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39 results on '"Biccari, F"'

1. Strain engineering of the electronic states of silicon-based quantum emitters

Author

Ristori, A., Granchi, N., Intonti, F., Khoury, M., Hannani, D., Ruiz, C. M., Salvalaglio, M., Filippatos, A., Amato, M., Herzig, T., Meijer, J., Pezzagna, S., Bollani, M., Barri, C., Abbarchi, M., and Biccari, F.

Subjects
Condensed Matter - Mesoscale and Nanoscale Physics
Abstract

Light-emitting complex defects in silicon have been considered a potential platform for quantum technologies based on spin and photon degrees of freedom working at telecom wavelengths. Their integration in complex devices is still in its infancy, and it was mostly focused on light extraction and guiding. Here we address the control of the electronic states of carbon-related impurities (G-centers) via strain engineering. By embedding them in patches of silicon on insulator and topping them with SiN, symmetry breaking along [001] and [110] directions is demonstrated, resulting in a controlled splitting of the zero phonon line (ZPL), as accounted for by the piezospectroscopic theoretical framework. The splitting can be as large as 18 meV and it is finely tuned by selecting patch size or by moving in different positions on the patch. Some of the split, strained ZPLs are almost fully polarized and their overall intensity is enhanced up to 7 times with respect to the flat areas, whereas their recombination dynamics is slightly affected. Our technique can be extended to other impurities and Si-based devices such as suspended bridges, photonic crystal microcavities, Mie resonators, and integrated photonic circuits., Comment: 14 pages; 10 figures

Published
2023

2. N-nH complexes in GaAs studied at the atomic scale by cross-sectional scanning tunneling microscopy

Author

Tjeertes, D., Verstijnen, T. J. F., Gonzalo, A., Ulloa, J. M., Sharma, M. S., Felici, M., Polimeni, A., Biccari, F., Gurioli, M., Pettinari, G., Şahin, C., Flatté, M. E., and Koenraad, P. M.

Subjects
Condensed Matter - Mesoscale and Nanoscale Physics
Abstract

Hydrogenation of nitrogen (N) doped GaAs allows for reversible tuning of the bandgap and the creation of site controlled quantum dots through the manipulation of N-nH complexes, N-nH complexes, wherein a nitrogen atom is surrounded by n hydrogen (H) atoms. Here we employ cross-sectional scanning tunneling microscopy (X-STM) to study these complexes in the GaAs (110) surface at the atomic scale. In addition to that we performed density functional theory (DFT) calculations to determine the atomic properties of the N-nH complexes. We argue that at or near the (110) GaAs surface two H atoms from N-nH complexes dissociate as an H$_2$ molecule. We observe multiple features related to the hydrogenation process, of which a subset is classified as N-1H complexes. These N-1H related features show an apparent reduction of the local density of states (LDOS), characteristic to N atoms in the GaAs (110) surface with an additional apparent localized enhancement of the LDOS located in one of three crystal directions. N-nH features can be manipulated with the STM tip. Showing in one case a switching behavior between two mirror-symmetric states and in another case a removal of the localized enhancement of the LDOS. The disappearance of the bright contrast is most likely a signature of the removal of an H atom from the N-nH complex., Comment: 11 pages, 12 figures

Published
2020
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3. Graphene-based electron transport layers in perovskite solar cells: a step-up for an efficient carrier collection

Author

Biccari, F., Gabelloni, F., Burzi, E., Gurioli, M., Pescetelli, S., Agresti, A., Castillo, A. E. Del Rio, Ansaldo, A., Kymakis, E., Bonaccorso, F., Di Carlo, A., and Vinattieri, A.

Subjects
Condensed Matter - Materials Science, Condensed Matter - Other Condensed Matter
Abstract

The electron transport layer (ETL) plays a fundamental role in perovskite solar cells. Recently, graphene-based ETLs have been proved to be good candidate for scalable fabrication processes and to achieve higher carrier injection with respect to most commonly used ETLs. In this work we experimentally study the effects of different graphene-based ETLs in sensitized MAPI solar cells. By means of time-integrated and picosecond time-resolved photoluminescence techniques, the carrier recombination dynamics in MAPI films embedded in different ETLs is investigated. Using graphene doped mesoporous TiO2 (G+mTiO2) with the addition of a lithium-neutralized graphene oxide (GO-Li) interlayer as ETL, we find that the carrier collection efficiency is increased by about a factor two with respect to standard mTiO2. Taking advantage of the absorption coefficient dispersion, we probe the MAPI layer morphology, along the thickness, finding that the MAPI embedded in the ETL composed by G+mTiO2 plus GO-Li brings to a very good crystalline quality of the MAPI layer with a trap density about one order of magnitude lower than that found with the other ETLs. In addition, this ETL freezes MAPI at the tetragonal phase, regardless of the temperature. Graphene-based ETLs can open the way to significant improvement of perovskite solar cells., Comment: 7 pages, 5 figures, Supporting Information

Published
2017
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9. Are all people with diabetes and cardiovascular risk factors or microvascular complications at very high risk? Findings from the Risk and Prevention Study

