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To investigate the thermal effect of the titanium (Ti) adhesion layer on the evolution of structure and properties of platinum (Pt) films, Pt films with different thicknesses of Ti adhesion layers were prepared using magnetron sputtering followed by vacuum heating. Results show that Ti particles diffused into the Pt film, and the level of Ti content on the surface is positively correlated with the proportion of Ti layer thickness. After high temperature annealing, particle agglomeration and recrystallisation of pure Pt films are intensified. Introduction of Ti adhesion layer can inhibit dewetting. With the increase of heat temperature, the enhanced atomic mobility leads to the intensification of Ti diffusion, and the alloying with Pt occurs more fully. The dominant phase in the film gradually changes from Pt to Pt 8 Ti and then Pt 3 Ti phase. Although the formation of intermetallic compounds leads to a gradual increase of the electrical resistivity, the introduction of Ti layer can greatly improve the adhesion force of the film and the substrate. In addition, due to that the Pt layer on the Ti layer can relieve some of the tensile stresses through deformation, the addition of the Ti layer can decrease the residual stress of the film. • Thermal effect of Ti on structure and properties evolution of Pt films was studied. • Ti adhesion layer can inhibit dewetting, reduce agglomeration and slow recrystal. • Alloying process of Ti with Pt occurs in thermal treatment conditions. • Diffusion and alloying of Ti after heating lead to an increase in film resistivity. • Ti adhesion layer can enhance the adhesion force between Pt film and substrate. [ABSTRACT FROM AUTHOR]

Nanofabrication is key to many technological advances, especially the challenge of merging nanophotonics with electronics. Here, we investigate the fabrication process of plasmonic interdigitated gold electrodes having a very high aspect ratio (i.e. long and thin geometries) and a large surface area. Stringent stability issues that arise when these structures are fabricated using inorganic adhesion layers, such as titanium or chromium, on silica substrates are highlighted. We ascribe these problems to thermodynamical non-equilibrium states of freshly deposited gold and, in particular, discuss the role of surface energy in determining the structural properties of high aspect ratio gold nanostructures. We then show that the use of organic silane self-assembled monolayers improves the long term stability of these structures and, finally, characterize the fabricated electrodes. This technology can unleash the potential of hybrid optoelectronic circuits where current and light are manipulated with the same component. [Display omitted] • The stability of elongated gold structures is dominated by their surface properties. • Fabricating gold nanostructures on glass substrates requires an adhesion layer. • The use of metallic adhesion layers leads to a deterioration of the structures. • Organosilane adhesion layers improve the stability of elongated gold structures. [ABSTRACT FROM AUTHOR]

Whereas noble metal films deposited directly onto an undulated photosensitive polymer exhibit plasmon-mediated resonant transmission of free-space waves accompanied by excess losses of approximately 40 %, adequate hard baking of the photosensitive polymer, together with pre- and post-deposition of nanometer-thick ZnS or MgF dielectric interfacial layers, restores excellent propagation conditions for the long-range plasmon mode, reducing resonant transmission excess losses to 10 %, and creating the conditions for the experimental evidence of the long-sought plasmonic anomalous reflection phenomenon. [ABSTRACT FROM AUTHOR]

Abstract: In the aircraft industry, an increasing demand for adhesion promotion layers for titanium based materials is observed to replace polluting and unhealthy substances. Plasma enhanced chemical vapour deposition (PECVD) at atmospheric pressure (AP) seems to be favourable for the deposition of thin silica-like layers. In this work, a linearly extended and scalable DC arc plasma source is used for PECVD of silica layers on Ti6Al4V. The influence of the precursor chemistry is evaluated for HMDSO and TEOS precursors. Using HMDSO, hydrophobic almost stoichiometric SiO2 coatings with a carbon content of 3at.-% to 5at.-% are deposited on the titanium alloy substrate. For TEOS, hydrophilic carbon-free stoichiometric SiO2 coatings are deposited. The dynamic deposition rate for TEOS is 3 times lower than that for HMDSO (up to 640nm•m/min). For the intended coating of slightly curved substrates, the film properties and deposition rates are studied for different working distances from 20mm up to 60mm. For 60mm the deposition rate is reduced by a factor 6 compared to 20mm, also the index of refraction of the film decreases from 1.45 at 20mm distance to 1.39 at 60mm. With increasing distance, the particle size and concentration on the surface increases and leads to less dense structures than in the case of shorter distances. The wedge test is used to evaluate the adhesion properties of the layer. The HMDSO-based coatings exhibit a good long-term durability and a high bonding strength comparable to that of the currently used standard pre-treatment, but without the use of harmful substances. [Copyright &y& Elsevier]

