Enhanced responsivity of Fe3O4 nanoparticles/porous silicon heterojunction photodetectors
摘要
In this work, Fe3O4 nanoparticles-embedded porous silicon heterojunction photodetectors were fabricated and their characteristics were introduced and analyzed. The Fe3O4 nanoparticles were prepared by DC reactive sputtering technique, while the porous silicon was prepared by laser-assisted electro-chemical etching (LAECE) method. The Fe3O4 nanoparticles showed direct and indirect energy band gaps of 3.35 eV and 2.2 eV, respectively, crystalline structure and cubic morphology, suggesting a well-defined crystalline structure. The electrical characteristics of the fabricated heterojunctions were studied under dark and illumination conditions and the ideality factor values were 1.47 and 1.32 for devices fabricated with Fe3O4 film thickness of 184 nm and 369 nm, respectively. The maximum photosensitivity achieved was 17.1 for the photodetector with a 184 nm Fe3O4 film. This photodetector demonstrated 0.357 A/W spectral responsivity, 98.4% external quantum efficiency, 9.63 × 10¹⁰ Jones specific detectivity, and a noise equivalent power of 3.65 pW at 450 nm. The photodynamic response revealed rise/fall times of 0.29 s/0.29 s for the 184 nm Fe3O4 film and 0.27 s/0.28 s for the 369 nm film.