High-performance artificial synapses based on two-dimensional MoSe2 powder with Se vacancies

High-performance artificial synaptic devices are essential for creating advanced brain-like neuromorphic systems. In this study, MoSe2 has been grown by a hydrothermal method and formed into films through a drop coating technique, which are characterized in detail using X-ray diffraction, Raman spectroscopy, field-emission scanning electron microscopy, energy dispersive spectroscopy and X-ray photoelectron spectroscopy. The hexagonal phase MoSe2 powder was used to fabricate memristor devices with a structure of Ag/MoSe2/fluorine-doped tin oxide (FTO) glass for artificial synaptic stimulations. The short-term plasticity of biological synapses was successfully simulated by evaluating the conductance responses of these devices at different time intervals, such as excitatory/inhibitory postsynaptic current and paired-pulse facilitation/depression. Long-term plasticity simulations of biological synapses represented by long-term potentiation and long-term depression have also been realized using these devices. Moreover, the cognitive processes of human brains, “learning, forgetting and relearning,” were mimicked using the present device. Additionally, the Ag/MoSe2/FTO device successfully demonstrated an associative learning behavior by simulating Pavlov's dog experiment.