Search

Francesco Menzella,1 Marco Bonavia,2 Matteo Bonini,3 Maria D’Amato,4 Salvatore Lombardo,5 Nicola Murgia,6 Vincenzo Patella,7,8 Massimo Triggiani,9 Girolamo Pelaia10 1Pneumology Unit, Arcispedale Santa Maria Nuova, Azienda USL di Reggio Emilia-IRCCS, Reggio Emilia, Italy; 2Pneumologia Riabilitativa - Ospedale Ge-Arenzano, ASL3-, Genoa, Italy; 3Department of Cardiovascular and Thoracic Sciences, Università Cattolica del Sacro Cuore, Rome, Italy; 4Respiratory Department- Monaldi Hospital AO Dei Colli, Naples, Italy; 5Pneumology Unit, Ospedale Giovanni Paolo II, Lamezia Terme, Italy; 6Section of Occupational Medicine, Respiratory Diseases and Toxicology, University of Perugia, Perugia, Italy; 7Division of Allergy and Clinical Immunology, Department of Medicine ASL Salerno, Santa Maria Della Speranza Hospital, Salerno, Italy; 8Postgraduate Program in Allergy and Clinical Immunology, University of Naples Federico II, Naples, Italy; 9Division of Allergy and Clinical Immunology, University of Salerno, Fisciano, Italy; 10Department of Health Sciences, Respiratory Unit, University “Magna Graecia” of Catanzaro, Catanzaro, ItalyCorrespondence: Francesco MenzellaPneumology Unit, Arcispedale Santa Maria Nuova, Azienda USL di Reggio Emilia-IRCCS, Reggio Emilia, ItalyTel +390522296073Email Francesco.Menzella@ausl.re.itPurpose: Severe eosinophilic asthma (SEA) is characterized by high eosinophilia, severe symptoms, important comorbidities, frequent exacerbations, and poor asthma control. Benralizumab, targeting the interleukin-5 receptor alpha, proved effective in inducing rapid eosinophil depletion and amelioration of symptoms and lung function; it also allowed to reduce exacerbations and the use of oral corticosteroids (OCS). The present case series, spanning different subtypes of SEA, aimed at expanding the real-world experience with benralizumab in Italy.Patients and Methods: We collected data from SEA patients treated with benralizumab, at baseline and during treatment. We focused on the effects of benralizumab in the following conditions and endpoints: i) overlap between high-IgE and high-eosinophilic asthma; ii) presence of nasal polyposis as comorbidity; iii) corticosteroid-sparing effect; iv) patient perception.Results: Ten SEA patients (females: N=7; age range: 19– 70 years) referred to 8 Italian Centers and treated with benralizumab were included, presenting with several comorbidities such as non-allergic disease (8/10), atopy (3/10), high IgE (5/10) and nasal polyposis (6/10). Overall, benralizumab yielded optimal disease control in all patients, particularly in terms of rapid clinical and functional improvement, decreased systemic steroid need (OCS therapy was completely discontinued in 7 cases) and amelioration of patient quality of life, except for 1 case, in whom other conditions not related to benralizumab therapy interfered with the patient perception.Conclusion: Our findings further support the efficacy and safety of benralizumab observed in randomized clinical trials, providing even better results for lung function improvement.Keywords: benralizumab, IL-5 receptor, oral corticosteroids, overlap IgE/eosinophilic asthma, polyposis, real world, severe eosinophilic asthma

Lipidomics is strategic in the discovery of biomarkers of neurodegenerative diseases (NDDs). The skin surface lipidome bears the potential to provide biomarker candidates in the detection of pathological processes occurring in distal organs. We investigated the sebum composition to search diagnostic and, possibly, prognostic, biomarkers of Alzheimer’s disease (AD) and Parkinson’s disease (PD). The observational study included 64 subjects: 20 characterized as “probable AD with documented decline”, 20 as “clinically established PD”, and 24 healthy subjects (HS) of comparable age. The analysis of sebum by GCMS and TLC retrieved the amounts (µg) of 41 free fatty acids (FFAs), 7 fatty alcohols (FOHs), vitamin E, cholesterol, squalene, and total triglycerides (TGs) and wax esters (WEs). Distributions of sebum lipids in NDDs and healthy conditions were investigated with multivariate ANOVA-simultaneous component analysis (ASCA). The deranged sebum composition associated with the PD group showed incretion of most composing lipids compared to HS, whereas only two lipid species (vitamin E and FOH14:0) were discriminant of AD samples and presented lower levels than HS sebum. Thus, sebum lipid biosynthetic pathways are differently affected in PD and AD. The characteristic sebum bio-signatures detected support the value of sebum lipidomics in the biomarkers search in NDDs.

