Sensor–Storage–Computing Integrated Synaptic Devices Based on SrTiO₃–TiO₂ Heterojunctions with Kilosecond-Level Retention

In this study, we deposited a TiO₂ photosensitive layer on SrTiO₃ film by the spin-coating method and successfully developed an artificial synaptic device with the integration of sense-store-computation functions. The energy band structure of the heterojunction and the direction of the built-in electric field are determined by steady-state absorption spectroscopy. The carrier relaxation dynamics at the femtosecond level of the device is observed by transient absorption spectroscopy, and it is determined that the built-in electric field of the heterojunction dominates the complex dynamics of the photogenerated carriers. External bias is used to modulate this electric field, and intelligent processing of the photovoltaic signals is realized. Through the comodulation of photoelectric signals on the artificial synaptic device, intelligent applications are realized in three dimensions: sensing-storage-computing. The device has a long retention time (>1000 s), function switching based on different wavelengths of light signals (positive and negative optical conductance and photodetector functions can be realized separately), and high handwriting digit set detection accuracy (>95%). This study integrates the dual advantages of low-cost processing and a simple preparation process to prepare an integrated sensor-storage-computing device, which opens up a manufacturing path for the construction of a high-density integrated photoelectric device.