A Chemically Programmable Retinomorphic GaN p-n Diode for Multimode Visual Sensing

Area of Science:

• Materials Science and Engineering
• Neuroscience and Bioengineering

Background:

• Real-world vision requires sensors that handle diverse illumination and rapid changes.
• Existing vision sensors lack chemical programmability, limiting biorealistic visual sensing.
• Current sensors are primarily modulated by physical stimuli, not chemical signals.

Purpose of the Study:

• To develop a chemically programmable retinomorphic diode for advanced visual sensing.
• To integrate spiking response, light adaptation, and chemical tunability in a single device.
• To explore bio-inspired visual processing and actuation through chemical programming.

Main Methods:

• Fabrication of an ultracompact retinomorphic p-n diode.
• Investigating the interplay between photoelectric and electrochemical processes at the semiconductor/electrolyte interface.
• Demonstrating switchable response modes via chemical modulation of ion/molecule species.

Main Results:

• The diode exhibits switchable response modes with chemical programmability.
• It generates spikes upon illumination transitions and allows bidirectional tuning of steady-state current.
• The device demonstrates spontaneous and chemically regulated light adaptation (scotopic to photopic).
• A proof-of-concept visual-motor pathway with chemically programmable actuation was constructed.

Conclusions:

• A chemically programmable retinomorphic platform combining physical and chemical modulation is demonstrated.
• This platform enables bio-inspired multimode visual sensing and actuation.
• The device offers a new paradigm for tunable, biorealistic vision systems.