Few-Layer WSe₂ Schottky Junction-Based Photovoltaic Devices through Site-Selective Dual Doping

Area of Science:

• Materials Science
• Condensed Matter Physics
• Nanotechnology

Background:

• Two-dimensional (2D) materials, such as transition metal dichalcogenides, are promising for advanced light-harvesting applications.
• Schottky junctions are crucial for efficient charge separation in photovoltaic devices.
• Site-selective doping offers precise control over material properties.

Purpose of the Study:

• To implement Schottky junction-based photovoltaic devices using site-selective surface doping of few-layer WSe2.
• To investigate the impact of local doping on photocurrent generation and device performance.
• To demonstrate the transferability of this device concept to other 2D materials.

Main Methods:

• Fabrication of lateral contact devices using few-layer WSe2.
• Application of a p-type dopant (NDP-9) to the drain region for Ohmic contact.
• Coating the source region with Al2O3 for local n-type doping and Schottky barrier formation.
• Utilizing scanning photocurrent microscopy with green laser illumination.

Main Results:

• Successful implementation of Schottky junction-based photovoltaic devices.
• Photocurrent generation localized to the source contact region due to photoinduced charge separation.
• Achieved photoresponsivity up to 20 mA W⁻¹.
• External quantum efficiency reached up to 1.3%.

Conclusions:

• Site-selective surface doping is an effective strategy for creating Schottky junctions in 2D materials.
• The demonstrated device architecture enables efficient photoinduced charge separation.
• This approach is readily adaptable to other van der Waals 2D materials for photovoltaic applications.