Lateral 2D WSe₂ p-n Homojunction Formed by Efficient Charge-Carrier-Type Modulation for High-Performance...

Area of Science:

• Materials Science, Nanotechnology, Condensed Matter Physics

Background:

• Two-dimensional (2D) materials, particularly transition metal dichalcogenides (TMDs), are crucial for advanced optoelectronics.
• Developing high-quality 2D p-n junctions is essential for next-generation electronic and photonic devices.

Purpose of the Study:

• To achieve facile electron doping of WSe₂ for creating high-quality intramolecular p-n junctions.
• To investigate the charge carrier manipulation mechanism in TMDs via chemical doping.
• To explore the potential of these p-n junctions in high-performance photodetectors.

Main Methods:

• Electron doping of WSe₂ using cetyltrimethyl ammonium bromide (CTAB).
• Theoretical investigation using density functional theory (DFT) calculations.
• Fabrication and characterization of photodetectors and field-effect transistors.

Main Results:

• Successful formation of an intramolecular p-n junction in WSe₂ via CTAB doping.
• Demonstrated enhancement of switching light ratio (I_light /I_dark) by 10³ compared to intrinsic WSe₂.
• Achieved high device performance with responsivity of 30 A W^-1 and specific detectivity > 10¹¹ Jones.
• Investigated charge transfer mechanisms in CTAB-doped 2D WSe₂ and WS₂.

Conclusions:

• CTAB is an effective agent for electron doping of 2D TMDs, enabling high-quality p-n junction formation.
• The developed method offers significant improvements in photodetector performance, including switching ratio and temporal response.
• This work provides valuable scientific insights into chemical doping of 2D materials and presents a promising route for efficient next-generation photoelectronic devices.