Search results for "Semiconductor device"
showing 10 items of 60 documents
The "Livio Scarsi" X-Ray Facility at University of Palermo for Device Testing
2015
In this work, we report on the characteristics of the Livio Scarsi X-ray facility at University of Palermo. The facility is able to produce low energy X rays, within the energy range of 0.1-60 keV, with fluence rates ranging from 105-108 photons/mm2 s. The laboratory is equipped with an innovative digital detection system, based on semiconductor detectors (Si and CdTe detectors), able to provide accurate and precise estimation of the fluence rate, the energy and the exposure of X rays, even at high counting rate conditions. Instrumentation for electrical characterization (DC-AC) of semiconductor devices, for both off-line and on-line (i.e. during the irradiation) measurements, is also avail…
Design, fabrication, and analysis of a spin-valve based current sensor
2004
Abstract In this work, we suggest a novel current sensor design, based on spin valve technology, with a full Wheatstone bridge configuration. The principal characteristic is that the four magnetoresistance sensing elements, fully active, are deposited and patterned at the same time. This way, differences among them should be insignificant, so improving voltage offset and drift temperature parameters. The complete IC fabrication process involves only three lithography steps, making the process cheaper and faster. In order to get a balanced bridge, the measured current must be properly driven, by means of an auxiliary PCB. Some prototypes, with different input impedances, have been fabricated…
A comparison of two innovative customer power devices for Smart Micro-Grids
2015
The paper presents a comparison of two prototypes of innovative Customer Power Devices designed for applications in Smart Micro-Grids. The devices are both equipped with Energy Storage Systems, consisting in Lithium batteries and have been assembled, independently, by the DIAEE of the University of Rome 'La Sapienza' and the DEIM of the University of Palermo in collaboration with the Italian National Agency for New Technologies, Energy and Sustainable Economic Development (ENEA). In the paper, the characteristics and the operating modes of the devices are examined and some consideration on their application in Low Voltage Smart Micro-Grids are provided. © 2015 IEEE.
UPS fuel cell based: An innovative back-up system
2007
The aim of the paper is to evaluate the technical feasibility and aspects related to the use, in an Uninterruptible Power Supply (UPS), of fuel cells instead of traditional electrochemical batteries. The proposed system, named UPS-FCB (Fuel Cell Based) presents a modular and versatile system configuration; particularly it is possible to integrate it with traditional UPS. Moreover the system features can be modified in terms of power, reliability, back-up time, etc., by changing the power devices. A detailed experimental analysis has been carried out on a passive stand-by UPS integrated with a FCB; experimental results can be easily extended to the other possible system architectures. © 2007…
Solar blind AlGaN photodetectors with a very high spectral selectivity
2006
Solar blind detectors based on AlGaN heterostructures grown on sapphire by Molecular Beam Epitaxy and with a dielectric interference filter deposited on the back side are demonstrated to provide record spectral selectivity. Rejection ratios of 2 x 10(4), and better than 5 x 10(4), measured between 280 and 320 nm, are achieved in Metal Semiconductor Metal detectors and Schottky diodes respectively. The whole detector process is fully compatible with low cost array fabrication.
Effects of 5 MeV electron irradiation on deep traps and electroluminescence from near-UV InGaN/GaN single quantum well light-emitting diodes with and…
2020
The electrical properties, electroluminescence (EL) power output and deep trap spectra were studied before and after 5 MeV electron irradiation of near-UV single-quantum-well (SQW) light-emitting diodes (LED) structures differing by the presence or absence of InAlN superlattice underlayers (InAlN SL UL). The presence of the underlayer is found to remarkably increase the EL output power and the radiation tolerance of LEDs, which correlates with a much lower and more slowly changing density of deep traps in the QW region with radiation dose, and the higher lifetime of charge carriers, manifested by higher short-circuit current and open-circuit voltage in current–voltage characteristics under …
Effect of the precursor's stoichiometry on the optoelectronic properties of methylammonium lead bromide perovskites
2017
International audience; Methylammonium lead bromide (MAPbBr 3) perovskites have been widely studied in applications such as lasers and light-emitting diodes, thanks to their favorable bandgap, efficient charge transport, and the possibility of processing by simple solution methods. The film morphology has a large impact on the optical and electronic properties of the material; hence the deposition methods and the type of precursors used are crucial in the preparation of efficient optoelectronic devices. Here we studied the effect of the precursor´s stoichiometry of solution processed MAPbBr 3 thin films on their optical and electronic properties. We found a drastic effect of the stoichiomet…
Direct temporal reconstruction of picosecond pulse by cross-correlation in semiconductor device
2012
Cross-correlation measurements using the two-photon absorption process in a semiconductor is experimentally demonstrated for two pulses of different wavelengths (shifted by ~200 nm) and durations (20 times ratio). These measurements were found to be highly repeatable and fully suitable for the determination of the temporal intensity profile of picosecond (ps) pulses.
Series and parallel resonant inverters for induction heating under short-circuit conditions considering parasitic components
1999
Series and parallel resonant inverters are the common structures in high power industrial generators for induction heating applications. In practical working conditions, short-circuit of the heating coil is very common, normally producing overvoltages that can damage the power transistors of the inverter if no special precautions are taken. The aim of the paper is to show the mechanism of how overvoltages are generated under short-circuit conditions of the heating coil for series and parallel inverters.
SIMULATION OF THERMAL EFFECTS IN OPTOELECTRONIC DEVICES USING COUPLED ENERGY-TRANSPORT AND CIRCUIT MODELS
2008
A coupled model with optoelectronic semiconductor devices in electric circuits is proposed. The circuit is modeled by differential-algebraic equations derived from modified nodal analysis. The transport of charge carriers in the semiconductor devices (laser diode and photo diode) is described by the energy-transport equations for the electron density and temperature, the drift-diffusion equations for the hole density, and the Poisson equation for the electric potential. The generation of photons in the laser diode is modeled by spontaneous and stimulated recombination terms appearing in the transport equations. The devices are coupled to the circuit by the semiconductor current entering the…