Electronic structure of strain-tunable Janus WSSe-ZnO heterostructures from first-principles

Area of Science:

• Condensed Matter Physics
• Materials Science
• Computational Chemistry

Background:

• Two-dimensional (2D) materials, including transition metal dichalcogenides (TMDs), exhibit tunable electronic structures influenced by their environment and external fields.
• Van der Waals (vdW) heterostructures, formed by stacking different 2D materials, offer enhanced control over electronic properties.
• Janus monolayer WSSe and monolayer ZnO possess intrinsic out-of-plane dipole moments, making them suitable for heterostructure engineering.

Purpose of the Study:

• To investigate the structural and electronic properties of a vdW heterostructure composed of Janus monolayer WSSe and monolayer ZnO.
• To examine the influence of strain, alignment, orientation, and electric fields on the dipole moments and band edge energies of the WSSe/ZnO heterostructure.
• To explore the potential of strain engineering for tuning the electronic properties of 2D heterostructures for applications.

Main Methods:

• Density functional theory (DFT) calculations were employed to model the vdW heterostructure.
• Calculations focused on determining the effects of various external stimuli (strain, electric field) on the system's electronic structure.
• Analysis included band edge energies, dipole moments, and their tunability under different conditions.

Main Results:

• The out-of-plane dipole moment of the ZnO monolayer was found to be highly sensitive to applied strain.
• Significant tunability of the heterostructure's band edge energies was achieved across experimentally relevant strain ranges.
• The interplay between strain and dipole moments provides a mechanism for precise electronic property control.

Conclusions:

• Strain engineering is a powerful strategy for controlling band offsets and alignment in vdW heterostructures.
• The WSSe/ZnO heterostructure demonstrates broad electronic tunability, particularly through strain.
• This approach holds promise for advancing clean energy technologies, especially in photocatalysis.