Zirconium and zirconium nitride coatings were deposited via magnetron sputtering by using high-purity zirconium or zirconium nitride targets. As a particularity, the zirconium nitride coatings were deposited by using a ZrN target via non-reactive mode or by using a Zr target via reactive technique, in argon/nitrogen environment. Depending on the time deposition, coatings with different thicknesses (200, 500 and 1000 nm) have been obtained. Chemical and phase composition, thickness of the coating and morphology of the surfaces were investigated by highly sensitive X-ray photoelectron spectroscopy (XPS), energy dispersive X-ray spectroscopy (EDX), scanning electron microscopy (SEM) and X-Ray diffraction (XRD). The wear tests have been performed by High Frequency Reciprocating Rig (HFRR). The wear scar diameters decrease with an increase of coatings thickness, while the friction coefficient for the coatings with 500 nm thickness revealed the lowest values for friction coefficients, for all type of coatings

Photovoltaic cells based on conductive polymers, such as poly(3-hexylthiophene-2.5-diyl) (P3HT) and [6,6]-phenyl C61 butyric acid methyl ester (PC61BM), and chlorophyll-a (Chl-a) were fabricated and characterized, in ambient atmosphere. The architecture of prepared samples has been completed by deposition of buffer layers facilitating the charge carriers' collection to electrodes. To improve the holes collection, poly(3.4-ethylenedioxythiophene)-poly(stryrenesulfonate) (PEDOT:PSS) and Chl-a were used, and lithium fluoride (LiF) for the electrons' collection, respectively. Both, the active layer and the holes selective layer (HSL) were customized as P3HT:PC61BM + Chl-a (1:1:1), and PEDOT:PSS + Chl-a (4:1) or the bi-layer structure Chl-a/PEDOT:PSS. Indium thin oxide (ITO) was preferred as anode, while aluminum as back electrode. The obtained devices were electrical and photo-electrical characterized, and their performances were discussed in terms of ITO/PEDOT:PSS/P3HT:PC61BM (1:1)/LiF/Al conventional structures. We demonstrated that a customized PEDOT:PSS + Chl-a (4:1) HSL improved with more than 50% the external quantum efficiency of fabricated photovoltaic cells, compared with the results of conventional structures. Modest values of open circuit voltage and fill factor were calculated in the case of Chl-a/PEDOT:PSS HSL based photovoltaic cells, most likely due to a non-optimized interface between Chl-a and PEDOT:PSS which lead to the creation of a great number of defects acting as recombination centers.

The antiwear properties of metal surfaces have been improved by applying surface coatings, and the results have been compared with those obtained by additivation of the lubricant with a classic antiwear additive. In order to enhance the antiwear properties, carbon nanowalls (CNWs) and copper coatings were applied to AISI-E 52100/535A99 steel substrate. The second phase of the experimental part was focused on the improvement of the antiwear properties of the lubricant by using an antiwear additive such as zinc-dialkyldithiophosphate (ZnDTP). Different concentrations of additive (1%, 3%, 5% and 10 wt. %) of ZnDTP were used in order to decrease the friction coefficient. It was observed that the optimum concentration of additive was found to be 5 wt. %. Carbon nanowalls (CNWs) layers obtained by PECVD and copper coatings obtained by magnetron sputtering were evaluated from friction and wear point of view by High Frequency Reciprocating Rig (HFRR) and Pin on Disk C. S.M tribometer. Composition, thickness of the layers and morphology of the surfaces were investigated by energy dispersive X-Ray spectroscopy and scanning electron microscopy (SEM). It was established that the thickness of the coatings influences the wear scar diameter imprinted on the steel ball.

In this paper we report a method for 0-level encapsulation using thin films deposition at temperatures below 200°C. The packaging method allows the use of photoresist as sacrificial layer, which facilitates sacrificial layer removal, being compatible with micromachining and CMOS integration This package was tested on an RF MEMS switch structure for K to W frequency bands (20-110GHz) and shows a very small influence over S parameters for all frequency range.

