Research On Memristor Based On Thiocyanate Two-Dimensional All-inorganic Perovskite

In recent years,due to the continuous development of information networks,people’s demand for information storage is increasing rapidly.Memristor is expected to be a promising candidate for the next generation of non-volatile storage technology due to its advantages of fast switching speed,high storage density and low power consumption,become the cornerstone of future electronics.All inorganic two-dimensional thiocyanate perovskite has shown excellent performance in the application of photodetectors and solar cells due to its excellent interlayer charge transfer ability due to its ultra-small interlayer spacing.However,its application in memristor as a resistive layer material has not been widely studied.Therefore,this paper explores the memristor performance of Cs2Pb(SCN)2Br2 and Cs2Pb(SCN)2I2 two-dimensional layered perovskite materials.By predepositing a TiO2 layer on FTO as the substrate of perovskite thin film to improve the film’s density and coverage rate to the substrate.On this basis,the device was designed for resistance switching performance testing and research.Firstly,the Ag/Cs2Pb(SCN)2Br2/TiO2/FTO memristor was successfully prepared based on Cs2Pb(SCN)2Br2 material.The test results show that the resistance switching ratio of the device reaches 103 under forward bias,the retention time is greater than 103 s,and the number of test cycles was more than 300.The device shows good non-volatile characteristics and stability.The I-V characteristic curves of different metal electrodes demonstrate the necessity of using Ag as the top electrode.Finally,by calculating the vacancy formation energy and fitting the I-V curve,it is shown that the device is an interface-dominated memristor switching memory with the aid of active electrode.The control of halogen vacancies on the barrier between interfaces at room temperature is the main reason for realizing the memristor characteristics.This is the first report on the resistivity of Cs2Pb(SCN)2Br2 memristor under electrical conditions.Secondly,the Ag/Cs2Pb(SCN)2I2/TiO2/FTO device structure memristor was prepared based on Cs2Pb(SCN)2I2 material for testing.The I-V curve of the device has an obvious"forming" process,and the retention performance can reach 2000 s,and the pulse cycle test can reach more than 500 times.The multi-level storage capacity of the device can be achieved by adjusting the compliance current.When the compliance current is 0.01 A,the resistance switching ratio can reach 103,showing different resistance switching behavior from the memristor based on Cs2Pb(SCN)2Br2 material.The I-V curves of different metal electrodes and resistive layers with different thicknesses indicate that the formation and fracture of conductive filaments inside the device are the cause of resistance switching,and are related to Ag metal electrodes.Finally,based on the experimental results and I-V curve fitting analysis,we propose a resistance switching mechanism of coexistence and competition between Ag metal conductive filaments and vacancy defect conductive filaments to explain the resistance switching phenomenon of the device.