Artificial optoelectronic synapses based on capture layer of silicon rich oxides

Abstract

The optoelectronic bionic synapse, as a new memory device with integrated storage and calculation, can respond to light stimulation, for use in the bio-visual system. These also have the advantages of large bandwidth, low crosstalk, and low power consumption. In this study, amorphous silicon (Si) films were annealed at 200 °C, 300 °C, 400 °C, and 500 °C, respectively. SiO_x defects were introduced at their interfaces and optoelectronic synapses, resulting in the formation of SiO_x/a-Si/P⁺⁺-Si. X-ray photoelectron spectroscopy was used to characterize the effect of different annealing temperatures on the composition of SiO_x. The devices successfully simulated a series of important synaptic functions, including excitatory postsynaptic currents, paired-pulse facilitation, short-term to long-term memory conversion, learning-experience behaviors, etc. The devices prepared under different annealing processes had different memory effects. Based on this, a 3 × 3 array of image memory optoelectronic synapse was prepared to simulate the human brain short-term, long-term, and after-repeated memory state, of human beings. Finally, based on the changes in the mode of Si and oxygen binding and the activation energy of oxygen, the reason for the differences in the memory properties of synaptic devices prepared at different annealing temperatures could be explained.