1,721,010 research outputs found
Micro-beam and pulsed laser beam techniques for the micro-fabrication of diamond surface and bulk structures
No full textMicro-fabrication in diamond is applicable in a wide set of emerging technologies, exploiting the exceptional characteristics of diamond for application in bio-physics, photonics and radiation detection. Micro ion-beam irradiation and pulsed laser irradiation are complementary techniques, which permit the implementation of complex geometries, by modification and functionalization of surface and/or bulk material, modifying the optical, electrical and mechanical characteristics of the material. In this article we summarize the work done in Florence (Italy), concerning ion beam and pulsed laser beam micro-fabrication in diamond. © 2014 Elsevier B.V. All rights reserved
Depth dependent properties of ITO thin films grown by pulsed DC sputtering
No full textA systematically prepared set of ITO layers for solar cell applications has been analyzed by spectroscopic variable angle ellipsometry in order to trace the dependence of free carriers' distribution along the film depth as a function of film thickness as well as its change upon annealing. Samples were deposited on silicon substrates with various thicknesses in steps of approximately 10-20 nm. This set was duplicated and these samples were annealed, so that for each thickness an as-deposited and an annealed sample is available. Conventionally measured electrical conductivity and morphological properties (AFM measurements) of the films have been compared with the optical constants' inhomogeneity, i.e. material properties along the film thickness modelled by variable-angle spectroscopic ellipsometry. The obtained results show that the optical as well as electrical properties of thin ITO films prepared by pulsed DC sputtering are depth dependent. For the deposition conditions used a well-determined reproducible non-uniform distribution of free carriers within the film thickness was determined. In particular it has been found that the majority of free carriers in as-deposited ultra-thin ITO films is concentrated at sample half-depth, while their distribution becomes asymmetric for the thicker films, with a maximum located at approximately 40 nm depth. The distribution of free carriers in annealed samples is qualitatively different from that of as-deposited layers. © 2012 Elsevier B.V. All rights reserved
Complex materials with plasmonic effects for optical thin film applications
No full textPlasmonic materials are complex nanostructures that can be designed and manufactured to significantly alter electromagnetic radiation in ways not available to traditional thin film devices. These new materials offer measurement and characterization challenges to determine their unique properties and improve our understanding of the underlying physics of nanostructured materials. Applications of plasmonics ranging from unique filters for spectral control to hyperbolic and negative refractive index materials enabling novel photonic devices are all very active areas of research today. © 2013 Woodhead Publishing Limited All rights reserved
Metamaterials for optical coatings
No full textMetamaterials, and complex materials having plasmonic properties in general, interact with external electromagnetic radiation in a particular way compared to traditional solid thin films. The reason lays in the physics of such artificial media. Such peculiarity of metamaterials defines the choice of suitable measurement techniques used for their characterization as well as adequate methodology for measurement data interpretation, specific for the case. Here we overview main issues on the physical properties of complex plasmonic materials and methods for their modelling. The approach to modeling of their optical parameters is considered as well. The emphasis on the optical thin film applications is made. © 2015 SPIE
The Optical Society's 2016 topical meeting on optical interference coatings: Introduction
No full textThis feature issue of Applied Optics is dedicated to the 13th Topical Meeting on Optical Interference Coatings, which was held June 19-24, 2016, in Tucson, Arizona, USA. The conference, taking place every three years, is a focal point for global technical interchange in the field of optical interference coatings and provides premier opportunities for people working in the field to present their new advances in research and development. Papers presented at the meeting covered a broad range of topics, including fundamental research on coating design theory, new materials, and deposition and characterization technologies, as well as the vast and growing number of applications in electronic displays, communication, optical instruments, high power and ultra-fast lasers, solar cells, space missions, gravitational wave detection, and many others. © 2017 Optical Society of America
Optical properties of fishnet metamaterials embedded in dielectrics
No full textThe impact of the optical properties of the adjacent dielectric layer(s) on the effective optical functions of fishnet metamaterials has been investigated for employment of fishnets in multilayer coatings. © OSA 2016
Hydrogen related phenomena at the ITO/a-Si:H/Si heterojunction solar cell interfaces
No full textProperties of thin a-Si:H and indium-tin oxide (ITO) layers as well as properties of interfaces of Si based heterojunction (HJ) ITO/(p)a-Si:H/n-Si structures were analyzed by means of atomic force microscopy (AFM) and scanning spreading resistance microscopy. It is shown that the morphology of thin ITO layers grown on n-type polished crystalline Si or on (p)a-Si:H/n-Si substrates depends on the deposition temperature and has peculiarities on nano-scale. Formation of highly conductive nano-dots on the surface and in the bulk of ITO layers is found. The observed nano-spots and nano-dots are attributed to the influence of hydrogen initiated reduction process, which occurs upon deposition of ITO films on an a-Si:H layer during the fabrication process of a HJ solar cell. This fact is confirmed by investigation of morphological properties of ITO surfaces after treatment by hydrogen plasma. It is shown that formation of conductive nano-particles on the ITO surface initiated by hydrogen does not change essentially transparency of an ITO layer. It is concluded that conductive nano-dots at the ITO/a-Si:H interface can be considered as local conductive channels, which provide a current flow through the ITO/(p)a-Si:H interface without essential shadowing of the solar cell structure. This finding opens an interesting way for the optimization of properties of the ITO/Si-based HJ solar cells. Copyright © 2013 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim
Improved ITO laser resistance by imbedding within a Fabry-Perot filter
No full textThe laser resistance of a transparent conductive layer such as ITO is increased by placement into the low electric field region of a Fabry-Perot multilayer filter. © OSA 2016
Prototyping fishnet metamaterials: Alumina-silver-based structures
No full textFishnet metamaterials (MM) conceived for optical coating applications have been simulated for metal-dielectric-metal structures based on silver and oxides. Preliminary experimental results on large-scale fabrication are presented here for alumina-silver based structures. Millimeter-size MM layers have been realized by combination of r.f. sputtering and focused-ion-beam writing. © 2015 SPIE
On-demand refractive index for interference optical coatings
No full textIn optics, artificially structured nanomaterials act as effective media whose complex refractive index may be ad-hoc designed for applications in multilayer coatings. © 2016 SPIE
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