Artificial Synapse Based on Bio-Hierarchical Porous Memristor Driven by Multilevel-Ions Migration

Artificial synapse with memristive characteristics has immense potential for neuromorphic computing due to their non-volatile, adjustable conductance, and high integration. Herein, an artificial synapse based on the bio-inspired hierarchical porous structure is demonstrated, which is composed of mixed-dimensional porous MoS₂ nanosheets (NS) and porous SiO_x. The device produces analog memristive characteristics with a high on-off ratio of 10⁶ and a long retention time of 10⁵ s. Diversity of synaptic plasticity is achieved, such as paired-pulse facilitation, spike-timing-dependent plasticity, multilevel long-term memory, and associative learning functions. Inspired by the hierarchical migration and storage of electrolyte ions in the natural bamboo membrane, the memristive mechanism is proposed. The systematical analysis of Raman scattering and conductive mechanism reveals multilevel-ions dynamic in hierarchical porous structure, which results in multistep formation and maintenance of conductive paths for Li-ions. The bio-inspired synaptic device with multifunctional synaptic characteristics is expected to play an important role in the future applications of neuromorphic computing and artificial intelligence.