Ferroelectrically modulated and enhanced photoresponse of a Ag/PZT/NSTO self-powered photodetector in the ultraviolet range

Ultraviolet (UV) photodetectors possess the capability to convert UV light into electrical signals, rendering them of great interest in various applications. The self-powered and tunable UV photodetectors have garnered considerable attention. In this study, self-powered Ag/PbZr_0.2Ti_0.8O₃(PZT)/Nb-doped SrTiO₃ (NSTO) heterojunction photodetectors are prepared, and their ultraviolet photoresponse can be effectively modulated and enhanced by ferroelectric polarization. The highest responsivity and detectivity can reach 7.4 × 10⁻⁴ A W⁻¹ and 7.4 × 10⁹ Jones at -5 V V_P (polarization voltage), marking enhancements of 1487.5% and 20 556% compared to the values obtained at +5 V V_P, respectively. This improvement can be attributed to the modulation of the built-in field at the PZT/NSTO interface by ferroelectric polarization, which facilitates the separation and transport of photo-generated carriers. Additionally, the heterojunction exhibits a switchable diode effect modulated by ferroelectric polarization. This work elucidates the relationship between the photoresponse and the polarization states of PZT and offers a promising strategy for the development of self-powered ultraviolet photodetectors that can be modulated and enhanced by the ferroelectric effect.