Effect of heavy metal and alkaline earth oxides on the optical and electrical mechanism of vanadium-phosphate amorphous glassy systems

Abstract

In the current work, the collective effects of the doping of heavy metal oxide (Bi2O3) and alkaline metal oxide (BaO) into the host glassy network having chemical formula xBi2O3-(0.4-x)BaO-0.3V2O5–0.3P2O5 (x = 0.05, 0.15, 025, and 0.35) are studied systematically. The X-ray diffraction reveals the amorphous nature of the composites under study. Physical properties like density and molar volume have been investigated and correlated with structural modifications. The findings of Tauc's plot have confirmed the increment in optical band gap energies from 2.81 eV to 3.51 eV and correlated with the decrement of Urbach energy values. Some spectroscopic parameters like refractive index, reflectivity, reflection factor, and non-linear refractive index have been examined and interpreted accordingly. The mechanism is accountable for AC conductivity has been inspected using Almond–West formalism and Jonscher's universal power law, revealing semiconducting features. The small polaron hopping route with various activation energies at numerous temperature ranges causes non-linearity in DC conductivity in all of the studied samples.