Synthesis of copper-doped zinc ferrite thin films via electric field-enhanced spray pyrolysis for visible-light photodetection

In this work, copper-doped zinc ferrite CuxZn1−xFe2O4 thin films with x ranging from 0 to 0.09 were synthesized by electric-field-enhanced spray pyrolysis, a novel and successful technique for depositing this cubic-structured material system. The films’ structural, morphological, and optoelectronic properties were characterized in detail by X-ray diffraction (XRD), photoluminescence (PL) spectroscopy, field-emission scanning electron microscopy (FE-SEM) imaging, and current–voltage (I-V) measurements to assess their overall suitability as visible-light photodetectors. XRD analyses confirmed a polycrystalline cubic spinel structure. Blue-to-near-infrared emission peaks were observed in PL spectra, and shifts associated with variations in crystallite size and defect states were considered. I-V measurements confirmed improved photoconductivity under illumination, with the best performance at x = 0.05, showing the highest photosensitivity (50.6%) and responsivity (3.39×10−4 A/W). Although high doping caused agglomeration and cracking, FE-SEM images showed improved particle uniformity at lower copper concentrations. The films were better suited for detecting blue light, showing theirhighest sensitivity at 420 nm. By optimizing composition to improve performance, these results highlight the potential of Cu-doped zinc ferrite thin films for optoelectronic devices, particularly photodetection. This work also describes how copper doping enhances the structural and functional characteristics of spinel ferrites for advanced technological applications.