Modulation Of Optoelectronic Properties Of Diamond Thin Films And Their Application In Optoelectronic Synapses

Optoelectronic synaptic devices are integrated perception,sensing,processing and storage with important functions similar to the human visual nervous system.This makes them important candidates for the development of artificial intelligence technologies.However,artificial optoelectronic synapse only with a wider spectral response range lower energy consumption and more complex functions can meet the current technology development.Diamond,as one of the most semiconductor materials,has excellent characteristics such as high breakdown voltage,high thermal conductivity and high saturation electron mobility.This makes it a promising development in the field of optoelectronic devices.In this paper,the effects of different Si doping contents on the optoelectronic properties of diamond are investigated,and an optoelectronic synaptic device based on Si-doped diamond films is designed.The main research of this paper is as follows:1.Diamond films with different Si doping contents were prepared by MPCVD.The crystal structure,surface morphology and optical properties of the films are characterized.It is found that the uneven distribution of the film grain size leads to a broad spectral response(222 to 650 nm);The average grain size of the film increases with increasing Si concentration.Doping creates defective energy levels associated with Si doping to trap photogenerated carriers,thereby increasing the photoresponse current and producing persistent photoconductivity phenomenen.With the increase of Si content,the photoresponse current and the persistent photoconductivity first increase and then decrease.The optimal optoelectronic performance of the Si-doped diamond film is obtained at the mixed gas flux of 2 sccm.2.The device with the best optoelectronic performance is selected for the simulation of synaptic properties.The excitatory postsynaptic currents,paired-pulse facilitation,transition from sensory memory to short-term memory,transition from short-term memory to long-term memory,and learning-experience behavior are successfully simulated.Importantly,the device can operate at an ultra-low voltage of 50μV and achieve ultra-low power consumption of 2.3 f J.3.Based on the outstanding synaptic plasticity of our devices,more functions of synaptic devices are further developed.The adaptive nature of the pupil and the visual interest learning behavior can be simulated by the regulation of the operating voltage.Boolean logic function and simulation of Pavlov’s conditioning experiments are implemented by all-optical stimulation.Finally,the perception and memory of images are achieved using a 23×15 artificial synaptic array.Therefore,the optoelectronic synapse based on Si-doped diamond film have great potential in the field of artificial intelligence and neuromorphic computing.