The Horizon 2020 project PECSYS aims to build a large area demonstrator for hydrogen production from solar energy via integrated photovoltaic (PV) and electrolysis systems of different types. In this study, Si- and CIGS-based photovoltaics are developed together with three different electrolyzer systems for use in the corresponding integrated devices. The systems are experimentally evaluated and a general model is developed to investigate the hydrogen yield under real climatic conditions for various thin film and silicon PV technologies and electrolyser combinations. PV characteristics using a Si heterojunction (SHJ), thin film CuInxGa1-xSe2, crystalline Si with passivated emitter rear totally diffused and thin film Si are used together with temperature dependent catalyst load curves from both acidic and alkaline approaches. Electrolysis data were collected from (i) a Pt-IrO2-based acidic electrolysis system, and (ii) NiMoW-NiO-based and (iii) Pt-Ni foam-based alkaline electrolysis systems. The calculations were performed for mid-European climate data from Julich, Germany, which will be the installation site. The best systems show an electricity-to-hydrogen conversion efficiency of 74% and over 12% solar-to-hydrogen (STH) efficiencies using both acidic and alkaline approaches and are validated with a smaller lab scale prototype. The results show that the lower power delivered by all the PV technologies under low irradiation is balanced by the lower demand for overpotentials for all the electrolysis approaches at these currents, with more or less retained STH efficiency over the full year if the catalyst area is the same as the PV area for the alkaline approach. The total yield of hydrogen, however, follows the irradiance, where a yearly hydrogen production of over 35 kg can be achieved for a 10 m(2) integrated PV-electrolysis system for several of the PV and electrolyser combinations that also allow a significant (100-fold) reduction in necessary electrolyser area for the acidic approach. Measuring the catalyst systems under intermittent and ramping conditions with different temperatures, a 5% lowering of the yearly hydrogen yield is extracted for some of the catalyst systems while the Pt-Ni foam-based alkaline system showed unaffected or even slightly increased yearly yield under the same conditions.

Wear out in the maximum power point condition of tandem microcrystalline Si/amorphous Si thin film PV modules due to extended light soaking is a well-known effect due to the Staebler–Wronski mechanism [ 1 ]. However, several studies [ [2] , [3] , [4] , [5] , [6] , [7] , [8] ] on a-Si:H single junction and tandem solar cells, have shown that, under suitable conditions of electric field in reverse bias, illumination, especially at well-defined wavelengths (700–800 nm), and temperature conditions, an improvement of the cell main electric parameters is possible. In this work, we report on new stress tests performed on tandem amorphous Silicon PV devices (both non-stabilized and stabilized), highlighting the improvement of their electrical performances, founded both in the tests performed on non-stabilized samples (essentially due to the reverse bias stresses carried out in these tests) and in the outdoor tests on stabilized samples (not subjected to reverse bias stresses) going from morning to afternoon illumination. In the latter tests, the efficiency improvement observed in the afternoon is stable overnight and observed also in the early stages of the morning outdoor test in the following day. Possible causes of such effect are discussed.

In this paper, we report on the performances of silicon photomultipliers (SiPMs) with commercial long-pass interferential and plastic filters integrated on the detector's package for environmental light rejection. Several applications, including functional near infrared (NIR) spectroscopy or light detection and ranging, would benefit from the use of highly sensitive detectors like SiPMs with optimized electro-optical characteristics in NIR wavelength range. To this purpose, it is fundamental to reduce the absorption of environmental spurious light leading in application to a decrease of the detector's sensitivity, especially for very weak photon fluxes. We will show how the use of both types of filters has a relevant impact on the electro-optical performances of the bare detectors, in terms of cross talk reduction at high overvoltage values, detection efficiency, spectral response and capability to shield effectively the devices from the absorption of stray light, at the different light wavelengths used for the measurements.

Photoelectrochemical water splitting is a promising method to produce H 2 by making use of solar energy. In this paper we report on a photocathode made by p-type crystalline Si covered with an n-type 3C-SiC polycrystalline film, acting as protective layer and transparent emitter. The photoelectrodes exhibit a saturated photocurrent above 30 mA cm −2 . No decay is observed after 9 h under constant current stress at 1 kW m −2 with AM1.5G spectrum illumination. Improvement of the photocurrent value is achieved by covering the 3C-SiC emitter with Au or Pt nanoparticles. Under suitable metal nanoparticles deposition conditions, compared to the samples without nanoparticles, two major effects are observed: first the onset potential is considerably reduced, and second, higher saturated photocurrent is found, up to 38 mA cm −2 , i.e. with a 27% increase. Optical and micro-structural studies on the nanoparticles provide insights on the origin of the observed effects.

