Biaxial strain engineering of CVD and exfoliated single- and bi-layer MoS2 crystals

Single- and bi-layer MoS2 are two-dimensional semiconductors able to withstand very large deformations before failure, standing out as suitable templates for strain engineering applications and flexible electronics. It is imperative, for the proper integration of this material in practical applications, that the relationship between material property and strain is well understood. Two dimensional MoS2 crystals fabricated by chemical vapor deposition or micromechanical exfoliation are transferred onto flexible substrates and subjected to biaxial tension on a carefully designed and assessed loading stage with high accuracy and control. The successful stress transfer from substrate to the overlying 2D crystal is identified by in-situ monitoring of the strain-induced phonon frequency and photoluminescence peak shifts. Reliable values for the mode Gruneisen parameters and exciton deformation potentials were obtained by studying a significant number of crystals. The experimental results are backed by density functional theory calculations and are in good agreement with the experiments. This work highlights the potential of these materials in strain engineering applications and gives accurate values for single- and bi-layer MoS2 thermomechanical parameters.

Automated summary

Single- and bi-layer MoS2 are two-dimensional semiconductors that can withstand large deformations, making them suitable for strain engineering applications and flexible electronics. By transferring MoS2 crystals onto flexible substrates and subjecting them to biaxial tension, researchers were able to accurately measure thermomechanical parameters and study the relationship between material property and strain. The results, confirmed through in-situ monitoring and density functional theory calculations, highlight the potential of MoS2 for strain engineering applications.