2012


Buldini P.L., Mevoli A.
(2012) Comprehensive Sampling and Sample Preparation, Vol. 4, pp. 521-534.
ENEA, Advanced Physical Technologies, Brindisi, Italy
Abstract
Membrane-based extraction procedures of food sample treatment are eco-friendly methods suitable to fully automate analytical process for routine monitoring of food safety. On-line connection is quick and easy and does not require significant adaptation of the procedure. The flexibility of the working arrangements makes these procedures conformable to most experimental approaches. Membrane-based extraction techniques are cheap, low hazard, safe, and give rapid separations that provide the highest selectivity and cleanup; they are also joined to high enrichment factors, of both inorganic and organic target analytes from complex nonhomogeneous hydrophilic or hydrophobic matrices. Thermally unstable components too are easily separated, due to no heating requirement. © 2012 Elsevier Inc. All rights reserved.
Author Keywords
Dialysis; Electro-dialysis; Food analysis; Green analytical chemistry; Membrane extraction with sorbent interface (MESI); Membrane-based extraction (Membrane interferents separation); Microporous membrane liquid-liquid extraction (MMLLE); Nonporous membranes; On-line automation; Pervaporation; Porous membranes; Sample treatment; Supported liquid membrane extraction (SLME); Ultrafiltration
Document Type: Book Chapter
Source: Scopus

 

Greco A.a, Maffezzoli A.a, Calò E.b, Massaro C.b, Terzi R.b
(2012) Journal of Thermal Analysis and Calorimetry, 109 (3), pp. 1493-1502. Cited 9 times.
aDepartment of Engineering for Innovation, University of Salento, Via per Monteroni, 73100 Lecce, Italy;
bAdvanced Physical Technologies and New Materials Department, ENEA - Italian National Agency for New Technologies, Energy and the Environment, S.S. 7 - Km 714, 72100 Brindisi, Italy
Abstract
The objective of this work is to study the sintering behavior of polyamide 6 (PA6) powders and PA6 nanocomposites by means of thermomechanical (TMA) and dimensionless analysis in view of its technological application in rotational molding. TMA analysis was used to monitor the bulk density evolution of PA6 powders and PA6 nanocomposites when heated above the melting temperature. Experimental TMA results indicate that the sintering of PA6 and PA6 nanocomposites occurs in two different steps, namely powder coalescence and void removal. Furthermore, TMA analysis showed that relevant degradation phenomena occur during the sintering of PA6 and PA6 nanocomposites, leading to gas formation in the molten polymer. The suitability of these materials in rotational molding was then assessed by defining a processing window, as the temperature difference between the endset sintering and the onset degradation. The heating rate dependence of the processing window was explained by means of dimensionless analysis, showing that powder coalescence is influenced by the viscosity evolution of the matrix, whereas void removal is influenced by the gas diffusivity inside the molten matrix. Therefore, the diffusion activation energy correlates the endset sintering temperature to the heating rate. On the other hand, the onset degradation temperature depends on the heating rate, due to the characteristic activation energy of the degradation process. Accordingly, the width of the processing window mainly depends on the values of the activation energies for diffusivity and degradation. The width of the processing window for neat PA6 was found to be too narrow to candidate this polymer for rotational molding. The addition of nanofiller causes a narrowing of the processing window, whereas the PA6 matrix modified with a thermal stabilizer showed a sufficiently broad processing window, compatible for use in rotational molding. © Akadémiai Kiadó, Budapest, Hungary 2011.
Author Keywords
Nanocomposites; Polyamide 6; Sintering; Thermomechanical analysis (TMA)
Document Type: Conference Paper
Source: Scopus

 

Galietti U.a, Dimitri R.b, Palumbo D.a, Rubino P.a
(2012) ECCM 2012 - Composites at Venice, Proceedings of the 15th European Conference on Composite Materials
a Dipartimento di Ingegneria Meccanica e Gestionale, Politecnico di Bari, Viale Japigia, 182, 70126, Bari, Italy;
b ENEA, Centro Ricerche Brindisi, S.S. 7 Appia Km 713.7, 72100, Brindisi, Italy
Abstract
Wind energy represents an interesting sector in the field of renewable energy in particular as regards to the use of innovative materials such as CFRP and GFRP materials. The thermographic technique can be a valuable tool in this application field because allows a non-contact inspection of large areas, as for example occurs for remotely controls of the blades of large wind turbines. The mechanical characterization tests of GFRP adhesive joints were preceded by lock-in thermography tests in order to detect bonding defects, or more generally, defects that might compromise the mechanical strength of joints.
Author Keywords
Adhesive joints; Lock-in thermography; Mechanical characterization
Document Type: Conference Paper
Source: Scopus

 