The Staebler-Wronski effect in amorphous silicon based photovoltaic devices is responsible for degradation of their power conversion efficiency, within approximately the first one thousand hours of light soaking. Several experimental studies led to highlight the performance instability phenomena for the mentioned devices, underling that recovery and improvement of such performance are observable, by subjecting such devices (both of single-junction and tandem types) to DC reverse bias stresses under illumination, or to operation in the Maximum Power Point (MPP) under variable conditions of temperature and illumination. In this work, we present and discuss the results of novel recent outdoor tests on stabilized specimens (i.e., exposed to 1000 h extended light soaking, before our tests) of tandem amorphous/microcrystalline Si (a-Si/&micro, c-Si) photovoltaic (PV) minimodules operating in their MPP, by analyzing the causes of the performance instability effects, systematically observed on a daily scale. During the mentioned tests, we have monitored the solar cell operating temperature and the incident solar spectrum at various times in different days to verify the effect of cell temperature and solar spectrum changes on the cell performances. The experimental results show a clear correlation between performance improvements of the photovoltaic modules and their thermal history during the outdoor tests, proving the interplay between defect build-up at a lower temperature and defect annealing at a higher temperature, taking place in the solar cells operated in MPP during conventional outdoor operation.

Aim of AMPERE is the setting-up of an European sustainable manufacturing full-scale automated industrial pilot line, to produce bifacial heterojunction technology (HJT) silicon solar cells and modules. In this work we illustrate the state of art of AMPERE project, started in May 2017, focusing on its technical results, industrial and economic sustainability and perspectives on LCOE in the frame of vertical integration along with EGP as its natural end-user. These expected outcomes will be assessed and evaluated as a solid backbone to pave the way to the GW factory scaling up. The decision to accelerate in the project timeframe, within 2019, the installation and start-up of a manufacturing line, leading to a nominal capacity of EGP Catania 3SUN site to 200 MWp, will support the demonstration of the viability of HJT solar module massive production in Europe.

Thin dielectric films are essential components of most micro- and nanoelectronic devices, and they have played a key role in the huge development that the semiconductor industry has experienced during the last 50 years. Guaranteeing the reliability of thin dielectric films has become more challenging, in light of strong demand from the market for improved performance in electronic devices. The degradation and breakdown of thin dielectrics under normal device operation has an enormous technological importance and thus it is widely investigated in traditional dielectrics (e.g., SiO2, HfO2, and Al2O3), and it should be further investigated in novel dielectric materials that might be used in future devices (e.g., layered dielectrics). Understanding not only the physical phenomena behind dielectric breakdown but also its statistics is crucial to ensure the reliability of modern and future electronic devices, and it can also be cleverly used for other applications, such as the fabrication of new-concept resistive switching devices (e.g., nonvolatile memories and electronic synapses). Here, the fundamentals of the dielectric breakdown phenomenon in traditional and future thin dielectrics are revised. The physical phenomena that trigger the onset, structural damage, breakdown statistics, device reliability, technological implications, and perspectives are described. Fil: Palumbo, Félix Roberto Mario. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina. Universidad Tecnológica Nacional. Facultad Regional Buenos Aires. Unidad de Investigación y Desarrollo de las Ingenierías; Argentina Fil: Wen, Chao. Soochow University; China Fil: Lombardo, Salvatore. Consiglio Nazionale delle Ricerche; Italia Fil: Pazos, Sebastián Matías. Universidad Tecnológica Nacional. Facultad Regional Buenos Aires. Unidad de Investigación y Desarrollo de las Ingenierías; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina Fil: Aguirre, Fernando Leonel. Universidad Tecnológica Nacional. Facultad Regional Buenos Aires. Unidad de Investigación y Desarrollo de las Ingenierías; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina Fil: Eizenberg, Moshe. Technion - Israel Institute of Technology; Israel Fil: Hui, Fei. Soochow University; China. Technion - Israel Institute of Technology; Israel Fil: Lanza, Mario. Soochow University; China

Background Brodie’s abscess is a form of chronic pyogenic osteomyelitis that usually affects the cancellous part of the long bones in children. Its treatment is represented by antibiotic therapy alone or in association with surgical procedures. Case presentation A 12-years-old male affected by a Brodie’s abscess of the tibia involving the distal growth plate was admitted to the Pediatric Department for a conservative treatment. After several attempts of antibiotic therapy interrupted for intolerance manifestations he was surgically treated with bioactive glass BAG-S53P4 (BonAlive, BonAlive Biomaterials Ltd., Biolinja, Finland), with excellent results. Conclusions In our experience BAG-S53P4 has proven to be an effective bone substitute without side effects even in the pediatric population. In our case it eradicated the infection without interfere with the growth; neither epiphysiodesis nor other disorders were found during the follow-up. For the publication of this case report we followed the CARE guidelines for good clinical case reports; the parents gave consent for publication.