Author

Marzona, Irene, Avanzini, Fausto, Lucisano, Giuseppe, Tettamanti, Mauro, Baviera, Marta, Nicolucci, Antonio, Roncaglioni, Maria Carla, Tombesi, M., Tognoni, G., Massa, E., Marrocco, W., Micalella, M., Caimi, V., Longoni, P., Avanzini, F., Franzosi, M. G., Roncaglioni, M. C., Marzona, I., Baviera, M., Monesi, L., Pangrazzi, I., Barlera, S., Milani, V., Nicolis, E., Casola, C., Clerici, F., Palumbo, A., Sgaroni, G., Marchioli, R., Silletta, M. G., Pioggiarella, R., Scarano, M., Marfisi, R. M., Flamminio, A., Macino, L., Ferri, B., Pera, C., Polidoro, A., Abbatino, D., Acquati, M., Addorisio, G., Adinolfi, D., Adreani, L., Agistri, M. R., Agneta, A., Agnolio, M. L., Agostini, N., Agostino, G., Airò, A., Alaimo, N., Albano, M., Albano, N., Alecci, G., Alemanno, S., Alexanian, A., Alfarano, M., Alfè, L., Alonzo, N., Alvino, S., Ancora, A., Andiloro, S., Andreatta, E., Angeli, S., Angiari, F., Angilletti, V., Annicchiarico, C., Anzivino, M., Aprea, R., Aprile, A., Aprile, E., Aprile, I., Aprile, L., Armellani, V., Arnetoli, M., Aronica, A., Autiero, V., Bacca, G., Baccalaro, A. M., Bacci, M., Baglio, G., Bagnani, M., Baiano, A., Baldari, A., Ballarini, L., Banchi, G., Bandera, R., Bandini, F., Baratella, M., Barbieri, A., Barbieri Vita, A., Bardi, M., Barlocchi, M., Baron, P., Bartoli, M., Basile, A., Basile, F., Basile, S., Battaggia, A., Battaglia, A., Baù, A., Beconcini, G., Beggio, R., Belfiore, P. A., Belicchi, M., Bellamoli, S., Bellini, C., Bellomo, M., Benetollo, C., Benetti, R., Beretta, E., Bertalero, P., Bertaso, F. G., Bertolani, U., Bettelli, G., Biagiotti, G., Bianchi, S., Bianco, G., Biccari, F., Bigioli, F., Bindi, M., Bisanti, G., Bitetti, E. M., Blasetti, M. P., Blesi, F., Boato, V., Boga, S., Boidi, E., Boldrin, G., Bollati, A., Bolzan, L., Bolzonella, S., Bonardi, P., Bonato, G. B., Bonci, M., Bonfitto, G., Bonincontro, E., Boninsegna, F., Bonissone, D., Bono, L., Bonollo, E., Borghi, M., Borioli, N., Borsatto, M., Bosco, T., Bosisio Pioltelli, M., Botarelli, C., Botassis, S., Bottini, F., Bottos, C., Bova, G., Bova, V., Bozzani, A., Bozzetto, R. M., Braga, V. T., Braglia, M., Bramati, E., Brazzoli, C., Breglia, G., Brescia, A., Briganti, D., Brigato, G., Brocchi, A., Brosio, F. A., Bruni, E., Buscaglia, E., Bussini, M. D., Bussotti, A., Buzzaccarini, F., Buzzatti, A., Caccamo, G., Cacciavillani, C., Caggiano, G., Caimi, V., Calciano, F. P., Calderisi, M., Calienno, S., Caltagirone, P., Calzolari, I., Cammisa, M., Campanaro, M., Campanella, G. B., Campese, F., Canali, G., Candiani, D. E. L., Canepa, R., Canini, D., Canino, A., Cantoro, E. A., Capilupi, V., Capotosto, P., Cappelli, B., Capraro, G., Carafa, F. A., Carano, Q., Carcaterra, V., Carriero, D., Carrozzo, G., Cartanese, M., Casalena, M., Casarola, M., Caso, C., Casotto, M., Castaldi, F., Castegnaro, R., Castellani, G., Castri, S., Catalano, E., Catinello, N., Caturano, G., Cavallaro, R., Cavallo, A. M., Cavallo, G., Cavion, M. T., Cavirani, G., Cazzaniga, F., Cazzetta, D., Cecconi, V., Cefalo, A., Celebrano, M., Celora, A., Centonze, P., Cerati, D., Cesaretti, D., Checchia, G., Checchin, A., Cherubini, M., Chianese, L., Chiappa, A., Chiappa, M. V., Chiariello, G., Chiavini, G., Chicco, M., Chiumeo, F., Ciacciarelli, A., Ciaci, D., Ciancaglini, R., Cicale, C., Cicale, S., Cipolla, A., Ciruolo, A., Citeri, A. L., Citterio, G., Clerici, M., Coazzoli, E., Collecchia, G., Colletta, F., Colombo, I., Colorio, P., Coluccia, S., Comerio, M., Comoretto, P., Compagni, M., Conte, O., Contri, S., Contrisciani, A., Coppetti, T., Corasaniti, F., Corradi, M. T., Corsano, A., Corsini, A., Corti, N., Costantini, G., Costantino, A., Cotroneo, S., Cozzi, D., Cravello, M. G., Cristiano, E., Cucchi, R., Cusmai, L., D’Errico, G. B., D’Agostino, P., Dal Bianco, L., Dal Mutto, U., Dal Pozzo, G., Dallapiccola, P., Dallatorre, G., Dalle Molle, G., Dalloni, E., D’Aloiso, A., D’Amicis, G., Danese, R., Danieli, D., Danisi, G., D’Anna, M. A., Danti, G., D’Ascanio, S., Davidde, G., De Angeli, D., De Bastiani, R., De Battisti, A., De Bellis, A., De Berardinis, G., De Carlo, F., De Giorgi, D., De Gobbi, R., De Lorenzis, E., De Luca, P., De Martini, G., De Marzi, M., De Matteis, D., De Padova, S., De Polo, P., De Sabato, N., De Stefano, T., De Vita, M. T., De Vito, U., De Zolt, V., Debernardi, F., Del Carlo, A., Del Re, G., Del Zotti, F., D’Elia, R., Della Giovanna, P., Dell’Acqua, L., Dell’Orco, R. L., Demaria, G., Di Benedetto, M. G., Di Chiara, G., Di Corcia, V., Di Domizio, O., Di Donato, P., Di Donato, S., Di Fermo, G., Di Franco, M., Di Giovannantonio, G., Di Lascio, G., Di Lecce, G., Di Lorenzo, N., Di Maro, T., Di Mattia, Q., Di Michele, E., Di Modica, R. S., Di Murro, D., Di Noi, M. C., Di Paoli, V., Di Santi, M., Di Sanzo, A., Di Turi, C., Diazzi, A., Dileo, I., D’Ingianna, A. P., Dolci, A., Donà, G., Donato, C., Donato, P., Donini, A., Donna, M. E., Donvito, T. V., Esposito, L., Esposito, N., Evangelista, M., Faita, G., Falco, M., Falcone, D. A., Falorni, F., Fanciullacci, A., Fanton, L., Fasolo, L., Fassina, R., Fassone, A., Fatarella, P., Fedele, F., Fera, I., Fera, L., Ferioli, S., Ferlini, M. G., Ferlino, R., Ferrante, G., Ferrara, F. N., Ferrarese, M. F., Ferrari, G., Ferrari, O., Ferreri, A., Ferroni, M., Fezzi, G., Figaroli, C., Fina, M. G., Fioretta, A., Fiorucci, C., Firrincieli, R., Fischetti, M., Fischietti, G., Fiume, D. C., Flecchia, G., Forastiere, G., Fossati, B., Franceschi, P. L., Franchi, L., Franzoso, F., Frapporti, G., Frasca, G., Frisotti, A., Fumagalli, G., Fusco, D., Gabriele, P., Gabrieli, A., Gagliano, D., Galimberti, G., Galli, A., Gallicchio, N., Gallio, F., Gallipoli, T., Gallo, P., Galopin, T., Gambarelli, L., Garbin, A., Garozzo, G. M., Gasparri, R., Gastaldo, M., Gatti, E., Gazzaniga, P., Gennachi, N., Gentile, R. V., Germani, P., Gesualdi, F., Gherardi, E., Ghezzi, C., Ghidini, M. G., Ghionda, F., Giacci, L., Gialdini, D., Giampaolo, C., Giancane, R., Giannanti, A., Giannese, S., Giannini, L., Giaretta, M., Giaretta, R., Giavardi, L., Giordano, P., Giordano, E., Giordano, B., Gioria, G. M., Giugliano, R., Grassi, E. A., Greco, A., Greco, L., Grilletti, N., Grimaldi, N., Grisetti, G., Groppelli, G., Gualtieri, L., Guarducci, M., Guastella, G., Guerra, M., Guerrini, F., Guglielmini, A., Guido, A., Gulotta, P., Iacono, E., Iadarola, G., Ianiro, G., Iarussi, V., Ieluzzi, M. L., Ierardi, C., Ingaldi, F., Interlandi, S., Iocca, M., Iorno, A., Ioverno, E., Iurato, R., La Pace, L., La Piscopia, C., La Selva, R., Lafratta, M., Lamparelli, M., Lanaro, G., Lancerotto, R., Larcher, M., Lassandro, M., Lattuada, G., Laurino, P., Lefons, C., Legrottaglie, F., Lemma, A., Leone, D., Leone, F., Leso, A., Leuzzi, G., Levato, G., Libardi, L., Libralesso, N., Licini, P. I., Licursi, G., Lidonnici, F., Lillo, C., Liveri, L., Livio, A., Loiero, R. A., Loison, M., Lombardo, G., Lombardo, T., Lomunno, V., Lomuscio, S., Lonedo, A., Longo, E., Longoni, P., Lora, L., Lotterio, A., Lucatello, L., Luongo, A., Lupoli, M., Macchia, C., Macri, G., Mafessanti, M., Maggialetti, V., Maggioni, A., Magnani, M., Maiellaro, G., Mancuso, A., Maniglio, A. R., Mannari, G. L., Manni, A., Manocchio, B., Mao, M., Maranò, A., Maraone, E., Marascio, D., Marcheselli, P., Marchetto, B., Marchetto, S., Marchi, A., Marchi, G. L., Mariano, C., Marinacci, S., Marinelli, S., Marini, G., Marra, V. C., Marrali, F., Marseglia, C., Martello, G., Martino, C., Martino, G., Martino, M., Marulli, C. F., Maruzzi, G., Marzotti, A., Mascheroni, G., Mascolo, P., Masoch, G., Masone, R., Massa, E., Massa, L., Massafra, M., Massi, M., Massignani, D. M., Matarese, A. M., Matini, G., Mauro, R., Mazzi, M., Mazzillo, A., Mazzocato, E., Mazzoleni, N. S., Mazzone, A., Melacci, A., Mele, E., Meliota, P., Menaspà, S., Meneghello, F., Merola, G., Merone, L., Metrucci, A., Mezzina, V., Micchi, A., Michielon, A., Migliore, N., Minero, G., Minotta, F., Mirandola, C., Mistrorigo, S., Modafferi, L., Moitre, R., Mola, E., Monachese, C., Mongiardini, C., Montagna, F., Montani, M., Montemurno, I., Montolli, R., Montorsi, S., Montresor, M., Monzani, M. G., Morabito, F., Mori, G., Moro, A., Mosca, M. F., Motti, F., Muddolon, L., Mugnai, M., Muscas, F., Naimoli, F., Nanci, G., Nargi, E., Nasorri, R., Nastrini, G., Negossi, M., Negrini, A., Negroni, A., Neola, V., Niccolini, F., Niro, C. M., Nosengo, C., Novella, G., Nuti, C., Obici, F., Olita, C., Oliverio, S. S., Olivieri, I., Oriente, S., Orlando, G., Paci, C., Pagano, G., Pagliara, C., Paita, G., Paladini, G., Paladino, G., Palano, T., Palatella, A., Palermo, P., Palmisano, M., Pando, P., Panessa, P., Panigo, F., Panozzo, G., Panvini, F., Panzieri, F., Panzino, A., Panzitta, F., Paoli, N., Papagna, R., Papaleo, M. G., Papalia, G., Parisi, R., Parotti, N., Parravicini, D., Passarella, P., Pastore, G. A., Patafio, M., Pavone, P., Pedroli, W., Pedroni, M., Pelligra, G., Pellizzari, M., Penati, A., Perlot, M., Perrone, A., Perrone, G., Peruzzi, P., Peselli, C., Petracchini, L., Petrera, L., Petrone, S., Peverelli, C., Pianorsi, F., Piazza, G. P., Piazzolla, G., Picci, A., Pienabarca, G., Pietronigro, T. P., Pignocchino, P., Pilone, R., Pinto, D., Pirovano, E., Pirrotta, D., Pisante, V., Pitotto, P., Pittari, L., Piva, A., Pizzoglio, A., Plantera, O. R., Plebani, W., Plessi, S., Podrecca, D., Poerio, V., Poggiani, F., Pogliani, W., Poli, L., Poloni, F. G., Porcelli, R., Porto, S., Pranzo, L., Prevedello, C., Profeta, C., Profico, D., Punzi, A., Quaglia, G. M., Racano, M., Raccone, A., Radice, F., Raho, C. A., Raimondi, R., Rainò, M., Ramponi, R., Ramunni, A., Ramunni, A. L., Ravasio, F., Ravera, M., Re Sartò, G., Rebustello, G., Regazzoli, S., Restelli, C., Rezzonico, M., Ricchiuto, F., Rigo, S., Rigon, G., Rigon, R., Rinaldi, O. V., Rinaldi, M., Risplendente, P. G., Rispoli, M., Riundi, R., Riva, M. G., Rizzi, A. L., Rizzi, D., Rizzo, L. D., Rocchi, L., Rondinone, B., Rosa, B., Rosati, F., Roselli, F., Rossetti, A., Rossetti, C., Rossi, R., Rossi, P. R., Rossi, A., Rossi, C. L., Rossitto, A., Ruffini, R., Ruffo, A., Ruggio, S., Ruo, M., Russo, B., Russo, L., Russo, R., Russo, S., Russo, U., Russo, V., Ruta, G., Sacchi, F., Sacco Botto, F., Saia, A., Salladini, G., Salmoiraghi, S., Saluzzo, F., Salvatore, C., Salvatori, E., Salvio, G., Sandri, P., Sandrini, T., Sangermano, V., Santoni, N., Saracino, A. D., Saracino, A., Sarasin, P., Sardo Infirri, C., Sarrì, B., Sartori, G., Sartori, N., Sauro, C., Scaglioni, M., Scalfi, C., Scamardella, A. M., Scandale, G., Scandone, L., Scannavini, G., Scarati, R., Scardi, A., Scarpa, F. M., Scazzi, P., Schifone, A., Schiroso, G., Scigliano, G., Scilla, A., Sciortino, M., Scolaro, G., Scollo, E., Scorretti, G., Sellitti, R., Selmo, A., Selvaggio, G., Sempio, A., Seren, F., Serio, L., Serra, C., Serra, L., Siciliano, D., Sideri, A., Sighele, M., Signore, R., Siliberto, F., Silvestro, M., Simioni, G., Simmini, G., Simonato, L., Sinchetto, F., Sizzano, E., Smajato, G., Smaldone, M., Sola, G., Sordillo, L., Sovran, C. S., Spagnul, P., Spanò, F., Sproviero, S., Squintani, A., Stella, L., Stilo, V., Stocchiero, B., Stornello, M. C., Stracka, G., Strada, S., Stranieri, G., Stucci, N., Stufano, N., Suppa, A., Susca, V. G., Sutti, M., Taddei, M., Tagliabue, E., Tagliente, G., Talato, F., Talerico, P., Talia, R., Taranto, R., Tartaglia, M., Tauro, N., Tedesco, A., Tieri, P., Tirelli, M., Tocci, L., Todesco, P., Tognolo, M., Tomba, A., Tonello, P., Tonon, R., Toscano, L., Tosi, A., Tosi, G., Toso, S., Travaglio, P., Tremul, L., Tresso, C., Triacchini, P., Triggiano, L., Trigilio, A., Trimeloni, J., Tripicchio, G., Tritto, G. S., Trono, F., Trotta, E., Trotta, G., Tubertini, A., Turri, C., Turri, L., Tuttolani, M. P., Urago, M., Ursini, G., Valcanover, F., Valente, L., Valenti, M., Valentini, F., Vallone, G., Valz, P., Valzano, L., Vanin, V., Vatteroni, M., Vegetti, L., Vendrame, D., Veramonti, I., Veronelli, G., Vesco, A., Vicariotto, G., Vignale, G., Villa, P. L., Vinciguerra, R., Visco, A., Visentin, G., Visonà, E., Vitali, E., Vitali, S., Vitti, F., Volpone, D. A., Zambon, N., Zammarrelli, A., Zanaboni, A., Zane, D., Zanetti, B., Zanibellato, R., Zappetti, M., Zappone, P., Zerilli, G., Zirino, V., Zoccali, R., Zuin, F., Altomonte, M., Anelli, N., Angiò, F., Annale, P., Antonacci, S., Anzilotta, R., Bano, F., Basadonna, O., Beduschi, L., Becagli, P., Bellotti, G., Blotta, C., Bruno, G., Cappuccini, A., Caramatti, S., Cariolato, M. P., Castellana, M., Castellani, L., Catania, R., Chielli, A., Chinellato, A., Ciaccia, A., Clerici, E., Cocci, A., Costanzo, G., D’Ercole, F., De Stefano, G., Decè, F., Di Cicco, N., Di Marco, A., Donati Sarti, C., Draghi, E., Dusi, G., Esposito, V., Ferraro, L., Ferretti, A., Ferri, E., Foggetti, L., Foglia, A., Fonzi, E., Frau, G., Fuoco, M. R., Furci, G., Gallo, L., Garra, V., Giannini, A., Gris, A., Iacovino, R., Interrigi, R., Joppi, R., Laner, B., La Fortezza, G., La Padula, A., Lista, M. R., Lupi, G., Maffei, D., Maggioni, G., Magnani, L., Marrazzo, E., Marcon, L., Marinò, V., Maroni, A., Martinelli, C., Mastandrea, E., Mastropierro, F., Meo, A. T., Mero, P., Minesso, E., Moschetta, V., Mosele, E., Nanni, C., Negretti, A., Nisticò, C., Orsini, A., Osti, M., Pacilli, M. C., Pennestre, C., Picerno, G., Piol, K., Pivano, L., Pizzuti, E., Poggi, L., Poidomani, I., Pozzetto, M., Presti, M. L., Ravani, R., Recalenda, V., Romagnuolo, F., Rossignoli, S., Rossin, E., Sabatella, C., Sacco, F., Sanità, F., Sansone, E., Servadei, F., Sisto, M. T., Sorio, A., Sorrentino, A., Spinelli, E., Spolaor, A., Squillacioti, A., Stella, P., Talerico, A., Todisco, C., Vadino, M., Zuliani, C., and Risk & Prevention Collaborative Group

