Ferroelectric\nPolarization Modulated Photodetection-Synaptic\nIntegration Functions of a‑GaO<sub><i>x</i></sub>/Bi<sub>0.85</sub>La<sub>0.15</sub>FeO<sub>3</sub> Semiconductor–Ferroelectric

The switchover between photodetection and synaptic characteristics\nin a single device triggers immense potential in multiscene applications\nowing to friendly integration and low power consumption. Accordingly,\na ferroelectric heterojunction optoelectronic device (FHOD) with controlled\nenergy band structure by polarization switching is developed for programmable\nphotoresponse to implement photodetection-synaptic integration functions.\nHerein, amorphous GaO<sub><i>x</i></sub>/Bi<sub>0.85</sub>La<sub>0.15</sub>FeO<sub>3</sub> FHOD is characterized by flexible\ntransformation between a self-powered photodetector (SPD) and an optoelectronic\nsynaptic device (OSD) manifested by simply exerting bias voltage.\nAdditional ferroelectric polarization switching offers a programmable\ndimension for modulating all-in-one metrics of SPD and OSD. When serving\nas SPD, the FHOD showcases boosted responsivity of 1.57 mA/W and detectivity\nof 5.3 × 10<sup>10</sup> Jones under upward-polarization state,\nfurther expanding its application in simulating optical communication.\nWhen the FHOD serves as OSD under bias voltage, switchable ferroelectric\npolarization-assisted ferroelectric heterojunction determines synaptic\nweight update and relaxation characteristics of synaptic plasticity,\nsuch as enhanced paired-pulse facilitation index and pronounced memory\nretention level under the downward-polarization state. Based on OSD\nfigures of merit, classical Pavlovian conditioning and color perception\nbehavior are successfully emulated. Furthermore, the recognition accuracy\nof handwritten digits can reach up to 90.1%. This work proposes a\npromising scheme for developing all-in-one FHOD toward multiscene\nswitching.