Avascular necrosis (AVN) is a disease due to the interruption of the blood supply to the bone. It is one of the most common and debilitating therapy-related sequelae of the antileukemic treatment and it may not be clinically recognized. Symptomatic AVN have been reported in 1-17% of children with acute lymphoblastic leukemia (ALL) during treatment or thereafter although an incidence of up to 72% of asymptomatic AVN has been detected with systematic screening by magnetic resonance imaging (MRI). In all cases AVN is related to ALL treatment and in particular to high-dose steroids. While the AVN of the hip is frequently reported in the literature, reports regarding AVN of the talus are lacking; moreover, there is little consensus about its incidence, diagnostic algorithm and treatment. Talus is an articular weight-bearing bone with over 60% of the surface covered by cartilage and a specific limited vascular supply. The aim of this article is to provide an up-to-date review about management of avascular necrosis of the talus highlighting the importance of early diagnosis based on ankle MRI imaging in pediatric patients affected with ALL.

In this work, the breakdown transients of metal-oxide-semiconductors (MOS) stacks with InGaAs channels and different oxide layers (Al2O3,HfO2 and Si3N4) have been studied in terms of the time-to-breakdown and the duration of the progressive breakdown regime. It is observed that dielectric layers with higher thermal conductivity show larger transient time during the progressive breakdown regime, and this provides a significant lifetime extension across the entire failure distribution. This is attributed to a lower temperature of the percolation path which reduces local electro-migration. Moreover, the overall results show that the progressive breakdown regime is uncorrelated with the initial degradation rate, and that the bending of failure distribution at low percentiles is exclusively attributed to the progressive increase of the gate current during the breakdown event. Fil: Palumbo, Félix Roberto Mario. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina. Universidad Tecnológica Nacional; Argentina. Comisión Nacional de Energía Atómica. Gerencia del Área Investigaciones y Aplicaciones no Nucleares; Argentina Fil: Lombardo,Salvatore. Consiglio Nazionale delle Ricerche; Italia Fil: Eizenberg, Moshe. Technion - Israel Institute of Technology; Israel

We built a fiber-less prototype of an optical system with 156 channels each one consisting of an optode made of a silicon photomultiplier (SiPM) and a pair of light emitting diodes (LEDs) operating at 700 nm and 830 nm. The system uses functional near-infrared spectroscopy (fNIRS) and diffuse optical tomography (DOT) imaging of the cortical activity of the human brain at frequencies above 1 Hz. In this paper, we discuss testing and system optimization performed through measurements on a multi-layered optical phantom with mechanically movable parts that simulate near-infrared light scattering inhomogeneities. The baseline optical characteristics of the phantom are carefully characterized and compared to those of human tissues. Here we discuss several technical aspects of the system development, such as LED light output drift and its possible compensation, SiPM linearity, corrections of channel signal differences, and signal-to-noise ratio (SNR). We implement an imaging algorithm that investigates large phantom regions. Thanks to the use of SiPMs, very large source-to-detector distances are acquired with a high SNR and 2 Hz time resolution. The overall results demonstrate the high potentialities of a system based on SiPMs for fNIRS/DOT human brain imaging applications.

We have realized tandem amorphous Si / microcrystalline Si PV cells and modules with an n+ SiOx emitter heterojunction with microcrystalline Si. The SiOx films show filamentary nanostructures and high electrical conductivity. Excellent photovoltaic characteristics are demonstrated.

In this work, we investigate some major issues for the use of silicon photomultiplier (SiPM) devices in continuous wave functional near-infrared spectroscopy (CW fNIRS). We analyzed the after-pulsing effect, proposing the physical mechanism causing it, and determining its relevance for CW fNIRS. We studied the SiPM transients occurring as the SiPM device goes from the dark (LED in off state) to the illumination (LED in on state) conditions. and vice-versa. Finally, we studied the SiPM SNR in standard CW fNIRS operation. (C) 2018 Optical Society of America under the terms of the OS.A Open Access Publishing Agreement

We study the electrical and the optical behavior of HIT solar cell by means of measurements and optoelectrical simulations by TCAD simulations. We compare the HIT solar cell with a conventional crystalline silicon solar cell to identify the strengths and weaknesses of the HIT technology. Results highlight different mechanisms of electrical and optical efficiency losses caused by the presence of the amorphous silicon layer. The higher resistivity of the a-Si layers implies a smaller distance between the metal lines that causes a higher shadowing. The worst optical coupling between the amorphous silicon and the antireflective coating implies a slight increase of reflectivity around the 600 nm wavelength.

We developed and tested in vivo a flexible multichannel Continuous Wave (CW) functional Near Infrared Spectroscopy (fNIRS) system based on Silicon Photomultipliers (SiPMs). SiPMs are inexpensive, low voltage and resilient semiconductor light detectors with sensitivity analogous to PhotoMultiplierTubes (PMTs). In contrast with PMTs, SiPMs allow contact with the head avoiding optical fibers. The coupling of SiPMs and Light Emitting Diodes (LEDs) located on the scalp made the optical probe wearable and robust against motion artifacts. After characterization of SiPMs performances and system SNR, the apparatus was compared through an in vivo experiment to a commercial system based on Laser Diodes, PMTs and optical fibers. The optical probes were positioned over the sensorimotor cortex and the similarities between the estimated hemodynamic responses to the same contralateral motor task were evaluated. When compared to other state of the art wearable fNIRS systems that employ photodiodes detectors, the single photon sensitivity and significant dynamic range of SiPMs can exploit the long and variable inter-optode distances needed for estimation of brain hemodynamics through CW-fNIRS.

