Structural and electrical properties of sol–gel grown Zn0.95Mn0.05O nanoparticles

Abstract

The structural and electrical properties of the synthesized Mn–doped ZnO–based sample were systematically investigated. X–ray diffraction (XRD) analysis confirmed the formation of a single–phase polycrystalline wurtzite structure, indicating high crystallinity and phase purity. Temperature–dependent measurements revealed that the refractive index and maximum barrier height decrease with increasing temperature, suggesting enhanced carrier mobility at elevated temperatures. DC resistivity was measured under varying applied currents (0.2 mA, 1 mA, and 5 mA), showing a strong dependence on both temperature and current. To analyze the conduction mechanism, the resistivity data were fitted using a combined Variable Range Hopping (VRH) and Small Polaron Conduction (SPC) model. Activation energies extracted from the fitting indicate that VRH governs long–range hopping between localized states, whereas SPC represents nearest–neighbor polaron hopping. Both activation energies decrease with increasing current, reflecting facilitated carrier transport under higher applied fields. The combined VRH + SPC model accurately describes the DC resistivity behavior of the samples, confirming thermally activated current–dependent conduction.