251 results on '"Miritello, M"'
Search Results
102. Direct evidence of light confinement and emission enhancement in active silicon-on-insulator slot waveguides
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Galli, M., primary, Gerace, D., additional, Politi, A., additional, Liscidini, M., additional, Patrini, M., additional, Andreani, L. C., additional, Canino, A., additional, Miritello, M., additional, Savio, R. Lo, additional, Irrera, A., additional, and Priolo, F., additional
- Published
- 2006
- Full Text
- View/download PDF
103. The influence of substrate on the properties of Er2O3 films grown by magnetron sputtering
- Author
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Miritello, M., primary, Lo Savio, R., additional, Iacona, F., additional, Franzò, G., additional, Bongiorno, C., additional, Irrera, A., additional, and Priolo, F., additional
- Published
- 2006
- Full Text
- View/download PDF
104. Strong enhancement of Er3+ emission at room temperature in silicon-on-insulator photonic crystal waveguides
- Author
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Galli, M., primary, Politi, A., additional, Belotti, M., additional, Gerace, D., additional, Liscidini, M., additional, Patrini, M., additional, Andreani, L. C., additional, Miritello, M., additional, Irrera, A., additional, Priolo, F., additional, and Chen, Y., additional
- Published
- 2006
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- View/download PDF
105. Electroluminescence properties of SiOx layers implanted with rare earth ions
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Irrera, A., primary, Miritello, M., additional, Pacifici, D., additional, Franzò, G., additional, Priolo, F., additional, Iacona, F., additional, Sanfilippo, D., additional, Di Stefano, G., additional, and Fallica, P.G., additional
- Published
- 2004
- Full Text
- View/download PDF
106. Local Order and Crystallization of Laser Quenched and Ion Implanted Amorphous Ge1-xTex Thin Films.
- Author
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Carria, E., De Bastiani, R., Gibilisco, S., Mio, A., Miritello, M., Pennisi, A. R., Bongiorno, C., Grimaldi, M. G., and Rimini, E.
- Published
- 2010
- Full Text
- View/download PDF
107. Crystallization of ion amorphized Ge2Sb2Te5 in nano-structured thin films.
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Mio, A. M., Carria, E., De Bastiani, R., Miritello, M., Bongiorno, C., D'Arrigo, G., Spinella, C., Grimaldi, M. G., and Rimini, E.
- Published
- 2010
- Full Text
- View/download PDF
108. Erbium-doped Si nanocrystals: optical properties and electroluminescent devices
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Pacifici, D., primary, Irrera, A., additional, Franzò, G., additional, Miritello, M., additional, Iacona, F., additional, and Priolo, F., additional
- Published
- 2003
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- View/download PDF
109. Electroluminescence properties of light emitting devices based on silicon nanocrystals
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Irrera, A., primary, Pacifici, D., additional, Miritello, M., additional, Franzo, G., additional, Priolo, F., additional, Iacona, F., additional, Sanfilippo, D., additional, Di Stefano, G., additional, and Fallica, P.G., additional
- Published
- 2003
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- View/download PDF
110. Electroluminescence at 1.54 μm in Er-doped Si nanocluster-based devices
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Iacona, F., primary, Pacifici, D., additional, Irrera, A., additional, Miritello, M., additional, Franzò, G., additional, Priolo, F., additional, Sanfilippo, D., additional, Di Stefano, G., additional, and Fallica, P. G., additional
- Published
- 2002
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- View/download PDF
111. Excitation and de-excitation properties of silicon quantum dots under electrical pumping
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Irrera, A., primary, Pacifici, D., additional, Miritello, M., additional, Franzò, G., additional, Priolo, F., additional, Iacona, F., additional, Sanfilippo, D., additional, Di Stefano, G., additional, and Fallica, P. G., additional
- Published
- 2002
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- View/download PDF
112. Silicon Nanocrystal Nucleation as a Function of the Annealing Temperature in SiOx Films.
- Author
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Daldosso, N., Das, G., Dalba, G., Larcheri, S., Grisenti, R., Mariotto, G., Pavesi, L., Rocca, F., Priolo, F., Franzò, G., Irrera, A., Miritello, M., Pacifici, D., and Iacona, F.
- Published
- 2003
- Full Text
- View/download PDF
113. Silicon nanowires: a building block for future technologies.
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Leonardi, A. A., Lo Faro, M. J., Morganti, D., Fazio, B., Musumeci, P., Miritello, M., Franzò, G., Nastasi, F., Puntoriero, F., Di Pietro, C., Priolo, F., and Irrera, A.
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- 2021
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- View/download PDF
114. Amorphous-Crystal Phase Transitions in GexTe1-x Alloys.
- Author
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Carria, E., Mio, A. M., Gibilisco, S., Miritello, M., Bongiorno, C., Grimaldi, M. G., and Riminic, E.
- Subjects
GERMANIUM alloys ,TELLURIUM alloys ,STOICHIOMETRY ,SEMICONDUCTOR films ,CRYSTALLIZATION ,PHASE transitions ,TRANSMISSION electron microscopy - Abstract
The crystallization of amorphous Ge
x Te1-x (x = 0.36,0.51, 0.63) films (50 nm) has been investigated by time resolved reflectivity, transmission electron microscopy, Raman spectroscopy and X-ray diffraction. The Ge-rich film has the highest crystallization temperature (354°C) with respect to both GeTe (180°C) and Te-rich samples(244°C). In non-stoichiometric films, the precipitation of the excess atomic species is the first step during the crystallization process: amorphous Ge and crystalline Te precipitates were detected in Ge and Te rich alloys, respectively. The atomic interdiffusivity was estimated to be ∼5×10-15 cm²/s at 220°C in the Te-rich alloy and ∼4×10-14 cm²/s in the Ge-rich film at 330°C. In both cases Tellurium is likely to be the diffusing species. This description accounts for the presence of amorphous Ge precipitates at the initial stage of the crystallization of the Ge rich alloy. The GeTe crystalline grains subsequently act as a seed for Ge crystallization. Non stoichiometric crystalline alloys have been reamorphized by laser or ion irradiation. In laser irradiated samples, the crystallization is similar to that of as deposited film since the precipitates mix with GeTe during the melt duration. In ion implanted samples this mixing doesn't occur and GeTe crystallization temperature is close to that of stoichiometric film. [ABSTRACT FROM AUTHOR]- Published
- 2012
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115. Silicon-Based Light-Emitting Devices: Properties and Applications of Crystalline, Amorphous and Er-Doped Nanoclusters.
- Author
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Iacona, F., Irrera, A., Franz, G., Pacifici, D., Crupi, I., Miritello, M. P., Presti, C. D., and Priolo, F.
- Abstract
In this paper, we summarize the results of an extensive investigation on the properties of MOS-type light-emitting devices based on silicon nanostructures. The performances of crystalline, amorphous, and Er-doped Si nanostructures are presented and compared. We show that all devices are extremely stable and robust, resulting in an intense room temperature electroluminescence (EL) at around 900 nm or at 1.54 mum. Amorphous nanoclusters are more conductive than the crystalline counterpart. In contrast, nonradiative processes seem to be more efficient for amorphous clusters resulting in a lower quantum efficiency. Erbium doping results in the presence of an intense EL at 1.54 mu m with a concomitant disappearance of the 900-nm emission. This suggests that under electrical pumping Er is excited through an efficient energy transfer from the silicon clusters which hence become dark. We have identified an Auger de-excitation of Er with trapped carriers as the main process competing with radiative emission and limiting EL efficiency. This process is particularly severe in presence of unbalanced carrier injection (electrons versus holes) and can be controlled in properly designed structures. These data are presented and their implications are discussed. [ABSTRACT FROM PUBLISHER]
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- 2006
- Full Text
- View/download PDF
116. Strong enhancement of Er3+ emission at room temperature in silicon-on-insulator photonic crystal waveguides.
- Author
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Galli, M., Politi, A., Belotti, M., Gerace, D., Liscidini, M., Patrini, M., Andreani, L. C., Miritello, M., Irrera, A., Priolo, F., and Chen, Y.
