The Research On Low Operating Voltage Organic Memristors

The era of Internet of Things,big data and artificial intelligence is coming,and information technology with huge storage capacity and efficient computing processing is urgently needed.However,the traditional Von Neumann architecture and silicon-based storage computing technology will reach their limits and cannot meet the requirements of ultra-small size,Storage requirements for ultra-high density and in-memory computing.Memristor is the most promising technology to solve the above problems,among which RRAM is a special example of memristor,which has the advantages of non-volatility,low power consumption,high endurance,etc.,and is a strong candidate for future memory electronics.Due to the many advantages of organic materials such as flexibility,low cost,and designability,which greatly meet the demand for flexible electronics in the future Internet of Things era,organic RRAM has been widely concerned,but the high operating voltage of organic RRAM is still a serious problem.question.The set voltage（Vset）and reset voltage（Vreset）of most organic-based RRAMs are more than 1 V,however the operating voltage required for RRAM should be less than 500 m V to reduce power consumption and simplify power circuit design.This seriously hinders the practical application of organic RRAM devices.In this dissertation,aiming at the key scientific issue of large operating voltage of organic RRAM devices,we explore different methods to realize low operating voltage organic RRAM devices.The specific research results are as follows:1.Using trehalose with abundant C-O-C and C-O-H（this functional group is conducive to the migration of metal ions）and good water solubility,trehalose with a thickness of about 50-60 nm is obtained by processing in aqueous solution.thin films with low film roughness（Ra=0.64 nm）.The corresponding device exhibits distinct RRAM characteristics,with small operating voltage（～0.4 V）,good retention characteristics（>10000 s）and good cycle tolerance（100 cycles）,high on-off ratio～10⁵.This result proves that the use of trehalose as the resistive functional layer is an effective solution to realize low operating voltage organic RRAM devices.2.Utilize chlorophyll copper sodium salt,its fast ion migration ability,and solve the problem of serious crystallization of the film when the solution concentration is increased by heating and stirring the solution for 5 hours.The organic RDTSM prepared based on sodium copper chlorophyll has stable bidirectional stability.Threshold switching behavior,ultra-low threshold voltage（<100m V）,high on/off ratio（～10⁶）,excellent uniformity of threshold switching behavior,good cycling tolerance（>6000 cycles）,turn-on switching slope can be Calculated to be～0.17 m V dec^-1,which is the highest value reported so far in any type of RDTSM.This result demonstrates that the development of organic functional layers with faster ion mobility has great benefits in reducing device operating voltage.3.Although doping has a significant effect on reducing the operating voltage of the device,due to the randomness and non-uniformity of doping,it may bring other negative effects that we cannot accept,such as poor stability.A new idea is to use the easy crystallization characteristics of sodium copper chlorophyll to adjust the morphology of the film by doping to produce a nano-pillar structure,thereby inducing the formation of conductive filaments near the nano-pillars,thereby improving the stability of the device,and has nano-pillars.Compared with the doped device without nanopillars,the doped device with pillar structure has greatly improved the comprehensive performance of the device,with low operating voltage（0.5 V）,good cycle tolerance（1000 times）,and good maintenance ability（>10000 s）,demonstrating the effectiveness of our approach.