Research On The Resistance Switching Of Carbon Multilayer Films

With the development of science and technology,the time of information has been fully popularized and developed,which results in the addition of demand for memory device,including its high performance and miniaturization?such as high stability,low power consumption and multiple functions?.It is necessary to study new materials and memory devices,which have characteristics about multiple functions and features.Memory device types mainly include non-volatile memory and volatile memory,in which non-volatile memory has attracted researchers and technology company attention owing to it meeting people's requirements for easy reading,long storage time and high stability.Volatile memory storage can only meet people's needs for short-term storage of information.Non-volatile memory device includes phase change memory,ferroelectric memory,magnetic memory and resistive memory.Phase change memory relies on the difference in electrical properties of phase change materials during phase change conversion to store information.Ferroelectric memory relies on different remanent polarization states of ferroelectric materials when they are spontaneously polarized to store information.Magnetic memory uses surface magnetic media for recording.Resistive memory refers to a memory in which a resistance of a specific material is changed between different resistance states for storing information.Resistive memory is considered as a candidate for the next generation of non-volatile random access memory owing to its high read speed,high memory density,long storage time,low power consumption and simple structure.Researchers have found resistance switching properties in many transition metal oxides,organics and perovskite oxides.However,the rich variety of resistive switch characteristics makes the interpretation of its mechanism uneven.Therefore,the further study of the resistance switch is particularly important for the interpretation of its mechanism.As a common non-metallic material,carbon is in the main group IV,which makes carbon have good electrical conductivity,high stability,high temperature resistance,soft texture,good smoothness and layered substance.Those characteristics makes carbon received widespread attention.Carbon does not have ferroelectricity and magnetic properties as BaTiO₃ and BiFeO₃,but it still has great research significance in non-volatile memories such as resistive memory.In the past few years,articles about carbon research have been commonplace,including carbon nanotubes,single-layer graphene and C₆₀.Among them,the study on garphene also won the 2010Nobel Prize in Physics.This dissertation introduces Carbon's structure,physical properties and the practical application in resistance switch.On this basis,we made a studied about containing Carbon multilayer films in resistance switch.In this dissertation,we explain some things in detail including the preparation process about sample,structural characterization,electrical properties measurement and related physical phenomena mechanism.The main contents are as follows:?1?We briefly introduce the Carbon about its structure,physical properties,research progress and application prospects.The non-volatile memory and its classification,as well as the classification and interpretation mechanism of resistance switch are described in detail.?2?C/BaTiO₃/ZnO multilayer was prepared on N-type non-conductive Si single crystal by magnetron sputtering,and the thickness of the cross section of the sample was characterized by scanning electron microscopy?SEM?,The ?-? curve of the sample was measured using Keithley 2400.At the same time,white-light-controlled resistive switching effect in the sample was also studied.The results show that the ?-? curve of the sample shows obvious bipolar resistance switch characteristics,the conductivity of the sample increases gradually with the increase of illumination intensity,and the ?-? curve of the sample has high stability in both dark and light.We use oxygen vacancies or defects to capture and release the charge to provide a reasonable explanation for these physical phenomena of the sample.?3?C/BaTiO₃/ZnO/BaTiO₃ samples were prepared by the coating technique of the above experiment,and the cross-sectional thickness and the ?-? curve of the sample were characterized and measured by SEM and Keithley 2400 respectively.The ?-? curve of the sample shows obvious unipolar resistance switching effect.At the same time,white-light-controlled resistive switching effect of the sample was studied as well.The results show that the conductivity of the sample increase gradually with the increase of illumination intensity,and the stability of the sample under the illumination conduction is higher that under the dark conduction.We use oxygen spaces or holes to capture and release the charge and the influence of Coke Joule to provide a reasonable explanation for these physical phenomena of the sample.?4?C/ZnO sample were grown on N-type Si single crystal by magnetron sputtering,and the cross-section thickness and ?-? curve of the sample were characterized and measured by SEM and Keithley 2400 respectively.The ?-? loop of the sample shows obvious hysteresis loop phenomenon,and white-light-controlled hysteresis loop of the sample was studied as well.The results show that the conductivity of the sample decrease gradually with the increase of illumination intensity,showing the“Negative Photoconductivity”,and the ?-? curve of the sample has high stability in the dark conditions.We use the capacitance storage charge mechanism formed between C and ZnO interface and the surface effect of ZnO material to make a reasonable explanation of these physical phenomenon of the sample.