Alberto Quaranta | University of Trento (original) (raw)

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Papers by Alberto Quaranta

MRS Proceedings, 2004

Ternary W-Si-N thin films have been reactively sputter-deposited from a W5Si3 target at different... more Ternary W-Si-N thin films have been reactively sputter-deposited from a W5Si3 target at different nitrogen partial pressures. The composition has been determined by 2.2 MeV 4 He + beam, the structure by x-ray diffraction and transmission electron microscope, the chemical bonds by Fourier transform - infrared spectroscopy and the surface morphology by scanning electron microscopy. Electrical resistivity was measured by four point probe technique on the as grown films. The film as-deposited is amorphous with the Si/W ratio increasing from about 0.1 up to 0.55 with the nitrogen content going from 0 to 60 at%. The heat treatments up to 980 °C induce a loss of nitrogen in the nitrogen rich samples. Segregation of metallic tungsten occurs in the sample with low nitrogen content (W 58 Si 21 N 21 ). Samples with high nitrogen content preserve the amorphous structure, despite of the precipitation of a more ordered phase inferred by FT-IR absorbance spectrum of the layer treated at highest te...

Sol-Gel Derived Organic - Inorganic Layers for the Detection of Aromatic Molecule

Silk fibroin is a well-known biopolymer used in several applications in which the interaction wit... more Silk fibroin is a well-known biopolymer used in several applications in which the interaction with biological tissue is required. In fact, fibroin is extremely versatile and can be shaped to form several constructs useful in tissue engineering applications. Confocal imaging is usually per-formed to test the cells behaviour on the construct and in this context the fibroin autofluorescence is regarded as a problem. In addition, the autofluorescence is not intense enough to provide useful morphological images. In fact, to control study the constructs morphology other techniques are used (i.e. SEM, Micro-CT). In this work we propose a method based on the fluorescence energy transfer (FRET) to suppress the fibroin autofluorescence moving it to higher wavelength accessible to the confocal microscopy for a direct imaging.

Science Advances, 2021

The direct detection of 5-MeV protons by a flexible organic thin-film device is here reported.

The Journal of Physical Chemistry C, 2020

In this study, a comprehensive investigation of the role of sulfur vacancies on the electronic st... more In this study, a comprehensive investigation of the role of sulfur vacancies on the electronic structure and surface reactivity of molybdenum disulfide is presented. A 2H-MoS 2 single crystal was annealed at two different temperatures, namely, 300 and 500°C in vacuum, in order to generate sulfur vacancies in a controlled manner. The detailed characterization of the electronic structure by means of X-ray and ultraviolet photoelectron spectroscopy clearly evidences the formation of a strong surface dipole as well as surface band bending due to the excess of negative charge on the Mo centers, as a consequence of the generated sulfur vacancies. After thermal treatment, a mercaptoundecylphosphonic acid molecule, which consists of a thiol (S−H) tail group and a phosphonic acid group on the other end, was covalently attached on the surface through wet chemical functionalization in order to refill the sulfur vacancies. As a consequence of the vacancy refilling, the surface band bending is reversed and the surface dipole is remarkably decreased, being close to the initial value of the pristine surface.

ACS Applied Materials & Interfaces, 2018

Transition metal dichalcogenides, such as molybdenum disulfide (MoS2), show peculiar chemical/phy... more Transition metal dichalcogenides, such as molybdenum disulfide (MoS2), show peculiar chemical/physical properties that enables their use in applications ranging from micro-and nanooptoelectronics to surface catalysis, gas and light detection and energy harvesting/production. One main limitation to fully harness the potential of MoS2 is given by the lack of scalable and low environmental impact synthesis of MoS2 films with high uniformity, hence setting a significant challenge for industrial applications. In this work, we develop a versatile and scalable sol-gel derived MoS2 film fabrication by spin coating deposition of an aqueous sol on different technologically relevant, flexible substrates with annealing at low temperatures (300°C) and

Radiation protection dosimetry, Jan 3, 2018

We report on a scintillator-based online detection system for the spectral characterization of po... more We report on a scintillator-based online detection system for the spectral characterization of polychromatic proton bunches. Using up to nine stacked layers of radiation hard polysiloxane scintillators, coupled to and readout edge-on by a large area pixelated CMOS detector, impinging polychromatic proton bunches were characterized. The energy spectra were reconstructed using calibration data and simulated using Monte-Carlo simulations. Despite the scintillator stack showed some problems like thickness inhomogeneities and unequal layer coupling, the prototype allows to obtain a first estimate of the energy spectrum of proton beams.

