Impact of Cu doping on the structural, morphological and optical activity of V(2)O(5) nanorods for photodiode fabrication and their characteristics

In this paper, we report a wet chemical precipitation method used to synthesize pure and Cu-doped V(2)O(5) nanorods with different doping concentrations (Cu(x)V(2)O(5) where x = 3, 5 or 7 at%), followed by annealing at 600 °C and characterizations using several techniques. Indeed, a growth mechanism explaining the morphological evolution under the experimental conditions is also proposed. The XRD patterns revealed that all of the studied samples consist of a single V(2)O(5) phase and are well crystallized with a preferential orientation towards the (200) direction. The presence of intrinsic defects and internal stresses in the lattice structure of the Cu(x)V(2)O(5) samples has been substantiated by detailed analysis of the XRD. Apart from the doping level, there was an assessment of identical tiny peaks attributed to the formation of a secondary phase of CuO. SEM images confirmed the presence of agglomerated particles on the surface; the coverage increased with Cu doping level. XPS spectral analysis showed that Cu in the V(5+) matrix exists mainly in the Cu(2+) state on the surface. The appearance of satellite peaks in the Cu 2p spectra, however, provided definitive evidence for the presence of Cu(2+) ions in these studied samples as well. Doping-induced PL quenching was observed due to the absorption of energy from defect emission in the V(5+) lattice by Cu(2+) ions. We have proposed a cost-effective, less complicated but effective way of synthesizing pure and doped samples in colloidal form, deposited by the nebulizer spray technique on p-Si to establish junction diodes with enhanced optoelectronic properties.