- Subjects
CRYSTALS ,WAVEGUIDES ,ELECTRICAL conductors ,ELECTRIC waves ,ELECTROMAGNETIC waves - Abstract
We have realized silicon-on-insulator photonic crystal (PhC) waveguides with intense 1.54 μm emission at room temperature. The slabs contain a thin layer of SiO
2 with Er3+ doped silicon nanoclusters embedded at the center of the Si core and are patterned with a triangular lattice of holes. An enhancement by more than two orders of magnitude of the Er3+ near-normal emission is observed when the transition is in resonance with an appropriate mode of the PhC slab. The results are in very good agreement with calculated photonic bands and emission spectra. These findings are important for the realization of Si-compatible efficient light emitters at telecom wavelengths. [ABSTRACT FROM AUTHOR]- Published
- 2006
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- View/download PDF
117. Erbium doped materials for a Si-based microphotonics
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Priolo, F., Franzò, G., Iacona, F., Irrera, A., Roberto Lo Savio, Miritello, M., and Pecora, E.
118. Crystallization of ion amorphized Ge2Sb2Te 5 in nano-structured thin films
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Mio, A. M., Carria, E., Bastiani, R., Miritello, M., Bongiorno, C., Giuseppe D'Arrigo, Spinella, C., Grimaldi, M. G., and Rimini, E.
119. Rare-earth doped Si nanostructures for microphotonics
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Pacifici, D., Franzo, G., Iacona, F., Irrera, A., SIMONA MARIA CRISTINA BONINELLI, Miritello, M., Priolo, F., Shin, Jh, Brongersma, M., and Buchal, C.
120. Silicon nanocrystal nucleation as a function of the annealing temperature in SiOx films
- Author
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Daldosso, N., Das, G., Dalba, G., Larcheri, S., Grisenti, R., Mariotto, G., Pavesi, L., Rocca, F., Priolo, F., Franzo, G., Irrera, A., Miritello, M., Pacifici, D., FABIO IACONA, Gregorkiewicz, T., Elliman, Rg, Fauchet, Pm, and Hutchby, Ja
121. Light Emission from Si Nanostructures
- Author
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Priolo, F., Franzo, G., Irrera, A., FABIO IACONA, Boninelli, S., Miritello, M., Canino, A., Bongiorno, C., Spinella, C., Sanfilippo, D., Di Stefano, G., Piana, A., Fallica, G., Cullis, Ag, and Midgley, Pa
122. New strategies to improve Eu light emission in SI-based matrices
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Vivien, Laurent, Honkanen, Seppo, Pavesi, Lorenzo, Pelli, Stefano, Shin, Jung Hun, Franzò, G., Bellocchi, G., Boninelli, S., Miritello, M., and Iacona, F.
- Published
- 2014
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123. Tuning the Crystallization Temperature of Amorphous Ge2Sb2Te5by O and Si Recoil Implantation
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Carria, E., Mio, A. M., Gibilisco, S., Miritello, M., Grimaldi, M. G., and Rimini, E.
- Abstract
The amorphous to crystal transition temperature has been measured in capped (10nmSiO2) and uncapped Ge2Sb2Te5(GST) films (20nmthick) after irradiation with a 40keVGe+in the range between 5×1013and 1×1015ions∕cm2. In the capped samples the crystallization temperature increases with fluence (15°Cat 1×1015ions∕cm2). This effect is due to the doping of the GST layer with a few atom percent of recoiled O and Si atoms. The influence of the chemical species on the crystallization kinetics overcomes the effect of the ion-induced local rearrangement that instead decreases the transition temperature by a few degrees in the uncapped samples. Recoil implantation through the use of a thin capping layer may then be a viable alternative to the direct doping of chalcogenide thin films.
- Published
- 2011
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124. Polymorphism of Amorphous Ge2Sb2Te5Probed by EXAFS and Raman Spectroscopy
- Author
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Carria, E., Mio, A.M., Gibilisco, S., Miritello, M., d’Acapito, F., Grimaldi, M.G., and Rimini, E.
- Abstract
The local order of amorphous Ge2Sb2Te5films (50 nm) prepared by sputtering (AD), melt quenching (MQ), or ion irradiation (II) has been probed by EXAFS and Raman spectroscopy. The Ge K edge of the AD sample shows a stronger contribution from homopolar Ge-Ge bonds with respect to irradiated films. Raman spectroscopy measurements indicate a greater abundance of homopolar Te-Te bonds in AD film with respect to MQ and II. Irradiation of deposited amorphous GST films results in a reduction of “wrong” homopolar bonds. This variation is probably the origin of the faster crystallization speed of MQ and II amorphous samples.
- Published
- 2011
- Full Text
- View/download PDF
125. Local Order and Crystallization of Laser Quenched and Ion Implanted Amorphous Ge1 − xTexThin Films
- Author
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Carria, E., Mio, A. M., Miritello, M., Gibilisco, S., De Bastiani, R., Pennisi, A. R., Bongiorno, C., Grimaldi, M. G., and Rimini, E.
- Abstract
Amorphous films of Ge1−xTex(x=0.37and 0.64) prepared by sputtering, melt quenching, or ion irradiation were annealed up to 450°C. The crystallized films consist of stoichiometric GeTe and precipitates of the excess element. The laser and ion irradiated Te-rich amorphous alloy exhibits higher stability with respect to the sputtered film, and an enhancement of the relative abundance of edge-sharing GeTe4tetrahedra at the expense of Ge-rich tetrahedra occurs with respect to the as-deposited amorphous layers. The crystallization temperature increases with the density of Ge–Te bonds because this local rearrangement delays Te precipitation and the subsequent GeTe crystallization. Irradiation does not affect the stability of the Ge-rich alloy in which crystallization is limited by Ge mobility, and the induced local rearrangements are probably prevented by the low atomic diffusivity.
- Published
- 2010
- Full Text
- View/download PDF
126. Calocube - A highly segmented calorimeter for a space based experiment
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S. Bottai, N. Daddi, S. B. Ricciarini, P. Spillantini, P. Papini, E. Vannuccini, Maria Miritello, A. Gregorio, G.F. Rappazzo, Marina Trimarchi, Alessia Tricomi, L. Pacini, G. Pauletta, O. Starodubtsev, R. D' Alessandro, G. Carotenuto, Anna Vedda, A. Tiberio, O. Adriani, M. Chiari, P. W. Cattaneo, A. Basti, A. Rappoldi, V. Bonvicini, N. Zampa, M. Bongi, Paolo Brogi, Antoniangelo Agnesi, Sebastiano Albergo, G. Castellini, S. Detti, L. Santi, Lucrezia Auditore, Lorenzo Bonechi, P. S. Marrocchesi, Mauro Fasoli, A. Sulaj, N. Finetti, Paolo Maestro, Antonio Trifiro, Federico Pirzio, J. E. Suh, B. Zerbo, S. Bonechi, G. Zampa, D. Cauz, Gabriele Bigongiari, Eugenio Berti, Piergiulio Lenzi, Nicola Mori, Maria Giuseppina Bisogni, Marco Grassi, Marco Incagli, Riccardo Paoletti and Giovanni Signorelli, D'Alessandro, R., Adriani, O., Agnesi, A., Albergo, S., Auditore, L., Basti, A., Berti, E., Bigongiari, G., Bonechi, L., Bonechi, S., Bongi, M., Bonvicini, V., Bottai, S., Brogi, P., Carotenuto, G., Castellini, G., Cattaneo, P. W., Cauz, D., Chiari, M., Daddi, N., Detti, S., Fasoli, M., Finetti, N., Gregorio, Anna, Lenzi, P., Maestro, P., Marrocchesi, P. S., Miritello, M., Mori, N., Pacini, L., Papini, P., Pauletta, G., Pirzio, F., Rappazzo, G. F., Rappoldi, A., Ricciarini, S., Santi, L. G., Spillantini, P., Starodubtsev, O., Suh, J. E., Sulaj, A., Tiberio, A., Tricomi, A., Trifiro, A., Trimarchi, M., Vannuccini, E., Vedda, A., Zampa, Gianluigi, Zampa, Nicola, Zerbo, B., D'Alessandro, R, Adriani, O, Agnesi, A, Albergo, S, Auditore, L, Basti, A, Berti, E, Bigongiari, G, Bonechi, L, Bonechi, S, Bongi, M, Bonvicini, V, Bottai, S, Brogi, P, Carotenuto, G, Castellini, G, Cattaneo, P, Cauz, D, Chiari, M, Daddi, N, Detti, S, Fasoli, M, Finetti, N, Gregorio, A, Lenzi, P, Maestro, P, Marrocchesi, P, Miritello, M, Mori, N, Pacini, L, Papini, P, Pauletta, G, Pirzio, F, Rappazzo, G, Rappoldi, A, Ricciarini, S, Santi, L, Spillantini, P, Starodubtsev, O, Suh, J, Sulaj, A, Tiberio, A, Tricomi, A, Trifiro, A, Trimarchi, M, Vannuccini, E, Vedda, A, Zampa, G, Zampa, N, and Zerbo, B
- Subjects
Physics ,Calorimeter ,Nuclear and High Energy Physics ,Astroparticle ,Crystals ,Instrumentation ,Calorimeter (particle physics) ,010308 nuclear & particles physics ,Detector ,Cosmic ray ,Space (mathematics) ,01 natural sciences ,Particle identification ,Nuclear physics ,Acceleration ,0103 physical sciences ,Crystal ,010306 general physics ,Energy (signal processing) - Abstract
Future research in High Energy Cosmic Ray Physics concerns fundamental questions on their origin, acceleration mechanism, and composition. Unambiguous measurements of the energy spectra and of the composition of cosmic rays at the “knee” region could provide some of the answers to the above questions. Only ground based observations, which rely on sophisticated models describing high energy interactions in the earth׳s atmosphere, have been possible so far due to the extremely low particle rates at these energies. A calorimeter based space experiment can provide not only flux measurements but also energy spectra and particle identification, especially when coupled to a dE/dx measuring detector, and thus overcome some of the limitations plaguing ground based experiments. For this to be possible very large acceptances are needed if enough statistic is to be collected in a reasonable time. This contrasts with the lightness and compactness requirements for space based experiments. A novel idea in calorimetry is discussed here which addresses these issues while limiting the mass and volume of the detector. In fact a small prototype is currently being built and tested with ions. In this paper the results obtained will be presented in light of the simulations performed.
