Research On Resistive Switching Effect Based On MoS_2-xO_x

Memristors have great application prospects in information storage,new logic computing,and neuromorphic computing,and provide new solutions for the development of integrated circuits and network technology.It is one of the current research priorities in academia and industry.In recent years,a large number of people have studied the resistance-switching effect of two-dimensional materials,among which the most representative material is MoS_2-xO_x,a new material formed by the oxidation of exfoliated molybdenum disulfide flakes,which has good resistance switching characteristics even at temperatures as high as 340℃also showed a stable resistive effect,but its switching ratio was as low as about 10.In addition,this type of resistive switching effect is caused by the movement of high-mobility oxygen vacancies under the action of an electric field to form the connection and disconnection of conductive filaments.This is a bulk-type resistive switching effect that destroys the crystal structure inside the material.Another interface-type resistive switching effect is caused by the change of the interface between metal and material caused by the movement of oxygen vacancies.At the same time,the oxygen vacancies of this material have high mobility,which will inevitably lead to changes in the interface barrier.Therefore,this paper mainly studies the interface-type resistive switching effect based on the new material MoS_2-xO_x.（1）Threshold-type resistive switching effect of the device Au/Fe₃Ge Te₂/MoS_2-xO_x/Au.MoS_2-xO_x was obtained by annealing for 90 min at a temperature of 250°C and an oxygen pressure of 1 KPa.Then peel off the upper layer of Fe₃Ge Te₂ to form a heterojunction,and prepare two devices(Au/MoS_2-xO_x/Au and Au/Fe₃Ge Te₂/MoS_2-xO_x/Au)on the same MoS_2-xO_x by design.After testing,it was found that the device Au/MoS_2-xO_x/Au has no resistive switching effect,but only forms a potential barrier in Au/MoS_2-xO_x,showing Schottky diode-like characteristics,while threshold-type resistive switching is found in Au/Fe₃Ge Te₂/MoS_2-xO_x/Au devices effect;more than 700 cycles were measured in the experiment.There are two main types of resistive switching effects,and the threshold windows are 10₂ and 10₃ respectively.The possible mechanism is that the mechanically exfoliated Fe₃Ge Te₂ has a thin oxide layer,and multiple filament-type conductive channels appear in Fe₃Ge Te₂,and when the voltage is reduced,the weaker conductive channels break first to form a multi-resistance platform.（2）Research on the resistance characteristics of the device Au/MoS_2-xO_x/Au.By exploring the annealing conditions of MoS₂,a resistive switching device with good performance based on the Schottky barrier mechanism was prepared,and the device showed a bipolar nonvolatile resistive switching effect.The on-off ratio is about 10,which decreases after 100 cycles.The device can still retain the data after 2×10 s,and it is predicted that the data can be retained for at least 20 h by fitting.Finally,by fitting the data well with the barrier model,it is concluded that the migration of oxygen vacancies leads to the change of the barrier between the top electrode and MoS_2-xO_x,and the change of the Schottky barrier causes the switching of resistance.（3）Research on the resistance characteristics of the device Au/Ti/MoS_2-xO_x/Au.Metal Ti has excellent oxygen absorption ability,and the preparation configuration is Au/Ti/MoS_2-xO_x/Au device.In the device of this configuration,the on-off ratio of the resistive switching effect of the device can reach 10³（two orders of magnitude higher than the second one）,and there is no degradation after more than 300 cycles while having high retention characteristics.Finally,characterization and analysis were carried out busing X-ray photoelectron spectroscopy and atomic force microscopy.When the device switches from a high resistance value to a low resistance value,the Ti layer at the interface contacts with oxygen to form a thin layer of Ti O_y,and when the low resistance value is switched to a high resistance value,the Ti oxide layer becomes thinner.