Fabrication Of Zinc Oxide Film And The Related Optoelectronic Synaptic Performance

Vision is the main channel for human to obtain external information.The development of visual bionic system can make some AI devices perceive external information like human eyes.However,the von Neumann system with physical separation of memory and processor will consume a lot of energy in the process of processing data.In contrast,in the human brain,data is stored and processed at the same location in the neural network.It is urgent to develop a new generation of visual bionic system to enable devices to process a large amount of information like the brain.Optoelectronic synaptic devices have a microscopic structure similar to biological synapses and can recognize,calculate and memorize optical information,which is the research focus of the new generation of artificial vision bionic system.In this dissertation,the zinc oxide（ZnO）was used as the research object.ZnO nanorods were successfully fabricated by wet chemical method,and the optoelectronic synaptic device structured as ITO/ZnO/ITO was first designed and realized based on ZnO nanorod film,and the optical and synaptic properties of the device were studied.Then,the second functional layers of CuAlO₂ or NiO were introduced to produce the optoelectronic synaptic devices as ITO/CuAlO₂@ZnO/ITO and ITO/NiO@ZnO/ITO with double-functional layers,respectively.The optoelectronic characteristics of the two devices were investigated,and some typical biological synaptic behaviors have been successfully simulated.The main results of this dissertation are as follows:1.The shape of ZnO nanorods is similar to a hexagonal prism,and the final diameter of the nanorods can be adjusted by changing the growth time and temperature.The ITO/ZnO/ITO optoelectronic synaptic devices exhibit persistent photoconductive effect by laser excitation at 405 nm,and can simulate various biological synapses behaviors such as short-term plasticity,learning experience and the transition from short-term plasticity to long-term plasticity.2.Based on the single functional layer devices,the second functional layers of CuAlO₂or NiO are introduced to form two kinds of double-functional layer optoelectronic synaptic devices as ITO/CuAlO₂@ZnO/ITO and ITO/NiO@ZnO/ITO with p-n junction successfully.Compared with the ITO/ZnO/ITO devices,the two double-functional layer optoelectronic synaptic devices have lower noise and wider response band,showing better performance in the short-term plasticity,learning experience and the transition from short-term plasticity to long-term plasticity as those in biological synapses.3.Three optoelectronic synaptic arrays are constructed to simulate the memory and recognition capabilities of the ITO/NiO@ZnO/ITO device.A better memory function of the device is successfully realized by the 3×3 synaptic array.Based on the 3×4optoelectronic synaptic array,the recognition of optical power has also been proved by the devices.Besides,the iris effect of human eye is simulatd through the learning and memory effects of the device with different reading voltages based the 3×5 synaptic array.