Realization of self-powered bidirectional photoresponse in the ultraviolet/visible wavelength region in ferroelectric heterojunctions

Abstract

Broadband and wavelength selective photodetection are of great importance for photodetectors in practical applications, while these two features are generally in conflict with each other in conventional semiconductor heterojunctions. In the current work, CH3NH3PbBr3/PbZr0.52Ti0.48O3 ferroelectric heterojunction photodetectors have been demonstrated to obtain a self-powered bidirectional photoresponse, which realized a broadband and wavelength selective photodetection in the ultraviolet (UV)/visible wavelength region. By a combination of bulk photovoltaic effects of ferroelectric PbZr0.52Ti0.48O3 and built-in electric field at the CH3NH3PbBr3/PbZr0.52Ti0.48O3 heterojunction interface, the photodetectors exhibited a positive sensitivity in the UV spectral range and a negative sensitivity in the visible spectral range. Specifically, the sensitivities were +0.22 mA/W at 340 nm and −0.032 mA/W at 530 nm, both at the bias voltage of 0 V. Notably, the photoresponse polarity in the UV spectral range can be further reversed through electrically polarizing the ferroelectric PbZr0.52Ti0.48O3. The results provided in this work highlight the superiorities of ferroelectric heterojunction photodetectors and open a window for the fabrication of broadband and wavelength selective photodetectors.