Single-step Zno nanorod bunches formation on p-type Si-conductive substrates by electrophoretic deposition

Real, Silvina; Espíndola, Omar; Zelaya, María Priscila; Marin, Oscar; Comedi, D.; Tirado, Mónica

doi:10.1016/j.surfin.2021.100930

Cited by 3 publications

(2 citation statements)

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“…The x-intercept value represented the band gap energy which was equal to 3.54 eV while the band gap values for bulk ZnO range between 3.3-3.4 eV [39]. A similar band gap shift was observed in the c-axis oriented self-assembled ZnO nanorods prepared by Real et al using electrophoretic deposition technique [40]. The size-dependent shift in band gap energy is more prominent when the particle size reaches the limit of exciton Bohr radius (r b ) which is the distance between a pair of bound electron and hole.…”

Section: Quantum Confinement In Colloidal Zno Nanoclusterssupporting

confidence: 60%

Template-free self-assembly of mesoporous ZnO nanocluster/ polymethyl methacrylate based anisotropic nanocomposite thin films with enhanced interfacial interactions and tuneable optical properties

Awasthi

Mohan

Singh

2023

J. Phys. D: Appl. Phys.

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Nature-inspired biomimetic growth of anisotropic, hierarchical nanostructures could offer insight into new and exciting crystalline properties for advanced multifunctional applications. Our study demonstrates diethanolamine-mediated mesoscopic self-assembly of semiconducting ZnO Quantum Dots (3-5 nm) into lattice-aligned, symmetrical nanoclusters (40-50 nm) via non-classical Oriented Attachment crystal growth observed in various biomineralization processes. Multifunctional nanocomposite thin films of self-assembled nanostructures and polymethyl methacrylate were spin-coated onto plasma-treated Si wafers and the surface and interfacial properties were rigorously studied. HR-TEM images depicted the oriented attachment growth process with neighboring nano-crystals having perfectly aligned lattices. Preferential orientation of the thin films along <100> direction was evident from the XRD data. Quantum confinement in ZnO QDs and surface defect originating sharp green PL emission were examined through UV-Vis absorption and Photoluminescence spectra respectively. DLS and Zeta potential studies of surface-engineered colloidal nanoclusters established excellent long-term physico-chemical stability with no agglomeration or transparency loss observed in ZnO mesocrystal suspension even after 6 months. Diethanolamine, due to its dual functionality radically enhanced the interaction between polar ZnO and non-polar PMMA matrix resulting in highly stable thin films (Class II hybrids) with enhanced surface and interfacial properties as evident from the extremely low surface roughness and homogenous nanofiller dispersion observed in AFM and FE-SEM studies. Chemical interactions at the interface were also established quantitatively by XPS binding energy measurements which suggested hydrogen bonds and covalent bonds between organic-inorganic phases promoted via diethanolamine surface engineering.

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Section: Quantum Confinement In Colloidal Zno Nanoclusterssupporting

confidence: 60%

Template-free self-assembly of mesoporous ZnO nanocluster/ polymethyl methacrylate based anisotropic nanocomposite thin films with enhanced interfacial interactions and tuneable optical properties

Awasthi

Mohan

Singh

2023

J. Phys. D: Appl. Phys.

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“…[42] Several publications consider that the visible emission is due to luminescent defect centers with states in the ZnO bandgap (defect band), [43] and surface defect states. [44] Although there is enough theoretical and experimental evidence supporting that the visible emissions originate from radiative recombination processes involving band to or from defect state transitions, the specific microscopic origin of each component to the visible emission band is still under discussion. In our measurements, we observe the results of a three-Gaussian fit to the visible bands emitted from the samples.…”

Section: Photoluminescencementioning

confidence: 99%

Magnetotransport Properties of Microstructured ZnO Thin Films Grown on a‐ and r‐Plane Sapphire Substrates

Barzola‐Quiquia¹,

Zelaya

Espíndola

et al. 2023

Physica Status Solidi (b)

