Electrical, photoluminescence and ferromagnetic characterization of pure and doped ZnO nanostructures

Sedky, A.; Amin, S. A.; Mohamed, Mansour

doi:10.1007/s00339-019-2612-y

“…It is also evident from Table 2 that ΔE = (Egh -Egl) is 0.58, 0.61, 0.58, 0.61and 0.61 eV for all samples, in which ΔE is constant. Anyhow, two Eg are also recorded for n-type semiconductors [113][114][115][116]. In that case, the doping of ZnO with Al may produce high carrier concentration and, as a result, more conduction band states are blocked, which causes an increase, which, in turn, causes an increment in Eg as obtained.…”

Section: 3-optical Measurementsmentioning

confidence: 86%

Structural, FTIR, optical and dielectric properties of Zn1-xAlxO ceramics for advanced applications

Sedky

¹

,

Ali

²

,

Algarni

³

2022

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We report here the structural, FTIR, optical and dielectric properties of Zn1-xAlxO with x = 00.00 < x < 0.20)). The wurtzite structure is conformed to all samples and the lattice constants, crystallite diameter, porosity and average crystalline size are generally decreased. The residual stress is compressive for pure samples, but it is changed to tensile for the doped samples. Interestingly, Debye temperature and elastic modulus are increased as x increases to 0.10, followed by a decrease at x = 0.20. Two different energy gaps Egh and Egl are apparent for each sample, corresponding of two transition absorption peaks. Interestingly, the ΔE = (Egh -Egl) ~ 0.60 for all samples. Further, the residual dielectric constant is decreased by increasing x to 0.10, followed by a sharp increase at x = 0.20 while the opposite behavior for (N/m * ). The dielectric constant ε′ is slightly increased as x increases to 0.025, followed by a sharp increase as x increases to 0.20, as well as the ac conductivity σ / . The conduction is electronic for x < 0.025 samples, but it is changed to hole with an increase of x to 0.20. The binding energy Wm was decreased as x increases to 0.20, but there is no exact trend against x for the behaviors of minimum hopping distance Rmin and density of localized states N. In addition, the density of states at Fermi level N (EF) has an optimum value at 195 KHz for all samples. The F-factor for solar cell design is increased as x increases to 0.10, but it is almost constant at x = 0.20. The Cole-Cole plot is a straight line for x = 0.00, a semicircle arc for x = 0.025 and a complete semicircle for x > 0.05. The impedance resistance of grain Z \ (g) and grain boundaries Z \ (gb) are gradually decreased by increasing x to 0.20. These outcomes indicate that the addition of Al to ZnO shifts the mechanical, optical, and dielectric medium to higher values, which is strongly recommended for the design of optoelectronic and solar cell instruments.

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“…Elastic properties can be correlated with thermodynamic properties of solids such as ZnO ceramic samples through Debye temperature θ D calculated using the relation [ 33 ]; where c is the velocity of light, is the average value of the waven umbers for the most identified absorption bands related to ZnO which are between (421.54–485.54 cm −1 ). Figure 7 shows the behavior of θ D against (Fe + M) content, and in which θ D are between (611.90–698.21 K) for all samples.…”

Section: Resultsmentioning

confidence: 99%

“…Hence, they can form a bound pair state (e–h) of finite binding energy. However, exciton energy, band gap energy, charge carrier concentration, dielectric lattice constant and inter-atomic distance can be determined from UV absorption analysis [ 33 ]. But unfortunately, further research still needed in order to take more advantage especially in case of ZnO co-doped by two different elements.…”

Section: Introductionmentioning

confidence: 99%

Structural, FTIR spectra and optical properties of pure and co-doped Zn1-x-yFexMyO ceramics with (M = Cu, Ni) for plastic deformation and optoelectronic applications

