Study On The Performance And Mechanism Of Perovskite Resistive Random Access Memory

The development of 5G has promoted the progress of emerging technologies such as artificial intelligence and cloud computing.Meanwhile,the demand of information storage is increasing gradually.With the rapid development of portable electronic devices,the proportion of flash memory is growing up in the memory market.However,flash technology is facing the physical limits due to the further miniaturization of the device size.Therefore,the development of the next generation of non-volatile storage technology is urgent.As one of the candidates for the next-generation non-volatile memory,the resistive random access memory has some excellent features like simple structure,high integration level and low power consumption.There are many materials used as resistive layer,such as binary oxide,multicomponent oxide and some organic materials.In recent years,perovskite materials have been widely used in photovoltaic field because of their high optical absorption intensity,adjustable band gap and long electron-hole diffusion length.What's more,perovskite materials perform excellent resistive switching behavior,which gives an approach in the field of storage.This thesis studies resistive random access memory based on different types of perovskite materials.First,the effect of passivation by oleic acid on device performance is studied.CH₃NH₃Pb I₃ films are prepared by one-step method and two-step method,respectively.It is found that the surface particles of CH₃NH₃Pb I₃ film prepared by one-step method are more uniform and more compact than the film fabricated by two-step method,and the XRD measurement illustrates that the film prepared by one-step method doesn't contain Pb I₂.Therefore,one-step method is applied in this chapter.Then,the CH₃NH₃Pb I₃film is passivated by oleic acid,which can reduce the contact with the air,and the top electrode W is prepared on the surface of CH₃NH₃Pb I₃ film subsequently.It is found that the device with oleic acid treatment has more stable properties than the device without oleic acid treatment and the high resistance state's conduction mechanism changes from SCLC conduction caused by defects to barrier-controlled Schottky emission.Therefore,oleic acid passivation can reduce defects of film and improve the stability of the device.Second,the properties of CsPbBr₃ memory are studied.The CsPbBr₃powder is prepared by solution synthesis and then dissolved in DMSO solvent.The pure and compact CsPbBr₃ film is prepared by one-step anti-solvent method,then Au electrode is fabricated on the CsPbBr₃film to prepare resistive memory.The measurement shows that the device has excellent resistive switching characteristics and large storage window.Also,the device exhibits good resistance performance at different temperatures and different placement times.In addition,the compactness and crystal structure of CsPbBr₃ film,as well as current conduction mechanism of the device,are hardly changed under high heating temperature and air placement for several months.Therefore,the device has good thermal stability and environmental stability.Finally,the performances of lead-free Bi-based perovskite resistive memory are studied.MA₃Bi₂I₉ film is prepared by two methods.The first method is to use spin-coating technology with solvent of DMSO and DMF,as well as anti-solvent of toluene.The second method is to use spin-coating technology with ethanol–MA solution as solvent.It is found that the device prepared by the second method has more stable I/V characteristic,larger storage window and better tolerance than the device fabricated by the first method.The structure of PEN/ITO/MA₃Bi₂I₉/Au device is fabricated on flexible substrate by the second method.The device shows good resistive switching performance under different bending degrees,indicating that the device has application value in wearable electronic devices.