The Staebler and Wronski light soaking effect [1-3] in hydrogenated amorphous silicon (a-Si:H) results as a worsening of solar cell performances under light soaking which results in a substantial loss of cell power conversion efficiency compared to time zero performance. In this work, comparing the behavior of single a-Si:H p-i-n devices with that of tandem a-Si:H / microcrystalline Si solar cells, we report on the performance improvement of the solar cells under prolonged exposure to reverse bias DC electric fields and illumination. In the paper we discuss about the radical differences between the forward and reverse bias stress and on the spectroscopic signature of the defects responsible for the instability / improvement effect. In addition, we determine the range of wavelengths where the photons are effective to improve the lifetime and cell efficiency. Finally, examples of reverse bias practical use in solar cell application are shown.

We study resistive switching memories with Hf or Ti metal oxygen exchange layers.STEM dark field and EELS are used to observe the conductive filament.The filament is a cone-shaped metal-rich region in the HfO2 dielectric layer.Composition of the metallic filament is dominated by Hf or Ti depending on the OEL. A detailed physical analysis of the conductive filament electrically formed in HfO2-based resistive switching memory devices with both Hf and Ti metal oxygen exchange layers is presented. The filament, observed by applying transmission electron microscopy (TEM), scanning TEM (STEM), and electron energy loss spectroscopy (EELS) techniques to 50i?50nm2 cells, is a cone-shaped metal-rich region in the HfO2 dielectric of the resistive switching device.

The ageing effects of hydrogenated amorphous Si (a-Si:H) under illumination have been investigated. These are strongly affected by the well-known Staebler-Wronski effect, occurring during light soaking of a-Si:H, producing a substantial loss of cell power conversion efficiency. In this work the light soaking effect was investigated and it was shown that the application of a strong electric field in reverse bias not only slows down the solar cell ageing kinetics but also even produces an improvement of the cells parameters. Such improvements have been investigated discussing the impact of temperature, electric field intensity, illumination level, substrate type and reversibility properties. Further information on the possible improvement causes are provided by the analysis of the behavior of single thin films of doped a-Si:H, and by comparing to the case of micromorph solar cells.

Dye-sensitized solar cells (DSSCs) are promising third generation photovoltaic devices given their potential low cost and high efficiency. Some factors still affect DSSCs performance, such structure of electrodes, electrolyte compositions, nature of the sensitizers, power conversion efficiency, long-term stability, etc. In this work we discuss the effect of electrical stresses, which allow to improve DSSC performance. We have investigated the outcomes of forward and reverse DC bias stress as a function of time, voltage, and illumination level in the DSSCs sensitized with the N719, Ruthenium complex based dye. We demonstrate that all the major solar cell parameters, i.e., open circuit voltage (VOC), short circuit current (ISC), series resistance (ROC), fill factor (FF), and power conversion efficiency are strongly influenced by the stress conditions and a clear reversibility of the parameters on the stress type is shown. In this context we examined the possible effects that emerge from the electrolyte composition.

We experimentally analyze the signal-to-noise ratio of continuous wave (CW) near infrared spectroscopy (NIRS) reflectance systems based on light emitting diodes and silicon photomultipliers for high performance low cost NIRS biomedical systems. We show that under suitable experimental conditions such systems exhibit a high SNR, which allows an SDS of 7 cm, to our knowledge the largest ever demonstrated in a CW-NIRs system. (C) 2016 Optical Society of America

We study the spontaneous recovery phenomenon displayed by solar cells sensitized with a ruthenium complex-based dye N719, which manifests with the increase over the time (from several minutes up to some days) of the short circuit current density J sc and the open circuit voltage V oc , during cell illumination. Under dark conditions the current decreases over time after the application of forward bias voltages. We investigate the effects of temperature and electrolyte composition by means of current–voltage measurements and electrochemical impedance spectroscopy, both under dark and illumination conditions. The main result is that the recovery of the performances depends on the charge transport mechanism at the TiO 2 /electrolyte interface and is caused by the increasing of the electron lifetime in the titania. This effect could be explained by intercalation of ions H + present in the electrolyte that limits the recombination of electrons from TiO 2 to the triiodide.

