Bipolar Modulation in a Self-Powered Ultra-Wide Photodetector Based on Bi₂Se₃/AlInAsSb Heterojunction for...

Area of Science:

• Optoelectronics
• Materials Science
• Semiconductor Devices

Background:

• Broadband photodetectors (PDs) are crucial for applications like military reconnaissance and medical imaging.
• Existing broadband detectors suffer from limited detection range, uneven photoresponse, and difficulty distinguishing multispectral signals.
• There is a need for advanced PDs with improved performance and uniformity.

Purpose of the Study:

• To develop a self-powered ultra-wideband photodetector (PD) based on a Bi₂Se₃/AlInAsSb heterojunction.
• To address the limitations of current broadband detectors, including detection range and photoresponse uniformity.
• To explore the potential of the novel PD for secure information encryption in communication systems.

Main Methods:

• Fabrication of a Bi₂Se₃/AlInAsSb heterojunction device.
• Characterization of optoelectronic performance across a wide spectral range (250 nm to 1900 nm).
• Analysis of photocurrent polarity reversal and its implications for secure communications.

Main Results:

• The self-powered ultra-wideband PD demonstrates detection from 250 nm to 1900 nm.
• Achieved outstanding performance: responsivity of 0.5 A/W, detectivity of 4.2 × 10¹² Jones, switching ratio of 1.1 × 10⁴, and EQE of 71.4%.
• Maintained detectivity > 10¹⁰ Jones across the entire broadband, ensuring uniform photoresponse and exhibiting photocurrent polarity reversal (650-680 nm).

Conclusions:

• The Bi₂Se₃/AlInAsSb heterojunction enables a self-powered ultra-wideband PD with superior optoelectronic properties.
• The detector's broadband and bipolar characteristics facilitate secure information encryption, enhancing communication security.
• This advancement significantly improves broadband PD technology for practical applications and secure communication solutions.