Structural, optical, photoluminescence and magnetic investigation of doped and Co-doped ZnO nanoparticles

Abstract

Abstract We report here the structural, optical, photoluminescence (PL), and magnetic investigation of Zn 1−x−y Fe x M y O nanoparticles. The lattice constants and crystallite size are decreased by Fe, followed by a further decrease up to (Fe + M) = 0.30. A compressive stress is approved and the size of particle is between 180 and 277 nm and follows the sample order of ZnO, (Fe + Cu), (Fe + Ni), and Fe. Although a single value of energy gap (E g ) is found for pure and Fe-doped ZnO, two values of E g (E gh and E gl ) are found for the co-doped samples. The E g is generally increased by Fe, followed by a further increase for the Cu-series, whereas it is decreased for the Ni-series. The refractive indices n K and n T proposed by different methods are generally decreased by Fe, followed by a further decrease for both series. Although Fe doped ZnO depressed the density of carriers (N/m*), it increased again for the co-doped samples. The residual dielectric constant ϵ L is decreased by Fe, followed by an increase for the Cu-series, but it is decreased for the Ni-series. The loss factor tan δ increases slightly with Fe, followed by an increase for the Ni-series, but it decreases in the Cu-series. A significant depression of optical conductivity σ opt by Fe was obtained, followed by a further decrease which is higher for the Cu-series. The PL shows four visible emissions. Interestingly, an IR emission at about 825 nm is only obtained for the co-doped samples. Furthermore, the blue emission (I blue ) was higher than UV (I UV ), [(I blue /I UV ) > 1], but it is greater for the Ni series than the Cu. Although ZnO exhibits diamagnetic behavior, the Fe and co-doped samples exhibit ferromagnetic with higher magnetization for the Ni-series than the Cu. The current results recommend the co-doped samples in nanoscale for some of advanced devices.

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