Polarization driven self-biased and enhanced UV–visible photodetector characteristics of ferroelectric thin film

BiFeO₃ is a promising multifunctional material in terms of its intriguing physics and diverse application potential. In this work, self-powered UV–visible photodetector characteristics of the polycrystalline BiFeO₃ thin film exhibiting pronounced photo-response under both UV and visible light are demonstrated. Interestingly, the film displays switchable photodetector characteristics in accordance with the polarization switching properties and thereby confirms the role of polarization driven depolarization field on the observed properties. Importantly, the photodetector performance parameters such as responsivity $23.9\times {10}^{-4}\text{A}{\text{W}}^{-1}$, detectivity $(2.2\times {10}^{10}\text{Jones})$, photoconductive gain $(8.5\times {10}^{-3})$, and external quantum efficiency (5.3 %) observed under UV light are 2 to 4 order of magnitude higher than the values reported in similar oxide ferroelectric systems. These studies establish the application of polycrystalline BiFeO₃ film as a self-powered UV–visible photodetector. (paper)