Center for Materials and Microsystems

Trento, Italy

Center for Materials and Microsystems

Trento, Italy
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Lion A.,University of Trento | Laidani N.,Center for Materials and Microsystems | Bettotti P.,University of Trento | Piotto C.,University of Trento | And 3 more authors.
Applied Surface Science | Year: 2017

Selective functionalization of the external/internal pore surface of porous silicon is of interest for the numerous potential applications of this material, in particular in pharmacology. With the aim of obtaining porous silicon platforms compatible with the aqueous environment and providing hydrophobic pores to load poorly water soluble molecules, we set-up a three step functionalization procedure consisting in two hydrosilylation reactions separated by the selective etching of the external surface. This procedure was applied both, to porous layers and porous microparticles. The characterization of the functionalized material by conventional techniques such as contact angle and FTIR showed a change of the properties of porous structures in line with the expected surface modifications. However, these techniques do not permit to clearly distinguish between internally and externally grafted functional groups. For this reason, an innovative procedure based on angle-resolved XPS was set-up and applied to differently functionalized pSi layers. By this technique, we obtained indications of prevalent grafting of hydrophilic moieties on the external surface and hydrophobic ones inside the pores. © 2017 Elsevier B.V.

Bisadi Z.,University of Trento | Fontana G.,University of Trento | Moser E.,University of Trento | Pucker G.,Center for Materials and Microsystems | Pavesi L.,University of Trento
Proceedings of SPIE - The International Society for Optical Engineering | Year: 2016

A random number generation approach comprising a silicon nanocrystals LED (Si-NCs LED), silicon single photon avalanche photodiode (Si SPAD) and a field-programmable gate array (FPGA) is introduced. The Si-NCs LED is the source of entropy with photon emission in the visible range detectable by silicon detectors allowing the fabrication of an all-silicon-based device. The proposed quantum random number generator (QRNG) is robust against variations of the internal and external parameters such as aging of the components, changing temperature, the ambient interferences and the silicon detector artifacts. The raw data show high quality of randomness and passed all the statistical tests in National Institute of Standards and Technology (NIST) tests suite without the application of a post-processing algorithm. The efficiency of random number generation is 4-bits per detected photon. © 2016 SPIE.

Ciappa M.,ETH Zurich | Koschik A.,ETH Zurich | Dapor M.,Center for Materials and Microsystems | Fichtner W.,ETH Zurich
Microelectronics Reliability | Year: 2010

Modeling of critical dimensions scanning electron microscopy with sub-nanometer uncertainty is required to provide a metrics and to avoid yield loss in the processing of advanced CMOS technologies. In this paper, a new approach is proposed, which includes a new Monte Carlo scheme, a new Monte Carlo code, as well as the coupling with electrostatic fields to take into account self-charging effects. © 2010 Elsevier Ltd. All rights reserved.

Lukowiak A.,CNR Institute for Photonics and Nanotechnologies | Lukowiak A.,Institute of Low Temperature And Structure Research | Wiglusz R.J.,Institute of Low Temperature And Structure Research | Chiappini A.,CNR Institute for Photonics and Nanotechnologies | And 6 more authors.
Journal of Non-Crystalline Solids | Year: 2014

Nanoparticles of lithium lanthanum tetraphosphates doped with different concentration of Eu3 + ions were synthesized. The selected tetraphosphate was used to fabricate a transparent composite where nanocrystals were immobilized in a sol-gel-derived silica-hafnia amorphous film. The structural and spectroscopic properties of the systems were investigated by XRD analysis, Raman spectroscopy, and photoluminescence measurements. For all the samples with the Eu3 + ions concentration from 1 to 100 mol% the monoclinic structure with a space group C12/c1 was determined. The mean diameter of nanocrystals determined by Scherrer equation was in the range of 40-55 nm. The luminescence of 10%Eu3 +:LiLa(PO3)4 in silica-hafnia matrix indicated the immobilization of Eu3 + ions into a distorted environment. The dependence of both luminescence intensity and lifetime on the Eu3 + concentration demonstrated effective reduction of concentration quenching in the tetraphosphate nanopowders. © 2013 Elsevier B.V.

A Beccara S.,University of Trento | Garberoglio G.,University of Trento | Garberoglio G.,Center for Materials and Microsystems | Faccioli P.,University of Trento | Pederiva F.,University of Trento
Journal of Chemical Physics | Year: 2010

We introduce a framework to investigate ab initio the dynamics of rare thermally activated reactions, which cannot be studied using the existing techniques. The electronic degrees of freedom are described at the quantum-mechanical level in the Born-Oppenheimer approximation, while the nuclear degrees of freedom are coupled to a thermal bath, through a classical Langevin equation. This method is based on the path integral representation for the stochastic dynamics and yields the time evolution of both nuclear and electronic degrees of freedom, along the most probable reaction pathways, without spending computational time to explore metastable states. As a first illustrative application, we characterize the dominant pathway in the cyclobutene→butadiene reaction, using the semiempirical Parametrized Model 3 (PM3) approach. © 2010 American Institute of Physics.