Suriano D.a, Rossi R.a, Alvisi M.a, Cassano G.a, Pfister V.a, Penza M.a, Trizio L.b, Brattoli M.b, Amodio M.b, De Gennaro G.b
(2012) Lecture Notes in Electrical Engineering, 109 LNEE, pp. 87-92. Cited 1 time.
a ENEA, Brindisi Technical Unit for Technologies of Materials, Brindisi, Italy;
b Department of Chemistry, University of Bari, Lenviros Srl, Bari, Italy
Abstract
A portable sensor-system based on solid-state gas sensors has been designed and implemented as proof-of-concept for environmental air-monitoring applications and malodours olfactometric control. Commercial gas sensors (metal-oxides, n-type) and nanotechnology sensors (carbon nanotubes, p-type) are arranged in a configuration of array for multisensing and multiparameter devices. Wireless sensors at low-cost are integrated to implement a portable and mobile node, that can be used as early-detection system in a distributed sensor network. Real-time and continuous monitoring of hazardous air-contaminants (e.g., NO2, CO, SO2, BTEX, etc.) has been performed by in-field measurements. Moreover, monitoring of landfill gas generated by fermentation of wastes in a municipal site has been carried out by the portable sensor-system. Also, it was demonstrated that the sensor-system is able to assess the malodours emitted from a municipal waste site and remarkably compared to the olfactometry method based on a trained test panel. © 2012 Springer Science+Business Media, LLC.
Document Type: Conference Paper
Source: Scopus

 

Calò E.a, Massaro C.a, Terzi R.a, Cancellara A.a, Pesce E.a, Re M.a, Greco A.b, Maffezzoli A.b, Gonzalez-Chi P.I.c, Salomi A.d
(2012) International Polymer Processing, 27 (3), pp. 370-377. Cited 8 times.
aENEA-Department of Advanced Physical Technologies and New Materials, Brindisi Research Centre, Brindisi, Italy;
bDepartment of Engineering for Innovation, University of Salento, 73100 Lecce, Italy;
cCentro de Investigacionn Cientifica de Yucatan, Unidad de Materiales, Merida, Mexico;
dTELCOM S.p.A, Ostuni, Italy
Abstract
The aim of this work was to develop polyamide-6/ organicmodified montmorillonite (omMMT) nanocomposites for the production of hollow parts by rotational molding. Particular emphasis was placed on the mechanical and flame retardancy properties needed for the fabrication of vessels for flammable liquids. The morphology of the melt compounded nanocomposites, produced by melt compounding, was investigated by Xray diffraction measurements (WAXD), and Transmission Electron Microscopy (TEM) showed an exfoliated structure. Rheological measurements were used in order to verify whether the viscosity of materials was adequate for rotational molding. While thermomechanical analysis has revealed that neat PA6 and its nanocomposites were not suitable for rotational molding, due to the very low thermal stability of the polymer, the addition of a thermal stabilizer, shifted the onset of degradation to higher temperatures, thus widening the processing window of both PA6 and PA6 nanocomposites. Largescale vessel prototypes were obtained by rotational molding of thermo-stabilized PA6 and its nanocomposites, and samples extracted from the rotomolded parts were characterized with respect to physical and mechanical properties. It was found that the PA6 nano composites exhibited significant improvements at cone calorimeter tests in comparison with neat PA6. © Carl Hanser Verlag, Munich Intern.
Document Type: Article
Source: Scopus

 

Persano L.ab, Camposeo A.ab, Di Benedetto F.a, Stabile R.a, Laera A.M.d, Piscopiello E.d, Tapfer L.d, Pisignano D.abc
(2012) Advanced Materials, 24 (39), pp. 5320-5326. Cited 8 times.
aNational Nanotechnology Laboratory of Istituto Nanoscienze-CNR, Università Del Salento, via Arnesano, 73100 Lecce, Italy;
bCenter for Biomolecular Nanotechnologies UNILE, Istituto Italiano di Tecnologia, Via Barsanti, 73010 Arnesano (LE), Italy;
cDipartimento di Matematica e Fisica ennio de Giorgi, Università Del Salento, via Arnesano, 73100 Lecce, Italy;
dENEA, Technical Unit of Material Technologies Brindisi, Strada Statale 7 Appia km. 706, 72100 Brindisi, Italy
Abstract
A straightforward, electron-beam induced synthesis and patterning approach to the in situ generation of CdS nanocrystals in nanocomposite films and light-emitting electrospun nanofibers is used. Smartly combining room-temperature nanoimprinting, electrospinning, and electron-beam decomposition of nanocrystal precursors and subsequent nucleation of nanoparticles in a polymer matrix allows exploitation of the most favorable flow conditions of organics to produce various nanocomposite nanostructures. Copyright © 2012 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.
Author Keywords
CdS nanocrystals; electrospinning; nanocomposite; nanofibers; nanoimprinting
Document Type: Article
Source: Scopus

 

