Moire-Assisted Strain Transfer in Vertical van der Waals Heterostructures

Strain provides a powerful method to study 2D monolayers and to tune their properties. The same approach also has great potential for van-der-Waals (vdW) heterostructures. However, we need to understand how strain can be applied to vertically stacked vdW structures, for which strain transfer from one layer to the next remains little explored. In our experiment, we fabricated vertical heterostructures consisting of transition metal dichalcogenides (TMDCs) monolayers that were deposited on a flexible substrate. These TMDC heterostructures allowed us to read out separately the strain in each monolayer by photo-luminescence measurements. We find that, in TMDC hetero-structures with large twist angles (>5 degrees), strain transfer is limited. However, for aligned heterostructures with small twist angles (<= 5 degrees), near unity strain transfer efficiency is observed. We correlate this finding with the moire domains formed in the aligned heterostructures by reconstruction.

Automated summary

This study investigates the transfer of strain in vertically stacked van-der-Waals heterostructures and finds that high strain transfer efficiency is observed in aligned heterostructures with small twist angles.