Core-shell nanodot arrays of Ti/Au/TiO 2 have been obtained on EBL patterned substrates by RF sputtering of Ti in a controlled ambient of Ar/O 2 plasma. X-ray diffraction analyses showed that the TiO 2 films crystallinity and the lattice strain is strongly affected by the O2 content. Photoluminescence emission bands at 2.97 eV and 2.59 eV evidenced the presence of point defects related to oxygen deficiency. MOS capacitors based on the Ti/Au/TiO 2 arrays were fabricated and the effect of TiO 2 /Au interface in tailoring the electronic band structure was analyzed in relationship with numerical models.

Thin films of carbon were synthesized by ns pulsed laser deposition in vacuum on silicon substrates, starting from graphite targets. Further on, the films were irradiated with a picosecond laser source emitting in visible at 532 nm. After tuning of laser parameters, we obtained a film surface covered by laser induced periodical surface structures (LIPSS). They were investigated by optical, scanning electron and atomic force microscopy. It was observed that changing the irradiation angle influences the LIPSS covered area. At high magnification it was revealed that the LIPSS pattern was quite complex, being composed of other small LIPSS islands, interconnected by bridges of nanoparticles. Raman spectra for the non-irradiated carbon films were typical for a-C type of diamond-like carbon, while the LIPSS spectra were characteristic to nano-graphite. The pristine carbon film was hydrophilic, while the LIPSS covered film surface was hydrophobic. (C) 2016 Elsevier B.V. All rights reserved.

In recent years, a lot of techniques for obtaining ZnO nanostructures were developed together with different methods for nanoparticles surface modification. Hence, the changing of particles chemical and physical properties improves their compatibility with different polymeric matrices leading to interesting, new practical applications of ZnO in various domains. In this study, the structural and optical properties of new types of ZnO nanoparticles surface modified with oleic acid and elaidic acid as capping agents are reported, that were used to control the size and the morphology of ZnO NPs. The suitable capping agents were chosen on the base of their ability to attach on the nanoparticles surface further improving their features. The structure and morphology of modified ZnO nanoparticles (ZnO-oleic acid and ZnO-elaidic acid) were analyzed in detail using X-ray diffraction (XRD), field emission scanning electron microscopy (FESEM) and Fourier transform infrared spectrometry (FT-IR). The optical properties of the as-prepared samples also were investigated using photoluminescence (PL) and absorption spectroscopy. Results showed the particles size was in the range of 30-50 nm and the morphology of the synthesized NPs to be dependent on the capping agent. FTIR spectra indicated the types of functional groups present on the surface of ZnO nanoparticles.

Despite the MEMS/NEMS devices are used in many applications, a lot of new characterization and testing methods have been developed in order to improve their functionality, reliability and stability. The correct material selection criteria are essential when designing micro/nano structures. The material properties of micro components depend on the the manufacturing and processing conditions. This article presents the investigations of two materials obtained by diverse deposition techniques, for manufacturing of MEMS used as vibration sensors and in bio applications. LPCVD undoped and doped polysilicon layers with a thickness varying from 50 nm to 2 mu m and a biocompatible polymeric material (SU-8) with a thickness of 10 mu m and 20 mu m were investigated using Atomic Force Microscope (AFM), nanoindentation techniques, X-ray Diffraction System (XRD) and Scanning Electron Microscopy (SEM) characterization tools. In order to demonstrate the applicability of the investigated materials two types of MEMS structures were manufactured.

Photovoltaic cells based on biologic (Chlorophyll-a, Chl-a) and polymeric (poly(3hexylthiophene-2,5-diyl), P3HT, and [6,6]-phenyl-C61 butyric acid methyl ester, PCBM) thin films were prepared and characterized. Two types of structures were fabricated, either with a bi-layer Chl-a/P3HT:PCBM(1:1, wt.%) or a single layer Chla:P3HT:PCBM(10:1:1, wt. %) design, the photoactive layers being deposited by spin coating technique. Their optical and photovoltaic properties were analyzed and compared with those of a bulk heterojunction P3HT:PCBM(1:1, wt.%) cell. Similar values were found for fill factor and open circuit voltage but an enlarged region of spectral response was observed in the case of the cells containing Chl-a. The short-circuit current measured in the case of Chl-a/P3HT:PCBM(1:1, wt.%) and Chl-a:P3HT:PCBM(10:1:1, wt.%) based cells was smaller than in the case of P3HT:PCBM(1:1, wt.%) cell.

