High-performance self-powered ultraviolet photodetector based on bismuth layered perovskite Bi3.15Nd0.85Ti3O12 ferroelectric thin films

The photovoltaic effect of ferroelectric materials has been widely concerned. With the development of wearable technology and the requirements of device miniaturization, self-powered devices have been studying by more and more researchers. The photovoltaic effect of ferroelectric materials provides a possibility for self-powered photodetectors. Here, we have investigated the photovoltaic effect and the self-powered ultraviolet photodetecting properties in Pt/Bi3.15Nd0.85Ti3O12 (BNT)/Pt heterostructure. The Bi3.15Nd0.85Ti3O12 (BNT) thin films were prepared by sol–gel method on Pt/Ti/SiO2/Si substrate. XRD pattern and P-E loops shows that BNT films are polycrystalline with typical ferroelectric hysteresis. The BNT films shows obvious photovoltaic characteristics, with an open-circuit voltage VOC of 0.67 ± 0.04 V and a short-circuit current density JSC of 2.27 ± 0.08 μA/cm2 at the wavelength of 365 nm of a power of 77.50 mW/cm2. The zero bias transient photocurrent response under light ON and OFF states confirms the photodetecting ability of the heterolayered structure. The responsivity and the detection rate of the self-powered ultraviolet photodetector were calculated to be 0.047 ± 0.003 mA/W and (1.47 ± 0.04) × 109 Jones, respectively. The reversal photocurrent response mechanism of the Pt/BNT/Pt heterostructure has been clarified based on the driving internal electric field for the separation and transport of the photo-excited electron-hole pairs. The JSC dependance on the polarization direction reveals the electrical manipulation nature of the BNT based self-powered photodetectors, providing a novel route for the design of photodetectors based on ferroelectric oxides.