Stacked Janus Device Concepts: Abrupt pn-Junctions and Cross-Plane Channels

Area of Science:

• Materials Science
• Condensed Matter Physics
• Nanotechnology

Background:

• Janus transition metal dichalcogenides (TMDs) are emerging 2D materials with inherent cross-plane (cp) asymmetry and large cp dipoles.
• These materials offer unique electronic and optical properties due to their broken inversion symmetry.

Purpose of the Study:

• To investigate the electronic properties of stacked graphene and Janus MoSSe structures.
• To demonstrate the formation of atomically thin pn-junctions and analyze charge transport mechanisms.
• To evaluate the potential of these heterostructures in optoelectronic applications, particularly photovoltaics.

Main Methods:

• First-principles calculations were employed to model the electronic structure and properties.
• A tailored charge transport method was utilized to simulate device performance.
• Heterostructures of graphene and Janus MoSSe were computationally designed and analyzed.

Main Results:

• Record high homogeneous doping of graphene was achieved when stacked with Janus MoSSe.
• Abrupt, atomically thin, cross-plane pn-junctions were successfully formed.
• Graphene demonstrated its capability to act as an electrode without screening the cp dipole.
• A large photocurrent response was predicted, dominated by a cp transport channel.

Conclusions:

• Graphene-Janus MoSSe heterostructures exhibit significant potential for electronic and optoelectronic devices.
• The observed high photocurrent, exceeding that of silicon, highlights their promise for advanced photovoltaic applications.
• The unique properties of Janus TMDs, combined with graphene, pave the way for novel device architectures.