Study On Resistive Switching Characteristics Of Protein-based Memristor

Memristor is a resistor with memory function,which is a device of two terminal system in structure,and the voltage current curve has hysteresis characteristics in the first and third quadrants.Memristor can carry out data storage and logic operation at the same time.It is considered that it is possible to replace the current non-volatile storage devices.It is also a new technology that may solve the problems of storage technology.At the same time,it can also simulate neural network.Generally,the materials for preparing memristor active layer include carbon-based materials,binary oxides,solid electrolytes,organic polymers,perovskite composite oxides,protein materials,etc.among many memristor active layer materials,the research on protein materials is particularly active and may become the best choice for manufacturing wearable storage devices in the future.In this paper,the resistive switching characteristics of three typical protein memristors are studied.The specific work is as follows:(1)Study on the resistive switching characteristics of egg protein memristor.Using ITO conductive glass as the substrate,the corresponding active layer films were prepared on the substrate by changing different spin coating speed,controlling the mixing ratio of egg protein and deionized water and the amount of graphene oxide,and then top electrode was vacuum evaporated on the active layer.In this way,a memristor with the structure of ITO/egg protein or egg protein and graphene oxide composite/Al is made.The memristor was characterized by scanning electron microscope.The memristor characteristics were mainly studied from the aspects of I-V characteristic curves,on/off current ratio,memristor retention time and repetition characteristics.The effects of film thickness,the mixing ratio of egg protein and deionized water and the blending of egg protein aqueous solution and graphene oxide on the memristor characteristics were studied.Experimental results show that all memristor are electrically bistable and rewritable flash storage characteristics.Doping graphene oxide in an appropriate proportion significantly enhances the repetition characteristics of the memristor.The reason may be that the doped graphene oxide participates in the conductivity of memristor.(2)Study on resistive switching characteristics of milk memristor.Using ITO conductive glass as the substrate,the active layer was spin coated on the substrate by changing different process conditions,and then the Al top electrode was vacuum evaporated on the active layer.The memristor with different film thickness,different mixing ratio of milk and deionized water and different mass of graphene oxide mixed in milk aqueous solution were prepared.The memristor characteristics are analyzed and compared in terms of on/off current ratio,retention time and repetition characteristics.The experimental results show that all memristors have the characteristics of nonvolatile flash memory.The on/off current ratio of the memristor based on milk is better than that based on egg protein,but the stability and repeatability are worse.Similarly,the incorporation of graphene oxide can also improve the number of repeated erasures of the memristors.(3)Study on resistive switching characteristics of gelatin memristor.Using ITO conductive glass as the substrate,the active layer was spin coated on the substrate by changing different process conditions,and then the Al top electrode was vacuum evaporated on the active layer.The memristor with different active layer thickness,different specific gravity and different curing temperature were prepared.The memristor characteristics of all memristor are studied in terms of memristor retention time and repetition characteristics.The experimental results show that all the memristor show a bistable resistive switching mode and good rewritable storage characteristics.The resistive switching characteristics of the memristor are the best when the aqueous gelatin solution with 2wt% specific gravity is cured at 105 ? for 10 minutes.Based on the above three proteins,the memristor have good memristor characteristics when changing different process conditions.The memristor characteristics of the three materials are analyzed theoretically.Using the fitting of the slope of I-V curve in the double logarithmic coordinate system,the I-V curves of egg protein,milk,gelatin and composite protein memristor with graphene oxide are re drawn in the double logarithmic coordinate system.The curves show that the on state(slope is about 1)of all memristor comply with Ohm's law,and the off state meets the law of space charge limiting current controlled by traps.The theory of unified carrier trap and detrap can be used to explain the resistive switching mechanism of protein memristor.