Semiconductive Properties Of Metal Oxides

Electrical properties Figure. 8 shows the temperature dependence of resistivity of the Co(II), Ni(II) and Cu(II) complexes. As seen, the data reveal a semiconductor behavior where the resistivity decreases with the increases of temperature. The decrease of the electrical resistivity with increase of temperature is resulted from the increase of the charge carriers that can overcome the energy barrier and participate in the electrical conduction where in metal complexes, the metal atoms act as charge carriers reservoir supply the complex with the free electrons and the metal ion can act as a bridge to facilitate the flow of current. To illustrate the effect of the metal type on the electrical resistivity of the ligand, isothermal …show more content…
10 shows the  -T plots of the metal oxides (Co2O3, NiO and CuO) nanostructures. The data confirm that the materials have semiconductive features where the resistivity decreases dramatically as the temperature increases. However, there is a significant difference between the isothermal resistivity values of the oxides. To be specific, the room temperature resistivity of Co2O3, NiO, and CuO ( ρ_300^CoO,ρ_300^NiO and ρ_300^CuO) where determined to be 16.4, 2.3 and 1.1 Ω.cm . The semiconductor behavior of the samples under study is in well coincidence with the data published elsewhere [47-49]. In order to understand the electrical conduction mechanisms, various theoretical models were applied to the obtained experimental data. It was found that, the behavior of the resistivity variation with temperature fits well with Eq. 8.The well fit of the -T data to Eq. 8 is evidenced by the linear behavior of the Ln() vs. 1000/T plots shown in Figure. 11. The plots depicted in Figure. 11 allows to calculate the activation energies Ea which were found to be 0.098 and 0.12 for Co and Cu oxides, respectively. These values are comparable to those published in other literature [47]. Although the temperature dependence of the temperature of NiO nanoparticles exhibits typical semiconductor feature like the other oxides under study, the -T data don't fit well with Eq.9 where the accurate analyses confirm that the data are better represented by the following

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