Published
2017
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10. Photonic Jet Writing of Quantum Dots Self-Aligned to Dielectric Microspheres

Author

Ristori, A, Hamilton, T, Toliopoulos, D, Felici, M, Pettinari, G, Sanguinetti, S, Gurioli, M, Mohseni, H, Biccari, F, Ristori A., Hamilton T., Toliopoulos D., Felici M., Pettinari G., Sanguinetti S., Gurioli M., Mohseni H., Biccari F., Ristori, A, Hamilton, T, Toliopoulos, D, Felici, M, Pettinari, G, Sanguinetti, S, Gurioli, M, Mohseni, H, Biccari, F, Ristori A., Hamilton T., Toliopoulos D., Felici M., Pettinari G., Sanguinetti S., Gurioli M., Mohseni H., and Biccari F.

Abstract

Owing to their ability to generate non-classical light states, quantum dots (QDs) are very promising candidates for the large-scale implementation of quantum information technologies. However, the high photon collection efficiency demanded by these technologies may be impossible to reach for “standalone” semiconductor QDs, embedded in a high-refractive index medium. In this work a novel laser writing technique is presented, enabling the direct fabrication of a QD self-aligned—with a precision of ±30 nm—to a dielectric microsphere. The presence of the microsphere leads to an enhancement of the QD luminescence collection by a factor 7.3 ± 0.7 when an objective with 0.7 numerical aperture is employed. This technique exploits the possibility of breaking the N−H bonds in GaAs (Formula presented.) Nx:H by a laser light, obtaining a lower-bandgap material, GaAs (Formula presented.) Nx. The microsphere, deposited on top of a GaAs (Formula presented.) Nx:H/GaAs quantum well, is used to generate a photonic nanojet, which removes hydrogen exactly below the microsphere, creating a GaAs (Formula presented.) Nx QD at a predefined distance from the sample surface. Second-order autocorrelation measurements confirm the ability of the QDs obtained with this technique to emit single photons.

Published
2021

11. Quantum Dots Luminescence Collection Enhancement and Nanoscopy by Dielectric Microspheres

Author

Biccari, F, Hamilton, T, Ristori, A, Sanguinetti, S, Bietti, S, Gurioli, M, Mohseni, H, Biccari F., Hamilton T., Ristori A., Sanguinetti S., Bietti S., Gurioli M., Mohseni H., Biccari, F, Hamilton, T, Ristori, A, Sanguinetti, S, Bietti, S, Gurioli, M, Mohseni, H, Biccari F., Hamilton T., Ristori A., Sanguinetti S., Bietti S., Gurioli M., and Mohseni H.

Abstract

In recent years, dielectric microspheres have been used in conjunction with optical microscopes to beat the diffraction limit and to obtain superresolution imaging. The use of microspheres on quantum dots (QDs) is investigated, for the first time, to enhance the light coupling efficiency. The enhancement of the QD luminescence collection in terms of extraction and directionality is demonstrated, as well as the enhancement of spatial resolution. In particular, it is found that a dielectric microsphere, placed on top of an epitaxial QD, increases the collected radiant energy by about a factor of 42, when a low numerical aperture objective is used. Moreover, if two or more QDs are present below the microsphere, the modification of the far field emission pattern allows selective collection of the luminescence from a single QD by simply changing the collection angle. Dielectric microspheres present a simple and efficient tool to improve the QD spectroscopy, and potentially QD-based devices.

Published
2020

12. GaAs epilayers grown on patterned (001) silicon substrates via suspended Ge layers

Author

Ballabio, A, Bietti, S, Scaccabarozzi, A, Esposito, L, Vichi, S, Fedorov, A, Vinattieri, A, Mannucci, C, Biccari, F, Nemcsis, A, Toth, L, Miglio, L, Gurioli, M, Isella, G, Sanguinetti, S, Ballabio A., Bietti S., Scaccabarozzi A., Esposito L., Vichi S., Fedorov A., Vinattieri A., Mannucci C., Biccari F., Nemcsis A., Toth L., Miglio L., Gurioli M., Isella G., Sanguinetti S., Ballabio, A, Bietti, S, Scaccabarozzi, A, Esposito, L, Vichi, S, Fedorov, A, Vinattieri, A, Mannucci, C, Biccari, F, Nemcsis, A, Toth, L, Miglio, L, Gurioli, M, Isella, G, Sanguinetti, S, Ballabio A., Bietti S., Scaccabarozzi A., Esposito L., Vichi S., Fedorov A., Vinattieri A., Mannucci C., Biccari F., Nemcsis A., Toth L., Miglio L., Gurioli M., Isella G., and Sanguinetti S.

Abstract

We demonstrate the growth of low density anti-phase boundaries, crack-free GaAs epilayers, by Molecular Beam Epitaxy on silicon (001) substrates. The method relies on the deposition of thick GaAs on a suspended Ge buffer realized on top of deeply patterned Si substrates by means of a three-temperature procedure for the growth. This approach allows to suppress, at the same time, both threading dislocations and thermal strain in the epilayer and to remove anti-phase boundaries even in absence of substrate tilt. Photoluminescence measurements show the good uniformity and the high optical quality of AlGaAs/GaAs quantum well structures realized on top of such GaAs layer.

Published
2019

13. N−nH complexes in GaAs studied at the atomic scale by cross-sectional scanning tunneling microscopy

Author

Tjeertes, D., primary, Verstijnen, T. J. F., additional, Gonzalo, A., additional, Ulloa, J. M., additional, Sharma, M. S., additional, Felici, M., additional, Polimeni, A., additional, Biccari, F., additional, Gurioli, M., additional, Pettinari, G., additional, Şahin, C., additional, Flatté, M. E., additional, and Koenraad, P. M., additional

Published
2020
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14. Temperature activated coupling in topologically distinct semiconductor nanostructures.

Author

Biccari, F., Bietti, S., Cavigli, L., Vinattieri, A., Nötzel, R., Gurioli, M., and Sanguinetti, S.

Subjects
*GALLIUM arsenide, *NANOSTRUCTURES, *QUANTUM dots, *QUANTUM rings, *PHOTOLUMINESCENCE
Abstract

We present a detailed analysis of the emission of individual GaAs/AlGaAs complex nano-systems composed of two concentric and topologically distinct quantum nanostructures, namely, a quantum dot and a quantum ring. Time resolved, temperature and excitation power density dependence of the photoluminescence from single and ensemble dot/ring structures have been used in order to determine the carrier dynamics. Despite the small spatial separation between the dot and the ring, the exciton dynamics in the two nanostructures is completely decoupled at low temperatures. At higher temperatures, we observe a clear change in the carrier dynamics, which shows the onset of the coupling between the two nanostructures. We attribute such change in carrier dynamics to the breaking of topology induced selection rules which allows the transfer of the carriers between the dot and the ring via an electronic quantum state, common to the two nanostructures. [ABSTRACT FROM AUTHOR]

Published
2016
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15. Near-field imaging of single walled carbon nanotubes emitting in the telecom wavelength range.

Author

La China, F., Caselli, N., Sarti, F., Biccari, F., Torrini, Intonti, F., Vinattieri, A., Durán-Valdeiglesias, E., Ramos, C. Alonso, Le Roux, X., Balestrieri, M., Filoramo, A., Vivien, L., and Gurioli, M.

