Annealing-induced characterization of sputtered V2O5 thin films and Ag/ V2O5/p-Si heterojunctions

V2O5 thin films were deposited on glass and p-type silicon substrates by radio frequency (RF) sputtering of a single V2O5 target. Half of the samples were annealed at 500 degrees C at room ambient for an hour. The morphological, structural, and optical properties of the thin films were analyzed by atomic force microscopy (AFM), scanning electron microscopy (SEM), X-ray diffraction (XRD), and UV-Vis data. The results showed that while the asgrown V2O5 thin films had smooth surfaces with an amorph phase, annealed films had rougher surfaces with grains in the polycrystalline phase. It is also reported that the band gap of V2O5 thin films decreased from 2.47 to 2.37 eV. Furthermore, the electrical properties of Ag/V2O5/p-Si junctions were analyzed by current-voltage (I-V) measurements. It was presented that both Ag/V2O5/p-Si structures with as-grown and annealed V2O5 thin films had exciting rectifying behaviors. It was observed that while the barrier heights of the rectifying junctions were nearly the same, the ideality factor and series resistance values of the Ag/V2O5/p-Si device fabricated by annealed V2O5 thin film were higher than the device with as grown V2O5 thin film. Finally, the photoelectrical properties of both samples were analyzed by I-V under various light intensities. It was seen that both Ag/V2O5/pSi devices had exciting photosensing behavior. While the increase in reverse bias current values with the increase in light intensity was observed for both devices, it was seen that the device obtained by as-grown thin film had much more sensitivity to light.