Harnessing the synergistic effect of CuO@Fe3O4/n-Si for high-efficiency photodiodes

High-performance photodetectors were fabricated using drop-casting method, employing pure CuO, Fe₃O₄ and CuO@Fe₃O₄ nanocomposite (NC). These devices aim to achieve enhanced responsivity (R), photosensitivity (P_s), detectivity (D∗), and external quantum efficiency (EQE). The XRD results indicate that the crystallite size of the CuO@Fe₃O₄ NC was reduced to around 20 nm, compared to 23 nm for pure CuO and 25 nm for pure Fe₃O₄. In addition, phase purity and functional groups were corroborated by Raman and FTIR analysis, supporting these findings. The bandgap energy of pure CuO and Fe₃O₄ was estimated to be around 1.25 and 1.22 eV, respectively, while the CuO@Fe₃O₄ NC exhibited a lower bandgap energy of 1.13 eV due to the interface between CuO and Fe₃O₄. Notably, the fabricated CuO@Fe₃O₄/n-Si photodiode exhibited excellent rectification properties under illumination, with an ideality factor (n) of 2.87 and a barrier height (Φ_B) of 0.83 eV. The device achieved high P_s of 773.4 %, R of 542.6 mA/W, EQE of 208.7 %, and D∗ of 2.91 × 10¹² Jones, demonstrating that the CuO@Fe₃O₄ NC is the most effective material for photodetection in this study.