- Published
- 2016
127. CALOCUBE: An approach to high-granularity and homogenous calorimetry for space based detectors
- Author
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Anna Vedda, G. Castellini, M. Trimarchi, Paolo Brogi, P. Cumani, A. Rappoldi, Gabriele Bigongiari, A Lamberto, Mauro Fasoli, P. Spillantini, Maria Miritello, Eugenio Berti, Nicola Mori, B. Zerbo, S. Bottai, V. Bonvicini, G. Pauletta, A. Gregorio, Lucrezia Auditore, O. Adriani, S. Bonechi, Raffaello D'Alessandro, P. Lenzi, S. Detti, P. S. Marrocchesi, S. B. Ricciarini, A. Sulaj, M. Bongi, P. Papini, E. Vannuccini, Antonio Cassese, G.F. Rappazzo, N. Zampa, O. Starodubtsev, G. Carotenuto, Antonio Trifiro, A Mezzasalma, A. Tiberio, G. Zampa, Sebastiano Albergo, Maria Grazia Bagliesi, P. W. Cattaneo, Mirko Boezio, D. Cauz, Lorenzo Bonechi, Paolo Maestro, Bongi, M., Adriani, O., Albergo, S., Auditore, L., Bagliesi, M. G., Berti, E., Bigongiari, G., Boezio, M., Bonechi, L., Bonechi, S., Bonvicini, V., Bottai, S., Brogi, P., Carotenuto, G., Cassese, A., Castellini, G., Cattaneo, P. W., Cauz, D., Cumani, Paolo, D'Alessandro, R., Detti, S., Fasoli, M., Gregorio, Anna, Lamberto, A., Lenzi, P., Maestro, P., Marrocchesi, P. S., Mezzasalma, A., Miritello, M., Mori, N., Papini, P., Pauletta, G., Rappazzo, G. F., Rappoldi, A., Ricciarini, S., Spillantini, P., Starodubtsev, O., Sulaj, A., Tiberio, A., Trifirò, A., Trimarchi, M., Vannuccini, E., Vedda, A., Zampa, G., Zampa, N., Zerbo, B., Bongi, M, Adriani, O, Albergo, S, Auditore, L, Bagliesi, M, Berti, E, Bigongiari, G, Boezio, M, Bonechi, L, Bonechi, S, Bonvicini, V, Bottai, S, Brogi, P, Carotenuto, G, Cassese, A, Castellini, G, Cattaneo, P, Cauz, D, Cumani, P, D'Alessandro, R, Detti, S, Fasoli, M, Gregorio, A, Lamberto, A, Lenzi, P, Maestro, P, Marrocchesi, P, Mezzasalma, A, Miritello, M, Mori, N, Papini, P, Pauletta, G, Rappazzo, G, Rappoldi, A, Ricciarini, S, Spillantini, P, Starodubtsev, O, Sulaj, A, Tiberio, A, Trifirò, A, Trimarchi, M, Vannuccini, E, Vedda, A, Zampa, G, Zampa, N, and Zerbo, B
- Subjects
History ,Physics::Instrumentation and Detectors ,Gamma ray ,Interaction length ,Budget control ,Geometry ,Electromagnetic particle ,FIS/07 - FISICA APPLICATA (A BENI CULTURALI, AMBIENTALI, BIOLOGIA E MEDICINA) ,Calorimetry ,Particle detector ,Radiation length ,Particle identification ,Education ,Physics and Astronomy (all) ,Cesium iodide ,Optics ,Gamma rays ,Particles (particulate matter) Absorption depths ,Energy resolutions ,Geometrical dimensions ,Radiation lengths ,Space experiments ,Space-based detector ,Energy resolution ,High energy physics ,Detectors and Experimental Techniques ,Physics ,Calorimeter ,Spectrometer ,Calorimeter (particle physics) ,business.industry ,Space experiment ,Computer Science Applications ,Computational physics ,Measuring instrument ,ComputingMethodologies_DOCUMENTANDTEXTPROCESSING ,Particles (particulate matter) Absorption depth ,Geometrical dimension ,Granularity ,business - Abstract
Future space experiments dedicated to the observation of high-energy gamma and cosmic rays will increasingly rely on a highly performing calorimetry apparatus, and their physics performance will be primarily determined by the geometrical dimensions and the energy resolution of the calorimeter deployed. Thus it is extremely important to optimize its geometrical acceptance, the granularity, and its absorption depth for the measurement of the particle energy with respect to the total mass of the apparatus which is the most important constraint for a space launch. The proposed design tries to satisfy these criteria while staying within a total mass budget of about 1.6 tons. Calocube is a homogeneous calorimeter instrumented with Cesium iodide (CsI) crystals, whose geometry is cubic and isotropic, so as to detect particles arriving from every direction in space, thus maximizing the acceptance, granularity is obtained by filling the cubic volume with small cubic CsI crystals. The total radiation length in any direction is more than adequate for optimal electromagnetic particle identification and energy measurement, whilst the interaction length is at least suficient to allow a precise reconstruction of hadronic showers. Optimal values for the size of the crystals and spacing among them have been studied. The design forms the basis of a three-year R&D; activity which has been approved and financed by INFN. An overall description of the system, as well as results from preliminary tests on particle beams will be described.
- Published
- 2015
128. Synthesis and characterization of light emitting Eu2O3 films on Si substrates
- Author
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Bellocchi, G., Franzò, G., Iacona, F., Boninelli, S., Miritello, M., and Priolo, F.
