A gate-free monolayer WSe₂ pn diode.

Area of Science:

• Materials Science
• Condensed Matter Physics
• Nanotechnology

Background:

• Controlling electrical properties in 2D materials is vital for electronic and optoelectronic devices.
• Conventional methods for creating pn junctions in 2D materials include vertical stacking or gate biasing.
• Developing novel methods for lateral carrier manipulation is essential for next-generation devices.

Purpose of the Study:

• To demonstrate a novel method for creating a lateral pn homojunction in 2D materials.
• To utilize ferroelectric polarization for non-volatile carrier manipulation.
• To explore the potential of gate-free pn homojunctions in 2D electronics and photonics.

Main Methods:

• Fabrication of a WSe2 pn homojunction on a ferroelectric BiFeO3 substrate.
• Utilizing locally reversed ferroelectric polarization to laterally manipulate carrier density.
• Characterization using optical methods, scanning probe microscopy, and scanning photoelectron microspectroscopy.

Main Results:

• Successful creation of a non-volatile WSe2 pn homojunction.
• Demonstration of clear rectifying behavior at the homo-interface.
• Quantitative understanding of the pn diode characteristics.

Conclusions:

• Ferroelectric polarization offers a viable route for gate-free, non-volatile pn homojunction formation in 2D materials.
• This approach expands the toolbox for 2D electron-photon applications.
• Paves the way for the development of advanced laterally structured 2D electronics and photonics.