Origin of the switchable photocurrent direction in BiFeO3 thin films
Journal article
Wang, Y., Daboczi, M., Zhang, M., Briscoe, J., Kim, J-S., Yan, H. and Dunn, S. (2023). Origin of the switchable photocurrent direction in BiFeO3 thin films. Materials Horizons. https://doi.org/10.1039/D3MH01510F
Authors | Wang, Y., Daboczi, M., Zhang, M., Briscoe, J., Kim, J-S., Yan, H. and Dunn, S. |
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Abstract | We report external bias driven switchable photocurrent (anodic and cathodic) in 2.3 eV indirect band gap perovskite (BiFeO3) photoactive thin films. Depending on the applied bias our BiFeO3 films exhibit photocurrents more usually found in p- or n-type semiconductor photoelectrodes. In order to understand the anomalous behaviour ambient photoemission spectroscopy and Kelvin-probe techniques have been used to determine the band structure of the BiFeO3. We found that the Fermi level (Ef) is at −4.96 eV (vs. vacuum) with a mid-gap at −4.93 eV (vs. vacuum). Our photochemically determined flat band potential (Efb) was found to be 0.3 V vs. NHE (−4.8 V vs. vacuum). These band positions indicate that Ef is close to mid-gap, and Efb is close to the equilibrium with the electrolyte enabling either cathodic or anodic band bending. We show an ability to control switching from n- to p-type behaviour through the application of external bias to the BiFeO3 thin film. This ability to control majority carrier dynamics at low applied bias opens a number of applications in novel optoelectronic switches, logic and energy conversion devices. |
Keywords | photochemistry ferroelectric bfo |
Year | 2023 |
Journal | Materials Horizons |
Publisher | Royal Society of Chemistry (RSC) |
ISSN | 2051-6355 |
Digital Object Identifier (DOI) | https://doi.org/10.1039/D3MH01510F |
Web address (URL) | https://pubs.rsc.org/en/content/articlelanding/2023/mh/d3mh01510f |
Publication dates | |
12 Oct 2023 | |
Publication process dates | |
Accepted | 11 Oct 2023 |
Deposited | 26 Oct 2023 |
Publisher's version | License File Access Level Open |
Accepted author manuscript | License File Access Level Controlled |
Supplemental file | File Access Level Restricted |
https://openresearch.lsbu.ac.uk/item/95587
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