Subjects
CARBON nanotubes, HYBRID systems, PHOTONICS, PHOTOLUMINESCENCE, SPATIAL distribution (Quantum optics)
Abstract

Hybrid systems based on carbon nanotubes emitting in the telecom wavelength range and Si-photonic platforms are promising candidates for developing integrated photonic circuits. Here, we consider semiconducting single walled carbon nanotubes (s-SWNTs) emitting around 1300 nm or 1550 nm wavelength. The nanotubes are deposited on quartz substrate for mapping their photoluminescence in hyperspectral near-field microscopy. This method allows for a sub-wavelength resolution in detecting the spatial distribution of the emission of single s-SWNTs at room temperature. Optical signature delocalized over several micrometers is observed, thus denoting the high quality of the produced carbon nanotubes on a wide range of tube diameters. Noteworthy, the presence of both nanotube bundles and distinct s-SWNT chiralities is uncovered. [ABSTRACT FROM AUTHOR]

Published
2016
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16. N-nH complexes in GaAs studied at the atomic scale by cross-sectional scanning tunneling microscopy

Author

Tjeertes, Douwe, Verstijnen, Tom, Gonzalo, Alicia, Ulloa, Jose M., Sharma, M.S., Felici, M., Polimeni, A., Biccari, F., Gurioli, M., Pettinari, G., Sahin, C., Flatté, Michael E., Koenraad, Paul M., Tjeertes, Douwe, Verstijnen, Tom, Gonzalo, Alicia, Ulloa, Jose M., Sharma, M.S., Felici, M., Polimeni, A., Biccari, F., Gurioli, M., Pettinari, G., Sahin, C., Flatté, Michael E., and Koenraad, Paul M.

Abstract

Hydrogenation of nitrogen (N) doped GaAs allows for reversible tuning of the band gap and the creation of site controlled quantum dots through the manipulation of N−nH complexes, N−nH complexes, wherein a nitrogen atom is surrounded by n hydrogen (H) atoms. Here we employ cross-sectional scanning tunneling microscopy (X-STM) to study these complexes in the GaAs (110) surface at the atomic scale. In addition to that we performed density functional theory (DFT) calculations to determine the atomic properties of the N−nH complexes. We argue that at or near the (110) GaAs surface two H atoms from N−nH complexes dissociate as an H2 molecule. We observe multiple features related to the hydrogenation process, of which a subset is classified as N-1H complexes. These N-1H related features show an apparent reduction of the local density of states (LDOS), characteristic to N atoms in the GaAs (110) surface with an additional apparent localized enhancement of the LDOS located in one of three crystal directions. N−nH features can be manipulated with the STM tip. Showing in one case a switching behavior between two mirror-symmetric states and in another case a removal of the localized enhancement of the LDOS. The disappearance of the bright contrast is most likely a signature of the removal of an H atom from the N−nH complex.

Published
2020

17. Site-controlled natural GaAs(111) quantum dots fabricated on vertical GaAs/Ge microcrystals on deeply patterned Si(001) substrates

Author

Biccari, F, Esposito, L, Mannucci, C, Taboada, A, Bietti, S, Ballabio, A, Fedorov, A, Isella, G, Von Känel, H, Miglio, L, Sanguinetti, S, Vinattieri, A, Gurioli, M, Biccari, F., Esposito, L., Mannucci, C., Taboada, A. G., Bietti, S., Ballabio, A., Fedorov, A., Isella, G., Von Känel, H., Miglio, L., Sanguinetti, S., Vinattieri, A., Gurioli, M., Biccari, F, Esposito, L, Mannucci, C, Taboada, A, Bietti, S, Ballabio, A, Fedorov, A, Isella, G, Von Känel, H, Miglio, L, Sanguinetti, S, Vinattieri, A, Gurioli, M, Biccari, F., Esposito, L., Mannucci, C., Taboada, A. G., Bietti, S., Ballabio, A., Fedorov, A., Isella, G., Von Känel, H., Miglio, L., Sanguinetti, S., Vinattieri, A., and Gurioli, M.

Abstract

Semiconductor quantum dots (QDs), made of III-V semiconductors alloys, have attracted increasing interest in the last two decades, especially for their possible usage in quantum information technology. However, for such advanced applications, the requisite control of the QD's position cannot be achieved by the conventional growth techniques. Moreover, silicon (Si) dominates the microelectronic technology but its use is limited for optoelectronic applications due to its indirect bandgap. Therefore, the possibility to integrate QDs made of III-V alloys on a Si-based platform and circuitry is of the utmost importance. However, this is hindered by the very different lattice constants and thermal expansion coefficients of Si and GaAs, which generate strain and defects. In this paper we overcome the mismatch problems using the self-limited growth of germanium on micro-patterned (001) Si to obtain a relaxed GaAs(111) oriented epilayer for the subsequent heteroepitaxy of III-V nanostructures. In particular we optically characterize a stack of three GaAs/AlGaAs quantum wells (QWs) grown on top of the Si/Ge pillars. We provide clear evidence of the presence of naturally formed QDs, due to QW thickness fluctuations, and their position control with micrometer resolution, given by the pillar distance

Published
2017

18. GaAs/AlGaAs heterostructures on suspended Ge epilayers on nominal (001) deeply patterned silicon substrates

Author

Bietti, S, Ballabio, A, Esposito, L, Fedorov, A, Scaccabarozzi, A, Vinattieri, A, Biccari, F, Nemcsics, Á, Tóth, L, Gurioli, M, Isella, G, Miglio, L, Sanguinetti, S, Bietti, S, Ballabio, A, Esposito, L, Fedorov, A, Scaccabarozzi, A, Vinattieri, A, Biccari, F, Nemcsics, Á, Tóth, L, Gurioli, M, Isella, G, Miglio, L, and Sanguinetti, S

Subjects
MBE, epitaxy, patterning, quantum well, III-V integration, micro photoluminescence, FIS/03 - FISICA DELLA MATERIA
Abstract

The integration of optoelectronic and photonic devices based on III–V semiconductors on Si-based integrated circuits is far from being optimized despite its technological relevance. Due to the differences in lattice parameters and thermal expansion coefficients, high density of defect is introduced. We propose a novel approach for the fabrication of GaAs/AlGaAs heterostructures on nominal (001) Si substrates based on suspended Ge epilayers. To eliminate dislocations and thermal cracks we use a patterned Si substrate on which we grow with a LEPECVD system, separated vertical Ge micro-crystals, efficient in eliminating the threading dislocations and the thermal strain. From such micro-crystals, a suspended Ge layer, hundreds of microns wide and free of thermal stress can be obtained. The suspended Ge shows a wavy surface on which double steps are formed, permitting the reduction of anti-phase domains even in absence of substrate tilt. GaAs layers were grown on such Ge/Si substrate in a MBE system. Different growth recipes were studied. We found that diffusion length of Ga adatom, which is related to the average nucleation distance of GaAs islands, has a crucial role in the determination of the average APD size. In the optimum growth conditions, it was possible to observe average dimensions of APD free area with a lateral dimension of 30 μm. Macro and Micro-PL of AlGaAs/GaAs QWs grew on top show that uniform, optical quality GaAs layers are fabricated.

Published
2017

19. Hybrid Carbon Nanotubes Integration In Silicon Photonic Platform

Author

Valdeiglesias, E.Duran, primary, Zhang, W., additional, Alonso-Ramos, C., additional, Roux, X.Le, additional, Serna, S., additional, Hoang, T.H.C., additional, Balestrieri, M., additional, Marris-Morini, D., additional, Biccari, F., additional, Vinattieri, A., additional, Gurioli, M., additional, Filoramo, A., additional, Cassan, E., additional, and Vivien, L., additional

Published
2018
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20. Generalized Fano lineshapes reveal exceptional points in photonic molecules

Author

Caselli, N., Intonti, F., La China, Federico, Biccari, F., Riboli, F., Gerardino, A., Li, L., Linfield, E.H., Pagliano, F., Fiore, A., Gurioli, M., Caselli, N., Intonti, F., La China, Federico, Biccari, F., Riboli, F., Gerardino, A., Li, L., Linfield, E.H., Pagliano, F., Fiore, A., and Gurioli, M.

Abstract

The optical behavior of coupled systems, in which the breaking of parity and time-reversal symmetry occurs, is drawing increasing attention to address the physics of the exceptional point singularity, i.e., when the real and imaginary parts of the normal-mode eigenfrequencies coincide. At this stage, fascinating phenomena are predicted, including electromagnetic-induced transparency and phase transitions. To experimentally observe the exceptional points, the near-field coupling to waveguide proposed so far was proved to work only in peculiar cases. Here, we extend the interference detection scheme, which lies at the heart of the Fano lineshape, by introducing generalized Fano lineshapes as a signature of the exceptional point occurrence in resonant-scattering experiments. We investigate photonic molecules and necklace states in disordered media by means of a near-field hyperspectral mapping. Generalized Fano profiles in material science could extend the characterization of composite nanoresonators, semiconductor nanostructures, and plasmonic and metamaterial devices.

