Construction Of Memristive Devices Based On Tungsten Oxide/Silver Composite Films And Research On Synaptic Bionics

The memristor is an emerging electronic component whose resistance is determined by the amount of electric charge flowing through it.Due to its unique performance,it has received extensive attention from researchers in the field of artificial nerve synapse bionics.The resistance of the memristor can be continuously adjusted by electrical signals,which is very similar to biological synapses.Tungsten oxide(WO₃)materials have been reported to be able to achieve a variety of synaptic functions,and are considered to be ideal materials for constructing memristive nerve synapses.However,the crystal form and morphology of WO₃have certain limitations for the development of optic nerve synapses.Silver(Ag)nanoparticles undergo plasmon resonance under light irradiation,and have the selectivity of illumination wavelength,intensity and time.When Ag nanoparticles and WO₃ are combined,the light absorption properties of the film can be effectively adjusted.In this paper,WO₃ and Ag materials are used as research objects to construct a new type of memristive device and explore its application in memristive synaptic bionics.The specific research content is as follows:(1)The preparation of WO₃/Ag:WO₃ composite thin film memristive device and the study of its memristive behavior.Characterization using atomic force microscope found that the film has good flatness.Comparing the nonlinear transmission characteristics of devices with different Ag doping concentrations,experiments show that devices doped with Ag for 10min have the best memristive characteristics.Based on thin-film devices with continuously adjustable resistance,simulations of multiple synaptic functions are realized:including excitatory postsynaptic current,double pulse facilitation,pulse timing dependent plasticity,etc.And by changing the pulse width to realize the regulation of conductance enhancement and suppression of nonlinearity,it provides the possibility to improve the accuracy of pattern recognition.Using visible light pretreatment to adjust the electrical behavior of the device,a variety of synaptic functions have been successfully simulated.(2)The preparation of WO₃/Ag/WO₃ composite thin film devices and the study of its optoelectronic functions.The device has a good light response to ultraviolet light and visible light:the device presents an activated state after visible light pretreatment;it becomes an inhibited state after ultraviolet light pretreatment.Experiments have found that the memristive behavior of the device depends on the illumination time,power and wavelength:as the illumination time and light power increase,the synaptic response of the device increases.After green light,blue light,red light and other light wavelengths are irradiated,the conductance of the device has different nonlinearity,and the linearity of the device is the highest after green light is irradiated.Finally,different wavelengths are used to preprocess different positions of the"heart"pattern to realize the multi-wavelength color image detection function.