This study presents the fabrication and magnetically tunable photoresponse behavior of p⁺-Si/CZFO/AZO and p⁺-Si/CZFDO/AZO trilayer heterostructures prepared by radio frequency magnetron sputtering. The structural, morphological, optical, and magnetic characteristics of Co0.7Zn0.3Fe2O4 (CZFO) and Dy3+ doped Co0.7Zn0.3Fe2O4 (CZFDO) spinel ferrite thin films were studied thoroughly. Photoresponse characteristics of the fabricated trilayer devices under broadband illumination (39.6 \(\:\text{m}\text{W}\) \(\:\text{c}\text{m}^{-2}\), 300–1100 \(\:\text{n}\text{m}\)) demonstrate that the CZFDO based photodetector exhibits nearly threefold higher photocurrent density (\(\:J\)), faster rise (\(\:{t}_{\text{R}\text{i}\text{s}\text{e}}\)) and decay times (\(\:{t}_{\text{F}\text{a}\text{l}\text{l}}\)), and greater responsivity \(\:\left(R\right)\) and specific detectivity (\(\:{D}^{*}\)) compared to the CZFO based device at + 5 \(\:\text{V}\) bias. The application of an external magnetic field (0 to 3000 \(\:\text{O}\text{e}\)) further enhances the photocurrent by promoting spin aligned carrier transport and reducing recombination losses, confirming magneto-photoelectric coupling. The values of \(\:R\), \(\:{t}_{\text{R}\text{i}\text{s}\text{e}}\), \(\:{t}_{\text{F}\text{a}\text{l}\text{l}}\), \(\:{D}^{*}\) also change significantly with the application of a magnetic field for both devices. The best obtained values of rise and fall times are \(\:40\) and \(\:52\:\text{m}\text{s}\) for the CZFDO based device at + 5 \(\:\text{V}\) bias and 3000 Oe field. Interestingly, both devices retain partial photocurrent even after removing the field. These heterostructure devices with high photocurrent to dark current ratios and fast switching action can play the role of magnetically tunable broadband photodetectors, suitable for potential applications in magneto-optoelectronic sensors and spintronic devices.