Published
2018

22. Are all people with diabetes and cardiovascular risk factors or microvascular complications at very high risk? Findings from the Risk and Prevention Study

Author

Marzona, I., Avanzini, F., Lucisano, G., Tettamanti, M., Baviera, M., Nicolucci, A., Roncaglioni, M. C., Tombesi, M., Tognoni, G., Massa, E., Marrocco, W., Micalella, M., Caimi, V., Longoni, P., Franzosi, M. G., Monesi, L., Pangrazzi, I., Barlera, S., Milani, V., Nicolis, E., Casola, C., Clerici, F., Palumbo, A., Sgaroni, G., Marchioli, R., Silletta, M. G., Pioggiarella, R., Scarano, M., Marfisi, R. M., Flamminio, A., Macino, L., Ferri, B., Pera, C., Polidoro, A., Abbatino, D., Acquati, M., Addorisio, G., Adinolfi, D., Adreani, L., Agistri, M. R., Agneta, A., Agnolio, M. L., Agostini, N., Agostino, G., Airo, A., Alaimo, N., Albano, M., Albano, N., Alecci, G., Alemanno, S., Alexanian, A., Alfarano, M., Alfe, L., Alonzo, N., Alvino, S., Ancora, A., Andiloro, S., Andreatta, E., Angeli, S., Angiari, F., Angilletti, V., Annicchiarico, C., Anzivino, M., Aprea, R., Aprile, A., Aprile, E., Aprile, I., Aprile, L., Armellani, V., Arnetoli, M., Aronica, A., Autiero, V., Bacca, G., Baccalaro, A. M., Bacci, M., Baglio, G., Bagnani, M., Baiano, A., Baldari, A., Ballarini, L., Banchi, G., Bandera, R., Bandini, F., Baratella, M., Barbieri, A., Barbieri Vita, A., Bardi, M., Barlocchi, M., Baron, P., Bartoli, M., Basile, A., Basile, F., Basile, S., Battaggia, A., Battaglia, A., Bau, A., Beconcini, G., Beggio, R., Belfiore, P. A., Belicchi, M., Bellamoli, S., Bellini, C., Bellomo, M., Benetollo, C., Benetti, R., Beretta, E., Bertalero, P., Bertaso, F. G., Bertolani, U., Bettelli, G., Biagiotti, G., Bianchi, S., Bianco, G., Biccari, F., Bigioli, F., Bindi, M., Bisanti, G., Bitetti, E. M., Blasetti, M. P., Blesi, F., Boato, V., Boga, S., Boidi, E., Boldrin, G., Bollati, A., Bolzan, L., Bolzonella, S., Bonardi, P., Bonato, G. B., Bonci, M., Bonfitto, G., Bonincontro, E., Boninsegna, F., Bonissone, D., Bono, L., Bonollo, E., Borghi, M., Borioli, N., Borsatto, M., Bosco, T., Bosisio Pioltelli, M., Botarelli, C., Botassis, S., Bottini, F., Bottos, C., Bova, G., Bova, V., Bozzani, A., Bozzetto, R. M., Braga, V. T., Braglia, M., Bramati, E., Brazzoli, C., Breglia, G., Brescia, A., Briganti, D., Brigato, G., Brocchi, A., Brosio, F. A., Bruni, E., Buscaglia, E., Bussini, M. D., Bussotti, A., Buzzaccarini, F., Buzzatti, A., Caccamo, G., Cacciavillani, C., Caggiano, G., Calciano, F. P., Calderisi, M., Calienno, S., Caltagirone, P., Calzolari, I., Cammisa, M., Campanaro, M., Campanella, G. B., Campese, F., Canali, G., Candiani, D. E. L., Canepa, R., Canini, D., Canino, A., Cantoro, E. A., Capilupi, V., Capotosto, P., Cappelli, B., Capraro, G., Carafa, F. A., Carano, Q., Carcaterra, V., Carriero, D., Carrozzo, G., Cartanese, M., Casalena, M., Casarola, M., Caso, C., Casotto, M., Castaldi, F., Castegnaro, R., Castellani, G., Castri, S., Catalano, E., Catinello, N., Caturano, G., Cavallaro, R., Cavallo, A. M., Cavallo, G., Cavion, M. T., Cavirani, G., Cazzaniga, F., Cazzetta, D., Cecconi, V., Cefalo, A., Celebrano, M., Celora, A., Centonze, P., Cerati, D., Cesaretti, D., Checchia, G., Checchin, A., Cherubini, M., Chianese, L., Chiappa, A., Chiappa, M. V., Chiariello, G., Chiavini, G., Chicco, M., Chiumeo, F., Ciacciarelli, A., Ciaci, D., Ciancaglini, R., Cicale, C., Cicale, S., Cipolla, A., Ciruolo, A., Citeri, A. L., Citterio, G., Clerici, M., Coazzoli, E., Collecchia, G., Colletta, F., Colombo, I., Colorio, P., Coluccia, S., Comerio, M., Comoretto, P., Compagni, M., Conte, O., Contri, S., Contrisciani, A., Coppetti, T., Corasaniti, F., Corradi, M. T., Corsano, A., Corsini, A., Corti, N., Costantini, G., Costantino, A., Cotroneo, S., Cozzi, D., Cravello, M. G., Cristiano, E., Cucchi, R., Cusmai, L., D'Errico, G. B., D'Agostino, P., Dal Bianco, L., Dal Mutto, U., Dal Pozzo, G., Dallapiccola, P., Dallatorre, G., Dalle Molle, G., Dalloni, E., D'Aloiso, A., D'Amicis, G., Danese, R., Danieli, D., Danisi, G., D'Anna, M. A., Danti, G., D'Ascanio, S., Davidde, G., De Angeli, D., De Bastiani, R., De Battisti, A., De Bellis, A., De Berardinis, G., De Carlo, F., De Giorgi, D., De Gobbi, R., De Lorenzis, E., De Luca, P., De Martini, G., De Marzi, M., De Matteis, D., De Padova, S., De Polo, P., De Sabato, N., De Stefano, T., De Vita, M. T., De Vito, U., De Zolt, V., Debernardi, F., Del Carlo, A., Del Re, G., Del Zotti, F., D'Elia, R., Della Giovanna, P., Dell'Acqua, L., Dell'Orco, R. L., Demaria, G., Di Benedetto, M. G., Di Chiara, G., Di Corcia, V., Di Domizio, O., Di Donato, P., Di Donato, S., Di Fermo, G., Di Franco, M., Di Giovannantonio, G., Di Lascio, G., Di Lecce, G., Di Lorenzo, N., Di Maro, T., Di Mattia, Q., Di Michele, E., Di Modica, R. S., Di Murro, D., Di Noi, M. C., Di Paoli, V., Di Santi, M., Di Sanzo, A., Di Turi, C., Diazzi, A., Dileo, I., D'Ingianna, A. P., Dolci, A., Dona, G., Donato, C., Donato, P., Donini, A., Donna, M. E., Donvito, T. V., Esposito, L., Esposito, N., Evangelista, M., Faita, G., Falco, M., Falcone, D. A., Falorni, F., Fanciullacci, A., Fanton, L., Fasolo, L., Fassina, R., Fassone, A., Fatarella, P., Fedele, F., Fera, I., Fera, L., Ferioli, S., Ferlini, M. G., Ferlino, R., Ferrante, G., Ferrara, F. N., Ferrarese, M. F., Ferrari, G., Ferrari, O., Ferreri, A., Ferroni, M., Fezzi, G., Figaroli, C., Fina, M. G., Fioretta, A., Fiorucci, C., Firrincieli, R., Fischetti, M., Fischietti, G., Fiume, D. C., Flecchia, G., Forastiere, G., Fossati, B., Franceschi, P. L., Franchi, L., Franzoso, F., Frapporti, G., Frasca, G., Frisotti, A., Fumagalli, G., Fusco, D., Gabriele, P., Gabrieli, A., Gagliano, D., Galimberti, G., Galli, A., Gallicchio, N., Gallio, F., Gallipoli, T., Gallo, P., Galopin, T., Gambarelli, L., Garbin, A., Garozzo, G. M., Gasparri, R., Gastaldo, M., Gatti, E., Gazzaniga, P., Gennachi, N., Gentile, R. V., Germani, P., Gesualdi, F., Gherardi, E., Ghezzi, C., Ghidini, M. G., Ghionda, F., Giacci, L., Gialdini, D., Giampaolo, C., Giancane, R., Giannanti, A., Giannese, S., Giannini, L., Giaretta, M., Giaretta, R., Giavardi, L., Giordano, P., Giordano, E., Giordano, B., Gioria, G. M., Giugliano, R., Grassi, E. A., Greco, A., Greco, L., Grilletti, N., Grimaldi, N., Grisetti, G., Groppelli, G., Gualtieri, L., Guarducci, M., Guastella, G., Guerra, M., Guerrini, F., Guglielmini, A., Guido, A., Gulotta, P., Iacono, E., Iadarola, G., Ianiro, G., Iarussi, V., Ieluzzi, M. L., Ierardi, C., Ingaldi, F., Interlandi, S., Iocca, M., Iorno, A., Ioverno, E., Iurato, R., La Pace, L., La Piscopia, C., La Selva, R., Lafratta, M., Lamparelli, M., Lanaro, G., Lancerotto, R., Larcher, M., Lassandro, M., Lattuada, G., Laurino, P., Lefons, C., Legrottaglie, F., Lemma, A., Leone, D., Leone, F., Leso, A., Leuzzi, G., Levato, G., Libardi, L., Libralesso, N., Licini, P. I., Licursi, G., Lidonnici, F., Lillo, C., Liveri, L., Livio, A., Loiero, R. A., Loison, M., Lombardo, G., Lombardo, T., Lomunno, V., Lomuscio, S., Lonedo, A., Longo, E., Lora, L., Lotterio, A., Lucatello, L., Luongo, A., Lupoli, M., Macchia, C., Macri, G., Mafessanti, M., Maggialetti, V., Maggioni, A., Magnani, M., Maiellaro, G., Mancuso, A., Maniglio, A. R., Mannari, G. L., Manni, A., Manocchio, B., Mao, M., Marano, A., Maraone, E., Marascio, D., Marcheselli, P., Marchetto, B., Marchetto, S., Marchi, A., Marchi, G. L., Mariano, C., Marinacci, S., Marinelli, S., Marini, G., Marra, V. C., Marrali, F., Marseglia, C., Martello, G., Martino, C., Martino, G., Martino, M., Marulli, C. F., Maruzzi, G., Marzotti, A., Mascheroni, G., Mascolo, P., Masoch, G., Masone, R., Massa, L., Massafra, M., Massi, M., Massignani, D. M., Matarese, A. M., Matini, G., Mauro, R., Mazzi, M., Mazzillo, A., Mazzocato, E., Mazzoleni, N. S., Mazzone, A., Melacci, A., Mele, E., Meliota, P., Menaspa, S., Meneghello, F., Merola, G., Merone, L., Metrucci, A., Mezzina, V., Micchi, A., Michielon, A., Migliore, N., Minero, G., Minotta, F., Mirandola, C., Mistrorigo, S., Modafferi, L., Moitre, R., Mola, E., Monachese, C., Mongiardini, C., Montagna, F., Montani, M., Montemurno, I., Montolli, R., Montorsi, S., Montresor, M., Monzani, M. G., Morabito, F., Mori, G., Moro, A., Mosca, M. F., Motti, F., Muddolon, L., Mugnai, M., Muscas, F., Naimoli, F., Nanci, G., Nargi, E., Nasorri, R., Nastrini, G., Negossi, M., Negrini, A., Negroni, A., Neola, V., Niccolini, F., Niro, C. M., Nosengo, C., Novella, G., Nuti, C., Obici, F., Olita, C., Oliverio, S. S., Olivieri, I., Oriente, S., Orlando, G., Paci, C., Pagano, G., Pagliara, C., Paita, G., Paladini, G., Paladino, G., Palano, T., Palatella, A., Palermo, P., Palmisano, M., Pando, P., Panessa, P., Panigo, F., Panozzo, G., Panvini, F., Panzieri, F., Panzino, A., Panzitta, F., Paoli, N., Papagna, R., Papaleo, M. G., Papalia, G., Parisi, R., Parotti, N., Parravicini, D., Passarella, P., Pastore, G. A., Patafio, M., Pavone, P., Pedroli, W., Pedroni, M., Pelligra, G., Pellizzari, M., Penati, A., Perlot, M., Perrone, A., Perrone, G., Peruzzi, P., Peselli, C., Petracchini, L., Petrera, L., Petrone, S., Peverelli, C., Pianorsi, F., Piazza, G. P., Piazzolla, G., Picci, A., Pienabarca, G., Pietronigro, T. P., Pignocchino, P., Pilone, R., Pinto, D., Pirovano, E., Pirrotta, D., Pisante, V., Pitotto, P., Pittari, L., Piva, A., Pizzoglio, A., Plantera, O. R., Plebani, W., Plessi, S., Podrecca, D., Poerio, V., Poggiani, F., Pogliani, W., Poli, L., Poloni, F. G., Porcelli, R., Porto, S., Pranzo, L., Prevedello, C., Profeta, C., Profico, D., Punzi, A., Quaglia, G. M., Racano, M., Raccone, A., Radice, F., Raho, C. A., Raimondi, R., Raino, M., Ramponi, R., Ramunni, A., Ramunni, A. L., Ravasio, F., Ravera, M., Re Sarto, G., Rebustello, G., Regazzoli, S., Restelli, C., Rezzonico, M., Ricchiuto, F., Rigo, S., Rigon, G., Rigon, R., Rinaldi, O. V., Rinaldi, M., Risplendente, P. G., Rispoli, M., Riundi, R., Riva, M. G., Rizzi, A. L., Rizzi, D., Rizzo, L. D., Rocchi, L., Rondinone, B., Rosa, B., Rosati, F., Roselli, F., Rossetti, A., Rossetti, C., Rossi, R., Rossi, P. R., Rossi, A., Rossi, C. L., Rossitto, A., Ruffini, R., Ruffo, A., Ruggio, S., Ruo, M., Russo, B., Russo, L., Russo, R., Russo, S., Russo, U., Russo, V., Ruta, G., Sacchi, F., Sacco Botto, F., Saia, A., Salladini, G., Salmoiraghi, S., Saluzzo, F., Salvatore, C., Salvatori, E., Salvio, G., Sandri, P., Sandrini, T., Sangermano, V., Santoni, N., Saracino, A. D., Saracino, A., Sarasin, P., Sardo Infirri, C., Sarri, B., Sartori, G., Sartori, N., Sauro, C., Scaglioni, M., Scalfi, C., Scamardella, A. M., Scandale, G., Scandone, L., Scannavini, G., Scarati, R., Scardi, A., Scarpa, F. M., Scazzi, P., Schifone, A., Schiroso, G., Scigliano, G., Scilla, A., Sciortino, M., Scolaro, G., Scollo, E., Scorretti, G., Sellitti, R., Selmo, A., Selvaggio, G., Sempio, A., Seren, F., Serio, L., Serra, C., Serra, L., Siciliano, D., Sideri, A., Sighele, M., Signore, R., Siliberto, F., Silvestro, M., Simioni, G., Simmini, G., Simonato, L., Sinchetto, F., Sizzano, E., Smajato, G., Smaldone, M., Sola, G., Sordillo, L., Sovran, C. S., Spagnul, P., Spano, F., Sproviero, S., Squintani, A., Stella, L., Stilo, V., Stocchiero, B., Stornello, M. C., Stracka, G., Strada, S., Stranieri, G., Stucci, N., Stufano, N., Suppa, A., Susca, V. G., Sutti, M., Taddei, M., Tagliabue, E., Tagliente, G., Talato, F., Talerico, P., Talia, R., Taranto, R., Tartaglia, M., Tauro, N., Tedesco, A., Tieri, P., Tirelli, M., Tocci, L., Todesco, P., Tognolo, M., Tomba, A., Tonello, P., Tonon, R., Toscano, L., Tosi, A., Tosi, G., Toso, S., Travaglio, P., Tremul, L., Tresso, C., Triacchini, P., Triggiano, L., Trigilio, A., Trimeloni, J., Tripicchio, G., Tritto, G. S., Trono, F., Trotta, E., Trotta, G., Tubertini, A., Turri, C., Turri, L., Tuttolani, M. P., Urago, M., Ursini, G., Valcanover, F., Valente, L., Valenti, M., Valentini, F., Vallone, G., Valz, P., Valzano, L., Vanin, V., Vatteroni, M., Vegetti, L., Vendrame, D., Veramonti, I., Veronelli, G., Vesco, A., Vicariotto, G., Vignale, G., Villa, P. L., Vinciguerra, R., Visco, A., Visentin, G., Visona, E., Vitali, E., Vitali, S., Vitti, F., Volpone, D. A., Zambon, N., Zammarrelli, A., Zanaboni, A., Zane, D., Zanetti, B., Zanibellato, R., Zappetti, M., Zappone, P., Zerilli, G., Zirino, V., Zoccali, R., Zuin, F., Altomonte, M., Anelli, N., Angio, F., Annale, P., Antonacci, S., Anzilotta, R., Bano, F., Basadonna, O., Beduschi, L., Becagli, P., Bellotti, G., Blotta, C., Bruno, G., Cappuccini, A., Caramatti, S., Cariolato, M. P., Castellana, M., Castellani, L., Catania, R., Chielli, A., Chinellato, A., Ciaccia, A., Clerici, E., Cocci, A., Costanzo, G., D'Ercole, F., De Stefano, G., Dece, F., Di Cicco, N., Di Marco, A., Donati Sarti, C., Draghi, E., Dusi, G., Esposito, V., Ferraro, L., Ferretti, A., Ferri, E., Foggetti, L., Foglia, A., Fonzi, E., Frau, G., Fuoco, M. R., Furci, G., Gallo, L., Garra, V., Giannini, A., Gris, A., Iacovino, R., Interrigi, R., Joppi, R., Laner, B., La Fortezza, G., La Padula, A., Lista, M. R., Lupi, G., Maffei, D., Maggioni, G., Magnani, L., Marrazzo, E., Marcon, L., Marino, V., Maroni, A., Martinelli, C., Mastandrea, E., Mastropierro, F., Meo, A. T., Mero, P., Minesso, E., Moschetta, V., Mosele, E., Nanni, C., Negretti, A., Nistico, C., Orsini, A., Osti, M., Pacilli, M. C., Pennestre, C., Picerno, G., Piol, K., Pivano, L., Pizzuti, E., Poggi, L., Poidomani, I., Pozzetto, M., Presti, M. L., Ravani, R., Recalenda, V., Romagnuolo, F., Rossignoli, S., Rossin, E., Sabatella, C., Sacco, F., Sanita, F., Sansone, E., Servadei, F., Sisto, M. T., Sorio, A., Sorrentino, A., Spinelli, E., Spolaor, A., Squillacioti, A., Stella, P., Talerico, A., Todisco, C., Vadino, M., and Zuliani, C.