Castelo A.a, Afonso C.N.a, Pesce, E.b, Piscopiello E.b
(2012) Nanotechnology, 23 (10), art. no. 105603, . Cited 2 times.
a Laser Processing Group, Instituto de Optica, CSIC, Serrano 121, E-28006 Madrid, Spain;
b ENEA-C R Brindisi, UTTMATB-COMP, S.S. 7 Appia, I-72100 Brindisi, Italy
Abstract
This work reports on the optical and structural properties of nanostructured films formed by Ag nano-objects embedded in amorphous aluminium oxide (a-Al2O3) prepared by alternate pulsed laser deposition (PLD). The aim is to understand the importance of the energetic species involved in the PLD process for nanostructuring, i.e.for organizing nanoparticles (NPs) in layers or for self-assembling them into nanocolumns (NCls), all oriented perpendicular to the substrate. In order to change the kinetic energy of the species arriving at the substrate, we use a background gas during the deposition of the embedding a-Al2O3 host. It was produced either in vacuum or in a gas pressure (helium and argon) while the metal NPs were always produced in vacuum. The formation of NPs or NCls is easily identified through the features of the surface plasmon resonances (SPR) in the extinction spectra and confirmed by electron microscopy. The results show that both the layer organization and self-assembling of the metal are prevented when the host is produced in a gas pressure. This result is discussed in terms of the deceleration of species arriving at the substrate in gas that reduces the metal sputtering by host species (by ≈58%) as well as the density of the host material (by 19%). These reductions promote the formation of large voids along which the metal easily diffuses, thus preventing organization and self-organisation, as well as an enhancement of the amount of metal that is deposited. © 2012 IOP Publishing Ltd.
Document Type: Article
Source: Scopus

 

Nenna G.a, Masala S.a, Bizzarro V.b, Re M.c, Pesce E.c, Minarini C.a, Di Luccio T.a
(2012) Journal of Applied Physics, 112 (4), art. no. 044508, . Cited 1 time.
aENEA, UTTP NANO, Centro Ricerche Portici, piazzale E. Fermi, 80055 Portici (NA), Italy;
bIMAST Portici, piazzale E. Fermi, 80055 Portici (NA), Italy;
cENEA, UTTMATB-COMP, Centro Ricerche Brindisi, SS7 Appia Km 713, 72100 Brindisi, Italy
Abstract
CdS nanoparticles of different sizes were synthesised in poly(N-vinylcarbazole) and studied in device structures glass/indium tin oxide (ITO)/PVK:CdS/Al. Electrical bistability and negative differential resistance (NDR) effects were observed in the current-voltage characteristics. In addition, the devices showed a considerable enhancement of the current magnitude. A dependence of the current conduction on the nanoparticle size and size distribution in the polymer was studied through electrical impedance measurements. The study revealed the importance of the charge effects of the nanoparticles resulting in a bistable behavior. A resonant tunneling current model was proposed to explain the NDR and its relation with the nanoparticle size and size distribution. © 2012 American Institute of Physics.
Document Type: Article
Source: Scopus

 

Penza M.
(2012) Carbon Nanomaterials for Gas Adsorption, pp. 333-468. Cited 1 time.
ENEA, Italian National Agency for New Technologies, Energy and Sustainable Economic Development, Brindisi Technical Unit of Technologies for Materials, Brindisi 72100, Italy
Abstract
This chapter reviews the gas sensing properties of the carbon nanotubes (CNTs) at the current state of art. The physical properties of the CNTs are an outstanding mix for advanced nanosensors at high sensitivity and very low sub-ppm level of gas detection at room temperature. Fabrication techniques of the CNTs are surveyed as well. Pristine, modified, purified, and functionalized CNTs are considered as chemically interfaced materials for gas adsorption by using various transducers as innovative platforms. Here we review the key developments of the CNTs gas sensors by means of a comparative analysis of the chemical sensing performance and outline promising applications, challenges, and future perspectives. © 2013 Pan Stanford Publishing Pte. Ltd. All rights reserved.
Document Type: Book Chapter
Source: Scopus

 

