Electric field poling effect on the photosensitivity of samarium-doped bismuth ferrite ceramics

Abstract

This work highlights improved photosensing performance in ITO/(Bi0.93Sm0.07)FeO3/Au heterostructure through a prior electric field poling. Maximal responsivity (R) of 2.0×10−2A/W and specific detectivity (D*) of 2.2×1011 Jones were obtained under 405-nm irradiation. The mechanism behind the observed photosensing performance is linked to the combined effects of the polarization-induced electric field and built-in electric fields at the interfaces (i.e., p–n junction and Schottky barrier). The net internal electric field established in the device serves as the driving force for the separation and transport of the photo-generated electron–hole pairs. The reduced direct optical bandgap (Eg) of 2.13 eV, the well-defined ferroelectric polarization hysteresis loops, and the conduction pathways formed by the electric field-stimulated interconnection of domain walls and grain boundaries play significant roles in the remarkable photosensitivity of (Bi0.93Sm0.07)FeO3 ceramics, thus providing insight into optimizing BiFeO3-based materials for near-UV photodetector.