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The transparent semiconductor ZnO has attracted substantial interest in the research community because of its potential applications as a transparent thin film, [1][2][3] transistor, [4][5][6] optoelectronic devices, [7][8][9] light-emitting diode, [10,11] among others. Another promising, non-inherent property is its roomtemperature ferromagnetism, which was first theoretically predicted to occur through doping with transition magnetic ions such as Fe, Co, or Ni. [12] However, many experimental studies revealed that the observed magnetic order is not related to the doping but certain defects. [13][14][15][16][17] A ferromagnetic ZnO, free of d-elements, opens new opportunities for applications in spintronics. The origin of the defect-induced magnetism (DIM) in defective ZnO samples is not always simple to explain, especially in samples where defects are introduced during the preparation of the samples, like Zn-or O-vacancies [15] or grain boundaries. [18] In these cases, the reproducibility of the magnetic order is low. Also, usual experimental techniques, such as SQUID (superconducting quantum interface device) magnetometry, cannot simply distinguish between defect-induced magnetic signals and those from other sources, like magnetic impurities on the samples or substrates. [19] However, recent theoretical and experimental studies using element-specific magnetic probes like X-ray magnetic circular dichroism (XMCD) in X-ray absorption spectroscopy [20] strongly suggest that Zn vacancies are the primary origin for the observed magnetic order in this compound. Oxygen vacancies, present in a more significant concentration than Zn vacancies, do not substantially contribute to the magnetic order due to their much smaller magnetic moment.Due to the low mass of thin films and weak magnetic signals (compared to the substrate), standard SQUID magnetometers are not the best choice for the magnetic characterization of ZnO thin films. Accounting for the influence of substrates by performing electrical transport measurements with an applied magnetic field is helpful. The measurement of the magnetoresistance (MR) and Hall effect (HE) [21] are powerful tools to explore the magnetic properties of conducting materials. In the case of MR, the sign of ferromagnetism is the opening of a butterfly-like hysteresis around zero field with extremes at fields corresponding to the coercive fields (H C ). When considering the HE, the appearance of an anomalous nonlinear contribution at low fields, in addition to the opening of a hysteresis with sign changes at fields corresponding to the coercive field, would be the case. We notice, however, that the field hysteresis depends on the coercive field of the investigated sample. Because H C is relatively weak in magnetic ZnO samples, that is, μ 0 Â H C ≤ 0.1 T, [15] high resolution is necessary to measure the hysteresis around zero field in the MR or HE. In general, with the field and temperature dependence of electrical-transport properties, it is possible to

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Ab Initio Modelling of g-ZnO Deposition on the Si (111) Surface

Alzhanova,

Mastrikov,

Yerezhep

2024

J. Compos. Sci.

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Recent studies show that zinc oxide (ZnO) nanostructures have promising potential as an absorbing material. In order to improve the optoelectronic properties of the initial system, this paper considers the process of adsorbing multilayer graphene-like ZnO onto a Si (111) surface. The density of electron states for two- and three-layer graphene-like zinc oxide on the Si (111) surface was obtained using the Vienna ab-initio simulation package by the DFT method. A computer model of graphene-like Zinc oxide on a Si (111)-surface was created using the DFT+U approach. One-, two- and three-plane-thick graphene-zinc oxide were deposited on the substrate. An isolated cluster of Zn3O3 was also considered. The compatibility of g-ZnO with the S (100) substrate was tested, and the energetics of deposition were calculated. This study demonstrates that, regardless of the possible configuration of the adsorbing layers, the Si/ZnO structure remains stable at the interface. Calculations indicate that, in combination with lower formation energies, wurtzite-type structures turn out to be more stable and, compared to sphalerite-type structures, wurtzite-type structures form longer interlayers and shorter interplanar distances. It has been shown that during the deposition of the third layer, the growth of a wurtzite-type structure becomes exothermic. Thus, these findings suggest a predictable relationship between the application method and the number of layers, implying that the synthesis process can be modified. Consequently, we believe that such interfaces can be obtained through experimental synthesis.

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Single-step Zno nanorod bunches formation on p-type Si-conductive substrates by electrophoretic deposition

Cited by 3 publications

References 57 publications

Template-free self-assembly of mesoporous ZnO nanocluster/ polymethyl methacrylate based anisotropic nanocomposite thin films with enhanced interfacial interactions and tuneable optical properties

Template-free self-assembly of mesoporous ZnO nanocluster/ polymethyl methacrylate based anisotropic nanocomposite thin films with enhanced interfacial interactions and tuneable optical properties

Magnetotransport Properties of Microstructured ZnO Thin Films Grown on a‐ and r‐Plane Sapphire Substrates

Ab Initio Modelling of g-ZnO Deposition on the Si (111) Surface

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