- Subjects
- *
OPTICAL properties of metallic films , *METALLIC oxides , *EUROPIUM compounds , *LIGHT sources , *SILICON , *SUBSTRATES (Materials science) , *MOLECULAR structure , *CRYSTAL growth - Abstract
Abstract: We have studied the optical and structural properties of Eu2O3 thin films grown by RF magnetron sputtering on Si substrates. The films have been annealed in O2 ambient to improve their properties. The intensity of the photoluminescence (PL) signal detected at room temperature from the films depends on the temperature of the thermal process. The structural characterization of the films, performed by transmission electron microscopy, energy filtered transmission electron microscopy and x-ray diffraction, reveals that annealing processes performed at temperatures higher than 900°C induce a mixing at the Eu2O3–Si interface, leading to the formation of a silicate-like layer, which is responsible for the observed decrease of the PL intensity. [Copyright &y& Elsevier]
- Published
- 2012
- Full Text
- View/download PDF
129. CaloCube: A new-concept calorimeter for the detection of high-energy cosmic rays in space
- Author
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Anna Vedda, E. Vannuccini, P. Papini, G. Castellini, O. Adriani, Raffaello D'Alessandro, Lorenzo Bonechi, A. Basti, P. W. Cattaneo, A. Sulaj, O. Starodubtsev, Gianluigi Zampa, G. Orzan, P. Spillantini, A. Tricomi, Maria Miritello, Antoniangelo Agnesi, L. Auditore, S. Albergo, J. E. Suh, M. Olmi, Emilio Berti, Mauro Fasoli, Nicola Mori, B. Zerbo, M. Bongi, S. Bonechi, Paolo Maestro, M. Trimarchi, S. B. Ricciarini, P. Lenzi, Gabriele Bigongiari, P. S. Marrocchesi, Paolo Brogi, Federico Pirzio, N. Finetti, A. Rappoldi, N. Zampa, G. Carotenuto, A. Tiberio, S. Detti, V. Bonvicini, S. Bottai, A. Trifiro, F. Stolzi, L. Pacini, M. G. Pellegriti, Vannuccini, E, Adriani, O, Agnesi, A, Albergo, S, Auditore, L, Basti, A, Berti, E, Bigongiari, G, Bonechi, L, Bonechi, S, Bongi, M, Bonvicini, V, Bottai, S, Brogi, P, Carotenuto, G, Castellini, G, Cattaneo, P, D'Alessandro, R, Detti, S, Fasoli, M, Finetti, N, Lenzi, P, Maestro, P, Marrocchesi, P, Miritello, M, Mori, N, Orzan, G, Olmi, M, Pacini, L, Papini, P, Pellegriti, M, Pirzio, F, Rappoldi, A, Ricciarini, S, Spillantini, P, Starodubtsev, O, Stolzi, F, Suh, J, Sulaj, A, Tiberio, A, Tricomi, A, Trifiro, A, Trimarchi, M, Vedda, A, Zampa, G, Zampa, N, and Zerbo, B
- Subjects
Scintillating crystal ,Nuclear and High Energy Physics ,Physics::Instrumentation and Detectors ,FIS/07 - FISICA APPLICATA (A BENI CULTURALI, AMBIENTALI, BIOLOGIA E MEDICINA) ,Cosmic ray ,Space (mathematics) ,01 natural sciences ,Scintillating crystals ,0103 physical sciences ,Ultra-high-energy cosmic ray ,Absorption (electromagnetic radiation) ,010303 astronomy & astrophysics ,Cosmic rays ,Instrumentation ,Nuclear and High Energy Physic ,Physics ,Calorimeter ,Basis (linear algebra) ,010308 nuclear & particles physics ,Isotropy ,Computational physics ,FIS/01 - FISICA SPERIMENTALE ,Granularity - Abstract
The direct observation of high-energy cosmic rays, up to the PeV region, will increasingly rely on highly performing calorimeters, and the physics performance will be primarily determined by their geometrical acceptance and energy resolution. Thus, it is extremely important to optimize their geometrical design, granularity, and absorption depth, with respect to the total mass of the apparatus, which is among the most important constraints for a space mission. Calocube is a homogeneous calorimeter whose basic geometry is cubic and isotropic, so as to detect particles arriving from every direction in space, thus maximizing the acceptance; granularity is obtained by filling the cubic volume with small cubic scintillating crystals. This design forms the basis of a three-year R & D activity which has been approved and financed by INFN. A comparative study of different scintillating materials has been performed. Optimal values for the size of the crystals and spacing among them have been studied. Different geometries, besides the cubic one, and the possibility to implement dual-readout techniques have been investigated. A prototype, instrumented with CsI(Tl) cubic crystals, has been constructed and tested with particle beams. An overview of the obtained results will be presented and the perspectives for future space experiments will be discussed.
- Published
- 2017
130. CaloCube: a novel calorimeter for high-energy cosmic rays in space
- Author
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N. Finetti, F. Stolzi, Gigi Cappello, P. W. Cattaneo, Lucrezia Auditore, S. Bottai, M. G. Pellegriti, A. Basti, A. Rappoldi, L. Pacini, A Vedda, J. E. Suh, S. Albergo, P. S. Marrocchesi, M. Olmi, P. Spillantini, M Fasoli, Maria Miritello, N. Zampa, Gabriele Bigongiari, S. Bonechi, Eugenio Berti, G. Zampa, Raffaello D'Alessandro, Paolo Brogi, P. Lenzi, Antonio Trifiro, G. Carotenuto, Bonvicini, S. Detti, A. Tiberio, Lorenzo Bonechi, Alessia Tricomi, A Agnesi, A. Sulaj, G. Castellini, S. B. Ricciarini, P. Papini, E. Vannuccini, O. Starodubtsev, M. Bongi, O. Adriani, A Italiano, F Pirzio, M. Trimarchi, Nicola Mori, G. Orzan, Paolo Maestro, Rappoldi, A, Morselli, A, Cattaneo, P, Adriani, O, Agnesi, A, Albergo, S, Auditore, L, Basti, A, Berti, E, Bigongiari, G, Bonechi, L, Bonechi, S, Bongi, M, Bonvicini, V, Bottai, S, Brogi, P, Cappello, G, Carotenuto, G, Castellini, G, D'Alessandro, R, Detti, S, Fasoli, M, Finetti, N, Italiano, A, Lenzi, P, Maestro, P, Marrocchesi, P, Miritello, M, Mori, N, Olmi, M, Orzan, G, Pacini, L, Papini, P, Pellegriti, M, Pirzio, F, Ricciarini, S, Spillantini, P, Starodubtsev, O, Stolzi, F, Suh, J, Sulaj, A, Tiberio, A, Tricomi, A, Trifirò, A, Trimarchi, M, Vannuccini, E, Vedda, A, Zampa, G, and Zampa, N
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Physics ,Calorimeter (particle physics) ,010308 nuclear & particles physics ,Physics::Instrumentation and Detectors ,QC1-999 ,Astrophysics ,Space (mathematics) ,7. Clean energy ,01 natural sciences ,Nuclear physics ,Physics and Astronomy (all) ,0103 physical sciences ,Ultra-high-energy cosmic ray ,Detectors and Experimental Techniques ,010306 general physics - Abstract
CaloCube is an R&D project borne to develop a novel calorimeter design, optimized for high-energy cosmic ray measurements in space. A small prototype made of CsI(Tl) elements has been built and tested on particle beams. A final version, made of 5Ã5Ã18 crystals and with dual readout (two photodiodes for each crystal), to cover the full required dynamic range, is under construction and will be tested at CERN SPS in Summer 2016. The dual readout compensation technique were developed and the feasibility to extract ÃÅ erenkov signals from CsI crystals verified.
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- 2017
131. CaloCube: an innovative homogeneous calorimeter for the next-generation space experiments
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L. Pacini, N. Finetti, N. Daddi, Raffaello D'Alessandro, F. Stolzi, Anna Vedda, Antonio Agnesi, J. E. Suh, A. Sulaj, M. Olmi, Paolo Maestro, Sebastiano Albergo, Gigi Cappello, A. Basti, S. Bonechi, P. W. Cattaneo, O. Adriani, Emanuele Berti, G. Orzan, P. Lenzi, M. G. Pellegriti, Lucrezia Auditore, P. Spillantini, Maria Miritello, G. Zampa, S. Detti, M. Chiari, Lorenzo Bonechi, M. Bongi, Antonio Trifiro, P. S. Marrocchesi, Gabriele Bigongiari, Alessia Tricomi, Paolo Brogi, S. B. Ricciarini, Federico Pirzio, P. Papini, E. Vannuccini, G. Castellini, O. Starodubtsev, G. Carotenuto, M. Trimarchi, V. Bonvicini, A. Tiberio, Nicola Mori, N. Zampa, S. Bottai, A. Rappoldi, Mauro Fasoli, Pacini, L, Adriani, O, Agnesi, A, Albergo, S, Auditore, L, Basti, A, Berti, E, Bigongiari, G, Bonechi, L, Bonechi, S, Bongi, M, Bonvicini, V, Bottai, S, Brogi, P, Cappello, G, Carotenuto, G, Castellini, G, Cattaneo, P, Chiari, M, Daddi, N, Dalessandro, R, Detti, S, Fasoli, M, Finetti, N, Lenzi, P, Maestro, P, Marrocchesi, P, Miritello, M, Mori, N, Orzan, G, Olmi, M, Papini, P, Pellegriti, M, Pirzio, F, Rappoldi, A, Ricciarini, S, Spillantini, P, Starodubtsev, O, Stolzi, F, Suh, J, Sulaj, A, Tiberio, A, Tricomi, A, Trifiro, A, Trimarchi, M, Vannuccini, E, Vedda, A, Zampa, G, and Zampa, N
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Physics ,History ,business.industry ,Physics::Instrumentation and Detectors ,Isotropy ,Monte Carlo method ,Detector ,Space launch ,Computer Science Applications ,Education ,Calorimeter ,Physics and Astronomy (all) ,Quality (physics) ,FIS/01 - FISICA SPERIMENTALE ,Particle ,Aerospace engineering ,Detectors and Experimental Techniques ,business ,Energy (signal processing) - Abstract
The direct measurement of the cosmic-ray spectrum, up to the knee region, is one of the instrumental challenges for next generation space experiments. The main issue for these measurements is a steeply falling spectrum with increasing energy, so the physics performance of the space calorimeters are primarily determined by their geometrical acceptance and energy resolution. CaloCube is a three-year R&D; project, approved and financed by INFN in 2014, aiming to optimize the design of a space-born calorimeter. The peculiarity of the design of CaloCube is its capability of detecting particles coming from any direction, and not only those on its upper surface. To ensure that the quality of the measurement does not depend on the arrival direction of the particles, the calorimeter will be designed as homogeneous and isotropic as possible. In addition, to achieve a high discrimination power for hadrons and nuclei with respect to electrons, the sensitive elements of the calorimeter need to have a fine 3-D sampling capability. In order to optimize the detector performances with respect to the total mass of the apparatus, which is the most important constraint for a space launch, a comparative study of different scintillating materials has been performed using detailed Monte Carlo simulation based on the FLUKA package. In parallel to simulation studies, a prototype consisting in 14 layers of 3 x 3 CsI(Tl) crystals per layer has been assembled and tested with particle beams. An overview of the obtained results during the first two years of the project will be presented and the future of the detector will be discussed too.