The effect of DC reflex and RF plasma is observed on three types of wood samples: beech, oak and spruce. The aim is to perform surface hydrophilization and hydrophobization and characterize the modifications occurring at the surface of the wood. FTIR-ATR measurements were performed to characterize and identify the chemical bonds on the surface of the treated samples.

In this paper we aim to perform a cross section morphological characterization of an acrylic polymer used for dental prostheses subjected to microwave disinfection. The method was largely investigated and the microbiological effectiveness is well established, but there are some issues regarding the in-depth alteration of the material. In our research, the surface roughness is insignificant and the samples were not polished or refined by any means. Two groups of 7 acrylic discs (20 mm diameter, 2 mm thickness) were prepared from a heat-cured powder. Half of the samples embedded a stainless steel reinforcement, in order to observe the changes at the interfaces between the polymer and metallic wire. After the gradual wet microwave treatment, the specimens - including the controls - were frozen in liquid nitrogen and broken into pieces. Fragments were selected for gold metallization to ensure a good contrast for SEM imaging. We examined the samples in cross section employing a high resolution SEM. We have observed the alterations occurred at the surface of the acrylic sample and at the interface with the metallic wire along with the increase of the power and exposure time. The bond configuration of acrylate samples was analysed by FTIR spectrometry.

The effect of annealing in air and in nitrogen atmosphere on the structure, luminescence emission and electrical properties of ZnO, Li:ZnO and Cu:ZnO doped thin films prepared by sol-gel method was investigated by scanning electron microscopy, X-ray diffraction, photoluminescence and resistivity measurements. The films annealed in nitrogen demonstrate smoother surfaces, improved crystallinity and conductivity. The residual stress in doped films changes from tensile type, when annealed in air, to compressive type in the case of annealing in nitrogen atmosphere. The effect is associated with the density of lattice defects in the films annealed in nitrogen.

This paper describes the fabrication technology for thin SiO2/Si3N4 membranes on a silicon wafer substrate, with areas ranging from 0.9 mm(2) to 34 mm(2). The main challenges were the deposition of stress compensated dielectric films, uniform etching of the whole 4 inch wafer, while releasing the membranes and dicing the wafer in individual chips.

There is a paradox: the people are interested in Science especially at the huge natural catastrophes (earthquakes, volcanic eruptions, tsunami waves, nuclear accidents). Other problems are related to the fact that the young people chose mainly carriers outside the scientific fields. Therefore, it is interesting to analyze the profile of the student at the Sciences faculties, in particular, at the faculties of Physics. In this work we present the profile of the student at the second Bologna cycle', master studies, at the Faculty of Physics from the University of Bucharest, Romania.In agreement with the Bologna system, master studies have two academic years duration, and they are in deep connection with the seven specializations at the Doctoral School in Physics. It is important to stress that the Doctoral School in Physics has a special direction for Education in Physics.Who is the master student at the faculty of Physics? First of all he/she is a graduate of one of the faculties of Physics from Romania or abroad, interested in a good education in selected field, as well a performing institution, recognize at the national and international level. A few of them are graduates of the Applied Sciences, Electronics and Computers, Material Sciences, Space Sciences etc from the technical universities, as Mathematics and Informatics, Chemistry, Geography, Geology and Biology from the "classical" universities. Some time, graduates from "exotic fields" like Law, Economics and Administration, Theology, etc.Why they selected master studies in Physics? Almost 70% from these mentioned passion for Science and/or scientific interests. 15%, mainly those coming from other field mentioned the requests of the labor market. Others mentioned the enlargement of the knowledge areas, scientific curiosity and academic interest.The ages of the applicants are, in a large majority, between 22 and 30 years, only a few having over 30 years. Initial tests - at the beginning of the first academic year, as well as a final test - at the end of the second academic year prove the performance. Such studies can help in the evaluation of the attractive degree of the master study programs and in the enlargement of the basis of specialists in different fields.