Journal of Applied Physics, 2016

a-alumina pre-sintered samples were subjected to flash sintering at 1200 C under differing electr... more a-alumina pre-sintered samples were subjected to flash sintering at 1200 C under differing electric field strengths. The analysis of the relation between the incubation time and pre-sintering temperature clearly shows that the presence of pores and surfaces within the sample plays a central role in field-assisted sintering behavior of the material. The observed behavior is accounted for by the strong non-linear electrical conductivity shown by porous alumina at high field strength. The observed non-ohmic conductivity can also be related to the "pre-breakdown" behavior previously described by Frenkel. Literature results suggest that the field involved in flash sintering of alumina is comparable with the dielectric strength at high temperature. We can also state that dielectric breakdown and flash sintering in alumina are associated with similar physical phenomena.

Applied Spectroscopy, 2016

Two different types of spectroscopic methods, namely diffuse reflection infrared spectroscopy (DR... more Two different types of spectroscopic methods, namely diffuse reflection infrared spectroscopy (DRIFTS) as a vibrational spectroscopy and ion-beam-induced luminescence (IBIL) as an optical spectroscopy, have been exploited for the analysis of three sand samples collected from the Adige, Bacchiglione, and Brenta rivers (Veneto, Northern Italy) with the aim to set up a procedure for the comparison of the relative abundance of silicates, carbonates, and feldspars. By fitting the spectra, the features corresponding to different geological compounds have been identified and descriptive indexes of their relative amount have been obtained by comparing the peak area ratios.

Spectrochimica Acta Part A: Molecular and Biomolecular Spectroscopy, 2017

In this work we present for the first time an application of PARAllel FACtor (PARAFAC) analysis t... more In this work we present for the first time an application of PARAllel FACtor (PARAFAC) analysis to the investigation of Ion Beam Induced Luminescence (IBIL) spectra of Ag+↔Na+ ion exchanged silicate glasses, in order to check the possibility to obtain additional information on the formation of silver aggregates under ion irradiation by a proper statistical rearrangement of experimental spectra. We decomposed the data by PARAFAC taking into account both IBIL emission features and their evolution as a function of the time. Shape and trend under irradiation of the extracted components were correlated to silver concentration and aggregates in the investigated systems. Strength and weakness of this statistical approach applied to IBIL spectra recorded as a function of time were evidenced and discussed.

Materials Chemistry and Physics, 2013

h i g h l i g h t s < Scintillators based on phenyl containing polysiloxane blends were synthesiz... more h i g h l i g h t s < Scintillators based on phenyl containing polysiloxane blends were synthesized. < Scintillation yield stability and radiation hardness was analyzed. < Scintillators with high scintillation yield and very stable even after 54 kGy of irradiation doese were obtained.

Journal of Applied Physics, 2002

ABSTRACT

The aim of this research is to establish reliable criteria to distinguish mobile sediments collec... more The aim of this research is to establish reliable criteria to distinguish mobile sediments collected from Veneto rivers that are expected to be of very similar composition since they share nearby hydrographic basins. In particular sediments from the riverbeds of Adige, Brenta, and Bacchiglione were collected and investigated by IBIL and DRIFT spectroscopy. Since it was recognized that likely sources for Roman building materials were rivers flowing close to the corresponding locations, results from the present study are expected to be useful in identifying the origin of sands obtained from mortars belonging to some I-century-AC Roman villas located in the X Regio [1]. In this work FT-IR and Ion Beam Induced Luminescence (IBIL) spectroscopies have been used for the first time for analyzing mobile sediments. In particular, the main spectral features, suitable for the identification of the provenance of the different samples, are examined.

Chemistry of Materials, 2004

Glow-discharge-induced sublimation (GDS) is used to deposit thin films of polyimide precursor mon... more Glow-discharge-induced sublimation (GDS) is used to deposit thin films of polyimide precursor monomers, i.e., 2,4,6-trimethyl m-phenylenediamine (TMPD), 4,4′-hexafluoroisopropylidene dianiline (6FDAm), 3,3′-diaminodiphenyl sulfone (DDS), 4,4′-hexafluoroisopropylidene diphthalic anhydride (6FDA), and 3,3′,4,4′-biphenyltetracarboxylic acid dianhydride (BPDA). Monomer films are also deposited by vacuum evaporation (VE) for the sake of comparison. In situ mass spectrometry points out both the sublimation of integer monomer molecules and the presence of molecular fragments in the glow discharge. AFM images of the film surfaces indicate that GDS allows obtention of smoother surfaces with respect to VE for most of the monomers. FT-IR analysis and UV-Vis fluorescence spectroscopy show that the deposition of integer monomer molecules onto the substrate and the partial incorporation of molecular fragments take place. In particular, the fluorescence features of GDS samples are different from those of VE samples and depend on the incorporated molecular fragments whose optical properties are similar to those of amorphous hydrogenated carbon structures.