- Published
- 2017
132. Sputtered cuprous oxide thin films and nitrogen doping by ion implantation
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F. Moscatelli, V. Privitera, Isodiana Crupi, Francesca Simone, Maria Miritello, Paolo Sberna, Sberna, P., Crupi, I., Moscatelli, F., Privitera, V., Simone, F., and Miritello, M.
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Oxidant ,Postimplantation annealing ,Lattice configuration ,Materials science ,Band gap ,Annealing (metallurgy) ,Nitrogen ,Inorganic chemistry ,Oxide ,Photovoltaic application ,02 engineering and technology ,01 natural sciences ,Oxygen vacancie ,Settore ING-INF/01 - Elettronica ,Settore FIS/03 - Fisica Della Materia ,chemistry.chemical_compound ,Sputtering ,0103 physical sciences ,Materials Chemistry ,Doping ,Semiconductor doping ,Conductivity enhancement ,Doping (additives) ,Thin film ,Ion ,Deposition ,Oxide film ,010302 applied physics ,Dopant ,Metals and Alloys ,Surfaces and Interfaces ,021001 nanoscience & nanotechnology ,Out of equilibrium ,Surfaces, Coatings and Films ,Electronic, Optical and Magnetic Materials ,Energy gap ,Optical and electrical propertie ,Ion implantation ,chemistry ,Thermal-annealing ,0210 nano-technology ,Copper ,Cuprous oxide - Abstract
The structural, optical and electrical properties of sputtered cuprous oxide thin films have been optimized through post-deposition thermal treatments. Moreover we have studied the effects of nitrogen doping introduced by ion implantation followed by the optimized oxidant thermal annealing. Three concentrations have been used, 0.6 N%, 1.2 N%, and 2.5 N%. Along with the preservation of the Cu 2 O phase, a slight optical band gap narrowing and a significant conductivity enhancement has been observed with respect to the undoped samples. These results can be justified by the absence of further oxygen vacancies promoted by dopant introduction and by the substitution of O atoms by N ones. This lattice configuration has been guaranteed by the post implantation annealing in oxidant atmosphere. The used doping technique represents an original out-of-equilibrium approach toward the formation of low-resistivity contacts on Cu 2 O films for photovoltaic applications.
- Published
- 2016
133. Optical Properties of Nanoporous Germanium Thin Films
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Maria Grazia Grimaldi, Maria Miritello, Beatrice Fraboni, Lucia Romano, Giuliana Impellizzeri, Daniela Cavalcoli, Cavalcoli, D., Impellizzeri, G., Romano, L., Miritello, M., Grimaldi, M.G., and Fraboni, B.
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Materials science ,business.industry ,Nanoporous ,Surface photovoltage ,photovoltaic applications ,chemistry.chemical_element ,Germanium ,surface photovoltage ,nanoporous germanium ,quantum confinement ,Blueshift ,chemistry ,Sputtering ,Quantum dot ,Optoelectronics ,General Materials Science ,ion implantation ,light trapping ,photovoltaic application ,Thin film ,business ,Molecular beam epitaxy - Abstract
In the present article we report enhanced light absorption, tunable size-dependent blue shift, and efficient electron hole pairs generation in Ge nanoporous films (np-Ge) grown on Si. The Ge films are grown by sputtering and molecular beam epitaxy; subsequently, the nanoporous structure is obtained by Ge+ self-implantation. We show, by surface photovoltage spectroscopy measurements, blue shift of the optical energy gap and strong signal enhancement effects in the np-Ge films. The blue shift is related to quantum confinement effects at the wall separating the pore in the structure, the signal enhancement to multiple light-scattering events, which result in enhanced absorption. All these characteristics are highly stable with time. These findings demonstrate that nanoporous Ge films can be very promising for photovoltaic applications.
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- 2015
134. Role of Ge nanoclusters in the performance of photodetectors compatible with Si technology
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C. Spinella, Salvatore Cosentino, Maria Miritello, Pei Liu, Domenico Pacifici, Sunghwan Lee, Salvo Mirabella, Giuseppe Nicotra, Antonio Terrasi, Son T. Le, David C. Paine, Isodiana Crupi, Alexander Zaslavsky, Cosentino, S., Mirabella, S., Liu, P., Le, S.T., Miritello, M., Lee, S., Crupi, I., Nicotra, G., Spinella, C., Paine, D., Terrasi, A., Zaslavsky, A., and Pacifici, D.
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Nanocluster ,Materials science ,chemistry.chemical_element ,Photodetector ,Germanium ,Photoconductive gain ,Settore ING-INF/01 - Elettronica ,Nanoclusters ,Response time (computer systems), Germanium ,High-efficiency photodetector ,High-efficiency photodetectors ,Sparse array ,High-efficiency ,Response time ,Materials Chemistry ,Gain ,business.industry ,Photoconductivity ,Internal quantum efficiency ,Metals and Alloys ,Surfaces and Interfaces ,Photon ,Surfaces, Coatings and Films ,Electronic, Optical and Magnetic Materials ,Recombination center ,chemistry ,Semiconductor photodetector ,Optoelectronics ,Spectral response ,Quantum efficiency ,business ,Excitation ,Spectral responsivity, Nanocluster - Abstract
In this work, we investigate the spectral response of metal-oxide- semiconductor photodetectors based on Ge nanoclusters (NCs) embedded in a silicon dioxide (SiO2) matrix. The role of Ge NC size and density on the spectral response was evaluated by comparing the performance of PDs based on either densely packed arrays of 2 nm-diameter NCs or a more sparse array of 8 nm-diameter Ge NCs. Our Ge NC photodetectors exhibit a high spectral responsivity in the 500-1000 nm range with internal quantum efficiency of ~ 700% at - 10 V, and with NC array parameters such as NC density and size playing a crucial role in the photoconductive gain and response time. We find that the configuration with a more dispersed array of NCs ensures a faster photoresponse, due to the larger fraction of electrically-active NCs and the partial suppression of recombination centers. The photoconduction mechanism, assisted by trapping of photo-generated holes in Ge NCs, is discussed for different excitation power and applied bias conditions. Our results provide guidelines for further optimization of high-efficiency Ge NC photodetectors. © 2013 Elsevier B.V. All rights reserved.
- Published
- 2013
135. Room-temperature efficient light detection by amorphous Ge quantum wells
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Maria Miritello, Corrado Spinella, Salvatore Cosentino, Giuseppe Nicotra, Francesca Simone, Antonio Terrasi, Isodiana Crupi, Salvatore Mirabella, Cosentino, S., Miritello, M., Crupi, I., Nicotra, G., Simone, F., Spinella, C., Terrasi, A., and Mirabella, S.
