Abstract
Poly(vinyl alchohol)-starch/magnetite nanoparticles (PVA-St/MNPs) composite film blend with 12%wt. MNPs was fabricated and examined for optical and photoelectric properties. The optical energy gap and Urbach energy were found to be 2.1 eV and 0.55 eV, respectively, suggesting the presence of traps levels distributed in the energy gap. These results also showed that the recombination process could be considered bimolecular. The composite PVA-St/MNPs photo detector showed high photosensitivity in the visible range. The figures of merit were determined by laser light at 532 nm with different intensity levels. The responsivity, external quantum efficiency, and detectivity were found to be 0.36 A/W, 84.1%, and 8.48 x 1010 jones, respectively. These values were found to decrease with increasing laser intensity and applied voltage. The detector showed a fast response to light. The response times of growth and decay were found to be 120 and 154 ms, respectively.