Subjects
Male, medicine.medical_specialty, Endocrinology, Diabetes and Metabolism, Population, 030209 endocrinology & metabolism, 030204 cardiovascular system & hematology, Overweight, 03 medical and health sciences, 0302 clinical medicine, Endocrinology, Prediction model, Internal medicine, Diabetes mellitus, Internal Medicine, Diabetes Mellitus, Medicine, Humans, Multicenter Studies as Topic, Myocardial infarction, Risk factor, education, Stroke, Aged, Randomized Controlled Trials as Topic, education.field_of_study, Lifestyle habits, business.industry, Major cardiovascular events, Atrial fibrillation, General Medicine, Middle Aged, medicine.disease, Cardiovascular Diseases, Heart failure, Physical therapy, Female, medicine.symptom, business, Diabetic Angiopathies
Abstract

To verify whether it is possible, in people with diabetes mellitus (DM) considered at very high cardiovascular (CV) risk, stratify this risk better and identify significant modifiable risk factor (including lifestyle habits) to help patients and clinicians improve CV prevention. People with DM and microvascular diseases or one or more CV risk factors (hypertension, hyperlipidemia, smoking, poor dietary habits, overweight, physical inactivity) included in the Risk and Prevention study were selected. We considered the combined endpoint of non-fatal acute myocardial infarction and stroke and CV death. A multivariate Cox proportional analysis was carried out to identify relevant predictors. We also used the RECPAM method to identify subgroups of patients at higher risk. In our study, the rate of major CV events was lower than expected (5 % in 5 years). Predictors of CV events were age, male, sex, heart failure, previous atherosclerotic disease, atrial fibrillation, insulin treatment, high HbA1c, heart rate and other CV diseases while being physically active was protective. RECPAM analysis indicated that history of atherosclerotic diseases and a low BMI defined worse prognosis (HR 4.51 95 % CI 3.04–6.69). Among subjects with no previous atherosclerotic disease, men with HbA1c more than 8 % were at higher CV risk (HR 2.77; 95 % CI 1.86–4.14) with respect to women. In this population, the rate of major CV events was lower than expected. This prediction model could help clinicians identify people with DM at higher CV risk and support them in achieving goals of physical activity and HbA1c.

Published
2016

24. Near-field speckle imaging of light localization in disordered photonic systems

Author

Caselli, N., Intonti, F., La China, F., Biccari, F., Riboli, F., Gerardino, A., Li, L., Linfield, E.H., Pagliano, F., Fiore, A., Gurioli, M., Caselli, N., Intonti, F., La China, F., Biccari, F., Riboli, F., Gerardino, A., Li, L., Linfield, E.H., Pagliano, F., Fiore, A., and Gurioli, M.

Abstract

Optical localization in strongly disordered photonic media is an attractive topic for proposing novel cavity-like structures. Light interference can produce random modes confined within small volumes, whose spatial distribution in the near-field is predicted to show hot spots at the nanoscale. However, these near-field speckles have not yet been experimentally investigated due to the lack of a high spatial resolution imaging techniques. Here, we study a system where the disorder is induced by random drilling air holes in a GaAs suspended membrane with internal InAs quantum dots. We perform deep-subwavelength near-field experiments in the telecom window to directly image the spatial distribution of the electric field intensity of disordered-induced localized optical modes. We retrieve the near-field speckle patterns that extend over few micrometers and show several single speckles of the order of λ/10 size. The results are compared with the numerical calculations and with the recent findings in the literature of disordered media. Notably, the hot spots of random modes are found in proximity of the air holes of the disordered system.