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Nanostructure ,Photon ,Materials science ,Photodetector ,CONFINEMENT ,Blue shift ,Optical oscillator strength ,Materials Science(all) ,Quantum confinement effect ,Light detection ,Quantum confinement ,General Materials Science ,Light absorption ,Quantum well ,Potential well ,Nano Express ,Photon absorption ,SUPERLATTICES ,Germanium ,business.industry ,Room temperature, Amorphous film ,Internal quantum efficiency ,NANOCLUSTERS ,Semiconductor quantum well ,Condensed Matter Physics ,Nanostructures ,Blueshift ,Amorphous solid ,Quantum dot ,Optoelectronics ,PHOTOLUMINESCENCE ,Quantum efficiency ,business ,Ultrathin films, Germanium ,Ge quantum well - Abstract
In this work, ultrathin amorphous Ge films (2 to 30 nm in thickness) embedded in SiO2 layers were grown by magnetron sputtering and employed as proficient light sensitizer in photodetector devices. A noteworthy modification of the visible photon absorption is evidenced due to quantum confinement effects which cause both a blueshift (from 0.8 to 1.8 eV) in the bandgap and an enhancement (up to three times) in the optical oscillator strength of confined carriers. The reported quantum confinement effects have been exploited to enhance light detection by Ge quantum wells, as demonstrated by photodetectors with an internal quantum efficiency of 70%. © 2013 Cosentino et al.
- Published
- 2013
136. Transient photoresponse and incident power dependence of high-efficiency germanium quantum dot photodetectors
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Salvatore Cosentino, Maria Miritello, Domenico Pacifici, Isodiana Crupi, Son T. Le, Alexander Zaslavsky, Sunghwan Lee, David C. Paine, Antonio Terrasi, Pei Liu, Salvo Mirabella, Liu, P., Cosentino, S., Le, S.T., Lee, S., Paine, D., Zaslavsky, A., Pacifici, D., Mirabella, S., Miritello, M., Crupi, I., and Terrasi, A.
- Subjects
Materials science ,Photoresponse ,Reverse bia ,General Physics and Astronomy ,chemistry.chemical_element ,Photodetector ,Germanium ,Optical power ,Photoconduction ,Time-resolved ,Settore ING-INF/01 - Elettronica ,Series resistance ,Optics ,Electrical resistance and conductance ,Equivalent series resistance ,Systematic study ,business.industry ,Photoconductivity ,Internal quantum efficiency ,Quantum-dot photodetector ,Photon ,Wavelength ,Semiconductor quantum dots, Germanium ,chemistry ,Quantum dot ,Transient current, Electric resistance ,Optoelectronics ,Incident power ,business - Abstract
We report a systematic study of time-resolved and power-dependent photoresponse in high-efficiency germanium quantum dot photodetectors (Ge-QD PDs), with internal quantum efficiencies greater than 100 over a broad wavelength, reverse bias, and incident power range. Turn-on and turn-off response times (τ on and τ off) are shown to depend on series resistance, bias, optical power, and thickness (W QD) of the Ge-QD layer, with measured τ off values down to ∼40 ns. Two different photoconduction regimes are observed at low and high reverse bias, with a transition around -3 V. A transient current overshoot phenomenon is also observed, which depends on bias and illumination power. © 2012 American Institute of Physics.
- Published
- 2012
137. Fast, high-efficiency Germanium quantum dot photodetectors
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Liu, P.a, S.T.a, Lee, S.a, Paine, D.a, Zaslavsky, A.a, Pacifici, Cosentino, S.b, Mirabella, Miritello, M.b, Crupi, I.b, Terrasi, A, Liu, P., Le, S., Lee, S., Paine, D., Zaslavsky, A., Pacifici, D., Cosentino, S., Mirabella, S., Miritello, M., Crupi, I., and Terrasi, A.
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Materials science ,business.industry ,Germanium ,Photoconductivity ,chemistry.chemical_element ,Response time ,Photodetector ,quantum dot ,Thermal conduction ,Settore ING-INF/01 - Elettronica ,Settore FIS/03 - Fisica Della Materia ,Optics ,chemistry ,Quantum dot ,Optoelectronics ,Transient (oscillation) ,photodetector ,Electrical and Electronic Engineering ,business ,Quantum - Abstract
We present on high efficiency metal-insulator-semiconductor (MIS) photodetectors based on amorphous germanium quantum dots (QDs) embedded in a SiO2 matrix. High internal quantum efficiencies (IQE) were achieved across a broad wavelength range, with peak value reaching 700% at-10 V applied bias due to high internal photoconductive gain. The transient photoresponse behavior is also studied and it was found that the response time of the photodetector depends on the thickness of the QD layer. We also discuss the conduction mechanism which leads to the high photoconductive gain. © 2012 IEEE.
- Published
- 2012
138. High-efficiency silicon-compatible photodetectors based on Ge quantum dots
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Alexander Zaslavsky, Antonio Terrasi, Son T. Le, Maria Miritello, Pei Liu, David C. Paine, Salvatore Cosentino, Salvo Mirabella, Isodiana Crupi, Domenico Pacifici, Sunghwan Lee, Cosentino, S., Le, P., Lee, S., Paine, D., Zaslavsky, A., Pacifici, D., Mirabella, S., Miritello, M., Crupi, I., and Terrasi, A.
- Subjects
Amorphous silicon ,Materials science ,Thermal budget ,Physics and Astronomy (miscellaneous) ,Silicon ,Silicon Technologie ,Responsivity ,chemistry.chemical_element ,Settore ING-INF/01 - Elettronica ,chemistry.chemical_compound ,Metal/insulator/semiconductor ,Ge quantum dot ,Wavelength ranges, Amorphous silicon ,Photocurrent generation ,Photodetector ,Optoelectronic device ,Photocurrent ,Germanium ,business.industry ,Semiconductor quantum dot ,Internal quantum efficiency ,matrix ,TRANSPORT ,Semiconductor ,NANOCRYSTALS ,Silica, Quantum efficiency ,chemistry ,Quantum dot laser ,Quantum dot ,Optoelectronics ,Quantum efficiency ,Transport mechanism ,GAIN ,business ,NANOCRYSTALS, TRANSPORT, GAIN ,Fully compatible ,High efficiency - Abstract
We report on high responsivity, broadband metal/insulator/semiconductor photodetectors with amorphous Ge quantum dots (a-Ge QDs) as the active absorbers embedded in a silicon dioxide matrix. Spectral responsivities between 1-4 A/W are achieved in the 500-900 nm wavelength range with internal quantum efficiencies (IQEs) as high as ∼700%. We investigate the role of a-Ge QDs in the photocurrent generation and explain the high IQE as a result of transport mechanisms via photoexcited QDs. These results suggest that a-Ge QDs are promising for high-performance integrated optoelectronic devices that are fully compatible with silicon technology in terms of fabrication and thermal budget. © 2011 American Institute of Physics.
- Published
- 2011
139. Light absorption and electrical transport in Si:O alloys for photovoltaics
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Isodiana Crupi, Francesca De Simone, F. Priolo, R. Lo Savio, M. A. Di Stefano, S. Di Marco, G. Di Martino, Salvo Mirabella, Maria Miritello, S. Gibilisco, Mirabella, S., Di Martino, G., Crupi, I., Gibilisco, S., Miritello, M., Lo Savio, R., Di Stefano, M., Di Marco, S., Simone, F., and Priolo, F.
