A Van Der Waals Photo‐Ferroelectric Synapse

Abstract

For hardware artificial intelligence, the central task is to design and develop artificial synapses with needed characteristics. Here, the design and experimental demonstration of a van der Waals (vdW) photo‐ferroelectric synapse are reported. In the photo‐ferroelectric synapse, the synaptic memory is extracted by reading the photocurrent, and written or edited by electrical pulses. The semiconducting vdW organic‐inorganic halide perovskite ((R)‐(–)‐1‐cyclohexylethylammonium)PbI3 (R‐CYHEAPbI3) photo‐ferroelectric serves as the model photo‐ferroelectric channel. Here, the vdW organic layer provides ferroelectric dipole and the PbI6 octahedron is responsible for photon absorption and charge transport. The R‐CYHEAPbI3 photo‐ferroelectric synapse show a writing/reading dynamics with >200 synaptic states, close to 103 on/off ratio, and reasonable endurance and retention characteristics. With the experimentally measured weight dynamics (parallel reading through ferroelectric photovoltaic effect and writing by electrical pulses) of R‐CYHEAPbI3 synapses, the feasibility of using a crossbar circuit to implement classic training and inference of hand‐written digits is presented. An image recognition accuracy of up to 90% is obtained. The demonstration of such a vdW photo‐ferroelectric synapse opens a window in the design of advanced devices for artificial intelligence.

Switchable ferroelectric photovoltaic response in Sc0.2Al0.8N-based optoelectronic devices

“…18) Recently, to solve this problem, Li et al, demonstrated optically induced polarization switching in BaTiO 3 -based ferroelectric heterostructures utilizing a two-dimensional (2D) narrow-gap transition metal dichalcogenide semiconductor (TMDs) material MoS 2 as a top electrode. 19,20) Comprising ferroelectrics and 2D narrow-gap TMDs materials, such as MoS 2 and MoTe 2 , can broaden the absorption spectrum of the device, increase the conductivity and improve the output photocurrent, thereby raising the efficiency of photovoltaic devices. 21,22) Our work reports ferroelectric properties of Sc 0.2 Al 0.8 N thin film and researches the switchable FePV effect and photo-diode characteristics of two-terminal Sc 0.2 Al 0.8 N devices.…”