Scientists now able to map defects in 2D crystals in liquid

Aleksandra Radenovic, Martina Lihter and Miao Zhang. Alain Herzog 2021 EPFL - A team of EPFL scientists has studied the behavior of defects on 2D crystals in water in order to better understand the crystals' properties and assess their quality. Monolayer crystals, often being referred as 2D crystals or 2D materials, possess the unique characteristic of having a single layer of regular atomic structure. And the more regular the structure is, the higher quality the crystal. In some cases, the atomic structure is repeated to perfection, but most of the time - as is usually the case in nature - there are some flaws. Molybdenum disulfide (MoS₂), a black crystal that looks like graphite, is one example of a crystal that has such layered structure in which defects can be present. "The atoms in the monolayer MoS₂ are arranged in three layers, like a sandwich - a bottom layer of sulfur atoms, and then a layer of metal atoms, and finally another layer of sulfur atoms," says Aleksandra Radenovic, the head of the Laboratory of Nanoscale Biology at EPFL's School of Engineering.