Strain relaxation via formation of cracks in compositionally modulated two-dimensional semiconductor alloysStrain relaxation via formation of cracks in compositionally modulated two-dimensional semiconductor alloys, Published online: 30 April 2018; doi:10.1038/s41699-018-0056-4Composition modulation synthesis of ternary alloys of atomically thin transition metal dichalcogenides gives rise to intrinsic biaxial strain. A team led by Ali Adibi at Georgia Institute of Technology reported the onset of a substantial biaxial strain in monolayer MoS2xSe2(1-x) that is intrinsically linked to the two-step composition modulation synthesis used to grow the ternary alloy. As the S atoms replace the Se atoms of the starting MoSe2 host crystal, the resulting alloy forms a stretched lattice and develops a large biaxial tensile strain. Morphological and spectroscopic characterisations suggest that such strain results in the onset of fracture in the crystal, and further relaxes via formation of cracks within the crystal domains. Theoretical modelling indicates that pre-existing cracks give a substantial contribution in weakening the strength of the synthesized van der Waals alloy.

Published in: "NPJ 2D Materials and Applications".