The photoelectrochemical (PEC) water splitting cell, a device that uses sunlight to produce hydrogen, has garnered very much interest due to its simple structure, low fabrication cost and good performance. In these cells, a semiconductor photoelectrode is immersed in a liquid and, when illuminated, hydrogen and/or oxygen can be generated on its surface by electrolysis. Metal catalysts are often used to enhance the activity of the semiconductor, but the lifetime of the semiconductor photoelectrode is still the main bottleneck of this technology. In this manuscript we report the ageing mechanisms of silicon photoanodes coated with nickel films of different thicknesses (under the light-driven oxygen evolution reaction, OER). The n-Si photoanodes coated with 2 nm-thick, 5 nm-thick and 10 nm-thick nickel layers showed lifetimes of similar to 18 h, similar to 150 h and >260 h, respectively. While the 2 nm-thick sample degraded due to the formation of a thin SiOX layer at the metal-silicon interface, the performance of the thicker samples decreased due to the formation of holes. The 5 nm-thick and 10 nm-thick nickel films turned into homogeneous potassium-free NiOX films suitable for water splitting, and this conversion markedly enhanced the performance of the cells. The density/size of holes in the surface decreased/increased with the metal thickness. The potassium contamination in the 2 nm-thick Ni sample took place in the form of nanofilaments, and we demonstrated that the widely used X-ray photoelectron spectroscopy tests are blind to these features, which may have been ignored in all previous reports. These results could be useful for understanding the degradation and enhancing the yield of water-splitting solar cells.

The dark current behavior of the pixels forming the Si photomultiplier as a function of the applied overvoltage and operation temperature is studied. The data are modeled by assuming that dark current is caused by current pulses triggered by events of diffusion of single minority carriers injected from the peripheral boundaries of the active area depletion layer and by thermal emission of carriers from Shockley-Read-Hall defects in the active area depletion layer.

In this paper, an extensive investigation of hybrid molecular/Si field-effect memories is presented, where redox ferrocene (Fc) molecules play the role of the memory charge storage nodes. Engineering of the organic linkers between Fc and Si is achieved by grafting Fc with different linker lengths. The study shows a clear correlation between results from atomistic computational density functional theory, electrochemical measurements (cyclic voltammetry) and electrical data obtained by a detailed study on capacitors and pseudo-MOS devices. Physical-chemical analyses (atomic force microscopy, high-resolution transmission electron microscopy, and X-ray photoelectron spectroscopy), corroborate the quality of molecular layers on devices.

Multiple gate tridimensional memory cells can have several additional advantages besides increased read current and excellent Ion/Ioff ratio, which are inherent in the multiple-gate transistor architecture. We show that tridimensional memory cells with rounded top geometry and SONOS storage stack strongly improve the Fowler–Nordheim tunneling program–erase performances because of an enhanced electric field effect and an increase of the cell coupling factor. Moreover, a remarkable enhancement of the tridimensional cell performances is expected if the blocking silicon oxide and the poly-silicon gate in the SONOS memory stack are replaced with a high-k dielectric and a high work-function metallic control gate.

We review some experimental data on the dielectric breakdown (BD) phenomenon under high field stress of important gate insulators used in MOSFETs. We first discuss the case of silicon oxides or oxynitrides in the thickness range of tens of nm down to about 1 nm focusing on the kinetics of the final hard BD event.We describe the dependence of the BD current transient on the oxide thickness and the electric field and voltage. In particular we focus on the progressive BD phenomenon, i.e., a gradual growth of the BD leakage occurring in a time scale which in operation conditions is relevant. We then discuss the BD phenomemon in the case of ultra-thin high polarizability constant (high-k) dielectrics with metal gates in comparison to the conventional SiO2/poly-Si devices and outline critical differences between these gate stacks.

Dielectric breakdown (BD) of nFETs with TiN metal gates and HfO 2 /interfacial layer with 1.09 nm EOT is studied. Occurrence of progressive BD at low current levels is demonstrated. A new measurement methodology for extraction of the PBD time and its dependence on gate voltage are reported.

NROM type non-volatile memories, having information charge stored in traps in silicon nitride layer, were subjected to different radiation sources in order to ascertain the radiation hardness. Fundamental device parameters, such as threshold voltage shift and current leakages were studied as function of the accumulated dose for gamma (60Co) and Boron ions irradiations to emulate real radiation environments for space and avionics applications. Radiation tolerance of NROM cells was registered with a pronounced degradation for doses exceeding 50 Krad and 1x1010 B/cm2 for gamma and Boron ions irradiations respectively.

High-k/metal gate stacks are a promising and viable approach for CMOS scaling. The high permittivity of the dielectric used can reduce the leakage current while preserving the low equivalent oxide (EOT) thickness needed for the future step of technologies. The recent advances are very encouraging, but reliability aspects, in particular TDDB characteristics, are much less developed. In this paper we investigate the issue of progressive dielectric breakdown, a debated aspect (1-3), which is critical for evaluation of the device lifetime.

