In2Se3 Synthesized by the FWF Method for Neuromorphic Computing

The development of next-generation in-memory and neuromorphic computing can be realized with memory transistors based on 2D ferroelectric semiconductors. Among these, In₂Se₃ is the interesting since it possesses ferroelectricity in 2D quintuple layers. Synthesis of large amounts of In₂Se₃ crystals with the desired phase, however, has not been previously achieved. Here, the gram-scale synthesis of α-In₂Se₃ crystals using a flash-within-flash Joule heating method is demonstrated. This approach allows the synthesis of single-phase α-In₂Se₃ crystals regardless of the conductance of precursors in the inner tube and enables the synthesis of gram-scale quantities of α-In₂Se₃ crystals. Then, α-In₂Se₃ flakes are fabricated and used as a 2D ferroelectric semiconductor FET artificial synaptic device platform. By modulating the degree of polarization in α-In₂Se₃ flakes according to the gate electrical pulses, these devices exhibit distinct essential synaptic behaviors. Their synaptic performance shows excellent and robust reliability under repeated electrical pulses. Finally, it is demonstrated that the synaptic devices achieve an estimated learning accuracy of up to ≈87% for Modified National Institute of Standards and Technology patterns in a single-layer neural network system.