A photoconversion device was fabricated based on SnO2 film prepared by a chemical spray pyrolysis technique. The SnO2 nanofilms were grown on the porous silicon (PS) nanosurface. Various affecting parameters were studied such as different current densities 20, 30, 40, 50 and 60 mA/cm2 with 16% HF concentration for 10 min at a substrate temperature of 400 °C. The structural, morphological and detector properties were measured. X-ray diffraction (XRD) confirmed the formation of porous silicon and the crystal size was reduced toward the nanometric scale of the face centered cubic structure, while the diffraction peaks of other SnO2 peaks were found to be much weaker compared to standard SnO2NPs. The Atomic Force Microscope (AFM) investigation showed the sponge-like structure of PS, the width of surface pits and surface roughness increased to a specific value then decreased with etching current density. This could be attributed to the different filling process depending on the pore sizes and homogenous distribution of PS. From the found photodetector measurements, the spectral responsivity and quantum efficiency curves included two regions; the first region was due to the absorption of UV light by SnO2NPs. The second region corresponded to the visible light absorption with the PS layer and strongly depended on fabrication conditions.
Keywords Porous silicon SnO2 films Spray pyrolysis Photodetectors
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