Low-voltage Oxide Based Electric-double-layer Transistors And Their Application In Photoelectric Synaptic Devices

The rapid development of artificial intelligence（AI）has triggered people's demand for accurate perception and memory of the external environment through visual perception systems.The construction of neuromorphic devices or integrated systems with various light-sensitive and responsive functions to imitate the visual behavior of biological systems is becoming a research hotspot.In the electrolyte-gated electric-double-layer transistors（EDLTs）,the electric-double-layer coupling at the electrolyte/channel interface will be realized by the movable ions in the electrolyte under the external electric field.This mechanism regulates the carrier densities in the channel,which is very suitable for simulating the synaptic behavior.In addition,the devices have excellent optical response,which plays a key role in simulating visual perception behavior.In this work,we first analyze the electrical properties of oxide electric-double-layer thin film transistors under dark and light conditions.Then,the devices with excellent optical response characteristics are used to simulate biological visual perception behavior and learning behavior.The main contents as follows:（1）Preparations of chitosan-based electrolyte ITO phototransistors and investigations of the electrical performance of the devices.The proton conductivity and the EDL capacitance of the chitosan membrane is as high as～8.9×10^-4S/cm and～3.7μF/cm²,respectively.The ITO phototransistors prepared by radio-frequency magnetron sputtering exhibit excellent electrical characteristics in both dark and light conditions.The device has a high I_ON/I_OFFratio of～1.7×10⁷.Subthreshold swing（SS）,threshold voltage(V_th)and carrier mobility(μ_sat)is～80 m V/dec,～0.3 V and～7.6 cm²/（V·s）,respectively.The ITO phototransistors were used as artificial vision devices to successfully simulate the optical synaptic behavior,including excitatory postsynaptic current（EPSC）and paired-pulse facilitation（PPF）.（2）Fabrications of starch-based electrolyte-gated IGZO photoelectric neuromorphic transistors.Starch electrolytes exhibit EDL capacitance of～1.5μF/cm²and proton conductivity of～5.1×10^-3S/cm.IGZO photoelectric neuromorphic transistors can operate at low voltage（<1.5V）and exhibit excellent electrical characteristics.The transfer curves of IGZO photoelectric neuromorphic transistors under light show the potential of long-term memory（LTM）.In addition,the device's conductance can be increased by changing the duration time and number of light stimuli.The device mimicked the short-term synaptic plasticities under electrical stimuli.In addition,the starch-gated IGZO photoelectric neuromorphic transistor have good biodegradability properties.（3）Emulations of photoelectric cooperative coupling characteristics on starch-gated IGZO photoelectric neuromorphic transistors.The combination of effective optical and electrical modulation in time and space is applied to the single neuron to achieve the photoelectric synergic spatiotemporal integration behaviors.Furthermore,by associating electric spikes with light spikes,the Pavlovian classical condition is mimicked.In summary,the prepared low-voltage oxide EDLTs have excellent electrical properties,and the devices exhibit optical response behavior.The devices'application in the field of optoelectronic neuromorphic electronics was explored,showing good optical and electrical synaptic plasticity.The devices'synaptic behavior under photoelectric was further tested,and the application potential in visual perception system was pointed out.