Doping induced modifications in the electronic structure and magnetism of ZnO films: Valence band and conduction band studies

Katba, Savan; Jethva, Sadaf; Udeshi, Malay; Trivedi, Priyanka; Vagadia, Megha; Shukla, D. K.; Choudhary, R. J.; Phase, D. M.; Kuberkar, D. G.

doi:10.1016/j.apsusc.2017.06.139

Cited by 19 publications

(5 citation statements)

References 54 publications

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“…Substitutional incorporation of Fe 3+ ions at Zn 2+ sites leads to tetrahedral crystal field around Fe 3+ ions surrounded by O 2− ions. The first excited 4 G state of free d 5 ions splits into 4 T 1 , 4 T 2 , 4 E and 4 A 1 in the order of increasing energy under this crystal field effects. 17 The observed transitions are from the 6 A 1g ground state to 4 T 1 , 4 T 2, 4 E and 4 A 1 excited states.…”

Section: ■ Results and Discussionmentioning

confidence: 96%

Section: Introductionmentioning

confidence: 99%

“…It has been reported that long-range ferromagnetic ordering can occur by coupling Fe 2+ ions with intrinsic defects like oxygen vacancies. The ferromagnetism observed in Fe-doped ZnO is due to Fe ions (Fe 2+ and Fe 3+ states), which are tetrahedrally incorporated, 3,4 whereas Fe 3+ , which exists in octahedral sites, destabilizes the ferromagnetism. 5 Chen et al reported that the dominant valence state of the Fe ion is Fe 3+ and the configuration of these ions varies from octahedral to tetrahedral as the doping concentration increases.…”

Section: ■ Introductionmentioning

confidence: 99%

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Local Structural Studies Through EXAFS and Effect of Fe²⁺or Fe³⁺ Existence in ZnO Nanoparticles

et al. 2021

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A simple solution-based chemical precipitation method was used to synthesize the Fe-doped ZnO nanoparticles. X-ray Photoelectron Spectroscopy (XPS) measurement showed that mostly Fe2+ ions are incorporated in a lower percentage of Fe doping, while a higher percentage leads to Fe3+. The broad absorption band in the visible range shows the d–d crystal field transitions between the multiplets of 3d5 configuration of the high spin Fe3+ substituting Zn2+ under the influence of a tetrahedral ZnO crystal field. Raman measurement also supports the optical absorption data. ESR results show that the occurrence of broad signals is due to the exchange interactions among the TM ions in the doped samples. Fe exists in a mixed phase in Fe1 and the wide curve in Fe10 is due to the exchange interaction among Fe3+– Fe3+. EXAFS measurements confirm that the spectral features showing the peak edge position is similar to Fe2O3 corresponding to the Fe3+ state. From this, it can be inferred that Fe exists mostly in a +3 oxidation state in all the samples, but there may be existence of +2 states in the surface layers as observed from XPS measurement. Fe1 shows RTFM with a coercivity of ∼70 Oe. The non-saturating, linear magnetic moment at higher applied magnetic field is due to the paramagnetic contribution from the uncoupled Fe3+ ions.

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Section: ■ Results and Discussionmentioning

confidence: 96%

Section: Introductionmentioning

confidence: 99%

Section: ■ Introductionmentioning

confidence: 99%

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Local Structural Studies Through EXAFS and Effect of Fe²⁺or Fe³⁺ Existence in ZnO Nanoparticles

et al. 2021

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“…As a result, given the experimental setting, there is a significant possibility that MM will be observed at RT in association with V O . Moreover, the vacancy atom, defect pairs, and co-doped elements have demonstrated a considerable impact in MM [1,35,37,40,41]. In addition to point defects, oxygen may also be seen at the interstitial site in octahedral and tetrahedral configurations, with corresponding distances of around 1.95 Å and 2.63 Å, respectively.…”

Section: Resultsmentioning

confidence: 99%

A first principle +U correction to the investigation of intrinsic vacancy and zinc vacancy-cluster induced magnetism in w-ZnO

Ahmed,

Senthilkumar

2023

Phys. Scr.

