| With the development of information science and electronic device technology, the size of the device has been continuously shrinking. However, when the size of the device decreases to nanoscale, the semiconductor industry is facing the dual challenges of technology and physical theory. Therefore, the electronic device miniaturization development became a central issue have loaded in the international technology roadmap of semiconductors.In the last decades, because of the traditional semiconductor memory device based on charge storage face the limitation of size brings, the serious physical theory and technology reduces, it has been unable to meet the needs of the rapid development of information technology. In order to overcome these limits, it is highly necesery that we should explore the next generation of new storage technologies with a higher storage density, non volatility and lower energy consumption. Recently, there are a lot of nonvolatile memory devices, including phase change memory, polymer memory, magnetic memory, ferroelectric memory and resistive switching memory. In these new memories, the resistive switching random access memory(RRAM), which have many advantages, such as nonvolatile, simple structure, low power consumption, fast read and write speed, high integration density, a single device can be reduced to dozens of nanometers. Therefore, the RRAM is pays much attention by more and more researchers, which is considered to be one of the candidates with the most the potential next generation memory.In the study on the resistive switching memory, the materials, which have the resistive switching effect at room temperature, is very fascinating. It has found the novel resistive switching effect in numerous semiconductor or insulator materials, such as binary metal oxide, complex perovskite structure oxides, sulfides and organic materials. In order to reveal the mechanism of resistive switching memory effect, it has made much progress so far. However, there is no one theory can make a clear explanation for the memory phenomenon. Therefore, the mechanism analysis of resistive switching memory is relatively incomplete. There are still a lot of research spaces. Therefore, it is an important and significant research topic for uncover the mysterious veil for the material resistance changes from a basic physical model. At the same time, it is also the research direction of priority among priorities for other means(such as optical-cntrolled) controlled resistive switching effect besides the electric pulse controlled resistive switching effect.In order to explore the wide application of resistive switching memory effect and the light-illumination controlled the resistive switching storage performance, this work around the resistive switching characteristics of multiferroic nanomaterials at room temperature, and by changing the material preparation technology and nanostructure, we detailed analysis these resistive switching memory characteristics, and we found the light illumination can controlled obviously the resistive switching effect, and some useful results are obtained. The main results are as follows:Firstly, we have synthzied respectively MnWO4 nanowires and FeWO4 nanowire arrays under the induction of surfactant by hydrothermal method. Then we use vacuum deposition or silver glue to prepare top electrodes, thus we have prepared some resistive switching memory devices with Ag/Mn WO4/Ag and Ag/FeWO4/Ti sandwich structures. Then, the resistive switching memory characteristics of two kinds of structures were prefored by an electrochemical workstation, we found an obvious hysteresis current-voltage(I-V) characteristics for two kinds of structures at room temperature, the characteristics of I-V may be attributed to the silver ions(Ag+) which are ionized in the silver electrode under the voltage, and the silver ions can diffusion respectively along MnWO4 nanowires and Fe WO4 nanowires, which can forme a conductive filaments in these nanowires. Therefore, the resistance switching memory effect of these devices is attributed to the formation and disconnect of conductive filaments. More importantly, for the device of Ag/MnWO4/Ag structure, we characterized quantitatively the content of silver element when the device at a high resistance state(HRS) and low resistance state(LRS) by elemental analysis, which fully proved that the resistive switching effect of the device is derived from the formation and disconnect of conductive filaments.Then, we have grown BiMnO3 nanowire arrays on the titanium(Ti) substrate and BiFe O3 thin films on the soft polyimide substrate by hydrothermal method and RF magnetron sputtering, respectively. Then we have preparated the resistive switching memory devices with Ag/BiMnO3/Ti and ITO/BiFeO3/Ti/Polyimide structures by silver glue printing and vacuum deposition. Finally, we studied the resistive switching memory characteristics of the above-mentioned structures by an electrochemical workstation, which were found the above two structures present the obvious hysteresis current-voltage(I-V) curves at room temperature, and have good stability. More importantly, these I-V characteristics of the above two devices can be regulated by white-light irradiation. Through the further mechanism analysis, it is revealed the resistive switching characteristics is closely related with the Schottky barrier formation at interface between nanostructures and adjacent conductive electrodes, and the polarization of the material can adjust the height of Schottky barrier. Further because the white-light irradiation can produce a large number of photogenerated carriers within the active material, and then change the interface carrier concentration, which affects the charge trapping/de-trapping, the results lead to the emergence of a light-controlled resistive switching effect. Particularly, it is worthing note that the light controlled resistive switching memory device of ITO/BiFe O3/Ti/Polyimide structure with soft and wearable properties, therefore, the device may be a rudiment for wearable light-controlled resistance switching memory devices, which greatly widens the application range of the resistive switching memory devices.Finally, we made a simple introduction for the preparation and application of bio-memristor device. From the current perspective of the development of resistive switching memory devices, the bio-memristor would be the development direction of meresistor in the future. In particular, the application of bio-meresistor based on cell level is an important aspect with the superiority of the bio-memristor, which fully demonstrate the memristor can be reduced to the nanometer scale, which are unmatched by traditional memory devices. |
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