Single polaron hopping in Fe doped glassy semiconductors: Structure-electrical transport relationship

The development of glassy nanocomposites, xFe-(1-x) (0.5 V2O5-0.4 CdO-0.1 ZnO) is particularly important not only for exploring their microstructures using x-ray diffraction, FT-IR, and UV-Vis techniques but also for exploring their electrical conduction mechanism in terms of hopping of small polarons. The presence of various nanophases, such as ZnO, CdO, Cd9.5Zn0.5, ZnV, and Zn3V2O8, have been identified and the size of estimated nanocrystallites is found to decrease with more incorporation of the Fe content in the compositions. As the value of lattice strain increases with the increase of the Fe content in the compositions, the present system becomes more and more unstable, which may be favorable for better electrical transport phenomena via the polaron hopping process. Electrical conductivity of the system has been analyzed using modified correlated barrier hopping model, Almond-West formalism, and the alternating-current conductivity scaling. Experimental data reveal that both optical photon and acoustical phonon transitions are responsible for the entire electrical conduction process. Polaron hopping is expected to be of percolation type, which has been validated from an estimated range of frequency exponents. All experimental data have been used to frame a schematic model to explore the conduction mechanism inside the present glassy system. Published under an exclusive license by AIP Publishing.

Automated summary

The development of glassy nanocomposites and the exploration of their microstructures and electrical conduction mechanism are of great importance. The presence of various nanophases and the decrease in nanocrystallite size with increased Fe content were observed. The increase in lattice strain due to Fe content resulted in an unstable system, favorable for electrical transport through polaron hopping. The study analyzed the electrical conductivity using different models and determined that both optical photon and acoustical phonon transitions contribute to the conduction process. A schematic model was proposed to explain the conduction mechanism in the glassy system.