Photogalvanic Effect in Partially Inverted Janus MoSSe Homostructures with Spontaneous Wrinkles

Area of Science:

• Materials Science
• Condensed Matter Physics
• Nanotechnology

Background:

• Two-dimensional (2D) Janus transition-metal dichalcogenides (TMDs) exhibit intrinsic strain due to asymmetric chalcogen layers.
• This strain leads to spontaneous structural deformations like curling, folding, and wrinkling.
• These properties offer opportunities for tuning optoelectronic characteristics and developing flexible electronic devices.

Purpose of the Study:

• To investigate the impact of spontaneous wrinkling in partially inverted Janus MoSSe nanoribbon homostructures.
• To explore how structural modifications influence electronic band structure and quantum transport properties.
• To assess the potential for enhancing photocurrent generation and device performance.

Main Methods:

• Density functional theory (DFT) calculations were employed to model nanostructure formation and optimize geometries.
• The non-equilibrium Green's function (NEGF) method was used for quantum transport simulations.
• Analysis of electronic band structure and photocurrent generation mechanisms.

Main Results:

• Spontaneous wrinkles form in partially inverted Janus MoSSe nanoribbons, reducing formation energy and breaking spatial symmetry.
• Wrinkling modifies the electronic band structure, causing upward energy shifts and altered band dispersion.
• Corrugated structures significantly enhance photocurrent via the photogalvanic effect (PGE) compared to flat counterparts.

Conclusions:

• Partial inversion of chalcogen layers in Janus TMDs provides a route to engineer optoelectronic properties.
• Wrinkling enhances photocurrent by reducing symmetry and creating graded band alignment, improving charge separation and transport.
• These findings highlight the potential of wrinkled Janus TMDs for advanced self-powered photodetector applications.