  Two-dimensional transition metal dichalcogenides (TMDs) are highly promising
candidates for various applications due to their unique electrical, optical,
mechanical, and chemical properties. Furthermore, heterostructures consisting
of TMDs with metals, oxides, and conductive materials have attracted
significant research interest due to their exceptional electronic properties.
In this study, we utilized density functional theory to investigate those
electronic and transport properties, which are relevant for the application of
tribo-piezoelectricity in creating novel nanogenerators: an interdisciplinary
approach with promising implications. The results of the study demonstrate that
the enhancement of charge transfer between layers and the orbital contribution
to the Fermi level under applied strain in MoS/IrO, MoS/TiO, MoS/WTe, and
MoTe/WS heterostructures is noteworthy. Additionally, non-equilibrium Green's
function calculations of electron transport properties provide valuable
insights into the behavior of these materials under different conditions. While
MoS/IrO and MoS/TiO hetero-bilayers are unsuitable due to their tendency to
exhibit large current flow with increasing voltage, others like MoS/WTe and
MoTe/WS hetero bilayers show promise due to their ability to prevent voltage
drop. The presented innovative concept of utilizing compressive strain of TMD
bilayers to generate a tribo-piezoelectric effect for nanogenerators has a
potential to contribute to the development of efficient and sustainable energy
harvesting devices.