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Pure ZnO shows the probable origin of the magnetic nature. Microscopic correlation to point defect VO and the cluster VZn is obtained by first-principle calculation and +U interaction energy of the p-d orbital subjected to improve band and DOS. Hydrogen contribution to the magnetic moment (MM) due to the coupling of vacancy and 1 s electron correlates with the experimental outcomes. Intrinsic vacancy modulates Fermi surface electron density, leading to the stoner criterion. A higher-order magnetic moment is associated with the cluster vacancy, and the change in the MM has accounted for the +U adjustment to the relevant orbital impact. Nonlinear relations are due to cluster vacancy complexes VZn-x/Oi-x (x = H, 2H), and the FM and AFM exchange has been analyzed. The material encloses large grains; hence, it is advantageous for VZn to develop near the grain edge, and in O-rich environments, chemisorbed O2 is formed near the grain surface.

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“…Recently theoretical and experimental studies agree that defect induced magnetization in ZnO is promoted by unpaired 2p electrons at O sites surrounding the V Zn and other authors describe the role of oxygen vacancies in the magnetic order . Particularly in Li et al the authors describe a strong correlation between the presence of V O and saturation magnetization.…”

Section: Introductionmentioning

confidence: 91%

Effect of Doping and Morphology on UV Emission in Low‐Dimensional ZnO:Na Structures

Straube

Bridoux

Zapata

et al. 2018

Physica Status Solidi (b)

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Band-edge photoluminescence of zinc oxide materials reveals a phononassisted ultraviolet emission enhanced by Na doping. We report the synthesis of ZnO and Na-doped ZnO, the changes in structure and optical properties as a function of doping concentration and synthesis temperature. The obtained samples are nanoneedles, microparticles, and microwires. The structural effect of Na doping is studied by X-ray diffraction and Raman spectroscopy. Room temperature photoluminescence reveals a contribution of band bending at the surface of the nanostructures, decreasing with Na concentration. Franz-Keldysh effect predicts strong electric field localized in the depletion region and appears to be the cause of red-shift in UV band emission of nanoneedles in comparison to microwires. Our results indicate that Na doping introduces an acceptor level between 150 and 200 meV above the valence band.

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Doping induced modifications in the electronic structure and magnetism of ZnO films: Valence band and conduction band studies

Cited by 19 publications

References 54 publications

Local Structural Studies Through EXAFS and Effect of Fe²⁺or Fe³⁺ Existence in ZnO Nanoparticles

Local Structural Studies Through EXAFS and Effect of Fe²⁺or Fe³⁺ Existence in ZnO Nanoparticles

A first principle +U correction to the investigation of intrinsic vacancy and zinc vacancy-cluster induced magnetism in w-ZnO

Effect of Doping and Morphology on UV Emission in Low‐Dimensional ZnO:Na Structures

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Doping induced modifications in the electronic structure and magnetism of ZnO films: Valence band and conduction band studies

Cited by 19 publications

References 54 publications

Local Structural Studies Through EXAFS and Effect of Fe2+or Fe3+ Existence in ZnO Nanoparticles

Local Structural Studies Through EXAFS and Effect of Fe2+or Fe3+ Existence in ZnO Nanoparticles

A first principle +U correction to the investigation of intrinsic vacancy and zinc vacancy-cluster induced magnetism in w-ZnO

Effect of Doping and Morphology on UV Emission in Low‐Dimensional ZnO:Na Structures

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Product

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Local Structural Studies Through EXAFS and Effect of Fe²⁺or Fe³⁺ Existence in ZnO Nanoparticles

Local Structural Studies Through EXAFS and Effect of Fe²⁺or Fe³⁺ Existence in ZnO Nanoparticles