Super-additive interaction of homo- and heterosynaptic plasticity in a hot electron transfer optosynapse for visual sensing memory and logic operations†

In the realm of cognitive neuroscience, the coupling of homosynaptic activation and heterosynaptic modulation plays a crucial role in enhancing consolidation and sharpening long-term memories. Building upon this understanding, the integration of optosynapses within neuromorphic visual systems offers a promising avenue to replicate the fundamental mechanisms of the human visual system, leading to not only reduced communication latency and power consumption but also a heightened level of cognitive performance. In this work, a hot electron transfer optosynapse is realized based on zinc–tin oxide (ZTO) with embedded Au nanoparticle (NP) heterostructure phototransistors. Gate voltage spikes of −5 V (V_G = −5 V) and 520 nm light are applied as the homosynaptic and modulatory heterosynaptic stimuli, respectively. Due to the light-bias coupling enhanced electron tunneling and hot electrons generated by the intraband transition in Au NPs, super-additivity of homosynaptic and heterosynaptic plasticity can be achieved in the ZTO/Au NPs optosynapse. The learning and memory performance of this bioinspired optosynapse is reinforced due to the super-additive interaction. Furthermore, the hot electron transfer optosynapse is capable of performing logic operations, making it a candidate for integration into neuromorphic computing architectures and the advancement of machine vision.