Resta V.a, Laera A.M.a, Camposeo A.bc, Piscopiello E.a, Persano L.bc, Pisignano D.bcd, Tapfer L.a
(2012) Journal of Physical Chemistry C , 116 (47), pp. 25119-25125. Cited 4 times.
aENEA, Technical Unit for Materials Technologies, Brindisi Research Centre, Strada Statale 7, Appia km 706, I-72100 Brindisi, Italy;
bNational Nanotechnology Laboratory, Istituto Nanoscienze-CNR, Università Del Salento, via Arnesano, I-73100 Lecce, Italy;
cCenter for Biomolecular Nanotechnologies at UNILE, Istituto Italiano di Tecnologia, via Barsanti, I-73010 Arnesano, LE, Italy;
dDipartimento di Matematica e Fisica Ennio de Giorgi, Università Del Salento, via Arnesano, I-73100 Lecce, Italy
Abstract
The in situ synthesis and patterning of CdS nanocrystals (NCs) is obtained by laser processing of a transparent polymer matrix doped with a cadmium thiolate methylimidazole (MI) modified complex, [Cd(SBz)2]2·MI. The precursor molecule structure ensures a uniform distribution inside the polymer and gives rise to a regular and homogeneous network of CdS NCs in the quantum size regime with a finely tunable bandgap by varying the laser fluence in the range 25-75 mJ cm-2 and shot number from 10 to 100. The simultaneous in situ synthesis of CdS NCs and patterning has been performed in confined regions with a 10 μm resolution by scanning the focused laser beam in the polymer/precursor composite. The emission signal of the irradiated regions presents contributions from both the band gap and the defect emission band, around 3.4 and 2.2 eV, respectively, the relative intensity of them depending on the laser fluence and number of shots. Complex geometries of μ-patterned CdS NCs inside the polymer matrix are achievable, thus enlarging the perspectives in the development of nanodevices and organic light emitting diode (OLED) systems. © 2012 American Chemical Society.
Document Type: Article
Source: Scopus

 

Ferrara M.C.a, Pilloni L.b, Mevoli A.a, Mazzarelli S.a, Tapfer, L.a
(2012) Materials Research Society Symposium Proceedings, 1352, pp. 97-102.
a ENEA, Brindisi Materials Technology Technical Unit (UTTMATB), Brindisi Research Centre, Strada Statale 7 Appia, 72100 Brindisi, Italy
b ENEA, Materials Technology Technical Unit (UTTMAT-CHI), Casaccia Research Centre, Via Anguillarese 301, 00060 S. M. di Galeria, Rome, Italy
Abstract
Nanocrystalline anatase titania thin films were prepared by using two different precursor solutions, a highly acid solution (Sol-1) and a polymer-like solution (Sol-2), via the dip-coating technique on different substrates (〈100〉-Si wafer, fused silica and soda lime glass). The influence of the two sol-gel titania precursor solutions and of the substrate type on the film morphology, coating porosity, surface roughness, crystalline phases and grain size of the titania films were investigated. Our experimental results clearly indicate that the sol - composition and substrate type remarkably influence the microstructural/morphological properties of the titanium dioxide. They consequently modify the optical response and hydrophilic performances of the samples. The photocatalytic oxidations of the methylene blue in water of the samples grown on the glass substrate were monitored to investigate the influence of the sol-gel precursor solution on the photocatalytic activity of the titania coatings, and the results were put in relation with the hydrophilic and optical properties of the films. The outcome demonstrates that the optical properties and the hydrophilic and photocatalytic performances of nanocrystalline titania can be opportunely tailored tuning the size dimension of the crystalline domain according to the specific coating applications. © 2011 Materials Research Society.
Document Type: Conference Paper
Source: Scopus

 

Di Girolamo G.a b, Alfano M.b, Pagnotta L.b, Taurino A.c, Zekonyte J.d, Wood R.J.K.d
(2012) Journal of Materials Engineering and Performance, 21 (9), pp. 1989-1997. Cited 1 time.

a ENEA, UTTMATB, Brindisi Research Centre, Strada Statale 7 Appia, km 706, Brindisi, 72100, Italy
b Department of Mechanical Engineering, University of Calabria, Ponte P. Bucci, Cubo 44C, Rende, 87036, Italy
c Institute for Microelectronics and Microsystems, National Research Council, Via per Monteroni, Lecce, 73100, Italy
d National Centre for Advanced Tribology (nCATS), University of Southampton, Southampton, SO171BJ, United Kingdom

Abstract
The aim of this study is to analyze the evolution of microstructural and room temperature mechanical properties of air plasma sprayed (APS) CoNiCrAlY coatings before and after early stage high-temperature oxidation. To this purpose, selected samples were isothermally heat treated at 1110 °C for different durations. Phase analysis and oxide scale characterization were performed using x-ray diffraction. Morphological and microstructural features of as-sprayed and oxidized CoNiCrAlY coatings were analyzed by scanning electron microscopy and energy dispersive x-ray spectroscopy. After heat treatment, a duplex oxide scale, composed of an inner α-Al2O3 layer and an outer spinel-type oxide layer, was observed on coating top-surface. The nanoindentation technique was employed to study the evolution of the mechanical properties. An increase in Young's modulus and hardness with increasing the aging time was observed, this effect was mainly addressed to the partial densification of coating microstructure. © 2012 ASM International.
Author Keywords
coatings; heat resistant metals; thermal spray

Document Type: Article
Source: Scopus

 

