Performance Modulation Of Transition Metal Oxide Selectors And Memristors

The rapid development of information technologies such as cloud computing and Internet of Things has put forward the requirements of higher density,faster speed,lower power consumption for semiconductor memories.However,there exist many problems for flash memory such as high operating voltage,slow read/write speed,high power consumption,and difficulty in further scaling.Therefore,it is imperative to develop a new generation of memory devices.The emergence of memristors has made it possible to overcome the bottlenecks of Flash memory,since memristors enable high-density and high-speed storage,in-memory computing and brain-like computing.However,large-scale applications of memristors require selectors to form 1S1 R cells to suppress the sneak current in the device networks.In this work,good performance of various selectors and memristors is achieved and modulated,based on the research of transition metal oxide thin films.The main research contents are as follows:In the gradient selector,two kinds of tri-layer tunneling barrier modulation mechanism are researched,namely the crested barrier and variable oxide thickness barrier.Gradient selectors with a linearity above 104 can be realized through a combination of different transition metal oxide layers.Researches have clarified the influence of the electron affinity difference of the transition metal oxide layers on the nonlinearity of the crested barrier selector.In the case of mutant selector and memristor,volatile threshold switch and nonvolatile resistive switch can both be realized through plasma treatment modulation on the resistive switching characteristics of Pt/Cu/HfO₂/Pt/Ti device.On this basis,the maximum 1S1 R array size that can be supported by the devices is calculated according to the equivalent simplified circuit model.At the same time,attempts are made to prepare Pt/Cu/HfO₂/Pt/Ti flexible mutant memristor with good bending resistance.In the aspect of gradient memristor,various functions such as optical encryption and electrical decryption are realized in Zn O nanorod array memristor under the modulation of ultraviolet light,which can be applied to the fields of data processing and secure communication.Meanwhile,bionic synaptic devices based on Zn O nanorod memristors can also emulate a variety of short-term synaptic plasticity.On this basis,the optically modulated neuromorphic function is realized combining the photosensitive properties of Zn O nanorods with the synaptic emulation of the memristor.This exhibits great analogy to the biological phenomenon observed in optogenetics,where optical stimuli are imposed to neurons to realize targeted modulation on synaptic activities with high speed and precision.