Atomic force microscopy (AFM) has emerged as a key technology in the field of 2D materials research, proving integral in the discovery and isolation of monomolecular graphitic sheets. Time after time, scientists have demonstrated the unique capacities of AFM for characterizing low dimensional structures with regards to morphology, tribology, electrical properties, and more. It has been certified as an essential analytical technique for a new generation of materials characterization and product manufacture.
Prior to 2004, 2D materials research was primarily a theoretical field. The discovery of graphene caused a seismic shift in thinking, and in just 14 years, dozens of other 2D systems have been synthesized using a growing number of techniques. Characterization of these new structures and synthesis techniques is still often carried out using AFM technology, which has expanded in conjunction with the burgeoning school of 2D materials research.
The primary factor behind AFM’s success in 2D materials research is the technology’s sub-angstrom scales of topographical resolution, enabling the easy and accurate distinction of monomolecular layers grown on a substrate. Metrology remains an important factor in 2D materials characterization. Film thickness, roughness, and uniformity are three of the most fundamentally critical parameters in the characterization of emerging low dimensional structures such as graphene and molybdenum disulfide (MoS2). Yet the capabilities of AFM have expanded beyond nanoscale morphology to enable analysis of lattice structure, tribology, electrical and functional responses, and various mechanical properties.
One of the more recent areas of interest in the field of 2D materials research is environmental control and the effect of the atmosphere on the growth process. Typical atomic force microscopes (AFMs) involve evaluating samples post-processing in the air, yet there have been several advances in top-down synthesis using liquid-phase reactions. Characterizing these materials in situ is desirable, but ultimately problematic using conventional AFMs.
The Cypher ES Environmental atomic force microscope (AFM) provides a novel solution to the issue of 2D materials research for materials grown in a liquid phase. It uses a hermetically-sealed sample cell with broad chemical compatibility to offer high-resolution analysis of 2D structures within a fluid or process gas. This is particularly promising for 2D materials research focusing on exfoliation growth techniques.
Another key area of interest in 2D materials research is the unique electrical and functional properties of low dimensional structures. This has proven catalytic for R&D into a range of theoretical electronic structures, including: quantum computers; microscale electronic circuits; single-molecule sensors; and lab-on-chip devices. Determining the potential of emerging monomolecular materials for electronic applications, however, requires a robust understanding of their electrical and functional responses.
Conductive AFM (CAFM) has emerged as one of the leading techniques for electrical characterization of emerging 2D materials. The ORCA module from Asylum Research has proven successful for nanoscale current mapping across a potential current range of ~1 pA to 10 µA.
Asylum Research is a specialist in the field of AFM solutions for 2D materials research. We have been developing a range of AFMs with innovative capabilities to support the exponential growth characterizing the low dimensional materials sector. Our award-winning Cypher range of microscopes has proven successful in some of the most exciting and innovative applications in the field of 2D materials research. Alongside in situ monitoring with environmental controls and enhanced electric response mapping, our AFMs can perform imaging of atomic lattices, measurements of 2D materials’ mechanical properties, and enhanced morphology assessments.
If you would like any more information about our AFM products or have a specific query about using AFM for 2D materials characterization, simply contact us directly.