Electronic Chip Mimics the Brain to Make Memories In a Flash

Here is an interesting way of creating neural network circuits. Phosphorus is an interesting element with a number of allotropes. Black phosphorus is an allotrope that is much like graphite with a layered hexagonal structure. The device utilizes defects in the black phosphorus structure and sensitivity to light to control electrical resistance.

Black phosphorus structure

"How the chip works:

Neural connections happen in the brain through electrical impulses. When tiny energy spikes reach a certain threshold of voltage, the neurons bind together -- and you've started creating a memory.

On the chip, light is used to generate a photocurrent. Switching between colors causes the current to reverse direction from positive to negative.

This direction switch, or polarity shift, is equivalent to the binding and breaking of neural connections, a mechanism that enables neurons to connect (and induce learning) or inhibit (and induce forgetting).

This is akin to optogenetics, where light-induced modification of neurons causes them to either turn on or off, enabling or inhibiting connections to the next neuron in the chain.

To develop the technology, the researchers used a material called black phosphorus (BP) that can be inherently defective in nature.

This is usually a problem for optoelectronics, but with precision engineering the researchers were able to harness the defects to create new functionality."

https://www.sciencedaily.com/releases/2019/07/190716103408.htm

https://onlinelibrary.wiley.com/doi/abs/10.1002/adfm.201901991