In this paper, we evaluate the potentialities of hafnium-aluminates (HfAlO) materials as possible candidates for the interpoly dielectrics of future Flash memory devices. HfAlO layers of different thicknesses and compositions are integrated in single-layers and in Oxide/HfAlO/Oxide (OHO) triple-layer stacks, and analyzed in terms of coupling and insulating capabilities. We demonstrate that increasing the Hf content allows reducing the leakage current at high voltages but it results in a stronger leakage current at low voltages. We also show that once normalized in electric fields, the leakage current characteristics are independent of the high-k thickness. The electron conduction modes in these materials, at different temperatures, are also investigated. The activation energy increases with the Hf concentration in the HfAlO alloy, resulting in a higher leakage current at elevated temperatures. Finally, it is demonstrated that the conduction in triple-layer stacks is limited by a Poole–Frenkel conduction in the high-k layers, while the trap contribution in the case of single-layers becomes dominant when the HfAlO layer is thicker than 8 nm.

In this paper, we present the results regarding the electrical and optical characterization of bidimensional arrays of silicon single photon avalanche photodiodes (SPAD). Low average dark count rates and crosstalk probability, good timing jitter and high quantum detection efficiency in the visible range have been measured over 5 × 5 SPAD arrays with 40 μm single pixel active area diameter. Moreover, a very good uniformity of these parameters has been found over the single pixels. These good electro-optical performances make our photodiodes attractive for the fabrication of arrays with a larger number of SPAD. In view of the design of a dense array to be used as a silicon photomultiplier (SiPM) for medical diagnostic tools, 5 × 5 SPAD arrays have been also tested in the photon-resolving mode. Charge spectra show that the arrays, in this configuration, allow to resolve several photoelectron peaks with a good single photoelectron resolution.

We report on the full process integration of nanocrystal (NC) memory cells in a stand-alone 16-Mb NOR Flash device. The Si NCs are deposited by chemical vapor deposition on a thin tunnel oxide, whose surface is treated with a low thermal budget process, which increases NC density and minimizes oxide degradation. The device fabrication has been obtained by means of conventional Flash technology, which is integrated with the CMOS periphery with high- and low-voltage transistors and charge pump capacitors. The memory program and erase threshold voltage distributions are well separated and narrow. The voltage distribution widths are related to NC sizes and dispersion, and bigger NCs can induce a cell reliability weakness. An endurance issue is also related to the use of an oxide/nitride/oxide. dielectric which acts as a charge trapping layer, causing a shift in the program/erase window and a distribution broadening during cycling.

In this letter we present the results regarding the electrical and optical characterization of Geiger mode silicon avalanche photodiodes (GMAP) fabricated by silicon standard planar technology. Low dark count rates, negligible afterpulsing effects, good timing resolution and high quantum detection efficiency in all the visible range have been measured. The very good electro-optical performances of our photodiodes make them attractive for the fabrication of arrays with a large number of GMAP to be used both in the commercial and the scientific fields, as telecommunications and nuclear medical imaging.

In this paper, the hot carrier degradation of laterally diffused nMOSFETs is investigated in detail by the analysis of the fundamental device parameters and charge pumping measurements. Starting from this experimental characterization a new approach based on charge pumping technique is developed to estimate the spatial distribution of the hot carrier damage. This methodology has been applied on test structures, obtaining good results in the prediction of both the interface states and the trapped charges profiling. The supporting assumptions have been verified by fitting to the electrical data and by means of a two-dimensional device simulation.

Si nanocrystal memory cells have been integrated in Flash-like stand-alone devices of 16 Mb along with high and low voltage CMOS logic circuitry. Process integration drawbacks such as nanocrystal residuals in the circuitry region have been eliminated by optimizing etching processes. The program/erase threshold voltage distributions of the memory sectors are well separated and narrow. The voltage distribution width is related to NC sizes, and bigger NCs induce cell reliability problems. Some reliability issues for endurance are also related to the use of ONO dielectric which acts as charge trapping layer, mainly causing program/erase window shift and threshold voltage distribution broadening during endurance.

This study aims at proving that single photon sensing can be made accessible in the form of cheap off-the-shelf micro-devices with micro-optical/micro-mechanical coupling systems. In order to achieve this challenging goal, use is made of different micro-technologies, not yet fully established but promising and innovative in and of themselves. It is planned to combine them into a more challenging micro-technology capable of making single photon handling off-the-shelf. Moreover, the technology to be implemented should make it possible to provide photonic sensors in a ready-to-go fashion.

We show and discuss some general features of dielectric breakdown of ultra-thin gate oxides for CMOS. We discuss III-V devices with high-k/metal gate, and compare to more classical structures with silicon substrates, SiOxNy or high-k as gate dielectrics, and poly-Si or metal gate. A model of the breakdown growth dependence on voltage, temperature, oxide thickness, etc., is discussed and compared to data.

