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1995
Martins, R.a, Lavareda Fortunato Soares Fernandes Ferreira G. a E. a. "A linear array position sensitive detector based on amorphous silicon." Review of Scientific Instruments. 66 (1995): 5317-5321. AbstractWebsite

A linear array thin film position sensitive detector (LTFPSD) based on hydrogenated amorphous silicon (a-Si:H) is proposed for the first time. Taking advantage of the optical properties presented by a-Si:H devices, we have developed a LTFPSD with 128 integrated elements able to be used in 3D inspections/measurements. Each element consists of a one-dimensional LTFPSD, based on a p-i-n diode produced in a conventional PECVD system, where the doped layers are coated with thin resistive layers to establish the required device equipotentials. By proper incorporation of the LTFPSD into an optical inspection camera it will be possible to acquire information about an object/surface, through the optical cross-section method. The main advantages of this system, when compared with the conventional CCDs, are the low complexity of hardware and software used and that the information can be continuously processed (analog detection). © 1995 American Institute of Physics.

Martins, Rodrigo, Lavareda Guilherme Fortunato Elvira Soares Fernando Fernandes Luis Ferreira Luis. "Linear thin-film position-sensitive detector (LTFPSD) for 3D measurements." Proceedings of SPIE - The International Society for Optical Engineering. Vol. 2415. 1995. 148-158. Abstract

A linear array thin film position sensitive detector (LTFPSD) based on hydrogenated amorphous silicon (a-Si:H) is proposed for the first time, taking advantage of the optical properties presented by a-Si:H devices we have developed a LTFPSD with 128 integrated elements able to be used in 3-D inspections/measurements. Each element consists on a one-dimensional LTFPSD, based on a p.i.n. diode produced in a conventional PECVD system, where the doped layers are coated with thin resistive layers to establish the required device equipotentials. By proper incorporation of the LTFPSD into an optical inspection camera it is possible to acquire information about an object/surface, through the optical cross-section method. The main advantages of this system, when compared with the conventional CCDs, are the low complexity of hardware and software used and that the information can be continuously processed (analogue detection).

Valtchev, S., {B. V. } Borges, and V. Anunciada. "LkW/250 kHz full bridge zero voltage switched phase shift DC-DC converter with improved efficiency." INTELEC 95 - SEVENTEENTH INTERNATIONAL TELECOMMUNICATIONS ENERGY CONFERENCE. IEEE, 1995. 803-807. Abstract
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{De Almeida Móra}, Iara, and {José Júlio} Alferes. "Modelling diagnosis systems with the logic programming." Progress in Artificial Intelligence - 7th Portuguese Conference on Artificial Intelligence, EPIA 1995, Proceedings. Vol. 990. Lecture Notes in Computer Science (including subseries Lecture Notes in Artificial Intelligence and Lecture Notes in Bioinformatics), 990. Springer-Verlag, 1995. 409-418. Abstract
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vanWesenbeeck, MPN, JB Klaassens, U. vonStockhausen, A. Munoz de Morales Anciola, and SS Valtchev. "Multiple switch high-voltage DC-DC converter." INTELEC, International Telecommunications Energy Conference (Proceedings) (1995): 322-329. Abstract
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Carvalho, J., Ferreira Fernandes Fidalgo Martins I. B. J. "Nd-YAG laser induced crystallization on a-Si:H thin films." Materials Research Society Symposium - Proceedings. Vol. 358. 1995. 915-920. Abstract

In this paper we present results concerning the influence of laser energy and shot density on the electrical resistance, X-ray diffraction pattern, and structure obtained by SEM, on recrystallized a-Si:H thin films produced by using a Nd-YAG laser, working in a wavelength of 532 nm. The base material (undoped and doped a-Si:H) was obtained by Plasma Enhanced Chemical Vapour Deposition (PECVD). The structure and electrical characteristics of the recrystallized thin films are dependent on the laser beam energy density, beam spot size and the number of shots applied to the base a-Si:H thin film used. Overall, the data show recrystallized material with grain sizes larger than 1μm, where the electrical resistance of both, undoped and doped materials, can be varied up to 5 orders of magnitude, by the proper choice of the recrystallization conditions.

