Self-assembly of the deposited graphene-like nanoparticles and possible nanotrack artefacts in AFM studies

• Published in: Nano express Vol. 1; no. 1; pp. 10004 - 10013
• Main Authors: Cherepanov, Vsevolod V, Naumovets, Anton G, Posudievsky, Oleg Yu, Koshechko, Vyacheslav G, Pokhodenko, Vitaly D
• Format: Journal Article
• Language: English
• Published: Bristol IOP Publishing 01.06.2020
• Subjects: 2D nanoparticles; Aggregates; Atomic force microscopy; Dispersions; Granulation; Graphene; lateral pushing; Mica; Microscopes; Nanoparticles; nanoscale friction; nanotracks; self-assembling; Self-assembly; Structural analysis; Substrates; Two dimensional materials
• ISSN: 2632-959X; 2632-959X
• DOI: 10.1088/2632-959X/ab763a

Atomic force microscopy (AFM) is widely used for structural characterization of 2D materials. We report here on the appearance of linear pseudo-structures of subnanometer height ('nanotracks'), observed in AFM images of 2D-nanoparticles of graphene, MoS2, WS2, BN, synthesized by the mechanochemical technique and deposited from dispersions on the mica surface. It is stated that the nanotracks appear as a result of nanoparticle displacement on the surface under the influence of the AFM tip during scanning. The appearance of the nanotracks is caused by a high relative concentration of monolayer nanoparticles in the prepared dispersions; their bulk aggregation; subsequent destruction of the aggregates by the AFM probe with formation of the nanoparticles weakly bound to the substrate. A method is proposed how to distinguish monolithic particles from granulated aggregates, as well as a technique to prevent their displacement during measurements. The possibility is considered of using AFM to develop effective nanolubricants and provide their precise nanoscale deposition on the specified surface areas.