Published
2017

25. Temperature activated coupling in topologically distinct semiconductor nanostructures

Author

Biccari, F, Bietti, S, Cavigli, L, Vinattieri, A, Nötzel, R, Gurioli, M, Sanguinetti, S, BIETTI, SERGIO, SANGUINETTI, STEFANO, Biccari, F, Bietti, S, Cavigli, L, Vinattieri, A, Nötzel, R, Gurioli, M, Sanguinetti, S, BIETTI, SERGIO, and SANGUINETTI, STEFANO

Abstract

We present a detailed analysis of the emission of individual GaAs/AlGaAs complex nano-systems composed of two concentric and topologically distinct quantum nanostructures, namely, a quantum dot and a quantum ring. Time resolved, temperature and excitation power density dependence of the photoluminescence from single and ensemble dot/ring structures have been used in order to determine the carrier dynamics. Despite the small spatial separation between the dot and the ring, the exciton dynamics in the two nanostructures is completely decoupled at low temperatures. At higher temperatures, we observe a clear change in the carrier dynamics, which shows the onset of the coupling between the two nanostructures. We attribute such change in carrier dynamics to the breaking of topology induced selection rules which allows the transfer of the carriers between the dot and the ring via an electronic quantum state, common to the two nanostructures.

Published
2016

26. GaAs nanostructures on Si platform

Author

Sanguinetti, S., primary, Bietti, S., additional, Scarpellini, D., additional, Ballabio, A., additional, Miglio, L., additional, Isella, G., additional, Esposito, L., additional, Frigerio, J., additional, Fedorov, A., additional, Gurioli, M., additional, Biccari, F., additional, Abbarchi, M., additional, and Vinattieri, A., additional

Published
2015
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27. Photonic Jet Writing of Quantum Dots Self-Aligned to Dielectric Microspheres

Author

Stefano Sanguinetti, Marco Felici, Hooman Mohseni, Andrea Ristori, Travis Hamilton, Francesco Biccari, Dimosthenis Toliopoulos, Massimo Gurioli, Giorgio Pettinari, Ristori, A, Hamilton, T, Toliopoulos, D, Felici, M, Pettinari, G, Sanguinetti, S, Gurioli, M, Mohseni, H, and Biccari, F

Subjects
Nuclear and High Energy Physics, Materials science, collection enhancement, site-controlled quantum dot, 02 engineering and technology, Dielectric, 01 natural sciences, Microsphere, photonic jet, 0103 physical sciences, Electrical and Electronic Engineering, 010306 general physics, Mathematical Physics, Jet (fluid), business.industry, Statistical and Nonlinear Physics, 021001 nanoscience & nanotechnology, Condensed Matter Physics, Electronic, Optical and Magnetic Materials, dilute nitride, Computational Theory and Mathematics, Quantum dot, microsphere, Optoelectronics, Photonics, 0210 nano-technology, business, dilute nitrides, microspheres, photonic jets, site-controlled quantum dots
Abstract

Owing to their ability to generate non-classical light states, quantum dots (QDs) are very promising candidates for the large-scale implementation of quantum information technologies. However, the high photon collection efficiency demanded by these technologies may be impossible to reach for “standalone” semiconductor QDs, embedded in a high-refractive index medium. In this work a novel laser writing technique is presented, enabling the direct fabrication of a QD self-aligned—with a precision of ±30 nm—to a dielectric microsphere. The presence of the microsphere leads to an enhancement of the QD luminescence collection by a factor 7.3 ± 0.7 when an objective with 0.7 numerical aperture is employed. This technique exploits the possibility of breaking the N−H bonds in GaAs (Formula presented.) Nx:H by a laser light, obtaining a lower-bandgap material, GaAs (Formula presented.) Nx. The microsphere, deposited on top of a GaAs (Formula presented.) Nx:H/GaAs quantum well, is used to generate a photonic nanojet, which removes hydrogen exactly below the microsphere, creating a GaAs (Formula presented.) Nx QD at a predefined distance from the sample surface. Second-order autocorrelation measurements confirm the ability of the QDs obtained with this technique to emit singlephotons.

Published
2021

28. Quantum Dots Luminescence Collection Enhancement and Nanoscopy by Dielectric Microspheres

Author

Francesco Biccari, Massimo Gurioli, Travis Hamilton, Hooman Mohseni, Sergio Bietti, Stefano Sanguinetti, Andrea Ristori, Biccari, F, Hamilton, T, Ristori, A, Sanguinetti, S, Bietti, S, Gurioli, M, and Mohseni, H

Subjects
Materials science, Photoluminescence, business.industry, near field, Near and far field, General Chemistry, Dielectric, Photonic nanojet, Condensed Matter Physics, Microsphere, Quantum dot, photonic nanojet, microsphere, Optoelectronics, General Materials Science, photoluminescence, business, Luminescence, FIS/03 - FISICA DELLA MATERIA
Abstract

In recent years, dielectric microspheres have been used in conjunction with optical microscopes to beat the diffraction limit and to obtain superresolution imaging. The use of microspheres on quantum dots (QDs) is investigated, for the first time, to enhance the light coupling efficiency. The enhancement of the QD luminescence collection in terms of extraction and directionality is demonstrated, as well as the enhancement of spatial resolution. In particular, it is found that a dielectric microsphere, placed on top of an epitaxial QD, increases the collected radiant energy by about a factor of 42, when a low numerical aperture objective is used. Moreover, if two or more QDs are present below the microsphere, the modification of the far field emission pattern allows selective collection of the luminescence from a single QD by simply changing the collection angle. Dielectric microspheres present a simple and efficient tool to improve the QD spectroscopy, and potentially QD-based devices.

Published
2020

29. Site-controlled natural GaAs(111) quantum dots fabricated on vertical GaAs/Ge microcrystals on deeply patterned Si(001) substrates

Author

Stefano Sanguinetti, Leo Miglio, C. Mannucci, Sergio Bietti, Alexey Fedorov, Massimo Gurioli, Francesco Biccari, Anna Vinattieri, Alfonso G. Taboada, Andrea Ballabio, H. von Känel, Giovanni Isella, Luca Esposito, Biccari, F, Esposito, L, Mannucci, C, Taboada, A, Bietti, S, Ballabio, A, Fedorov, A, Isella, G, Von Känel, H, Miglio, L, Sanguinetti, S, Vinattieri, A, and Gurioli, M

Subjects
0301 basic medicine, Materials science, patterning, business.industry, Quantum Dot, Defect free, GaAs/Si Integration, Micro photoluminescence, 03 medical and health sciences, 030104 developmental biology, Quantum dot, Quantum Dots, Optoelectronics, micro photoluminescence, GaAs(111) Substrates, General Materials Science, Materials Science (all), Defect Free, business
Abstract

Semiconductor quantum dots (QDs), made of III-V semiconductors alloys, have attracted increasing interest in the last two decades, especially for their possible usage in quantum information technology. However, for such advanced applications, the requisite control of the QD's position cannot be achieved by the conventional growth techniques. Moreover, silicon (Si) dominates the microelectronic technology but its use is limited for optoelectronic applications due to its indirect bandgap. Therefore, the possibility to integrate QDs made of III-V alloys on a Si-based platform and circuitry is of the utmost importance. However, this is hindered by the very different lattice constants and thermal expansion coefficients of Si and GaAs, which generate strain and defects. In this paper we overcome the mismatch problems using the self-limited growth of germanium on micro-patterned (001) Si to obtain a relaxed GaAs(111) oriented epilayer for the subsequent heteroepitaxy of III-V nanostructures. In particular we optically characterize a stack of three GaAs/AlGaAs quantum wells (QWs) grown on top of the Si/Ge pillars. We provide clear evidence of the presence of naturally formed QDs, due to QW thickness fluctuations, and their position control with micrometer resolution, given by the pillar distance.

Published
2017
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30. Direct Determination of Carrier Parameters in Indium Tin Oxide Nanocrystals.

Author

Gabbani A, Della Latta E, Mohan A, Scarperi A, Li X, Ruggeri M, Martini F, Biccari F, Kociak M, Geppi M, Borsacchi S, and Pineider F

Abstract

We develop here a comprehensive experimental approach to independently determine charge carrier parameters, namely, carrier density and mass, in plasmonic indium tin oxide nanocrystals. Typically, in plasmonic nanocrystals, only the ratio between these two parameters is accessible through optical absorption experiments. The multitechnique methodology proposed here combines single particle and ensemble optical and magneto-optical spectroscopies, also using 119 Sn solid-state nuclear magnetic resonance spectroscopy to probe the surface depletion layer. Our methodology overcomes the limitations of standard fitting approaches based on absorption spectroscopy and ultimately gives access to carrier effective mass directly on the NCs, discarding the use of literature value based on bulk or thin film materials. We found that mass values depart appreciably from those measured on thin films; consequently, we found carrier density values that are different from reported literature values for similar systems. The effective mass was found to deviate from the parabolic approximation at a high carrier density. Finally, the dopant activation and defect diagram for ITO NCs for tin doping between 2.5 and 15% are determined. This approach can be generalized to other plasmonic heavily doped semiconductor nanostructures and represents, to the best of our knowledge, the only method to date to characterize the full Drude parameter space of 0-D nanosystems.

Published
2024
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31. Temperature-Dependent Amplified Spontaneous Emission in CsPbBr 3 Thin Films Deposited by Single-Step RF-Magnetron Sputtering.

Author

Morello G, Milanese S, De Giorgi ML, Calisi N, Caporali S, Biccari F, Falsini N, Vinattieri A, and Anni M

Abstract

Due to their high optical efficiency, low-cost fabrication and wide variety in composition and bandgap, halide perovskites are recognized nowadays as real contenders for the development of the next generation of optoelectronic devices, which, among others, often require high quality over large areas which is readily attainable by vacuum deposition. Here, we report the amplified spontaneous emission (ASE) properties of two CsPbBr 3 films obtained by single-step RF-magnetron sputtering from a target containing precursors with variable compositions. Both the samples show ASE over a broad range of temperatures from 10 K up to 270 K. The ASE threshold results strongly temperature dependent, with the best performance occurring at about 50 K (down to 100 µJ/cm 2 ), whereas at higher temperatures, there is evidence of thermally induced optical quenching. The observed temperature dependence is consistent with exciton detrapping up to about 50 K. At higher temperatures, progressive free exciton dissociation favors higher carrier mobility and increases trapping at defect states with consequent emission reduction and increased thresholds. The reported results open the way for effective large-area, high quality, organic solution-free deposited perovskite thin films for optoelectronic applications, with a remarkable capability to finely tune their physical properties.

