Surface Charge Transfer Doping Enabled Large Hysteresis in van der Waals Heterostructures for Artificial Synapse

Exploitation of the I – V hysteresis property in a van der Waals heterostructure is significant to modulate its electronic properties and develop unique applications. In this work, we report a two-terminal MoS 2 floating-gate (FG) artificial synaptic device, the surface of which was functionalized by an ultrathin deposition (0.1 nm) of MoO 3 on the channel region. The surface functionalization together with the FG field effect greatly enhance hysteresis of the device, resulting in a significantly expanded memory window (from 6 to 14.8 V) and a remarkably increased ON/OFF current ratio (from 10 to 10 7 ). In addition, essential synaptic functions were successfully emulated in this synaptic two-terminal device, including transition from short-term to long-term potentiation, paired-pulse facilitation/depression, and spike timing-dependent plasticity. These findings promise surface charge transfer doping as an effective method to broaden the functionality of two-dimensional transition metal dichalcogenides-based electronic devices and provide a platform for the development of electric-modulated neuromorphic architectures.