Single ferroelectric-domain photovoltaic switch based on lateral BiFeO 3 cells

Abstract

The bistability of ferroelectric polarization states serves as a basis for solid-state memory. This phenomenon can also yield an interesting photovoltaic effect in such a way that the directional photocarrier motion follows the inherent potential gradient imposed by the ferroelectric polarization vectors. Here, we demonstrate a single-domain photovoltaic switch based on lateral BiFeO3 channels, in which such photovoltaic switching is achieved by a coherent single-domain reversal with a short electrical pulse. We then provide visual evidence for such operations with a series of spatially and spectrally resolved short-circuit photocurrent images. Specifically, we reveal that the sequential photovoltaic current images directly reflect the remanent polarization states of a single-domain channel. We also verify that, in multidomain channels, diffusive switching characteristics are determined not only by the internal polarization vector within the domain but also by oxygen vacancy accumulation at the domain walls. © 2013 Nature Japan K.K. All rights reserved.