- Subjects
Materials science ,Absorption spectroscopy ,Four-point ,Analytical chemistry ,General Physics and Astronomy ,Absorption coefficient ,Chemical vapor deposition ,Boron implantation ,Settore ING-INF/01 - Elettronica ,Settore FIS/03 - Fisica Della Materia ,symbols.namesake ,Electrical resistivity and conductivity ,Plasma-enhanced chemical vapor deposition ,Thin film ,Absorption (electromagnetic radiation) ,Electrical sheet resistance ,Si content ,SEMIINSULATING POLYCRYSTALLINE SILICON ,SOLAR-CELLS ,3RD-GENERATION PHOTOVOLTAICS ,OPTICAL-PROPERTIES ,AMORPHOUS-SILICON ,THIN-FILMS ,CRYSTALLINE ,Optical absorption ,Probe method ,Electrical resistivity ,Alloy deposition ,Sputter deposition ,Electrical transport ,symbols ,Oxygen-rich silicon ,Raman spectroscopy ,Optical gap ,Reflectance spectrum ,Photovoltaic - Abstract
Thin films (100-500 nm) of the Si:O alloy have been systematically characterized in the optical absorption and electrical transport behavior, by varying the Si content from 43 up to 100 at. %. Magnetron sputtering or plasma enhanced chemical vapor deposition have been used for the Si:O alloy deposition, followed by annealing up to 1250 °C. Boron implantation (30 keV, 3-30× 1014 B/cm2) on selected samples was performed to vary the electrical sheet resistance measured by the four-point collinear probe method. Transmittance and reflectance spectra have been extracted and combined to estimate the absorption spectra and the optical band gap, by means of the Tauc analysis. Raman spectroscopy was also employed to follow the amorphous-crystalline (a-c) transition of the Si domains contained in the Si:O films. The optical absorption and the electrical transport of Si:O films can be continuously and independently modulated by acting on different parameters. The light absorption increases (by one decade) with the Si content in the 43-100 at. % range, determining an optical band gap which can be continuously modulated into the 2.6-1.6 eV range, respectively. The a-c phase transition in Si:O films, causing a significant reduction in the absorption coefficient, occurs at increasing temperatures (from 600 to 1100 °C) as the Si content decreases. The electrical resistivity of Si:O films can be varied among five decades, being essentially dominated by the number of Si grains and by the doping. Si:O alloys with Si content in the 60-90 at. % range (named oxygen rich silicon films), are proved to join an appealing optical gap with a viable conductivity, being a good candidate for increasing the conversion efficiency of thin-film photovoltaic cell. © 2010 American Institute of Physics.
- Published
- 2010
140. Light absorption in silicon quantum dots embedded in silica
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Francesca Simone, Maria Miritello, R. Lo Savio, Rita Agosta, S. Di Marco, Isodiana Crupi, Salvatore Mirabella, Giorgia Franzò, M. A. Di Stefano, Antonio Terrasi, Mirabella, S., Agosta, R., Franzó, G., Crupi, I., Miritello, M., Lo Savio, R., Di Stefano, M., Di Marco, S., Simone, F., and Terrasi, A.
- Subjects
SOLAR-CELLS ,Photoluminescence ,Materials science ,EFFICIENCY ,Silicon ,Analytical chemistry ,General Physics and Astronomy ,chemistry.chemical_element ,Chemical vapor deposition ,OPTICAL-PROPERTIES ,Rutherford backscattering spectrometry ,FILMS ,Settore ING-INF/01 - Elettronica ,3RD-GENERATION PHOTOVOLTAICS ,Settore FIS/03 - Fisica Della Materia ,MULTIPLE EXCITON GENERATION ,chemistry ,X-ray photoelectron spectroscopy ,Plasma-enhanced chemical vapor deposition ,Quantum dot ,RAY PHOTOELECTRON-SPECTROSCOPY ,LUMINESCENCE ,SI NANOCRYSTALS ,COEFFICIENT ,Absorption (electromagnetic radiation) - Abstract
The photon absorption in Si quantum dots (QDs) embedded in SiO2 has been systematically investigated by varying several parameters of the QD synthesis. Plasma-enhanced chemical vapor deposition (PECVD) or magnetron cosputtering (MS) have been used to deposit, upon quartz substrates, single layer, or multilayer structures of Si-rich- SiO2 (SRO) with different Si content (43-46 at. %). SRO samples have been annealed for 1 h in the 450-1250 °C range and characterized by optical absorption measurements, photoluminescence analysis, Rutherford backscattering spectrometry and x-ray Photoelectron Spectroscopy. After annealing up to 900 °C SRO films grown by MS show a higher absorption coefficient and a lower optical bandgap (∼2.0 eV) in comparison with that of PECVD samples, due to the lower density of Si-Si bonds and to the presence of nitrogen in PECVD materials. By increasing the Si content a reduction in the optical bandgap has been recorded, pointing out the role of Si-Si bonds density in the absorption process in small amorphous Si QDs. Both the photon absorption probability and energy threshold in amorphous Si QDs are higher than in bulk amorphous Si, evidencing a quantum confinement effect. For temperatures higher than 900 °C both the materials show an increase in the optical bandgap due to the amorphous-crystalline transition of the Si QDs. Fixed the SRO stoichiometry, no difference in the optical bandgap trend of multilayer or single layer structures is evidenced. These data can be profitably used to better implement Si QDs for future PV technologies. © 2009 American Institute of Physics.
- Published
- 2009
- Full Text
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141. Silicon-based light-emitting devices: Properties and applications of crystalline, amorphous and er-doped nanoclusters
- Author
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Fabio Iacona, C.D. Presti, Alessia Irrera, Maria Miritello, Giorgia Franzò, D. Pacifici, F. Priolo, Isodiana Crupi, Iacona, F., Irrera, A., Franzò, G., Pacifici, D., Crupi, I., Miritello, M., Presti, C., and Priolo, F.
- Subjects
Materials science ,Silicon ,Electroluminescent device ,chemistry.chemical_element ,Nanocrystal ,QUANTUM DOTS ,Electroluminescence ,Settore ING-INF/01 - Elettronica ,Settore FIS/03 - Fisica Della Materia ,Nanoclusters ,Erbium ,Integrated optoelectronic ,Electroluminescence (EL) ,Light-emitting device ,Optical interconnection ,Electrical and Electronic Engineering ,business.industry ,Doping ,OPTICAL-PROPERTIES ,Atomic and Molecular Physics, and Optics ,Amorphous solid ,1.54 MU-M ,chemistry ,Optoelectronics ,Quantum efficiency ,SI NANOCRYSTALS ,ENERGY-TRANSFER ,business - Abstract
In this paper, we summarize the results of an extensive investigation on the properties of MOS-type light-emitting devices based on silicon nanostructures. The performances of crystalline, amorphous, and Er-doped Si nanostructures are presented and compared. We show that all devices are extremely stable and robust, resulting in an intense room temperature electroluminescence (EL) at around 900 nm or at 1.54 μm. Amorphous nanoclusters are more conductive than the crystalline counterpart. In contrast, nonradiative processes seem to be more efficient for amorphous clusters resulting in a lower quantum efficiency. Erbium doping results in the presence of an intense EL at 1.54 μm with a concomitant disappearance of the 900-nm emission. This suggests that under electrical pumping Er is excited through an efficient energy transfer from the silicon clusters which hence become dark. We have identified an Auger de-excitation of Er with trapped carriers as the main process competing with radiative emission and limiting EL efficiency. This process is particularly severe in presence of unbalanced carrier injection (electrons versus holes) and can be controlled in properly designed structures. These data are presented and their implications are discussed. © 2006 IEEE.
- Published
- 2006
142. Cost-Effective Fabrication of Fractal Silicon Nanowire Arrays.
- Author
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Leonardi AA, Lo Faro MJ, Miritello M, Musumeci P, Priolo F, Fazio B, and Irrera A
- Abstract
Silicon nanowires (Si NWs) emerged in several application fields as a strategic element to surpass the bulk limits with a flat compatible architecture. The approaches used for the Si NW realization have a crucial impact on their final performances and their final cost. This makes the research on a novel and flexible approach for Si NW fabrication a crucial point for Si NW-based devices. In this work, the novelty is the study of the flexibility of thin film metal-assisted chemical etching (MACE) for the fabrication of Si NWs with the possibility of realizing different doped Si NWs, and even a longitudinal heterojunction p-n inside the same single wire. This point has never been reported by using thin metal film MACE. In particular, we will show how this approach permits one to obtain a high density of vertically aligned Si NWs with the same doping of the substrate and without any particular constraint on doping type and level. Fractal arrays of Si NWs can be fabricated without any type of mask thanks to the self-assembly of gold at percolative conditions. This Si NW fractal array can be used as a substrate to realize controllable artificial fractals, integrating other interesting elements with a cost-effective microelectronics compatible approach.
