Cerium-Doped Bi₂S₃ Thin Films Fabricated by Nebulizer-Assisted Spray Pyrolysis Method for Photodetector Applications

In this study, the performances of highly sensitive Ce-doped Bi₂S₃ thin film-based photodetectors is discussed. The Bi₂S₃:Ce thin films were successfully coated by using the nebulizer spray pyrolysis method on glass substrates with varying Ce concentrations of 0%, 2%, 4%, 6%, and 8%. Furthermore, the physical properties such as crystalline size, morphology and optical response of Bi₂S₃:Ce thin films were investigated through x-ray diffraction (XRD), field-emission scanning electron microscopy (FESEM), atomic force microscopy, optical absorption spectrophotometry, and photoluminescence spectroscopy (PL). The XRD study showed that 4% Ce-doped Bi₂S₃ film shows higher crystallinity. UV–visible studies showed that the absorption spectrum has a direct electronic transition with an energy gap of about 1.68 eV. The morphological studies revealed that the Bi₂S₃:Ce samples showed uniformly distributed nanoflakes. The 4% Ce-doped Bi₂S₃ film photodetector exhibited high responsivity (R) and detectivity (D*) and showed a fast photoresponse for about 5 s and 2.6 s with the external quantum efficiency (EQE) of 435%, which makes it highly suitable as a high-performance photodetector. Graphical Abstract: [Figure not available: see fulltext.]