Deformation Mechanisms of Vertically Stacked WS2/MoS2 Heterostructures: The Role of Interfaces

S Susarla and P Manimunda and YM Jaques and JA Hachtel and JC Idrobo and SAS Amnulla and DS Galvao and CS Tiwary and PM Ajayan, ACS NANO, 12, 4036-4044 (2018).

DOI: 10.1021/acsnano.8b01786

The mechanical and optical properties generated due to the stacking of different atomically thin materials have made it possible to tune and engineer these materials for next-generation electronics. The understanding of the interlayer interactions in such stacked structures is of fundamental interest for structure and property correlation. Here, a combined approach of in situ Raman spectroscopy and mechanical straining along with molecular dynamics (MD) simulations has been used to probe one such interface, namely, the WS2/MoS2 heterostructure. Vertical heterostructures on poly(methyl methacrylate), when flexed, showed signs of decoupling at 1.2% strain. Theoretical calculations showed strain induced stacking changes at 1.75% strain. The sliding characteristics of layers were also investigated using scanning probe microscopy based nanoscratch testing, and the results are further supported by MD simulations. The present study could be used to design future optoelectronic devices based on WS2/MoS2 heterostructures.

Return to Publications page