Alvisi M., Aversa P., Cassano G., Serra E., Tagliente M.A., Schioppa M., Rossi R., Suriano D., Piscopiello E., Penza M.
(2012) Lecture Notes in Electrical Engineering, 109 LNEE, pp. 79-85.
ENEA, Brindisi Technical Unit for Technologies of Materials, Brindisi, Italy
Abstract
A Quartz Crystal Microbalance (QCM) gas sensor coated with carbon nanotubes (CNTs) layered films as chemically interactive nanomaterial is described. A QCM resonator integrated on AT-cut quartz substrate has been functionally characterized as oscillator at the resonant frequency of 10 MHz. The CNTs have been grown by chemical vapor deposition (CVD) system onto alumina substrates, coated with 2.5 nm thick Fe catalyst, at a temperature of 750°C in H2/C2H2 gaseous ambient as active materials for gas sensors. CNTs multilayers, with and without buffer layer of cadmium arachidate (CdA), have been prepared by the Langmuir-Blodgett (LB) technique to coat at the double-side the QCM sensors for organic vapor detection, at room temperature. It was demonstrated that the highest mass sensitivity has been achieved for CNTs multilayer onto CdA buffer material due to the greatest gas adsorbed mass. The sensing properties of the CNTs-sensors at enhanced mass sensitivity have been investigated for different vapors of ethanol, methanol, acetone, m-xylene, toluene and ethylacetate in a wide range of concentration from 10 to 800 ppm. The CNTs-based QCM-sensors exhibit high sensitivity (e.g., 5.55 Hz/ppm to m-xylene of the CNTs-multilayer) at room temperature, fast response, linearity, reversibility, repeatability, low drift of the baseline frequency, potential sub-ppm range detection limit. © 2012 Springer Science+Business Media, LLC.
Document Type: Conference Paper
Source: Scopus

 

Rossi R., Alvisi M., Cassano G., Pentassuglia R., Dimaio D., Suriano D., Serra E., Piscopiello E., Pfister V., Penza M.
(2012) Lecture Notes in Electrical Engineering, 109 LNEE, pp. 115-119.
ENEA, Brindisi Technical Unit for Technologies of Materials, Brindisi, Italy
Abstract
In this work, carbon nanomaterials have been prepared by CVD technology onto alumina substrates, coated by nanosized Co-catalyst at different thickness (2.5 nm and 7.5 nm) and used for a simple gas sensor device. The surface has been functionalized with sputtered Pt-nanocluster at a tuned loading of 8, 15 and 30 nm. The response of the chemiresistors in terms of p-type electrical conductance has been investigated as a function of the thickness of the Pt-nanoclusters towards different gases (NO2, NH3, CO, CH4, CO2). Furthermore, the effect of the temperature ranging from 20°C to 250°C on the sensor response has been addressed as well. Additionally, a short-term stability of the carbon nanomaterials based sensor towards NO2 gas detection has been investigated for a 2-month period. The gas sensors based on Pt-modified carbon nanomaterials exhibit higher sensitivity compared to unmodified material, fast response, reversibility, repeatability, moderate drift of the baseline signal, sub-ppm range detection limit. © 2012 Springer Science+Business Media, LLC.
Document Type: Conference Paper
Source: Scopus

 

Trizio L.a, Brattoli M.a, De Gennaro G.a, Suriano D.b, Rossi R.b, Alvisi M.b, Cassano G.b, Pfister V.b, Penza M.b
(2012) Lecture Notes in Electrical Engineering, 109 LNEE, pp. 139-144.
a Department of Chemistry, University of Bari, Bari, Italy
b ENEA, Brindisi Technical Unit for Technologies of Materials, Brindisi, Italy
Abstract
A sensors array based on two different types of chemical sensors such as tin dioxide commercial sensors and carbon nanotubes innovative sensors developed in the ENEA laboratories to monitor gases (e.g., CO, NO2, SO2, H2S and CO2) of relevance in polluted air has been analyzed. Measurements of chemical sensing of the sensors array have been performed in laboratory to create a database for applying artificial neural networks (ANNs) algorithms to quantify gas concentration of individual air pollutants and binary gas-mixture. A total number of 3,875 data-samples based on 413 distinct gas concentrations measured by 14 gas sensors has been used in the database. The ANN performance has been assessed for each targeted air-pollutant. The lowest normalized mean square error (NMSE) of 6%, 9% and 11% has been achieved for NO2, SO2 and CO2, respectively. In the contrast, NMSE as high as 28% and 39% has been measured for CO and H2S, respectively. The aim of this study is the selection of an optimal set of gas sensors in the array for enhanced environmental measurements of gas concentration in real-scenario. © 2012 Springer Science+Business Media, LLC.
Document Type: Conference Paper
Source: Scopus

 

