Influence of V2O5 concentration on structural and electrical transport properties of semiconducting ternary glass and glass-ceramics nanocomposite system

The effects of V ₂O ₅ concentration on semiconducting xV ₂O ₅–(1- x) (0.25Nd ₂O ₃–0.75ZnO) glass nanocomposites were investigated by structural, optical, and electrical conductivity studies. The composition dependency of physical attributes like density, molar volume, bond dissociation energy, number of bonds per unit volume, etc., was established. Using X-ray diffraction and field-emission scanning electron microscopy, we identified the presence of different nanocrystallites and amorphousness. DC electrical conductivity was caused by the small polaron hopping due to the presence of V ⁴⁺ and V ⁵⁺ valence states, enhanced as the small polaron radius was reduced with rising V ₂O ₅ concentration. The non-overlapping small polaron tunnelling (NSPT) model was the preferred AC conduction process, and reducing nature of tunnelling distance enhanced AC conductivity with increasing V ₂O ₅ concentration. We modified the existing NSPT model to get reasonable values for fitting parameters. The scaled AC conductivity spectra revealed temperature independence and the composition-dependent conductivity relaxation process of small polarons.