Low power MoS${}_2$/Nb${}_2$O${}_5$ memtransistor device with highly reliable heterosynaptic plasticity

Artificial synapses based on 2D MoS${}_2$ memtransistors have recently attracted considerable attention as a promising device architecture for complex neuromorphic systems. However, previous memtransistor devices occasionally cause uncontrollable analog switching and unreliable synaptic plasticity due to random variations in the field-induced defect migration. Herein, a highly reliable 2D MoS${}_2$/Nb${}_2$O${}_5$ heterostructure memtransistor device is demonstrated, in which the Nb${}_2$O${}_5$ interlayer thickness is a critical material parameter to induce and tune analog switching characteristics of the 2D MoS${}_2$. Ultraviolet photoelectron spectroscopy and photoluminescence analyses reveal that the Schottky barrier height at the 2D channel-electrode junction of the MoS${}_2$/Nb${}_2$O${}_5$ heterostructure films is increased, leading to more effective contact barrier modulation and allowing more reliable resistive switching. The 2D/oxide memtransistors attain dual-terminal (drain and gate) stimulated heterosynaptic plasticity and highly precise multi-states. In addition, the memtransistor devices show an extremely low power consumption of ≈6 pJ and reliable potentiation/depression endurance characteristics over 2000 pulses. A high pattern recognition accuracy of ≈94.2% is finally achieved from the synaptic plasticity modulated by the drain pulse configuration using an image pattern recognition simulation. Thus, the novel 2D/oxide memtransistor makes a potential neuromorphic circuitry more flexible and energy-efficient, promoting the development of more advanced neuromorphic systems. (© 2021 Wiley‐VCH GmbH)