- Published
- 2021
- Full Text
- View/download PDF
143. Erbium emission in Er:Y 2 O 3 decorated fractal arrays of silicon nanowires.
- Author
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Lo Faro MJ, Leonardi AA, Priolo F, Fazio B, Miritello M, and Irrera A
- Abstract
Disordered materials with new optical properties are capturing the interest of the scientific community due to the observation of innovative phenomena. We present the realization of novel optical materials obtained by fractal arrays of silicon nanowires (NWs) synthesized at low cost, without mask or lithography processes and decorated with Er:Y
2 O3 , one of the most promising material for the integration of erbium in photonics. The investigated structural properties of the fractal Er:Y2 O3 /NWs demonstrate that the fractal morphology can be tuned as a function of the sputtering deposition angle (from 5° to 15°) of the Er:Y2 O3 layer. We demonstrate that by this novel approach, it is possible to simply change the Er emission intensity by controlling the fractal morphology. Indeed, we achieved the increment of Er emission at 560 nm, opening new perspectives on the control and enhancement of the optical response of novel disordered materials.- Published
- 2020
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144. Hybrid nickel-free graphene/porphyrin rings for photodegradation of emerging pollutants in water.
- Author
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Ussia M, Urso M, Miritello M, Bruno E, Curcuruto G, Vitalini D, Condorelli GG, Cantarella M, Privitera V, and Carroccio SC
- Abstract
A novel hybrid photoactive material based on graphene foam (G) coupled with porphyrin-based polymers (Porph rings) was formulated by using a time-saving procedure to remove nickel from the final device. Specifically, Porph rings were spin coated onto the G platform with the double function of a visible-light photocatalyst and protective agent during nickel etching. The characterization of G-Porph rings was assessed by Scanning Electron microscopy (SEM), X-ray photoelectron spectroscopy (XPS) and photoluminescence (PL). The novel material showed photocatalytic ability in degrading different classes of pollutants such as the herbicide 2,4 dichlorophenoxyacetic acid (2,4-D), polyethylene glycol (PEG) as an ingredient of care and health products, and also the methylene blue (MB) dye. UV-Vis spectroscopy, total organic carbon (TOC) and soft mass spectrometry techniques were used to monitor the photocatalytic process. The best performance in terms of photocatalytic efficiency was exhibited versus PEG and MB degradation. Furthermore, to determine the individual contribution of Reactive Oxygen Species (ROS) produced, free radical and hole scavenging tests were also carried out. Finally, a detailed map of the photocatalytic degradation mechanisms was proposed, reporting also the calculation of Porph rings' Highest Occupied Molecular Orbital (HOMO) and Lowest Occupied Molecular Orbital (LUMO) energy level values., Competing Interests: There are no conflicts to declare., (This journal is © The Royal Society of Chemistry.)
- Published
- 2019
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145. Near-infrared modulation by means of GeTe/SOI-based metamaterial.
- Author
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Petronijevic E, Leahu G, Di Meo V, Crescitelli A, Dardano P, Coppola G, Esposito E, Rendina I, Miritello M, Grimaldi MG, Torrisi V, Compagnini G, and Sibilia C
- Abstract
Today, nanophotonics still lacks components for modulation that can be easily implementable in existing silicon-on-insulator (SOI) technology. Chalcogenide phase change materials (PCMs) are promising candidates for tuning in the near infrared: at the nanoscale, thin layers can provide enough contrast to control the optical response of a nanostructure. Moreover, all-dielectric metamaterials allow for resonant behavior without having ohmic losses in the telecom range. Here, a novel hybridization of a SOI-based metamaterial with PCM GeTe is experimentally investigated. A metamaterial based on Si nanorods, covered by a thin layer of GeTe, is designed and fabricated. Switching GeTe from amorphous to crystalline leads to a rather high resonance-governed reflection contrast at 1.55 μm. Additional confocal Raman imaging is done to differentiate the crystallized zones of the metamaterials' unit cell. The findings are in good agreement with numerical analysis and show good perspectives of all-dielectric tunable near-infrared nanophotonics.
- Published
- 2019
- Full Text
- View/download PDF
146. β-Bi 2 O 3 reduction by laser irradiation in a liquid environment.
- Author
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D'Angelo D, Filice S, Miritello M, Bongiorno C, Fazio E, Neri F, Compagnini G, and Scalese S
- Abstract
This study reports the structural and stoichiometric modifications of bismuth oxide nanoparticles in the β phase (β-Bi2O3) by UV pulsed laser irradiation in water or ethanol solutions. Scanning electron microscopy, X-ray diffraction, X-ray photoelectron spectroscopy, UV-vis diffuse reflectance and high-resolution transmission electron microscopy were used to characterize the synthesized nanomaterials. The various analyses demonstrate that the laser irradiation of β-Bi2O3 nanospheres is a green, fast and effective method to produce Bi2O2CO3 nanosheets or metallic Bi nanoparticles depending on the liquid environment used. Bi subcarbonate is obtained by laser irradiation in water, whereas metallic Bi is produced by laser irradiation in ethanol, and in particular the relative amount of metallic Bi is found to depend on the laser fluence. These typologies of materials find application in several fields, such as photocatalytic processes, light filters and environmental sensors.
- Published
- 2018
- Full Text
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147. Visible emission from bismuth-doped yttrium oxide thin films for lighting and display applications.
- Author
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Scarangella A, Fabbri F, Reitano R, Rossi F, Priolo F, and Miritello M
- Abstract
Due to the great development of light sources for several applications from displays to lighting, great efforts are devoted to find stable and efficient visible emitting materials. Moreover, the requirement of Si compatibility could enlarge the range of applications inside microelectronic chips. In this scenario, we have studied the emission properties of bismuth doped yttrium oxide thin films grown on crystalline silicon. Under optical pumping at room temperature a stable and strong visible luminescence has been observed. In particular, by the involvement of Bi ions in the two available lattice sites, the emission can be tuned from violet to green by changing the excitation wavelength. Moreover, under electron beam at low accelerating voltages (3 keV) a blue emission with high efficiency and excellent stability has been recorded. The color is generated by the involvement of Bi ions in both the lattice sites. These peculiarities make this material interesting as a luminescent medium for applications in light emitting devices and field emission displays by opening new perspectives for the realization of silicon-technology compatible light sources operating at room temperature.
- Published
- 2017
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148. Optical and photocatalytic properties of TiO 2 nanoplumes.
- Author
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Scuderi V, Zimbone M, Miritello M, Nicotra G, Impellizzeri G, and Privitera V
- Abstract
Here we report the photocatalytic efficiency of hydrogenated TiO
2 nanoplumes studied by measuring dye degradation in water. Nanoplumes were synthesized by peroxide etching of Ti films with different thicknesses. Structural characterization was carried out by scanning electron microscopy and transmission electron microscopy. We investigated in detail the optical properties of the synthesized material and related them to the efficiency of UV photodegradation of methylene blue dye. The obtained results show that TiO2 nanoplumes act as an effective antireflective layer increasing the UV photocatalytic yield of the film.- Published
- 2017
- Full Text
- View/download PDF
149. Multicolor Depth-Resolved Cathodoluminescence from Eu-Doped SiOC Thin Films.
- Author
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Bellocchi G, Fabbri F, Miritello M, Iacona F, and Franzò G
- Abstract
A very bright room-temperature cathodoluminescence (CL) signal, tunable in the visible range by changing the Eu(2+) concentration, has been observed in Eu-doped SiOC films. Depth-resolved CL measurements demonstrate that a bilayer consisting of two SiOC films containing different Eu concentrations allows the continuous tuning of the Eu(2+) emission from blue to green by changing the energy of the exciting electrons. Furthermore, the proper control at the nanoscale of the electron penetration depth allows to obtain a high-quality white light emission. The compatibility of SiOC films with Si technology opens the way to promising applications of Eu-based materials in lighting and display technologies.
- Published
- 2015
- Full Text
- View/download PDF
150. Optical Properties of Nanoporous Germanium Thin Films.
- Author
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Cavalcoli D, Impellizzeri G, Romano L, Miritello M, Grimaldi MG, and Fraboni B
- Abstract
In the present article we report enhanced light absorption, tunable size-dependent blue shift, and efficient electron-hole pairs generation in Ge nanoporous films (np-Ge) grown on Si. The Ge films are grown by sputtering and molecular beam epitaxy; subsequently, the nanoporous structure is obtained by Ge+ self-implantation. We show, by surface photovoltage spectroscopy measurements, blue shift of the optical energy gap and strong signal enhancement effects in the np-Ge films. The blue shift is related to quantum confinement effects at the wall separating the pore in the structure, the signal enhancement to multiple light-scattering events, which result in enhanced absorption. All these characteristics are highly stable with time. These findings demonstrate that nanoporous Ge films can be very promising for photovoltaic applications.
- Published
- 2015
- Full Text
- View/download PDF
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