Layered black phosphorous is a 2D material – similar to graphene – that tends to oxidize under ambient conditions. These intrinsic defect states give rise to novel photoelectronic effects including the ability to distinguish between UV-A and UV-B light. The researchers were able to generate a photocurrent that could be switched in polarity thus simulating synaptic behaviour. Switching between colors causes the current to reverse direction from positive to negative.
The research team also demonstrated that serially connected devices can be used to perform digital logic operations under optical control.
"We're able to simulate the brain’s neural approach simply by shining different colours onto our chip," said research leader Sumeet Walia. Taimur Ahmed is lead author of the study, which was published in Advanced Functional Materials.
The technology was developed at the Micro Nano Research Facility and is compatible with existing electronics and has also been demonstrated on a flexible platform, for integration into wearable electronics.
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