Confined Crack Propagation in MoS<sub>2</sub>Monolayers by Creating Atomic Vacancies
Yolanda Manzanares-Negro, Guillermo López‐Polín, Kazunori Fujisawa, Tianyi Zhang, Fu Zhang, Ethan Kahn, Néstor Perea‐López, Mauricio Terrones, Julio Gómez‐Herrero, Cristina Gómez‐Navarro
Abstract
In two-dimensional crystals, fractures propagate easily, thus restricting their mechanical reliability. This work demonstrates that controlled defect creation constitutes an effective approach to avoid catastrophic failure in MoS2 monolayers. A systematic study of fracture mechanics in MoS2 monolayers as a function of the density of atomic vacancies, created by ion irradiation, is reported. Pristine and irradiated materials were studied by atomic force microscopy, high-resolution scanning transmission electron microscopy, and Raman spectroscopy. By inducing ruptures through nanoindentations, we determine the strength and length of the propagated cracks within MoS2 atom-thick membranes as a function of the density and type of the atomic vacancies. We find that a 0.15% atomic vacancy induces a decrease of 40% in strength with respect to that of pristine samples. In contrast, while tear holes in pristine 2D membranes span several microns, they are restricted to a few nanometers in the presence of atomic and nanometer-sized vacancies, thus increasing the material’s fracture toughness.