Enhanced responsivity of Zr-doped BiFeO3 based self-powered UV–visible heterojunction photodetector fabricated via spray pyrolysis technique

Abstract

Herein, we report enhanced responsivity of Zr-substituted BiFeO3 thin film fabricated through spray pyrolysis technique in ultraviolet & visible region of the solar spectrum. Optimum substitution of Zr4+ ions at Fe site reduced the oxygen vacancies and optical bandgap from 2.3 eV to ∼2.08 eV. Both X-ray Diffraction and Raman results confirm that BiFe1-xZrxO3 (x = 0.0, 0.05, 0.10) films belong to rhombohedral phase. Besides, X-ray photoelectron spectroscopy and Electron paramagnetic resonance analysis confirms optimum substitution of Zr4+ ions reduce the leakage current and enhance the remnant polarization. The AZO/BiFe1-xZrxO3 (x = 0.0, 0.05, 0.10) interface junction confines the optical absorption within the ferroelectric layer, expands the space charge region and reduces charge carrier recombination. The PEDOT: PSS thin film deposited upon photoactive ferroelectric layer facilitates hole transport. The achieved maximum responsivity, detectivity, and response time of the AZO/BiFe0.95Zr0.05O3/PEDOT: PSS device for 365 nm (50 μW/cm2) light is 18 mA/W, 8.72 × 1010 Jones, and ∼0.2 s. The device responsivity for 100 mW/cm2 white light is 0.14 mA/W; and LEDs (10 mW/cm2) of wavelengths of 405 and 450 nm are 2.38 mA/W and 0.67 mA/W, respectively. This work confirms that optimum Zr substitution at Fe-site enhances the optoelectronic properties of BiFeO3 based UV–vis self-powered photodetector heterojunction.