Influence of plasmon resonance on the luminescence of titanium dioxide thin films doped with rare earth ions

In this work the study of the optical properties of europium doped titanium dioxide thin films (TiO2:Eu) enhanced by gold plasmonic nanostructures are presented. Plasmonic platforms were manufactured by thermal annealing of thin film of Au, deposited on a Corning glass substrate. As a result of thermal treatment, gold spherical nanostructures with average dimensions of 50 nm were obtained. Luminescent TiO2:Eu film was deposited by RF magnetron sputtering method, from mosaic target. Morphology of gold nanostructures was investigated by SEM and TEM microscopes, while composition of oxides film was analysed by XPS methods. Luminescence properties were studied on the basis of excitation and emission spectra. Experiments have shown that such structures exhibit interesting luminescent properties and could be potential candidates for optoelectronics applications.

Quantum Confinement Effects of Thin Co3O4 Films

Thin Co films were deposited on quartz and Corning glass by radio frequency magnetron sputtering. The films were postannealed at 500 °C in a furnace in air atmosphere. The resulting samples were examined with X-ray diffraction experiments, which revealed that they consist of single-phase, polycrystalline Co3O4. The morphology of selected samples was recorded by atomic force microscopy. Ultraviolet-visible light absorption spectroscopy experiments probed the absorbance of the films in the wavelength range 200–1,100 nm. Two types of transitions (energy gaps) were clearly identified. Both of them were found to be “blue shifted” with decreasing film thickness; this is interpreted as evidence of quantum confinement effects. For the case of the first gap value, this was corroborated by calculations based on a combination of the Potential Morphing Method and the effective mass approximation.

On the Localized Surface Plasmonic Resonances of AgPd Alloy Nanoparticles by Experiment and Theory

Ag/Pd multilayers and AgPd alloyed ultrathin films were deposited on Corning glass by magnetron sputtering. After being annealed in a furnace in air at 460 °C, self-assembled nanoparticles were formed. Localized surface plasmon resonances were observed only for the Ag-rich samples in the full range of the visible light spectrum. The resonance position was found to depend on the initial film thickness. In order to gain further physical insight, rigorous theoretical calculations were carried out via the rigid coupled-wave analysis method for the entire compositional range between Ag and Pd. Theoretical calculations were proven to be in suitable agreement with the experimental results.

Optical Communications: The Beginning

The first efforts by Alexander Graham Bell at optical communications by incoherent light are discussed. Those were very inefficient at the time but after the invention of the laser it was only a question of time when coherent optical communication will dominate the communications scene The beginning was slow because propagation both in air and in fibre waveguide was too large. Enormous efforts by the Corning Glass Works brought down the attenuation to a figure as low as a few dbs per kilometre making some further applications feasible. The next break-through was the invention of the fibre amplifier enabling the erection of long relay-free lines (maybe up to 10,000 km) possible range of applications was greatly extended by the invention of the fibre amplifier. Coherent light propagation in thin, single-mode fibres is discussed a very thin fibre is discussed. It is shown that an optical fibre can carry an enormous number of communication channels. The laser was invented just in time to help produce the signals, and it also became possible to produce pure enough glass fibres in which an optical signal could propagate with low attenuation. The invention of erbium-doped fibre amplifiers allowed them to be spread all over the world, including large number of lines under the oceans.

Optical interpretation for plasmonic adjustment of nanostructured Ag-NiO thin films

Ultrathin Ag and Ni/NiO films are sequentially produced on Corning glass and silicon substrates by means of magnetron sputtering. Post annealing treatment in a furnace with air at [Formula: see text]C and [Formula: see text]C may lead to the formation of Ag nanostructures in NiO environment. Some of these samples present local surface plasmon resonances (SPRs). The sequence in which each layer is deposited, as well as, the state of the structure on which the layer is deposited, appears to play a pivotal role in the optical properties of these nanostructures, which are attributed to the growth properties of the nanocomposite thin films. Ultimately, rigorous theoretical calculations have been made for comparison and discussion with the experimental results.

Fabrication of Transparent Superhydrophobic Surface from ZnO Nanorods

A transparent superhydrophobic surface was fabricated from ZnO nanorods grown on Si and glass substrates in a thermal furnace for industrial applications such as surface coating. Two types of glasses were used for the substrates: slide glass and Corning glass. The ZnO nanorods were then coated with PTFE using existing sputtering technology and then grown on the glasses. The optical transparency and processing temperature of the nanorods on the substrates with and without a ZnO buffer layer were investigated, for comparison. The superhydrophobic surface formed on Corning glass with a 50-nm-thick ZnO buffer layer exhibited a transparency of 80% or higher and a water contact angle of 150° or higher in the visible light region. High optical transmittance of the superhydrophobic surface was achieved by controlling the size and growth direction of the nanorods. X-ray diffraction and scanning electron microscopy images showed that the nanorods on the glass substrates were thicker than those on Si, and the nanorods predominantly grew in the vertical direction on the buffer layer. However, the growth direction did not affect the wettability of the surface. Vertically grown nanorods can still affect optical transmittance because they facilitate the propagation of light. In the case of Corning glass, superhydrophobic surfaces with contact angles of 150° and 152.3° were formed on both samples with buffer layers of 50 nm and 100 nm, respectively. Therefore, a buffer layer thickness in the range of 50–100 nm is suitable for realizing a transparent superhydrophobic surface on a glass substrate.

Modification of Nanocrystalline Porous Cu2−xSe Films during Argon Plasma Treatment

Cu2−xSe films were deposited on Corning glass substrates by radio frequency (RF) magnetron sputtering and annealed at 300 °C for 20 min under N2 gas ambient. The films had a thickness of 850–870 nm and a chemical composition of Cu1.75Se. The initial structure of the films was nanocrystalline with a complex architecture and pores. The investigated films were plasma treated with RF (13.56 MHz) high-density low-pressure inductively coupled argon plasma. The plasma treatment was conducted at average ion energies of 25 and 200 eV for durations of 30, 60, and 90 s. Notably, changes are evident in the surface morphology, and the chemical composition of the films changed from x = 0.25 to x = 0.10 to x = 0.00, respectively, after plasma treatment at average ion energies of 25 and 200 eV, respectively.

Fabrication and characterization of Yb-doped Y2O3 powders and thin films

Yttrium oxide (Y2O3) and ytterbium (Yb)-doped Y2O3 particles were synthesized via the sol-gel method from the aqueous solution of their nitrate salts. The synthesized powders were then deposited on Corning glass substrates using an electron beam evaporation technique to examine the growth morphology of the thin films. The effect of the Yb dopant concentration on the microstructure and morphology of the Y2O3 powders and thin films was investigated using various characterization techniques. The synthesized powders and fabricated thin films have body-centered cubic structures with space group Ia-3. Based on the X-ray peak broadening, crystallite size and lattice parameters were evaluated with the Williamsom-Hall and Cohen-Wagner methods. The lattice parameter and crystallite size decrease with increasing Yb concentration. The intensities of the Raman peaks decrease due to microstructural disorder caused by the increase in the Yb dopant concentration. The band gap values of the powders also decrease depending on the dopant concentration, similar to the lattice parameter and crystallite size. While the synthesized powders have a sponge-like morphology, they exhibit different morphological structures depending on the dopant concentration when converted into thin films.