Publications

In this contribution the peculiarities of the behaviour of strange quark matter in respect to ordinary ions in silicon are investigated, and a tentative to identify possible observable effects of degradation is made.

Ceramic based Ba(Zn1/3Ta2/3)O-3 materials were prepared by solid-state reaction. Studies on microwave dielectric parameters in correlation with structural and Raman investigations were performed. Sintering temperatures higher than 1600 degrees C are required in order to obtain dielectric properties suitable for millimeter wave applications.

Electrodeposition of manganese- and copper-doped ZnO wires into polycarbonate membranes, from an aqueous solution containing 0.05 mol dm(-3) Zn(NO3)(2)+ 0.01 mol dm(-3) Mn(NO3)(2)+ 0.0005 mol dm(-3) Cu(NO3)(2)+ 0.0075 mol dm(-3) lactic acid, pH = 4.7 was investigated using linear sweep voltammetry and electrochemical impedance spectroscopy (EIS). The equivalent electrical circuits for fitting experimental results were similar to those for characterization of metal/polymer coating systems. impedance data and voltarnmetric curves showed that an increase of local pH due to reduction process of nitrate ions induces the co-precipitations of metal ions in the proximity of electrode as oxides. Copyright (c) 2008 John Wiley & Sons, Ltd.

Nano-technology is a very attractive area of research and innovation because it allows the current trends in miniaturization to continue. The transition from micro scale to nano scale devices has already taken place in many applications such as electronics, magnetic recording and nano-biophysics. However, as we scale down the size of the structures and devices, it becomes obvious that the classical behavior will break down at the nano-scale and an interesting superposition of classical and quantum effects will emerge. Therefore, the validity of classical physics is questioned and many aspects of physics are now being revisited from the point of view of nano-technologies. In line with the new developments in miniaturization and nano-technologies, we propose in this letter a simple mechanism that applies the Faraday effect at the nano-scale in order to create a possible solid-state energy nano-generator device. The proposed nano-generator functionality is based oil what we shall call the Super-Paramagnetic Electromotive Force (SPEF) effect. This has the potential to produce a very small voltage on short time scales by converting directly thermal energy at room temperature to electromotive energy Without the need for external work or mechanical motion.

We present results of ab initio. supercell calculations performed in the DFT-L(S)DA framework on rutile TiO2 phase with neutral oxygen vacancies (OVs), in the low defect concentration range (<= 6.25 at. %). The different OVs distributions in the supercell allow us to determine the localization and structure of the vacancy-induced states, the effect of vacancy concentration on the occupation numbers, as well as vacancy energetics. The present studs, benefits of the high accuracy in the total energy and band structure calculations of the full potential method utilized

In this paper a new type of dual-mode compact resonator for mobile communication systems, in the 900 MHz frequency band, is investigated. This compact planar resonator, developed on a 0.635 mm substrate with a 10.8 dielectric constant, has a square shape with an edge of 20.5 mm. For this dual resonator, several methods of modes coupling were considered. The radiation characteristics of this new resonator were investigated.

Pulsed Laser Deposition (PLD) is an ideal technique to be used for combinatorial approaches. By simply changing the deposition targets one can obtain alternating layers with different periodicities both vertically and laterally, along the substrate surface. By changing the laser impact area location and the number of pulses on each target used for ablation, one can grow films with a continuous variation of the chemical composition, which will be a function of the location on the substrate. To illustrate the advantages and versatility of this Combinatorial PLD (C-PLD) technique, several examples of films used in applications where more than one property should be tailored or optimized are presented. Investigations of thermo-chemical stability, chemical bonding and crystalline structure of thin films of mixtures of HfO2 and Al2O3 that are used as high-k dielectric layers in advanced C-MOS transistors is the first example, followed by a study of structural, mechanical, optical and electrical properties of mixtures of indium tin oxide and doped or pure zinc oxide that are used as transparent and conductive layers. The third example is from the deposition of multilayers of ZrC and ZrN with variable thicknesses to obtain hard coatings.

Hydrothermal techniques have been used to synthesize samples of ZnxFe3-O-x(4) (x = 0.0-1.0) starting with ZnSO4 center dot 7H(2)O/FeSO4 center dot 7H(2)O aqueous solution. The sequence of phases, structural and magnetic properties were followed by X-ray diffraction (XRD), Mossbauer spectroscopy and transmission electron microscopy (TEM). Refinement of the XRD spectra yielded the dependence of the lattice parameters of zinc-doped magnetite and zinc ferrite phase as function of the Zn molar concentration x. As well, the particle diameter was derived and represented as a function of Zn content x. As a function of Zn concentration, the phase content of hydrothermally synthesized samples was found to consist of zinc-doped magnetite, goethite and zinc ferrite. Consistent with the XRD results, Mossbauer spectroscopy data indicate the presence of magnetite and goethite at x <= 0.2, magnetite and zinc ferrite at x <= 0.9 and pure zinc ferrite only at high zinc concentrations. The presence of different magnetite phases was confirmed by TEM and particles with a size of 50 nm were identified. Our results show that zinc ferrite is formed at high zinc concentration by the hydrothermal method and an acicular component of goethite-magnetite is obtained at low zinc content. (C) 2007 Elsevier B.V. All rights reserved.

n-Type epitaxial silicon layers of different thickness and resistivity, grown on highly Sb doped CZ-substrate by ITME (Warsaw), and n-type MCz silicon supplied by Okmetic (Finland) were used for the processing of planar diodes at CiS (Erfurt). For the epi-diodes a standard as well as a diffusion oxygenation process was employed. Irradiations had been performed with 26 MeV protons at the cyclotron of the Karlsruhe University and with neutrons at the TRIGA reactor of the Ljubljana University. Microscopic investigations using the DLTS method were done. The correlation of the IO(2i)-defect and the oxygen concentration was studied by a depth-profile measurement. The annealing behavior of the IO(2i)-defect at different temperatures was investigated and the activation energy extracted. (C) 2007 Elsevier B.V. All rights reserved.

N-type epitaxial layers of 72 mu m thickness and a resistivity of 150 Omega cm have been grown on highly Sb-doped Cz-substrates at ITME (Warsaw). The diode processing was performed at CiS-Erfurt. For comparison a batch of 280 mu m thick n-type MCZ wafers with a resistivity of >600 Omega cm from Okmetic (Finland) was added to the process run. Depth profiles of the oxygen and carbon concentration were measured via the SIMS-method on as grown epi-layers and after different device-process steps at CiS including an oxygen enrichment at 1100 degrees C for 24 h. For the MCz material the profiles were measured on untreated samples and after the full device process. Irradiation runs were performed with neutrons at the TRIGA reactor of Ljubljana up to a fluence value of 10(16) cm(-2). The development of the macroscopic device parameters (effective doping concentration and charge collection for a-particles) as function of fluence is presented for the standard and oxygenated epi-devices and compared with the MCz-diodes. The results are discussed in the frame of defect studies resulting from TSC-measurements. (C) 2007 Elsevier B.V. All rights reserved.