Whereas resonant transverse magnetic transmission across an undulated continuous metal film is achieved with the mediation of plasmon modes excited by the undulation, it is shown here that transverse electric (TE) resonant transmission through a continuous metal film can also be achieved with the mediation of the second-order TE mode of a dielectric slab waveguide having the metal film sandwiched at its middle. The demonstration is made by using the materials currently used in the domain of optical security and counterfeit deterrence: ZnS is shown to possibly be a lossless interface/adhesion layer between a polymer and a noble metal for plasmonic resonant elements. [ABSTRACT FROM AUTHOR]

The near-field resonances of gold bowtie antennae are numerically modeled. Besides the short-range surface plasmon polariton (SR-SPP) mode along the main axis of the structure, a coupled SPP mode is also found in the gap region (G-SPP). The influence of adhesion layers is considered, which depends on the refractive index and the absorption of the adhesion material and whether it is continuous or etched. A high refractive index causes the peak of the SR-SPP to red-shift. High absorption quenches the intensity of the SR-SPP. The magnitude of influence depends on the overlap of the adhesion layer with the SR-SPP and G-SPP modes. The near-field resonance of the SPP mode on the top surface is also considered. An etched metal adhesion layer changes the near-field localization in the gap and causes the enhancement peaks at different heights within the gap to red-shift from top to bottom. A simple optimization method for the near-field localization by the combination of different top and bottom layers is demonstrated. [ABSTRACT FROM AUTHOR]

Adhesion layers and intermediate layers exert important effects on the adhesion and cutting performance of PVD multilayer coatings. In this work, TiAlSiN multilayer coatings with different combinations of adhesion layers and intermediate layers were deposited, and their microstructure, adhesion and milling performance were assessed. Rockwell indentation and scratch results showed that delamination from the interfaces between the adhesion layers and intermediate layers occurred both for the T1 coating (TiN adhesion layer + Al 17.5 Ti 80 Si 2.5 N intermediate layer) and T2 coating (Al 33 Ti 67 N adhesion layer + Al 43 Ti 54 Si 3 N intermediate layer). Synchrotron radiation glancing incidence X-ray diffraction (SR-GIXRD) investigation on T2 coating revealed the discontinuities in lattice constant a and micro-strain at the interfaces between intermediate layer and adhesion layer, which resulted in poor cohesion of them. The T3 coating (Al 67 Ti 33 N adhesion layer + Al 64 Ti 34 Si 2 N intermediate layer) exhibited the lower residual stress (−3.7 GPa), and better cohesion and adhesion (L c2 = 72 N). The T3 coating also had the longer milling life corresponding to a cut length 1700 m, due to its better cohesion and adhesion increased the "steady wear" stage. This improved cohesion and cutting performance of the multilayer coatings could be achieved by using proper combinations of adhesion layers and intermediate layers. [Display omitted] • TiAlSiN coatings with various adhesion and intermediate layers were fabricated. • SR-GIXRD technology revealed the depth information of multilayer coatings. • Approximate Al contents and microstructures in multi-layers were recommended. • Decrease of difference in CTEs and properties between sub-layers was beneficial. • Improved cutting performance was achieved by tailoring multilayer structures. [ABSTRACT FROM AUTHOR]

Gold plasmonic nanostructures with several different adhesion layers have been studied with monochromated electron energy loss spectroscopy in the scanning transmission electron microscope (STEM-EELS) and with surface enhanced Raman spectroscopy (SERS). Compared to samples with no adhesion layer, those with 2nm of Cr or Ti show broadened, lower intensity plasmon peaks as measured with EELS. This broadening is observed in both optically active ("bright") and inactive ("dark") plasmon modes. When the former are probed with SERS, the signal enhancement factor is lower for samples with Cr or Ti, another indication of reduced plasmon resonance. This work illustrates the capability of STEM-EELS to provide direct near-field measurement of changes in plasmon excitation probability with nano-scale spatial resolution. Additionally, it demonstrates that applications which require high SERS enhancement, such as biomarker detection and cancer diagnostics, can be improved by avoiding the use of a metallic adhesion layer.