Bulk photovoltaic effect in ferroelectrics

Abstract

The bulk photovoltaic (PV) effect in ferroelectric materials has attracted worldwide attention for novel optoelectronic applications utilizing above-bandgap photovoltages, light-polarization-dependent photocurrents, photocurrent generation by terahertz light, etc. One of the drawbacks is its weak photoresponse under visible-light irradiation, and thereby the development of visible-light-active ferroelectrics has been an important issue. In this review, firstly, we introduce the history, mechanisms, and physical features of the bulk PV effect. Secondly, we summarize the properties of representative ferroelectric oxides and two-dimensional nanomaterials. Moreover, we describe a material design for enhancing the visible-light photoresponse based on bandgap tuning and gap-state engineering. Finally, we discuss future prospects of ferroelectric PV devices with a high conversion efficiency.