Studies On Resistive Switching Characteristics And Interfacial Modulation Of H-LuFeO₃-based Resistive Switching Devices

With the advent of the era of big data,resistive random-access memory has attracted much attention due to its fast-operating speed,high storage density,and low energy consumption.Negative differential resistance effect is a non-linear transmission characteristic in which the current decreases with increasing voltage.Its existence can help the resistive switching devices to achieve multi-level storage and gradual resistance modulation.However,the appearance of negative differential resistance effect in the resistive switching devices is usually related to some unstable factors,which leads to its poor reproducibility.In addition,the resistive switching parameters dispersion is relatively large due to the randomness of the formation and fracture of the conductive filament,and the operating voltages are relatively high in the conductive filament-based resistive switching devices.These problems severely limit its commercial application process.h-LuFeO₃ is a room-temperature multiferroic material,which shows great potential in the high-density storage field.However,it has not yet been investigated in the direction of resistive switching.In this article,h-LuFeO₃-based resistive switching devices were prepared,and the resistive switching characteristics was explored firstly.Then,the method of interfacial modulation was used to achieve high reproducible negative differential resistance effect in the ferroelectric resistive switching devices based on h-LuFeO₃/CoFe₂O₄heterojunctions.The transformation of ferroelectric resistive switching to the conductive filament-based resistive switching was realized by further interfacial modulation,and the resistive switching parameters were optimized.The specific work content and research results are as follows:（1）The methods of pulsed laser deposition and magnetron sputtering were used to prepare h-LuFeO₃ film and Pt electrode on Pt/Si O₂/Si substrate in sequence to form the Pt/h-LuFeO₃/Pt/Si O₂/Si device.And then,the current-voltage curves were tested and analyzed.The results show that the device has a double-threshold switching characteristic,which is controlled by the formation and rupture of conductive filaments composed of oxygen vacancies.The off-state current of the device is around 100 p A,the on-off ratio of the resistance can reach 10³ when the current is limited to 100 n A,and the double-threshold switching behavior is still stable after hundreds of cycles in direct-current mode.（2）The h-LuFeO₃/CoFe₂O₄-based resistive switching device was designed and prepared,and the effects of interfacial effect and polarization on the negative differential resistance effect were studied.The results show that the insertion of CoFe₂O₄ improves the crystalline quality and ferroelectric properties of the h-LuFeO₃film,and the device exhibits both resistive switching and negative differential resistance effects.According to the analysis,the negative differential resistance effect originates from polarization switching-induced charge injection and subsequently trapping or detrapping at the interface.In direct-current mode,this effect can still be stable after hundreds of cycles,while the switching ratio of the resistive switching effect remains at about 10.（3）The interfacial modulation was used to realize the transition of the resistive switching behavior in h-LuFeO₃/CoFe₂O₄ heterojunctions-based resistive switching devices and multi-level storage was achieved.And then,the density of the nanotips on the electrode surface was modulated to further optimize the resistive switching performance.The low-density nanotips can further reduce the randomness of nucleation and growth of conductive filaments comparing with high-density nanotips,as well as the operating voltages.The device exhibits ultra-low Set/Reset voltage of 0.25 V/0.33V,high ON/OFF ratio and long retention time.