Artificial Synapse Based on Back‐Gated MoS 2 Field‐Effect Transistor with High‐ k Ta 2 O 5 Dielectrics

Herein, a multilayer MoS 2 ‐based low‐power synaptic transistor using Ta 2 O 5 as a back‐gate dielectric for mimicking the biological neuronal synapse is reported. The use of high‐ k dielectric allows for a lower‐voltage swing compared with using conventional SiO 2 , thus offering an attractive route to low‐power synaptic device architectures. Exfoliated MoS 2 is utilized as the channel material, and the hysteresis in the transfer characteristics of the transistor is exploited to demonstrate excitatory and inhibitory postsynaptic currents, long‐term potentiation, and long‐term depression (LTP/LTD), indirect spike timing‐dependent plasticity (STDP) based on single and sequential gate ( V g ) pulses, respectively. The synapse had achieved a 35% weight change in channel conductance within 15 electrical pulses for negative synaptic gate pulse and 28% change for positive synaptic gate pulse. A complete tunability of weight in the synapse by spike amplitude‐dependent plasticity (SADP) at a low voltage of 4 V is also demonstrated.