Bulk photovoltaic effect in a BiFeO₃thin film on a SrTiO₃substrate

Abstract

Epitaxial BiFeO 3 (BFO) thin films with striped-and single-domain structures have been grown on SrTiO 3 (STO) ( 103) and ( 113) substrates by radiofrequency planar magnetron sputtering. The domain structure of BFO was controlled by the orientation of the STO substrate. Piezoelectric force microscopy revealed that BFO thin films on STO (103) and STO (113) had a striped-domain structure with 71°domain walls running along o010p STO , and a single-domain structure, respectively. To confirm the photovoltaic property, rectangular Pt electrodes with widths of 150-200 µm were deposited on BFO surfaces with interelectrodes distances of 200-250 µm. I-V characteristics were measured under an illumination of a collimated violet laser (λ = 405 nm) with a power density of 380 W/cm 2 . In the striped-domain-structure BFO film with Pt electrodes fabricated along domain walls, above-band-gap open-circuit voltage (V OC ) of 29 V was observed. In addition, single-domain-structured BFO thin film with Pt electrodes fabricated along h 110i also showed above-band-gap V oc of 26 V despite the absence of domain walls. It is considered that these largeV oc values originated from the photovoltaic effect not at the domain walls but in bulk BFO.

Above‐Bandgap Photovoltages in Antiferroelectrics

“…The growth details are found in the Experimental Section; here, we just point out that solution‐processing fabrication is relatively simple and readily up‐scalable for photovoltaic cell manufacturing . Short exposure time to high temperature during the solution process helps preserve the integrity of the transparent bottom electrode, thus allowing the thin film device depicted in Figure to be fabricated in a vertical configuration, instead of the more usual lateral architecture . This allows the entire area of the device to be illuminated from below without any shadow effects.…”

First-Principles Materials Design of High-Performing Bulk Photovoltaics with theLiNbO3Structure

“…Several studies have attempted to elucidate the various contributions to the photovoltaic response -bulk or otherwise -in ferroelectrics [15][16][17][18][19][20][21][22][23]. In particular, bismuth ferrite (BFO) has been found to generate significant bulk photocurrents; combined with its unusually low band gap of 2.7 eV, it has attracted a great deal of attention for its potential in photovoltaic applications [21,[23][24][25][26][27][28][29][30][31]. The understanding of the fundamental physics behind the effect has advanced as well; recently we demonstrated that the BPVE can be attributed to "shift currents", and that the bulk photocurrents may be calculated from first-principles.…”

Perovskites for photovoltaics: a combined review of organic–inorganic halide perovskites and ferroelectric oxide perovskites

“…33 and 165 proposed a model regarding potential steps at domain walls as the driving force for charge separation (Fig. 184 Second, BFO thin films with periodic domain structures (both 71 o and 109 o domains), showed angular dependency of photocurrent on the incident light polarization. In the dark, a large electric field (~50 kV/cm) will be formed within the domain wall, and the potential step causes the offset of conduction band and valence band (Fig.…”