High-Performance Self-Powered WSe₂/ReS₂ Photodetector Enabled via Surface Charge Transfer Doping

Area of Science:

• Materials Science
• Condensed Matter Physics
• Nanotechnology

Background:

• Two-dimensional (2D) van der Waals heterostructures are crucial for photodetection, but limited response time and photoresponsivity hinder high-sensitivity applications.
• Surface charge transfer doping (SCTD) offers a simple, effective, and lattice-preserving method for doping low-dimensional materials.

Purpose of the Study:

• To investigate the performance enhancement of WSe₂/ReS₂ heterojunctions using SCTD for high-performance photodetectors.
• To fabricate and characterize p-i-n junction photodetectors via SCTD of WSe₂/ReS₂ heterojunctions.

Main Methods:

• Fabrication of WSe₂/ReS₂ heterojunctions.
• Application of surface charge transfer doping using F₄-TCNQ molecules to create a p-i-n structure.
• Characterization of photodetector performance, including responsivity, detectivity, external quantum efficiency, response time, and cutoff frequency.

Main Results:

• SCTD reduced the Schottky barrier and increased the built-in electric field in WSe₂/ReS₂ heterojunctions.
• Photodiodes exhibited significantly enhanced responsivity (0.08 to 0.29 A/W), detectivity (1.89 × 10¹² to 8.02 × 10¹² Jones), and external quantum efficiency (12.67% to 46.29%).
• The p-i-n structure achieved a fast photovoltaic response time (7.56/6.48 μs) and a -3 dB cutoff frequency exceeding 85 kHz.

Conclusions:

• SCTD is an effective strategy for developing high-performance, low-power optoelectronic devices based on 2D van der Waals heterostructures.
• The enhanced photodetector performance demonstrates the potential of SCTD for advanced photodetection applications.