PHENOMENA AND MECHANISMS OF PHOTOVOLTAIC EFFECTS IN FERROELECTRIC BIFEO3 THIN FILMS

Abstract

In this study, high quality epitaxial ferroelectric BiFeO3 (BFO) films are fabricated by sputter deposition. The PV property of the BFO films and its mechanisms are systematically investigated. The results show that both depolarization field and the bulk photovoltaic effect (BPVE) contribute to the observed PV processes in BFO films with sandwich structures. The photocurrents from these two mechanisms in BFO are probably opposite to each other and partially cancel out. This could be one of the factors that limit the efficiency in these samples. The photoelectrolytic reaction of water splitting using BFO as the photoelectrode is investigated. Significant anodic photocurrents are observed. A possible monolithic water splitting cell based on BFO is proposed. The results from this study show that the PV effects in ferroelectric materials can be used to achieve unique functionalities in novel devices, and even possibly contribute to energy harvesting.