Masala S.a, Bizzarro V.b, Re M.c, Nenna G.a, Villani F.a, Minarini C.a, Di Luccio T.a
(2012) Physica E: Low-Dimensional Systems and Nanostructures, 44 (7-8), pp. 1272-1277. Cited 2 times.
a ENEA Italian National Agency for New Technologies, Energy and Sustainable Economic Development, Centro Ricerche Portici, Piazzale E. Fermi 1, I-80055 Portici Naples, Italy;
b IMAST Portici, Piazzale E. Fermi, I-80055 Portici Naples, Italy;
c ENEA Italian National Agency for New Technologies, Energy and Sustainable Economic Development, Centro Ricerche Brindisi, SS7 Appia Km 713, I-72100 Brindisi, Italy
Abstract
In this work we studied the optical and transport properties of hybrid nanocomposites of CdS quantum dots (QDs) and poly(N-vinylcarbazole) (PVK) polymer. The CdS QDs were prepared by thermal decomposition (thermolysis) of a single source precursor, Cd bis-thiolate, in a high boiling solvent, octadecene (ODE). The optical characterization of the QDs has been carried out by UV-vis absorption and photoluminescence spectroscopy while the morphological properties have been investigated atomic force microscopy and transmission electron microscopy. The analyses have shown that CdS QDs of diameter below 6 nm can be synthesized by such route with good light emission in the UV range. The QDs have been dispersed in a poly(N-vinylcarbazole) (PVK) matrix to obtain a PVK:CdS nanocomposite layers. An increase of conductivity and a quenching of the photoluminescence have been observed when the nanocomposite layer was inserted in ITO/PVK:CdS/Al structures. © 2012 Elsevier B.V.
Document Type: Article
Source: Scopus

 

Rizzo A.a, Signore M.A.a, Valerini D.a, Altamura D.b, Cappello A.a, Tapfer L.a
(2012) Surface and Coatings Technology, 206 (10), pp. 2711-2718. Cited 4 times.
a ENEA - Italian National Agency for New Technologies Energy and Sustainable Economic Development, Technical Unit for Materials Technologies, Brindisi Research Center, S.S. 7 Appia km. 706, 72100 Brindisi, Italy
b Istituto di Cristallografia (IC), CNR, Via Amendola 122/O, 70126 Bari, Italy
Abstract
A scrupulous cleaning and degreasing of the deposition chamber allows to make a ZrN film with stoichiometry of 1.3 and to achieve a level of oxygen contamination equal to 5%. This film exhibits a low number of carriers estimated at N*=3×1021cm-3 and with a very high electrical resistivity value of about 105μΩ.m. This result points the way for further improvements in the quality of the material.This amount of oxygen contamination may be reduced in conditions in which only the oxygen will be removed without disturbing the zirconium presence in the film. A bias voltage value between 8. eV and 20. eV reduces the oxygen contamination.The ionic assistance is often proposed as a mean to minimize the oxygen contamination. However, one must consider the negative phenomena as re-sputtering, ion implantation, atom displacement and stress generation that introduce defects in the film and affect its properties. This work proposes a very low bias voltage value to control oxygen contamination. The bias voltage value is chosen higher than the nitrogen sputtering threshold energy and lower than the argon sputtering threshold energy. The re-sputtering phenomenon, far from being a problem, can be used to achieve the stoichiometry if one starts from a nitrogen-rich compound. In this way, ZrN x is grown with x about 1, with an effective free electron concentration N*=8.9×1021cm-3. Furthermore its resistivity value is about 2μΩ.m and the oxygen Secondary Ion Mass Spectrometry (SIMS) signal is similar to the noise signal. © 2011 Elsevier B.V.
Author Keywords
Oxygen contamination; R. F. sputtering magnetron; Zirconium nitride

Document Type: Article
Source: Scopus

 

Signore M.A.a, Sytchkova A.b, Dimaio D.a, Cappello A.a, Rizzo A.a
(2012) Optical Materials, 34 (4), pp. 632-638. Cited 4 times.
a ENEA-Technical Unit Material Technology, Research Centre of Brindisi, S.S. 7 Appia km 706, 72100 Brindisi, Italy
b ENEA-Technical Unit Material Technology, Research Centre of Casaccia, Via Anguillarese 301, 00123 Rome, Italy
Abstract
Silicon nitride (SiNx) thin films were deposited by RF magnetron sputtering at room temperature in (Ar + N2) atmosphere by tuning the reactive gas flux percentage in the mixture. The samples were analyzed by UV-Vis-NIR and Fourier transform infrared (FTIR) spectrophotometry and by SIMS (Secondary Ion Mass spectroscopy). The effects of the nitrogen content in the gas mixture on the growth process and on SiNx films optical and chemical properties were investigated. A qualitative description of the growth process, which analyzes the role of nitrogen dissociation or ionization in (Ar + N2) atmosphere for the sputtering of a silicon target, is the key factor to interpret the obtained results. It perfectly matches with the thin films physical response. Optical analysis supplied the optical constants (n and k) and optical bandgap values. They increase by rising nitrogen content in the mixture but their values are lower than that of Si3N4 stoichiometric film. This has been attributed to the contaminant presence (oxygen and hydrogen) as well supported by SIMS and FTIR spectra. © 2011 Elsevier B.V. All rights reserved.
Author Keywords
FTIR; Silicon nitride; SIMS; Sputtering deposition

Document Type: Article
Source: Scopus

 