The interest toward alternative energy sources to fossil fuels (still the most convenient in terms of efficiency and cost) is current. Initiatives that seek to convert wind, geothermal energy, hydropower, marine, solar thermal energy, and photovoltaics or derived from biomass energy into other forms continue to involve several research groups. For example, the transfer from solar energy into electricity, which in turn can be used for water splitting and for the subsequent production of hydrogen, seems a major challenge to provide a sustainable contribution to the “Earth system” together with the realization of devices having high conversion efficiencies, low environmental impact, and low production costs. In our opinion the use of heterogeneous forms of available energy could definitely give a rational response to the growing global demand of energy, respecting the environment. This special issue is following a series that began in 2010. The aim is to provide a continuous update on state-of-the-art in the field of materials, nanotechnology, theoretical models, and technological aspects that belong to the science of thin film photovoltaics (TFPV). Despite this issue having a limited number of contributions, it is interesting to point out that the contribution provided by colleagues with their research have kept alive this initiative undertaken by this journal. Here is a timely synthesis of all contributions received which can stimulate the development of new ideas in the field of photovoltaic and highlight interest in this initiative in the future.

We study the filament structure in 50 nm × 50 nm Resistive Random Access Memory (ReRAM) cells in the forming/set state with a Hf/HfO2/TiN metal-insulator-metal stack by scanning transmission electron microscopy in cross section view. We reveal the filament morphology and, by the measurement of filament size and electrical resistance, evaluate the average resistivity of the filament material. The combination of the various data indicates the nanostructure of the conductive filament.

We outline the possible applications of newly developed single photon avalanche detectors (SPAD) operating at low voltage and fabricated in silicon planar technology, reporting on tests done with scintillators. We envisage the integration of large arrays of identical sensors, employing a common read-out mode in order to achieve a high resolution and high sensitivity solid state photomultiplier. The applications of such a device would be many, particularly if we consider that we are also working on the production of microoptical components, perfectly suited for the lossless coupling of these photosensors to several light sources (lasers, ordinary and scintillating fibers, scintillators, optical devices), by exploiting the promising deep lithography with ions (DLI) technology. Crossed time-of-flight and charge measurements between SPADs and usual photomultipliers, coupled to scintillators, have allowed to compare their relative performance. Specific issues regarding the SPAD and the scintillating fiber readout are presented, also in view of possible applications in the field of particle/radiation tracking systems.

In this paper, we present a nanometer-sized floating-gate memory device, fabricated on silicon-on-insulator substrate and using silicon nanocrystals as storage nodes. Single electron charging and discharging phenomena occurring at room temperature will be demonstrated and discussed by means of simple analytical models. A deeper investigation of the impact of critical dimensions of the memory cell (i.e., active area and channel width and length) on the device operation (in particular, memory programming window), performed on a large number of samples, will be reported. Qualitative explanations for the observed experimental behaviors will be given.

Nanoscale structures have been recently proposed as charge storage nodes due to their potential applications for future nanoscale memory devices. Our approach is based on the idea of using Si nanodots as discrete floating gates. To experimentally investigate such potential, we have fabricated MOS structures with Si nanocrystals. The dots have been deposited onto an ultra-thin tunnel oxide by chemical vapor deposition (CVD) of SiH 4 , and then annealed at 1000 °C for 40 s, to crystallize all the dots. After deposition, the dots have been covered by a CVD SiO 2 layer, thus resulting completely embedded into stoichiometric silicon oxide. The nanocrystal density and size have been studied by energy filtered TEM (EFTEM) analysis. An electrostatic force microscope has been used to locally inject and image charge. By applying a relatively large tip voltage and reducing the tip to sample separation down to the contact with the surface sample, a few dots have been charged, by appearing as protrusions on the surface. The charged dots have been monitored for up to 30 min, by showing no discharge effects either vertically, through the double barrier of oxide layers, or laterally, via cross talk effect between other close dots.

Design and fabrication of single photon avalanche detector (SPAD) in planar technology is reported. Device design and critical issues in the technology are discussed. Experimental test procedures are described for dark-counting rate, afterpulsing probability, photon timing resolution, and quantum detection efficiency. Low-noise detectors are obtained, with dark counting rates down to 10 c/s for devices with 10 /spl mu/m diameter, down to 1 kc/s for 50 /spl mu/m diameter. The technology is suitable for monolithic integration of SPAD detectors and associated circuits.

Silicon quantum dots have been deposited on top of a 3-nm tunnel oxide by Low Pressure Chemical Vapour Deposition (LPCVD) and coated with a 7-nm Chemical Vapour Deposited (CVD) oxide. This stack was then incorporated in Metal-Oxide-Semiconductor structure and used as floating gate of a memory cell. The presence of 3 nm of tunnel oxides allows the injection of the charge by direct tunnel (DT) using low voltages for both program and erase operations. The charge stored in the quantum dots is able to produce a well-detectable flat band shift in the capacitors or, equivalently, a threshold voltage shift in the transistors. Furthermore, due to the presence of SiO 2 between the grains, the lateral charge loss is reduced and, thus, long retention time are possible. In this work we present good memory action characterised by low write voltages, write times of the order of milliseconds and long retention time in spite of the low tunnel oxide thickness. © 2002 Elsevier Science B.V. All rights reserved.