Naim

¹

,

Sedky

²

,

Afify

³

et al. 2021

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We report here a considered novel study on the structural, FTIR spectra and optical properties of pure and co-doped Zn 0.90- x Fe 0.1 M x O with ((M = Cu, Ni and ( x = 0.00, 0.10) and (0.00 < y < 0.20)) at different sintering temperatures T s ( T s = 850 °C for series I and 1000 °C series II). Although the ZnO wurtzite structure is conformed for all samples, some secondary lines with little intensity are formed. But the number of these lines is higher for series I than for series II. The ( c / a ) value and U -parameter are almost constant for all samples, while Zn–O bond length L is slightly increased. The porosity and crystallite size are decreased by Fe, and also for (Fe + Cu) samples, and their values for series I are lower than for series II. The residual stress is tensile for most samples. Interestingly, the Young’s, rigid and bulk modulus, Poisson’s ratio and Debye temperature, obtained from FTIR analysis, are increased by Fe addition with a further increase for Fe + Ni) samples for both series. A ductile nature is obtained for pure, Fe and (Fe + Cu) samples; whereas a brittle nature is approved for (Fe + Ni) samples. On the other hand, the energy gap ( E g ), residual lattice dielectric constant ( ε L ) and carrier density N are increased by Fe addition, followed by a further increase for (Fe + Cu) samples, while the vice is versa for the inter-atomic distance R . For example, E g was increased from 3.153 eV for pure ZnO to 3.974 eV for (Fe + Cu) samples (i.e., 0.821 eV more), while it was decreased to 2.851 eV for (Fe + Ni) samples (i.e., 0.302 eV less). A direct behavior is obtained between E g and both elastic modulus ( Y , β ), lattice and micro strains ( ε L , ε m ) , dislocation density ( δ ), residual stress ( σ ) and carrier density N, whereas a reverse behavior is obtained between E g and both crystallite size ( D ), porosity (PS) and inter-atomic distance ( R ) . These results are explained in terms of the generated blocked states of the conduction band as indicated by the Burstein Moss effect. These novel findings reveal that the co-doping has intense ZnO and moderate metal oxide modes in the ZnO matrix structure, which makes ZnO co-doped with (Fe + Cu) more suitable for gas sensors and optoel...

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“…improved by increasing T s for all samples, it is slightly decreased for Fe and (Fe + Cu) samples, but it is significantly increased for (Fe + Ni) samples. The density of carriers n is also calculated by; (σ 1 = neμ), and 100 cm 2 V −1 s −1 value was taken for the carrier mobility μ at 300 K, for simplicity [23,65]. It is evident from the behavior of n shown in On the other hand, the electrical conductivity of the upturn region σ L is calculated in terms of α and σ 1 as follows [19];…”

Section: Resultsmentioning

confidence: 99%

Structural morphology and nonlinear behavior of pure and co-doped Zn1-x-yFexMyO varistors with (M = Cu, Ni)

Naim

¹

,

Afify

²

,

Sedky

³

et al. 2021

Self Cite

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We report here structural morphology and nonlinear behavior of pure and co-doped Zn 0.90-x Fe 0.1 M x O with (M = Cu, Ni and ( x = 0.00, 0.10) and (0.00 ≤ y ≤ 0.20)) at different sintering temperatures ( T s = 850 and 1000 °C). It is found that the co-doping of ZnO by (Fe + Cu) or (Fe + Ni) up to 0.30 does not deform the well-known wurtzite structure of ZnO, as well as pure and 0.1 of Fe-doped ZnO. The SEM micrographs did not show any secondary phases at the boundaries of grains as compared to ZnO, the average grain size is decreased for Fe and (Fe + Cu) samples, while it is increased for (Fe + Ni) samples. The nonlinear coefficient α and breakdown field E B are generally increased by 0.1 of Fe addition, but they are shifted to lower values as T s increases for all samples. Furthermore, they are gradually increased/decreased to higher/lower values for (Fe + Cu/Fe + Ni) samples up to 0.30 of co-doping content. The values of α and E B are increased from 30.06, 2115.38 V/cm for ZnO at 850 °C to 50.07, 5012 V/cm by (0.1Fe + 0.2Cu) co-doping, and from 23.53, 1956.52 V/cm to 45.58, 4750 V/cm at 1000 °C, while they are, respectively, decreased by (0.1Fe + 0.2Ni) to 13.19, 312 V/cm and 11.85, 172.42 V/cm. Similar behavior was generally obtained for nonlinear conductivity σ L and height of potential barrier φ B , whereas the vice is versa for the behavior of leakage current J k and residual voltage K r . Our results are discussed in terms of the comparative participation between the effects of co-doping of (Fe + Cu) and (Fe + Ni) to ZnO for supporting the potential barrier as compared to individual doping by Fe, Cu and Ni. This study perhaps recommended these samples for optoelectronic and ferromagnetic investigation after COVID-19 is over.

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Electrical, photoluminescence and ferromagnetic characterization of pure and doped ZnO nanostructures

Cited by 31 publications

References 89 publications

Structural, FTIR, optical and dielectric properties of Zn1-xAlxO ceramics for advanced applications

Structural, FTIR, optical and dielectric properties of Zn1-xAlxO ceramics for advanced applications

Structural, FTIR spectra and optical properties of pure and co-doped Zn1-x-yFexMyO ceramics with (M = Cu, Ni) for plastic deformation and optoelectronic applications

Structural morphology and nonlinear behavior of pure and co-doped Zn1-x-yFexMyO varistors with (M = Cu, Ni)

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