Preparation of Nb2O5 nanoflakes by hydrothermal route for photodetection applications: The role of deposition time

The effect of the deposition time on the crystallinity, optical, electrical properties, morphology, and surface roughness of Nb2O5 nanoflakes (NFs) was studied. The deposition time was changed from 12 to 168 h under heating at 150 degrees C. The values of optical energy gap of the Nb2O5 films were in the range of (3.21-4.18 eV). Scanning electron microscope (SEM) results revealed that the diameter of NFs was in the range of (31-91) nm with the length of several microns depending on deposition time. We have found that the best properties of Nb2O5 NFs film prepared at deposition time of 72 h. The responsivity, quantum efficiency and specific detectivity of the Nb2O5/Si photodetector prepared 72 h were investigated. have been estimated and compared. A responsivity of 0.224 A/W at 400 nm was obtained for the photodetector fabricated at 72 h. The energy band diagram of Nb2O5 NFs/Si heterojunction photodetector under illumination was constructed.