Investigation of Analog Resistive Switching in Solution-Processed Lead-Free Perovskite Cs₂SnI₆Memristor for Synaptic Application

Efficient learning processes in neuromorphic computing and the advancement of next-generation artificial intelligence are heavily dependent on synaptic functions, specifically potentiation, and depression, which must be implemented through two-terminal memristive devices exhibiting good linearity. The human brain utilizes neurons and synapses to perform memory and computation functions with exceptional linearity. This study investigates the resistive switching dynamics in cesium tin iodide (Cs2SnI6) perovskite-based memristive devices with silver (Ag) and platinum (Pt) electrodes, fabricated using an e-beam evaporation system. The crystal structure, element composition, surface microstructure, and memristive device structure Cs2SnI6 of deposited films have been characterized by using grazing incidence X-Ray diffraction (GIXRD), energy dispersive X-ray (EDX), and field-emission scanning electron microscope (FESEM). The fabricated memristive device has shown analog resistive switching (ARS) dynamics and synaptic behavior. The electrical response of fabricated ARS devices has been studied by a Keithley-4200 semiconductor parameter analyzer with a customized probe station by applying low sweeping voltage (-1/+1 V) at room temperature (RT). We observed the potentiation/depression behavior of the device by applying multiple low dc pulses, both positive and negative, to mimic and implement biological synaptic rules. Finally, we evaluated the performance of the memristor by analyzing its excitatory postsynaptic current, as well as its excellent linearity at reading voltages of 0.1 and 0.2 V, with applied voltages (set/reset) of 1 and 1.5 V, respectively.