Simulating and Implementing Broadband van der Waals Artificial Visual Synapses Based on Photoconductivity and...

Area of Science:

• Materials Science
• Nanotechnology
• Neuroscience

Background:

• Advancements in artificial neural networks drive demand for neuromorphic synaptic devices.
• Human vision is a critical sensory input, necessitating sophisticated artificial visual systems.
• Existing visual synapses require enhancement for multifunctional applications and broader operational ranges.

Purpose of the Study:

• To develop a multifunctional artificial visual synapse using a novel heterojunction.
• To investigate the cooperative photoconductivity and pyroconductivity mechanisms for synaptic emulation.
• To evaluate the device's performance across a broad spectrum and under various optical stimuli.

Main Methods:

• Fabrication of a MoS₂/WSe₂ van der Waals heterojunction.
• Utilizing photoconductivity and pyroconductivity for synaptic function emulation.
• Characterizing synaptic properties by adjusting optical power, pulse width, and pulse number.

Main Results:

• The heterojunction successfully simulated artificial visual synaptic properties.
• Broadband detection was achieved from visible to near-infrared spectrum (405-1550 nm) with low power consumption (0.3-1.1 pJ/spike).
• High specific detectivity (D*) up to 3.98 × 10¹¹ Jones was demonstrated, particularly for ultraweak optical signals at 660 nm.

Conclusions:

• The MoS₂/WSe₂ vdW heterojunction serves as a promising platform for artificial visual synapses.
• The device exhibits excellent broadband spectral response and high sensitivity, suitable for complex visual information processing.
• This work paves the way for integrated sensing and memory processing devices in neuromorphic engineering.