Fortunato, E., Soares Lavareda Martins F. G. R. "New linear array thin film position sensitive detector (LTFPSD) for 3D measurements." Materials Research Society Symposium - Proceedings. Vol. 377. 1995. 797-802. Abstract

A Linear array Thin Film Position Sensitive Detector (LTFPSD) based on hydrogenated amorphous silicon (a-Si:H) is proposed for the first time, taking advantage of the optical properties presented by a-Si:H devices we have developed a LTFPSD with 128 integrated elements able to be used in 3D inspections/measurements. Each element consists on an one-dimensional TFPSD, based on a p.i.n. diode produced in a conventional PECVD system, where the doped layers are coated with thin resistive layers to establish the required device equipotentials. By proper incorporation of the LTFPSD into an optical inspection camera it will be possible to acquire information about an object/surface, through the optical cross-section method. The main advantages of this system, when compared with the conventional CCDs, are the low complexity of hardware and software used and that the information can be continuously processed (analogue detection).

Rosa, MJ, M. N. de Pinho, M. H. Godinho, and AF Martins. "Optical polarizing studies of cellulose acetate membranes prepared by phase-inversion." Molecular Crystals and Liquid Crystals. 258.1 (1995): 163-171. Abstract
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Cidade, M. T., C. R. Leal, M. H. Godinho, AF Martins, and P. Navard. "Rheological properties of acetoxypropylcellulose in the thermotropic chiral nematic phase." Molecular Crystals and Liquid Crystals. 261.1 (1995): 617-625. Abstract
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Martins, R., M. Vieira, I. Ferreira, and E. Fortunato. "Role of oxygen partial pressure on the properties of doped silicon oxycarbide microcrystalline layers produced by spatial separation techniques." Journal of Vacuum Science & Technology A: Vacuum, Surfaces, and Films. 13.4 (1995): 2199-2209. Abstract
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Martins, R.a, Vieira Ferreira Fortunato M. b I. a. "Role of oxygen partial pressure on the properties of doped silicon oxycarbide microcrystalline layers produced by spatial separation techniques." Journal of Vacuum Science and Technology A: Vacuum, Surfaces and Films. 13 (1995): 2199-2209. AbstractWebsite

The aim of this work is to present experimental data concerning the role of the oxygen partial pressure during the production process on the properties (structure, morphology, composition, and transport properties) exhibited by doped microcrystalline silicon oxycarbide films. The films were produced by a two consecutive decomposition and deposition chamber system, where a spatial separation between the plasma and the growth regions is achieved. The films produced by this technique are highly conductive and highly transparent with suitable properties for optoelectronic applications requiring wide band-gap and low-conductivity materials. © 1995, American Vacuum Society. All rights reserved.

Martins, Rodrigo, Fortunato Elvira. "Simulation of the lateral photo effect in large-area 1D a-Si:H p-i-n thin-film position-sensitive detectors." Proceedings of SPIE - The International Society for Optical Engineering. Vol. 2397. 1995. 745-756. Abstract

The aim of this work is to provide the basis for the interpretation, under steady state, of the lateral photoeffect in p-i-n a-Si:H 1D Thin Film Position Sensitive Detectors (1D TFPSD) through an analytical model. The experimental data recorded in 1D TFPSD devices with different performances are compared with the predicted curves and the obtained correlation's discussed.

Fantoni, Alessandro, Vieira Manuela Martins Rodrigo. "Spatial microscopic/macroscopic control and modeling of the p.i.n devices stability." Proceedings of SPIE - The International Society for Optical Engineering. Vol. 2397. 1995. 695-702. Abstract

The introduction into a traditional p.i.n. structure of two defective buffer layers near the p/i and i/n interfaces can improve the device stability and efficiency through an enhancement of the electric field profile at the interfaces and a reduction of the available recombination bulk centers. The defectous layer (`i-layer'), grown at a higher power density, present a high density of the defects and acts as `gettering centers' able to tailor light induced defects under degradation conditions. If the i-layer density of states remains below 1016 eV-1 cm-3 and assuming a Gaussian distribution of defect states, the gettering center distribution will not affect significantly the carrier population but only its spatial distribution. We report here about a device numerical simulation that allows us to analyze the influence of the `i- layer' position, thickness and density of states on the a-Si:H solar cells performances. Results of some systematic simulation rom the ASCA program (Amorphous Solar Cell Analysis), and for different configurations will be presented.

