Study Of The Resistive Random Access Memory Based On CdSe/CdS Core/Shell Quantum Dots As An Electrode Modification Layer

In order to meet the increasing development and application of information technologies,the memory must meet higher requirements.At this time resistive random access memory(RRAM)enters people's field of vision due to its high response speed,low power consumption,high integration density,and compatibility with CMOS processes.Based on its more excellent capability to complete tasks of information storage with high speed and convenience,and to complete in-store calculations combining calculation with storage,RRAM will definitely occupy an important position in the fields of information storage,artificial simulation of neurons and neural network computing in the future.However,the unstable and uncontrollable resistance switching process has always been one of the biggest problems preventing it from practical application.For this reason,it is imperative to explore the device with new structures and new materials,furthermore the corresponding resistance switching mechanisms.In this work,our research started with the dielectric functional layer of RRAM,with metal oxide Ta O_x as the resistance switching layer,and simultaneously inorganic colloidal CdSe/CdS core/shell quantum dots was synthesized as the upper electrode modification layer of the device in an efficient and convenient way to prepare a new type of bipolar resistive RAM.At the same time,the details of the internal changes in the resistive switching process of this device are explored by establishing an accelerated migration model based on the oxygen vacancy concentration,temperature field and electric field.The main research contents are as follows:(1)A new type of Pt/Cd Se-Cd S QDs/Ta O_x/Ta resistive memory is proposed,and the internal structure and morphology of the device are observed under various characterization methods.Eelectrical tests have proven that this device has excellent resistance switching characteristics,including lower threshold voltages,better consistency among resistance switching cycles,excellent duration and retention characteristics,and self-limiting current mechanism.Control experiments reveal that quantum dots and annealing have been proven to have important optimization effects on the device's resistive switching consistency,reduction of threshold voltages,suppression of Reset degradation,and self-limiting current mechanism.(2)Based on the fitting results of the current-voltage curve of the device in high and low resistance states,the conduction mode in high and low resistance states was deduced,and a Cd Se-Cd S QDs/Pt Schottky interface model was further proposed to explain the relevant experimental phenomena.(3)A Pt/Cd Se-Cd S QDs/Ta O_x/Ta device model was established from a simulation perspective.The resistive switching characteristics of the model were calculated under test boundary conditions such as periodic sweep voltage,periodic pulse voltage,and gradual sweep voltage,then compared with corresponding experimental results.Through the gradual sweep voltage test,the relationship between the resistance of high-resistance state(R_HRS)and the maximum Reset voltage(V_stop)was studied,and an empirical formula was given within a certain range.In addition,by comparing distribution changes of the potential,temperature,and oxygen vacancy in this model with the Pt/Ta O_x/Ta model during the Reset process,the role of the quantum dot layer in the resistive switching process of the device was explored in detail.Finally,simulation models of conductive filaments with different widths were established to study the effect of conductive filament width on the performance of devices.