The biological synapses are functional links between neurons, through which 'information' transmitted in the neuron network. The information can be stored and processed simultaneously in the same synapse through tuning synaptic weight, which is defined as the strength of the correlation between two neighboring neurons, and the operation is collective and adaptive. Although silicon-based complementary metal-oxide-semiconductor circuits have been developed to emulate synaptic behaviors, it is still facing significant challenges in large-scale integrations and huge energy consumption. Memristive devices, in which the conductance can be retained according to the history of applied voltage and current, provide a more promising way to emulate synapses by substantial reduction in complexity and energy consumption. Recently, ionic/electronic hybrid three-terminal memristive devices have been introduced. It gives a more flexible operation for the signal processing and learning in synaptic circuits. In this work, we investigated a lateral three terminal memristive device based on α-phase molybdenum oxide (α-MoO3), a typical two-dimensional (2D) transition metal oxides, in ambient atmosphere, and capitalized on the nanoscale device to mimic a biological synapse. Ionic liquid was selected as gate terminal, serving as pre-synaptic neuron to generate neurotransmitters. The ultrathin α-MoO3 single crystal flake serves as post-synaptic neuron, whose conductance can be modulated. The excitatory post-synaptic current, depression and potentiation of synaptic weight, paired-pulse facilitation, the transition of short-term plasticity to long-term potentiation have been demonstrated in the three terminal devices. These results provide an insight into the potential application of two-dimentional α-MoO3 for synaptic devices with high scaling ability, low energy consumption, and high processing efficiency.
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