Published
2023
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32. Tailoring the optical properties of dilute nitride semiconductors at the nanometer scale.

Author

Pettinari G, Marotta G, Biccari F, Polimeni A, and Felici M

Abstract

We report on the innovative approaches we developed for the fabrication of site-controlled semiconductor nanostructures [e.g. quantum dots (QDs), nanowires], based on the spatially selective incorporation and/or removal of hydrogen in dilute nitride semiconductor alloys [e.g. Ga(AsN) and (InGa)(AsN)]. In such systems, the formation of stable nitrogen-hydrogen complexes removes the effects nitrogen has on the alloy properties, which in turn paves the way to the direct engineering of the material's electronic-and, thus, optical-properties: not only the bandgap energy, but also the refractive index and the polarization properties of the system can indeed be tailored with high precision and in a reversible manner. Here, lithographic approaches and/or plasmon-assisted optical irradiation-coupled to the ultra-sharp diffusion profile of hydrogen in dilute nitrides-are employed to control the hydrogen implantation and/or removal process at a nanometer scale. This results in a highly deterministic control of the spatial and spectral properties of the fabricated nanostructures, eventually obtaining semiconductor nanowires with controlled polarization properties, as well as site-controlled QDs with an extremely high control on their spatial and spectral properties. The nanostructures fabricated with these techniques, whose optical properties have also been simulated by finite-element-method calculations, are naturally suited for a deterministic coupling in optical nanocavities (i.e. photonic crystal cavities and circular Bragg resonators) and are therefore of potential interest for emerging quantum technologies.

Published
2021
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33. Large-Area Nanocrystalline Caesium Lead Chloride Thin Films: A Focus on the Exciton Recombination Dynamics.

Author

Falsini N, Calisi N, Roini G, Ristori A, Biccari F, Scardi P, Barri C, Bollani M, Caporali S, and Vinattieri A

Abstract

Caesium lead halide perovskites were recently demonstrated to be a relevant class of semiconductors for photonics and optoelectronics. Unlike CsPbBr 3 and CsPbI 3 , the realization of high-quality thin films of CsPbCl 3 , particularly interesting for highly efficient white LEDs when coupled to converting phosphors, is still a very demanding task. In this work we report the first successful deposition of nanocrystalline CsPbCl 3 thin films (70-150 nm) by radio frequency magnetron sputtering on large-area substrates. We present a detailed investigation of the optical properties by high resolution photoluminescence (PL) spectroscopy, resolved in time and space in the range 10-300 K, providing quantitative information concerning carriers and excitons recombination dynamics. The PL is characterized by a limited inhomogeneous broadening (~15 meV at 10 K) and its origin is discussed from detailed analysis with investigations at the micro-scale. The samples, obtained without any post-growth treatment, show a homogeneous PL emission in spectrum and intensity on large sample areas (several cm 2 ). Temperature dependent and time-resolved PL spectra elucidate the role of carrier trapping in determining the PL quenching up to room temperature. Our results open the route for the realization of large-area inorganic halide perovskite films for photonic and optoelectronic devices.

Published
2021
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34. First Proof-of-Principle of Inorganic Lead Halide Perovskites Deposition by Magnetron-Sputtering.

Author

Borri C, Calisi N, Galvanetto E, Falsini N, Biccari F, Vinattieri A, Cucinotta G, and Caporali S

Abstract

The present work reports the application of RF-magnetron sputtering technique to realize CsPbBr 3 70 nm thick films on glass substrate by means of a one-step procedure. The obtained films show highly uniform surface morphology and homogeneous thickness as evidenced by AFM and SEM investigations. XRD measurements demonstrate the presence of two phases: a dominant orthorhombic CsPbBr 3 and a subordinate CsPb 2 Br 5 . Finally, XPS data reveals surface bromine depletion respect to the stoichiometrical CsPbBr 3 composition, nevertheless photoluminescence spectroscopy results confirm the formation of a highly luminescent film. These preliminary results demonstrate that our approach could be of great relevance for easy fabrication of large area perovskite thin films. Future developments, based on this approach, may include the realization of multijunction solar cells and multicolor light emitting devices.

Published
2019
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35. GaAs epilayers grown on patterned (001) silicon substrates via suspended Ge layers.

Author

Ballabio A, Bietti S, Scaccabarozzi A, Esposito L, Vichi S, Fedorov A, Vinattieri A, Mannucci C, Biccari F, Nemcsis A, Toth L, Miglio L, Gurioli M, Isella G, and Sanguinetti S

Abstract

We demonstrate the growth of low density anti-phase boundaries, crack-free GaAs epilayers, by Molecular Beam Epitaxy on silicon (001) substrates. The method relies on the deposition of thick GaAs on a suspended Ge buffer realized on top of deeply patterned Si substrates by means of a three-temperature procedure for the growth. This approach allows to suppress, at the same time, both threading dislocations and thermal strain in the epilayer and to remove anti-phase boundaries even in absence of substrate tilt. Photoluminescence measurements show the good uniformity and the high optical quality of AlGaAs/GaAs quantum well structures realized on top of such GaAs layer.

Published
2019
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36. Tailoring carbon nanotubes optical properties through chirality-wise silicon ring resonators.

Author

Durán-Valdeiglesias E, Zhang W, Alonso-Ramos C, Serna S, Le Roux X, Maris-Morini D, Caselli N, Biccari F, Gurioli M, Filoramo A, Cassan E, and Vivien L

Abstract

Semiconducting single walled carbon nanotubes (s-SWNT) have an immense potential for the development of active optoelectronic functionalities in ultra-compact hybrid photonic circuits. Specifically, s-SWNT have been identified as a very promising solution to implement light sources in the silicon photonics platform. Still, two major challenges remain to fully exploit the potential of this hybrid technology: the limited interaction between s-SWNTs and Si waveguides and the low quantum efficiency of s-SWNTs emission. Silicon micro-ring resonators have the potential capability to overcome these limitations, by providing enhanced light s-SWNT interaction through resonant light recirculation. Here, we demonstrate that Si ring resonators provide SWNT chirality-wise photoluminescence resonance enhancement, releasing a new degree of freedom to tailor s-SWNT optical properties. Specifically, we show that judicious design of the micro-ring geometry allows selectively promoting the emission enhancement of either (8,6) or (8,7) SWNT chiralities present in a high-purity polymer-sorted s-SWNT solution. In addition, we present an analysis of nanometric-sized silicon-on-insulator waveguides that predicts stronger light s-SWNT interaction for transverse-magnetic (TM) modes than for conventionally used transverse-electric (TE) modes.

Published
2018
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37. Site-Controlled Single-Photon Emitters Fabricated by Near-Field Illumination.

Author

Biccari F, Boschetti A, Pettinari G, La China F, Gurioli M, Intonti F, Vinattieri A, Sharma M, Capizzi M, Gerardino A, Businaro L, Hopkinson M, Polimeni A, and Felici M

Abstract

Many of the most advanced applications of semiconductor quantum dots (QDs) in quantum information technology require a fine control of the QDs' position and confinement potential, which cannot be achieved with conventional growth techniques. Here, a novel and versatile approach for the fabrication of site-controlled QDs is presented. Hydrogen incorporation in GaAsN results in the formation of N-2H and N-2H-H complexes, which neutralize all the effects of N on GaAs, including the N-induced large reduction of the bandgap energy. Starting from a fully hydrogenated GaAs/GaAsN:H/GaAs quantum well, the NH bonds located within the light spot generated by a scanning near-field optical microscope tip are broken, thus obtaining site-controlled GaAsN QDs surrounded by a barrier of GaAsN:H (laterally) and GaAs (above and below). By adjusting the laser power density and exposure time, the optical properties of the QDs can be finely controlled and optimized, tuning the quantum confinement energy over more than 100 meV and resulting in the observation of single-photon emission from both the exciton and biexciton recombinations. This novel fabrication technique reaches a position accuracy <100 nm and it can easily be applied to the realization of more complex nanostructures., (© 2018 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.)

Published
2018
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38. Generalized Fano lineshapes reveal exceptional points in photonic molecules.

Author

Caselli N, Intonti F, La China F, Biccari F, Riboli F, Gerardino A, Li L, Linfield EH, Pagliano F, Fiore A, and Gurioli M

Subjects
Semiconductors, Spectrum Analysis, Nanostructures, Optical Phenomena, Photons
Abstract

The optical behavior of coupled systems, in which the breaking of parity and time-reversal symmetry occurs, is drawing increasing attention to address the physics of the exceptional point singularity, i.e., when the real and imaginary parts of the normal-mode eigenfrequencies coincide. At this stage, fascinating phenomena are predicted, including electromagnetic-induced transparency and phase transitions. To experimentally observe the exceptional points, the near-field coupling to waveguide proposed so far was proved to work only in peculiar cases. Here, we extend the interference detection scheme, which lies at the heart of the Fano lineshape, by introducing generalized Fano lineshapes as a signature of the exceptional point occurrence in resonant-scattering experiments. We investigate photonic molecules and necklace states in disordered media by means of a near-field hyperspectral mapping. Generalized Fano profiles in material science could extend the characterization of composite nanoresonators, semiconductor nanostructures, and plasmonic and metamaterial devices.

Published
2018
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39. Narrow-linewidth carbon nanotube emission in silicon hollow-core photonic crystal cavity.

Author

Hoang THC, Durán-Valdeiglesias E, Alonso-Ramos C, Serna S, Zhang W, Balestrieri M, Keita AS, Caselli N, Biccari F, Le Roux X, Filoramo A, Gurioli M, Vivien L, and Cassan E

Abstract

Polymer-sorted semiconducting single-walled carbon nanotubes (SWNTs) provide room-temperature emission at near-infrared wavelengths, with potential for large volume production of high-quality solutions and wafer-scale deposition. These features make SWNTs a very attractive material for the realization of on-chip light sources. Coupling SWNT into optical microcavities could enhance and guide their emission, while enabling spectral selection by cavity resonance engineering. This could allow the realization of bright, narrowband sources. Here, we report the first demonstration of coupling SWNTs into the resonant modes of Si hollow-core photonic crystal cavities. We exploit the strong evanescent field in these resonators to interact with SWNT emission, coupling it into an integrated access waveguide. Based on this concept, we demonstrate narrowband SWNT emission resonantly coupled into a Si bus waveguide with a full width at half-maximum of 0.34 nm and an off-resonance rejection exceeding 5 dB.

Published
2017
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