Two-Dimensional Bi₂Se₃/MoSe₂ Heterostructure for Photodetection Applications

Area of Science:

• Materials Science
• Condensed Matter Physics
• Optoelectronics

Background:

• Van der Waals (vdW) heterostructures offer unique electronic and optical properties.
• Type-II heterojunctions enable efficient charge separation, crucial for photodetector performance.

Purpose of the Study:

• To fabricate and characterize a MoSe₂/Bi₂Se₃ type-II vdW heterojunction photodetector (PD).
• To evaluate the PD's performance for optical signal detection across a broad spectral range.
• To analyze the device physics, including charge transport and Schottky diode characteristics.

Main Methods:

• Experimental fabrication of a MoSe₂/Bi₂Se₃ vdW heterojunction.
• Performance testing of the PD for optical signals between 400 and 1000 nm.
• Analysis of current-voltage (I-V) characteristics to extract Schottky diode parameters.

Main Results:

• The PD achieved a peak responsivity of 13.35 A/W and detectivity of 5.7 × 10¹³ Jones at 400 nm.
• An ultrahigh external quantum efficiency of 4038% was recorded at 400 nm.
• The built-in potential effectively separated photogenerated electron-hole pairs, with modeled I-V characteristics showing <6.21% error.

Conclusions:

• The MoSe₂/Bi₂Se₃ vdW heterojunction PD exhibits excellent performance for optical detection.
• The device's properties are attributed to efficient charge carrier dynamics at the type-II interface.
• The study validates the potential of vdW heterostructures for advanced photodetector applications.