Garberoglio G.,University of Trento | Garberoglio G.,University of Pittsburgh | Garberoglio G.,U.S. National Energy Technology Laboratory | Garberoglio G.,Center for Materials and Microsystems | And 2 more authors.
ACS Nano | Year: 2010

The effect of the quantized rotational degrees of freedom of hydrogen on the adsorption and sieving properties in carbon nanotubes is studied using computer simulations. We have developed a highly efficient multiple timestep algorithm for hybrid Monte Carlo sampling of quantized rotor configurations and extended the grand canonical Boltzmann bias method to rigid linear molecules. These new computational tools allow us to calculate accurately the quantum sieving selectivities for cases of extreme two-dimensional confinement as a function of pressure. The para-T2/para-H2 selectivity at 20 K is analyzed as a function of the tube diameter and the density of adsorbed hydrogen. Extraordinarily high selectivities, up to 2.6 × 108, are observed in the narrowest nanotube. The quantized nature of the rotational degrees of freedom is found to dramatically affect adsorption and selectivity for hydrogen isotopes adsorbed in very narrow nanotubes. The T 2/H2 zero-pressure selectivity increases from 2.4 × 104 to 1.7 × 108 in the (3,6) nanotube at 20 K when quantum rotations are accounted for. The isotopic selectivity is found to increase with pressure, tending to a constant value at saturation. A simplified mean-field model is used to discuss the origin of this behavior. © 2010 American Chemical Society.

Jedlovszky P.,Eötvös Loránd University | Jedlovszky P.,HAS Research Group of Technical Analytical Chemistry | Garberoglio G.,University of Trento | Garberoglio G.,Consorzio Nazionale Interuniversitario per le Science Fisiche della Materia | And 2 more authors.
Journal of Physics Condensed Matter | Year: 2010

We report results of molecular dynamics simulations of supercooled bulk water at 180 K, close to the liquid/liquid coexistence lines recently discovered in the supercooled regime, both experimentally and by computer simulations. Despite the considerable differences in the densities of the three states considered, the obtained velocity autocorrelation functions display very similar behaviour in every case. On the other hand, the corresponding spectra show the presence of three well-defined modes. The two modes at higher frequencies are assigned to the symmetric and asymmetric stretching motions, respectively, whereas the lowest frequency mode to the bending and torsional motions in clusters of five hydrogen-bonded water molecules. A careful fitting procedure demonstrates the presence of such clusters also in the normal liquid phase of water at ambient conditions. © 2010 IOP Publishing Ltd.

Adami A.,Center for Materials and Microsystems | Pedrotti S.,Center for Materials and Microsystems | Collini C.,Center for Materials and Microsystems | Lorenzelli L.,Center for Materials and Microsystems
Lecture Notes in Electrical Engineering | Year: 2014

This work presents the development of a "all-solid state" integrated reference electrode based on a PVC membrane doped with lipophilic salts (tetrabutylammonium tetrabutylborate (TBA-TBB) and Potassium tetrakis (4-chlorphenyl)borate (KTClpB)) for the integration with ISFETs sensors using a Si3N4 dielectric as sensitive material. The described system is intended for the implementation of fully integrated large sensor arrays for high throughput cell assays. Electrode preparation and evaluation of potential stability to pH is described, demonstrating the suitability of the approach. © 2014 Springer Science+Business Media.

Bagolini A.,Center for Materials and Microsystems | Boscardin M.,Center for Materials and Microsystems | Balucani M.,University of Rome La Sapienza | Balucani M.,Rise Technology S.r.l.
Proceedings of the 2015 18th AISEM Annual Conference, AISEM 2015 | Year: 2015

3D manufacturing at micron scale with very low roughness is a key enabling technology for the realization of micromechanical parts both for mechanical devices and for critical components such as printer head nozzles and high precision molds. The only currently available technique in the field of IC micro technology is nanolithography by two photon absorption [1]. We report the implementation of a technique based on multiple Deep Reactive Ion Ecthing (DRIE) [2] that allows to realize complex 3D geometries in silicon with a limited number of lithographic steps. A mold is demonstrated with 1/30 aspect ratio, 6 depth levels, including wafer-through features, with a dimensional accuracy of 5um. © 2015 IEEE.

Mulloni V.,Center for Materials and Microsystems | Solazzi F.,Center for Materials and Microsystems | Ficorella F.,Center for Materials and Microsystems | Collini A.,Center for Materials and Microsystems | Margesin B.,Center for Materials and Microsystems
Microelectronics Reliability | Year: 2013

Most of the actual applications for RF-MEMS switch require high reliability, but consolidated qualification procedures are still lacking. This paper focuses, in particular, on the role of temperature on the switch reliability from a mechanical point of view, showing how this depends on the switch architecture and membrane material. Double clamped switches are sensitive to buckling, and this is the factor limiting their operational temperature, even though the range exploitable can be wide enough for many applications. Residual stress and thermal expansion coefficient of the mobile membrane are the most important parameters to understand and control this phenomenon. Cantilever switches are less influenced by the temperature in their performances, and have a much wider operational range. Other temperature-related factors are affecting the switch reliability in this case, such as elastic modulus variation, dielectric charging effects and creep. © 2013 Elsevier Ltd. All rights reserved.

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