Geometry-Engineered Bipolar Photodetectors for Multivalued Logic-Gate Encrypted Optical Communication.

Area of Science:

• Optoelectronics
• Materials Science
• Optical Communication

Background:

• Bipolar photodetectors are crucial for logic-gate-encrypted optical communication.
• Precise photocurrent balancing is essential to minimize errors and ensure accuracy.

Purpose of the Study:

• Develop a self-powered bipolar photodetector with balanced photocurrents.
• Implement a universal strategy for photocurrent symmetry.
• Demonstrate reconfigurable logic gates for secure optical communication.

Main Methods:

• Fabrication of a parallel-structured, self-powered photoelectrochemical photodetector (PEC-PD) using amorphous p-NiOₓ and n-GaOₓ thin films.
• Utilized thermal annealing to mitigate initial photocurrent asymmetry.
• Employed a geometry-engineered strategy by adjusting the area ratio of photoactive materials to achieve precise photocurrent balancing.

Main Results:

• Achieved dual-band (254 nm/365 nm) bipolar photoresponses with balanced positive and negative photocurrents.
• Demonstrated robust photocurrent symmetry across diverse wavelengths via geometry engineering.
• Successfully implemented reconfigurable binary and ternary exclusive OR (XOR and TXOR) logic gates.

Conclusions:

• Presented a universal strategy for balanced bipolar photodetectors through geometry engineering.
• The ternary encryption scheme significantly enhances information throughput and key space.
• Facilitated applications in secure, high-throughput underwater optical communication systems.