Rizzo A.a, Signore M.A.a, Mirenghi L.a, Tapfer L.a, Piscopiello E.a, Salernitano E.b, Giorgi R.b
(2012) Thin Solid Films, 520 (9), pp. 3532-3538. Cited 4 times.
a ENEA-Technical Unit Material Technology, Research Centre of Brindisi, S. S. 7 Appia km 706, 72100 Brindisi, Italy
b ENEA-Technical Unit Material Technology, Research Centre of Casaccia, Via Anguillarese 301, 00123 Rome, Italy
Abstract
The interest about zirconium oxynitrides is growing with the attention for zirconium nitrides phase at high zirconium content. In recent years a great progress has been made to realize both the higher nitride phase (Zr 3N 4) and the higher oxynitride phase (Zr 2ON 2) in more ordered crystal structures. In this work the abovementioned two phases are realized by RF magnetron sputtering technique. The characterization results, illustrated in the present paper, push towards the evidence of an evolution from zirconium N-rich nitride to the oxynitride films by introducing a very small percentage (0.5%) of water vapor in a sputtering atmosphere made only of nitrogen gas. In particular, structural analysis identified zirconium N-rich nitride as c-Zr 3N 4 and zirconium oxynitride as c-Zr 2ON 2. The formation of zirconium oxynitride is due to oxygen presence, coming from the water dissociation in the plasma. Both phases request an additional energy supplied by substrate bias assistance for c-Zr 3N 4 and by more energetic particles reflected by the Zr target for c-Zr 2ON 2. © 2012 Elsevier B.V. All rights reserved.
Author Keywords
Radio-frequency sputtering; X-ray diffraction; X-ray photoelectron spectroscopy; Zirconium nitride; Zirconium oxynitride

Document Type: Article
Source: Scopus

 

Abazović N.D.a, Čomor M.I.a, Mitrić M.N.a, Piscopiello E.b, Radetić T.c, Janković I.A.a, Nedeljković J.M.a
(2012) Journal of Nanoparticle Research, 14 (4), pp. 1-10. Article number 810. Cited 3 times.
a Vinča Institute of Nuclear Sciences, University of Belgrade, P.O. Box 522, Belgrade, 11001
b Department of Advanced Physics Technology and New Materials (FIM), ENEA, Strada Statale 'Appia', Brindisi, 72100, Italy
c Lawrence Berkeley National Laboratory, Berkeley, 94720, United States
Abstract
Nanosized AgInSe2 particles (d ∼ 7-25 nm) were synthesized using colloidal chemistry method at 270 °C. As solvents/surface ligands 1-octadecene, trioctylphosphine, and oleylamine were used. It was shown that choice of ligand has crucial impact not only on final crystal phase of nanoparticles, but also at mechanism of crystal growth. X-ray diffraction and TEM/HRTEM techniques were used to identify obtained crystal phases and to measure average size and shape of nanoparticles. UV/Vis data were used to estimate band-gap energies of obtained samples. It was shown that presented routes can provide synthesis of nanoparticles with desired crystal phase (tetragonal and/or orthorhombic), with band-gap energies in the range from 1.25 to 1.53 eV. © Springer Science+Business Media B.V. 2012.
Author Keywords
AgInSe2; Chalcogenide semiconductors; Ligands; Oleylamine (OLAM); Synthesis; Trioctylphosphine (TOP); UV/Vis absorption; XRD
Document Type: Article
Source: Scopus

 

Nacucchi M.a, Alvisi M.a, Altamura D.b, Pfister V.a, Valerini D.a, Mello D.c, Giannini C.b
(2012) IOP Conference Series: Materials Science and Engineering, 32 (1), art. no. 012017.
a ENEA, Materials Technology Unit, Research Centre of Brindisi, S.S. 7 Appia - km 706.00, IT-72100 Brindisi, Italy
b Consiglio Nazionale Delle Ricerche (CNR), Institute of Crystallography, Via G. Amendola 122/0, IT-70126 Bari, Italy
c ST Microelectronics, QA and Phys. Lab., Stradale Primosole 50, IT-95100 Catania, Italy
Abstract
In this work, the use of unconventional reference materials to determine experimentally the Cliff-Lorimer factor for EDS quantitative analysis with a TEM is checked by means of an alternative experimental procedure. The k-factor is determined by the extrapolation method based on pure elements, by measuring the normalized X-ray intensities emitted by thin films of pure gold and pure silver of different thickness, accurately measured by X-ray reflectivity. The goal of this work is to confirm the value of the k-factor previously obtained by the use of unconventional reference materials consisting of a bi-layer of pure gold on pure silver. The current result is in accordance with the previous one when considering their error bars, however, their relative difference is about 13 %, probably due to some uncertainties in mass thickness measurements. The mass thickness measurement of the layers of pure elements needs to be performed by different methods in order to reduce its uncertainty.
DOCUMENT TYPE: Conference Paper
SOURCE: Scopus

