This paper featured a study on undoped and Indium doped Gadolinium oxide Gd2O3: In thin films, elaborated on a glass substrates at temperature of 500 °C by homemade Spray Pyrolysis technique, at different Indium concentrations as follow 0, 2, 4, 6 and 8 at %. This thin layers, where a subjects to a numerous characterization techniques to study the effect caused by introducing the dopant element “Indium” in Gadolinium oxide lattice on the structural properties (X-Ray Diffraction and Raman spectroscopy) and optical properties. The structural characterization carried by the X-ray diffraction (XRD) reveals a polycrystalline Monoclinic B-type structure for all Gd2O3:In thin films. Moreover, these findings are verified by the Raman spectroscopy results. Concerning the optical properties of our thin films, the optical measurements carried by UV-VIS-NIR spectrophotometer shows an increase in the transmittance value within the visible region [370-900 nm] and in the band gap energy value by raising Indium doping rate from 0 at % to 6 at %, also the disorder caused inside the thin films were estimated by the Urbach equation. That said, the 2 at % Indium doped gadolinium oxide thin film provides interesting results that can be applied in solar cells as an optical window material.
Metal nanohole arrays are a famous example of plasmonic nanostructured materials, which are crucial plasmonic devices that display resonances and high electromagnetic confinement in the visible and near-infrared range. Therefore, they have been suggested for use in many applications, including communications and biosensing. In this work, we present the asymmetry in nanoholes and examine its impact on the electromagnetic response using numerical models and broadband experimental measurements. We fabricated a 2D hexagonal array of asymmetric nanoholes in Ag using a low-cost production method called nanosphere lithography combined with tilted silver evaporation. Our experimental setup is based on a laser with fine input and output polarization control that is broadly controllable in the near-infrared spectrum.When the nanohole array is activated with linear polarization, we next determine the circular polarization degree of the transmitted light. We explain the asymmetry of the nanohole, which is supported by numerical simulations, as the cause of the imbalance between left and right transmitted light. We propose that such straightforward plasmonic shape could be optimized to create multipurpose flat-optic devices.
Plasmonic nanostructured materials made of nanohole arrays in metal are signi cant plasmonic devices exhibiting resonances and strong electromagnetic con nement in the visible and near-infrared range. As such, they have been proposed for use in many applications such as biosensing and communications. In this work, we introduce the asymmetry in nanoholes, and investigate its in uence on the electromagnetic response by means of broadband experimental characterization and numerical simulations. As a lowcost fabrication process, we use nanosphere lithography, combined with tilted silver evaporation, to obtain a 2D hexagonal array of asymmetric nanoholes in Ag. Our experimental set-up is based on a laser, widely tunable in the near-infrared range, with precise polarization control in the input and in the output.We next resolve the circular polarization degree of the transmitted light when the nanohole array is excited with linear polarization. We attribute the disbalance of left and right transmitted light to the asymmetry of the nanohole, which we support by numerical simulations. We believe that the optimization of such simple plasmonic geometry could lead to multifunctional at-optic devices.
Nickel oxide (NiO) Thin film was successfully deposited on the glass substrate using an inexpensive spray pyrolysis (SP) technique. The structural, morphological, and optical properties have been studied, thus the electrochemical behavior of NiO film in Alkaline electrolytes has been investigated. The X-ray diffraction (XRD) analysis showed that NiO thin film exhibit a polycrystalline cubic rock-salt structure with a preferential orientation on the plane (111). This result was confirmed using Raman spectroscopy. The Scanning Electron Microscopy (SEM) images exhibit a smooth and dense surface without major cracks. Optical analysis shows an average transmission of about 55% in the visible light range, and the optical band gap energy was estimated by Tauc’s method and showed a value of 3,71 eV. Electrochemical properties as specific capacitance (Csp), optical density variation (ΔOD), and Coloration efficiency (CE) were studied using cyclic voltammetry in 1M KOH and 1M NaOH electrolytes. The results indicated that the behavior of the NiO layer in KOH is more effective than in NaOH electrolytes.
2D metasurfaces based on periodic nanoholes in metal have been proposed in various plasmonic platforms. Specifically, their resonant features have led to applications spanning in biosensing. Here we investigate additional degree of freedom in elliptical nanohole arrays with hexagonal geometry: chiro-optical effects. Namely, the in-plane asymmetry and a slightly elliptical shape of nanoholes were previously shown to differently extinct light of opposite handedness, even at normal incidence. We now fully characterize nanoholes in Ag, fabricated by low-cost nanosphere lithography. We first measure the dependence of the transmitted intensity for opposite handedness, in a broad spectral and angle of incidence range. We then resolve the circular polarization degree of the transmitted light when the nanohole array is excited with linear polarization. Finally, we numerically investigate the origin of the chiro-optical effect at the nanoscale. We believe that circular polarization resolving of the transmitted degree could be further adapted as a highly sensitive tool in chiral sensing.
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