Fig. 2: Tunable polarization and photoresponse in FE-PS.
From: In situ training of an in-sensor artificial neural network based on ferroelectric photosensors
a Schematic of the device structure of the Pt/PZT/SRO FE-PS. b PFM phase image after writing a box-in-box pattern (outer: +5 V; inner: –5 V) on the bare PZT film. Vp-dependent c bipolar, d positive monopolar, and e negative monopolar P–V hysteresis loops for the device. f Top and bottom panels: illuminated I–V curves measured after applying positive and negative pulses with different Vp, respectively. Middle panel: schematics of the different polarization states corresponding to the different Vp, which produce photocurrents with different magnitudes and directions. These schematics are drawn based on the results in (d, e). In (d–f) and anywhere else, the States I to IV refer to the full Pup, half Pup, near-zero-polarization, half Pdown, and full Pdown states, respectively.
