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Romcevic N.,University of Belgrade | Rudolf R.,University of Maribor | Trajic J.,University of Belgrade | Romcevic M.,University of Belgrade | And 3 more authors.
Materiali in Tehnologije | Year: 2011

In this paper the results of optical properties investigations on plastically deformed copper are presented. The optical properties of the plastically deformed copper were studied using spectroscopic ellipsometry in the ultraviolet-visible (UV-VIS) range. Chemically pure copper was deformed by applying the Equal Channel Angular Pressing (ECAP) technique. During the last decade, equal-channel angular pressing procedure was used for the fabrication of ultrafine-grained metals and alloys. The plastic deformation of metallic materials leads to the production of bulk nano-scale structures with ultrafine grains and cross-sections, which remain about equal before and after deformation. The parameters of the sample were calculated using a two-film model together with the Bruggeman effective medium approximation. Source

Dalarsson M.,KTH Royal Institute of Technology | Norgren M.,KTH Royal Institute of Technology | Dalarsson N.,KTH Royal Institute of Technology | Jaksic Z.,IHTM Institute of Microelectronic Technologies and Single Crystals
2011 10th International Conference on Telecommunications in Modern Satellite, Cable and Broadcasting Services, TELSIKS 2011 - Proceedings of Papers | Year: 2011

The transmission and reflection properties of lossy structures involving left-handed materials with graded permittivity and permeability have been investigated. We present an exact analytical solution to Helmholtz' equation for a lossy case with the graded real parts of permittivity and permeability profile changing according to a hyperbolic tangent function along the direction of propagation. The simple analytical solutions and graphical results for the field intensity along the graded structure are presented. The model straightforwardly allows for arbitrary temporal dispersion. © 2011 IEEE. Source

Matovic J.,Vienna University of Technology | Jaksic Z.,IHTM Institute of Microelectronic Technologies and Single Crystals
Microelectronic Engineering | Year: 2010

In this work we report structural functionalization of metal-composite nanomembranes through formation of micrometer-sized three-dimensional hollow self-supported shapes with tailorable ordering and dimensions. The basic idea is to use double-sided, two-stage etching of the sacrificial layer, first to define the preform for the nanomembrane sculpting, then to fully remove the sacrificial structure and release the nanomembrane. In our experiments we utilized 15-20 μm thick <100> Si diaphragms as sacrificial layers. Conventional KOH-based bulk micromachining was used to sculpt pyramidal holes within the diaphragms and modified radiofrequent sputtering to deposit a 5-20 nm Cr-based nanomembrane precursors. After the removal of sacrificial membranes the released freestanding nanomembranes had an aspect ratio up to 1000,000 and contained hollow micrometer-sized pyramidal shapes which do not collapse in spite of their large wall-to-side aspect ratio (>1000). Although the geometry of the sculpted shapes in our experiments is defined by the Si bulk micromachining, one may readily fabricate a number of other shapes, including hemispherical, ellipsoidal, etc., the sizes and shapes being limited by the particular microfabrication technique chosen for the diaphragm pre-forming. Some potential applications of 3D sculpted nanomembranes can be found in subwavelength diffractive optics, plasmonics, energy harvesting, microfluidics, biointerfaces, to name just a few. © 2009 Elsevier B.V. All rights reserved. Source

Jaksic Z.,IHTM Institute of Microelectronic Technologies and Single Crystals | Tanaskovic D.,IHTM Institute of Microelectronic Technologies and Single Crystals | Matovic J.,Institute of Sensors and Actuators
2010 27th International Conference on Microelectronics, MIEL 2010 - Proceedings | Year: 2010

In this work we analyze fishnet-type optical metamaterials with full electromagnetic symmetry, fabricated in an ultrathin, freestanding film (self-supported nanomembrane). We utilized the finite element method to simulate the response of various laminar fishnet geometries, including metal-dielectric-metal and dielectric-metal-dielectric-metal-dielectric multilayers. We varied metal and dielectric thickness, nanoaperture radius, metal and dielectric materials. We considered the tunability of the spectral characteristics of the fishnet by bringing a dielectric analyte in contact with its exposed surfaces. Such tunability is of importance for all-optical sensors of chemical or biological analytes, but also for the performance of general fishnet nanoaperture arrays in real operating conditions, where the introduction of the ambient gases and fluids will modify their plasmonic properties. © 2010 IEEE. Source

Djuric Z.G.,IHTM Institute of Microelectronic Technologies and Single Crystals | Jokic I.M.,IHTM Institute of Microelectronic Technologies and Single Crystals | Djukic M.M.,IHTM Institute of Microelectronic Technologies and Single Crystals | Frantlovic M.P.,IHTM Institute of Microelectronic Technologies and Single Crystals
Microelectronic Engineering | Year: 2010

This paper presents the analysis of fluctuations of both the number and the mass of particles adsorbed on the surface of MEMS/NEMS structures, as well as the fluctuations of the micro/nanostructure resonant frequency, in the case of adsorption in the arbitrary number of layers. The presented theory shows that the fluctuations, calculated assuming multilayer adsorption, are higher than those obtained by using a monolayer (Langmuir) model. Since the multilayer adsorption is more realistic case than the monolayer adsorption, this theory enables a more accurate estimation of both AD noise and the minimal detectable signal of a MEMS/NEMS sensor. © 2009 Elsevier B.V. All rights reserved. Source

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