Ferroelectric modulated rectification and photoelectric properties of PEDOT/PZT/NSTO P–I–N heterojunctions

The rectification and photoelectric properties of PN junctions depend considerably on the depletion zone, which is usually difficult to modulate in situ without bias voltage. However, lead zirconate titanate (PZT) ceramics with a self-polarization field can induce nonvolatile modulation effects on the transport characteristics of heterostructures. In this study, PEDOT:PSS/PbZr0.2Ti0.8O3/Nb:SrTiO3 (PEDOT/PZT/NSTO) P–I–N heterostructures are prepared, and their electrical and photoelectric characteristics are modulated in situ by varying the polarization voltage (VP). Specifically, in a sample with 2-nm PZT thickness, the rectification ratios (RR) exhibit a cyclic variation from 0.55 to 654 between +3 and −6 V VP, which indicates a controllable reversion of the rectification direction in this device, and the coefficient of rectification ratio (CRR) is 1189. After writing the −6 V VP, the open-circuit voltage (VOC) shows reversible characteristics when turning the light on (VOC = +0.20 V) and off (VOC = −0.15 V). In addition, the modulation behaviours of P–I–N heterostructures with various PZT layer thicknesses (2–16 nm) are investigated, and the CRR shows a maximum peak value of ∼2 × 106 when the PZT thickness is 8 nm. This study provides a promising approach for developing nonvolatile modulation in self-driven photoelectric devices.