| At present,the outbreak of big data has led to an increasing demand for large data storage,with the rapid development of information technology and artificial intelligence.And the large data storage needs to be built on a high-performance and large-capacity information storage memory.Non-volatile memory has the potential to become a high-performance and large-capacity storage device because of the fact that the data does not disappear when the power is off.Resistive random access memory?RRAM?is a new type of non-volatile memory with the advantages of fast reading/writing speed?ns?,low power consumption and high density,etc.RRAM has enough potential to become a big data storage device.At present,RRAM based on two-dimensional materials has low power consumption(VSET?3 V),small size and good flexibility,which has attracted many researcher's attention.But the resistive mechanism of RRAM based on two-dimensional transition metal sulfide is still not clear,the stability and endurance characteristics of the device are not good enough.Based on the above factors,this paper mainly studies the factors affecting the resistive properties of two-dimensional transition metal sulfide RRAM,aiming to improve the performance of RRAM.First,an Al/PVP/ITO/PET device without resistive switching behavior is prepared by studying the effects of different preparation parameters on the device.For the next step study of the resistive switching properties of Al/MoS2&PVP/ITO/PET devices.Secondly,Molybdenum disulphide?MoS2?,the two-dimensional transition metal sulfide,was synthesized by hydrothermal method.According to the characterization results,the single-layer or few-layers MoS2 nanoflakes were successful prepared by liquid-phase ultrasonication.Preparation of Al/MoS2&PVP/ITO/PET device by spain-coated a MoS2&PVP solution on indium tin ocide?ITO?subtrate as resistive layer and Al deposited on the resistive layer as a top electrode.The resistive switching characteristics,conduction mechanism and resistive switching mechanism of the Al/MoS2&PVP/ITO/PET device are analyzed.It is concluded that the three differents I-V characteristics?Typical bipolar resistive switching,Asymmetrical bipolar resistive switching,Threshold switching?of Al/MoS2&PVP/ITO/PET can be explained by the formation and rupture of conducting filaments?CFs?consisting of sulfur vacancy filaments in MoS2 nanoflakes and sulfur ions filaments in PVP.These CFs form from three different kinds of grain boundaries?GBs?,intersecting-GB,bisecting-GB and bridge-GB in which GBs attach one electrode,parallel to the two electrodes,and attach both electrodes,respectively,corresponding to the three modes of I-V characteristics.These three kinds of GBs coexist in one device and the CF forms randomly from one kind of them during sweeping loops.The mechanism was experimentally proved by our results of the increasing probability of typical bipolar RS with one layer of PVP thin film inserted into the interface of MoS2&PVP and ITO.The experimental results show that when intersecting-GB is increased,the probability of the typical bipolar resistive switching increases significantly.From this,the conclusion is drawn and the method is summarized:by adding a layer of PVP thin film between the interface of MoS2&PVP and ITO,the probability of the typical bipolar resistive switching can be effectively increased.Al/MoS2&PVP/ITO/PET resistive switching devices still have high power consumption.In order to further realize the functions of low-power consumption,the resistive switching of the Al/TiS2&PMMA/ITO/PET prepared at different parameters,such as stripping solvent,electrode size,device structure,solution concentration ratios and limiting current,are studied.Single or multi-layered titanium disulfide?TiS2?nanosheets were obtained by liquid-phase ultrasonication.Preparation of Al/TiS2&PMMA/ITO/PET device by spain-coated a TiS2&PMMA solution on ITO subtrate as resistive layer and Al deposited on the resistive layer as a top electrode.The results of experiments show that the device has low power consumption?the working voltage and current is-1 V to 1 V,and 10-55 A,respectively?when stripping solvent is DFM.By reducing the size of the electrode,the ION/IOFFFF and the stability of the device can be improved.When the film of PMMA is inserted between bottom electrode and resistive flim,the ION/IOFFFF and high resisitive state are improved further.It is concluded that PMMA layer can improve the ION/IOFF.However,the power consumption increased?the working voltage and current is-4 V to 4 V and 10-55 A,respectively?.Based on this analysis of the experimental results,the performance of the Al/TiS2&PMMA/ITO/PET device was further optimized by improving the solution concentration to achieve low powerconsumptionandhighION/IOFF.Theoptimizeddevice?Al/TiS2&PMMA/ITO/PET?has a working voltage range of-2 V to 2 V and an increased ION/IOFF?1.46?103?.But the device still does not show typical resistive switching.By increasing the limiting current,the typical resistive switching with high ION/IOFF is successfully obtained. |
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