Dual-functional GaN photodiode for photodetection and neuromorphic computing with high specific detectivity

Area of Science:

• Optoelectronics
• Neuromorphic Engineering
• Materials Science

Background:

• Integrating photodetectors (PDs) and photosynapses into single devices is challenging due to differing photoresponse characteristics.
• Existing devices often require complex architectures to achieve dual functionality.

Purpose of the Study:

• To demonstrate a single device with switchable photodetector and photosynapse functionalities.
• To overcome the limitations of current optoelectronic and neuromorphic computing hardware.

Main Methods:

• Fabrication of a novel device leveraging photovoltaic and photoconductive effects.
• Utilizing bias voltage polarity to switch between photodetector and photosynapse modes.
• Characterization of device performance under varying electrical and optical conditions.

Main Results:

• The device functions as a high-performance photodetector (low dark current, high detectivity) under reverse/zero bias.
• Under positive bias, the device exhibits synaptic behaviors including excitatory postsynaptic current and memory effects.
• Successful switching between photodetector and photosynapse operations was achieved by altering bias voltage polarity.

Conclusions:

• The developed dual-functional device offers a promising solution for integrating light detection and neuromorphic processing.
• This technology holds potential for applications in weak light sensing and advanced computing systems.
• The bias-controlled switching mechanism simplifies device design and enhances versatility.