 

Camposeo A.a, Polo M.a, Neves A.A.R.a, Fragouli D.b, Persano L.a, Molle S.a, Laera A.M.c, Piscopiello E.c, Resta V.c, Athanassiou A.abd, Cingolani R.d, Tapfer L.c, Pisignano D.abe
(2012) Journal of Materials Chemistry, 22 (19), pp. 9787-9793. Cited 2 times.
a National Nanotechnology Laboratory, Istituto Nanoscienze, CNR, via Arnesano, 73100 Lecce, Italy;
b Center for Biomolecular Nanotechnologies, Istituto Italiano di Tecnologia at UNILE, via Barsanti 1, I-73010 Arnesano, LE, Italy;
c ENEA, Technical Unit Material Technology Research Centre of Brindisi (UTTMATB), S.S. 7 Appia km 706, I-72100 Brindisi, Italy;
d Istituto Italiano di Tecnologia (I.I.T.), via Morego 30, I-16163 Genova, Italy;
e Dipartimento di Matematica e Fisica Ennio de Giorgi, Universitá Del Salento, via Arnesano, I-73100 Lecce, Italy
Abstract
The in situ synthesis and patterning of CdS nanocrystals in a polymer matrix is performed via multi-photon absorption. Quantum-sized CdS nanocrystals are obtained by irradiating a cadmium thiolate precursor dispersed in a transparent polymer matrix with a focused near infrared femtosecond laser beam. High resolution transmission electron microscopy evidences the formation of nanocrystals with wurtzite crystalline phase. Fluorescent, nanocomposite patterns with sub-micron spatial resolution are fabricated by scanning the laser beam on the polymer-precursor composite. Moreover, the emission energy of the CdS nanocrystals can be tuned in the range 2.5-2.7 eV, by changing the laser fluences in the range 0.10-0.45 J cm-2. This method enables therefore the synthesis of luminescent, CdS-based composites to be used within patterned nanophotonic and light-emitting devices. © 2012 The Royal Society of Chemistry.
DOCUMENT TYPE: Article
SOURCE: Scopus

 

Cretì A.a, Valerini D.b, Taurino A.a, Quaranta F.a, Lomascolo M.a, Rella R.a
(2012) Journal of Applied Physics, 111 (7), art. no. 073520. Cited 2 times.
a IMM - CNR, Institute for Microelectronics and Microsystems, Campus Universitario, Via per Monteroni, 73100 Lecce, Italy;
b ENEA, UTTMATB, Brindisi Research Center, S.S. 7 Appia - km 706, 72100 Brindisi, Italy
Abstract
The optical response by NO2 gas adsorption at different concentrations has been investigated, at room temperature, in ZnO nanostructured films grown by controlled vapor phase deposition. The variation (quenching) in the photoluminescence signal from excitonic and defects bands, due to the interactions between the oxidizing gas molecules and the sample surface, has been detected and dynamic responses and calibration curves as a function of gas concentration have been obtained and analyzed for each band. We showed that the sensing response results larger in excitonic band than in defect one and that the emission signal rises from two different quenchable and unquenchable states. A simple model was proposed in order to explain the quenching processes on the emission intensity and to correlate them to the morphological features of the samples. Finally, the reversibility of the quenching effects has also been tested at high gas concentration. © 2012 American Institute of Physics.
DOCUMENT TYPE: Conference Paper
SOURCE: Scopus

 

Di Girolamo G.ab
(2012) Sensors and Actuators, A: Physical, 178, pp. 136-140. Cited 2 times.
a ENEA, UTMATB, Brindisi Research Center, Strada Statale 7 Appia, km 706, 72100 Brindisi, Italy
b Institute for Microelectronics and Microsystems-Unit of Lecce, National Research Council, Via Monteroni, 72100 Lecce, Italy
Abstract
Ion implantation can be successfully employed to produce thin conductive films in insulating polymers. To this aim, epoxy bulk samples were implanted at room temperature with C + ions of 50-100 keV, ion fluences ranging from 1.5 × 10 17 to 3 × 10 17 ions/cm 2 and current density of 0.5-2 μA/cm 2. The distribution and the depth profile of the implanted ions were calculated by SRIM and TRIDYN codes. The electrical resistance of the implanted samples was measured at room temperature: a significant conductivity was obtained when all the irradiation parameters were set to their highest value. The changes in electrical resistance were studied during compression and three-point bending tests, in order to evaluate the sensitivity of the implanted polymers and to study their capability to absorb distortions. A linear relationship between electrical resistance and surface load was noticed. The results showed that these innovative strain gauges exhibit very high sensitivity and reliability. They can be easily integrated in complex components and used for in-service monitoring of their structural stability and mechanical strain. © 2012 Elsevier B.V.
Author Keywords
Ion implantation; Polymer; Strain gauge
Document Type: Article
Source: Scopus