F. Turker, et al. Advanced Materials, e16133 (2025).