Spatially Resolved Photodetection in Leaky Ferroelectric Oxides

Abstract

Leaky ferroelectric oxides can serve as optoelectronic circuit elements in which potential gradients due to the sponataneous polarization yield asymmetric and nonlinear photocarrier dynamics. Ferroelectric domains and domain walls should each influence photocarrier generation, separation and transport differently, but the microscopic mechanisms are unknown. Therefore systematic experiments of the spatially resolved, and spectrally resolved photoresponse in the epitaxial BiFeO3 thin film would reveal how the photoresponse depends on dynamic domain configurations. Locally, photocurrent direction is determined by local domain orientation, whereas magnitude is spectrally centered around charged domain walls that are associated with oxygen vacancy migration. Our observations demonstrate that photodetection can be electrically controlled by manipulating domains, which suggests non-volatile optoelectronic memory applications.