Structural and optical properties of cobalt slanted nanopillars conformally coated with few-layer graphene

High permittivity polymer-ceramic nanocomposite dielectric films take advantage of the ease of flexibility in processing of polymers and the functionality of electroactive ceramic fillers. Hence, films like these may be applied to embedded energy storage devices for printed circuit electrical boards. However, the incompatibility of the hydrophilic ceramic filler and hydrophobic epoxy limit the filler concentration and therefore, dielectric permittivity of these materials. Traditionally, surfactants and core-shell processing of ceramic fillers are used to achieve electrostatic and steric stabilization for adequate ceramic particle distribution but, questions regarding these processes still remain. The purpose of this work is to understand the role of surfactant concentration ceramic particle surface morphology, and composite dielectric permittivity and conductivity. A comprehensive study of barium titanate-based epoxy nanocomposites was performed. Ethanol and 3-glycidyloxypropyltrimethoxysilan surface treatments were performed, where the best reduction in particle agglomeration, highest value of permittivity and the lowest value of loss were observed. The results demonstrate that optimization of coupling agent may lead to superior permittivity values and diminished losses that are ~2–3 times that of composites with non-optimized and traditional surfactant treatments.

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“…This can be further solved for the final Bruggeman's formula [65,66], which is shown as Equation (8).…”

Section: Of 26mentioning

confidence: 99%

Enhanced Dielectric Permittivity of Optimized Surface Modified of Barium Titanate Nanocomposites

2020

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“…The process of organic and inorganic layer attachment onto SCTFs is well characterized in previous work. 37,43,[46][47][48]91,92,94,96,97 From our previous results, we derive here a new sensitivity limit for laterally-resolved detection of surface mass density with our ACOM instrumentation. We then present a quantitative measurement of laterally-resolved surface mass density of titanium dioxide nanoparticles dispensed within predefined areas of a calibrated anisotropic filter.…”

Section: Resultsmentioning

confidence: 99%

“…86,87 A series of recent publications have reported on GSE investigations for a variety of SCTFs prepared from dielectric, semiconductor, metallic, and magnetic materials. 24,37,40,[89][90][91][92][93][94] C. Instrumentation calibration and operation Figure 6(a) depicts a flow chart for operation of the ACOM instrumentation. Initially, a wavelength is selected.…”

Section: B Anisotropic Filtermentioning

confidence: 99%

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Anisotropic contrast optical microscope

Peev

Hofmann

Kananizadeh

et al. 2016

Review of Scientific Instruments

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An optical microscope is described that reveals contrast in the Mueller matrix images of a thin, transparent, or semi-transparent specimen located within an anisotropic object plane (anisotropic filter). The specimen changes the anisotropy of the filter and thereby produces contrast within the Mueller matrix images. Here we use an anisotropic filter composed of a semi-transparent, nanostructured thin film with sub-wavelength thickness placed within the object plane. The sample is illuminated as in common optical microscopy but the light is modulated in its polarization using combinations of linear polarizers and phase plate (compensator) to control and analyze the state of polarization. Direct generalized ellipsometry data analysis approaches permit extraction of fundamental Mueller matrix object plane images dispensing with the need of Fourier expansion methods. Generalized ellipsometry model approaches are used for quantitative image analyses. These images are obtained from sets of multiple images obtained under various polarizer, analyzer, and compensator settings. Up to 16 independent Mueller matrix images can be obtained, while our current setup is limited to 11 images normalized by the unpolarized intensity. We demonstrate the anisotropic contrast optical microscope by measuring lithographically defined micro-patterned anisotropic filters, and we quantify the adsorption of an organic self-assembled monolayer film onto the anisotropic filter. Comparison with an isotropic glass slide demonstrates the image enhancement obtained by our method over microscopy without the use of an anisotropic filter. In our current instrument, we estimate the limit of detection for organic volumetric mass within the object plane of ≈49 fg within ≈7 × 7 μm object surface area. Compared to a quartz crystal microbalance with dissipation instrumentation, where contemporary limits require a total load of ≈500 pg for detection, the instrumentation demonstrated here improves sensitivity to a total mass required for detection by 4 orders of magnitude. We detail the design and operation principles of the anisotropic contrast optical microscope, and we present further applications to the detection of nanoparticles, to novel approaches for imaging chromatography and to new contrast modalities for observations on living cells.

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“…We further find that passivation of cobalt nanocolumns by an ultrathin conformal overlayer of alumina fully inhibits oxidation of the cobalt nanocolumns at normal ambient as well as during our annealing procedure similar to our previous results with conformal coating of a few layers of graphene. [15][16][17] Highly ordered, spatially coherent slanted columnar thin films (SCTFs) can be fabricated by glancing angle deposition (GLAD), which utilizes particle flux at oblique incidence angles. 18 These films exhibit extreme birefringence and dichroism properties that can be tailored by choice of deposition parameters.…”

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confidence: 99%

Anisotropy, band-to-band transitions, phonon modes, and oxidation properties of cobalt-oxide core-shell slanted columnar thin films

Mock

Korlacki

Briley

et al. 2016

Applied Physics Letters

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Structural and optical properties of cobalt slanted nanopillars conformally coated with few-layer graphene

Abstract: "Structural and optical properties of cobalt slanted nanopillars conformally coated with few-layer graphene" (2015). Faculty Publications --Chemistry Department. 86.

Cited by 8 publications

References 38 publications

Enhanced Dielectric Permittivity of Optimized Surface Modified of Barium Titanate Nanocomposites

Enhanced Dielectric Permittivity of Optimized Surface Modified of Barium Titanate Nanocomposites

Anisotropic contrast optical microscope

Anisotropy, band-to-band transitions, phonon modes, and oxidation properties of cobalt-oxide core-shell slanted columnar thin films

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