Physical property modulation in 2D TMDs homo- and hetero-structures via pressure engineering

2D TMDs and their van der Waals heterostructures (vdWs HSs), exhibit attractive optical and optoelectronic properties thanks to the different band alignments and interlayer interactions. Their sensitivity to interlayer distance allows effective tuning of material properties through external modulation of lattice parameters. Therefore, it is of both fundamental and practical importance to explore interlayer excitons in vdWs HSs, especially their dynamic response and underlying mechanisms to different tuning techniques. So far, only limited changes in lattice parameters have been achieved, hampering effective tuning of physical properties in vdWs HSs.
In this talk, we demonstrate effective tuning of the excitonic states by controlling the interlayer distance in TMDs vdWs HSs, and further tune the interlayer spacing and thus the band structure using hydrostatic pressure. In addition, we perform DFT calculations and achieve good agreement with the experimental observations, revealing a pressured-induced changeover in the band structure of the HSs. This may offer new insights into the strong interlayer interaction and electron-phonon coupling in TMDs via pressure engineering, which can be exploited for designing new excitonic devices based on 2D vdWs HSs.