Martins, R., Fortunato E. "Static behaviour of thin-film position-sensitive detectors based on p-i-n a-Si:H devices." Sensors and Actuators: A. Physical. 51 (1995): 143-151. AbstractWebsite

The aim of this work is to provide the basis for the interpretation of the lateral photoeffect in p-i-n a-Si:H one-dimensional thin-film position-sensitive detectors (1D TFPSDs) under steady state, through an analytical model. The experimental data recorded in 1D TFPSD devices with different characteristics are compared with the predicted curves and the obtained correlations are discussed. © 1996.

Martins, R., Vieira Ferreira Fortunato M. I. E. "Structure and composition of doped silicon oxycarbide microcrystalline layers produced by spatial separation techniques." Materials Research Society Symposium - Proceedings. Vol. 358. 1995. 787-792. Abstract

This work presents experimental data concerning the role of the oxygen partial pressure used during the preparation process, on the structure, composition and optoelectronic properties of wide band gap doped microcrystalline silicon oxycarbide films produced by a TCDDC system [1].

Meng, L., Macarico Martins A. R. "Study of annealed indium tin oxide films prepared by rf reactive magnetron sputtering." Materials Research Society Symposium - Proceedings. Vol. 388. 1995. 379-384. Abstract

Tin doped indium oxide (ITO) films were deposited on glass substrates by rf reactive magnetron sputtering using a metallic alloy target (In-Sn, 90-10). The post-deposition annealing has been done for ITO films in air and the effect of annealing temperature on the electrical, optical and structural properties of ITO films was studied. It has been found that the increase of the annealing temperature will improve the film electrical properties. The resistivity of as-deposited film is about 1.3×10-1 Ω* cm and decreases down to 6.9×10-3 Ω* cm as the annealing temperature is increased up to 500°C. In addition, the annealing will also increase the film surface roughness which can improve the efficiency of amorphous silicon solar cells by increasing the amount of light trapping.

Meng, L.-j., Maçarico Martins A. R. "Study of annealed indium tin oxide films prepared by rf reactive magnetron sputtering." Vacuum. 46 (1995): 673-680. AbstractWebsite

Tin doped indium oxide (ITO) films were deposited on glass substrates by rf reactive magnetron sputtering using a metallic alloy target (In-Sn, 90-10). The post-deposition annealing has been done for ITO films in air and the effect of annealing temperature on the electrical, optical and structural properties of ITO films was studied. It has been found that the increase of the annealing temperature will improve the film electrical properties. The resistivity of as deposited film is about 1.3 × 10-1 gW*cm and decreases down to 6.9 × 10-3 Ω*cm as the annealing temperature is increased up to 500 °C. In addition, the annealing will also increase the film surface roughness which can improve the efficiency of amorphous silicon solar cells by increasing the amount of light trapping. © 1995.

Lanca, M. C., J. Domingues, and I. Franco Study of fractal properties in Lichtenberg figures., 1995. AbstractWebsite
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Lanca, M. C., J. Domingues, and I. Franco Study of fractal properties in Lichtenberg figures., 1995. AbstractWebsite
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Valtchev, SS, and M. P. van Wesenbeeck. "Super-Resonant Converter with Switched Resonant Inductor with PFM-PWM Control." IEEE Transactions on Power Electronics. 10 (1995): 760-765. Abstract
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Abreu, Fernando Brito, Miguel Goulão, and Rita Esteves. "Toward the Design Quality Evaluation of Object-Oriented Software Systems." 5th International Conference on Software Quality. Austin, Texas, EUA: American Society for Quality, 1995. 44-57. Abstract
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Cerdeira, Jorge Orestes. "When is a 0-1 knapsack a matroid ?" Portugaliae Mathematica 52 (1995) 475–480 (1995). Abstract
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Martins, R., I. Ferreira, and E. Fortunato. "Wide Band Gap Microcrystalline Silicon Thin Films." DIFFUSION AND DEFECT DATA PART B SOLID STATE PHENOMENA (1995): 299. Abstract
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Ferreira, Isabel, Rodrigo Martins, and Elvira Fortunato. "Wide Band Gap Microcrystalline Silicon Thin Films." Solid State Phenomena. 44 (1995): 299-346. Abstract
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Silva, J. a M. C., and A. M. C. Moutinho. "{Multitechnique description surface analysis system}." Vaccum. 46 (1995): 1205-1209. Abstract

A new multitechnique surface analysis system is presented. It has been designed for research on ion-solid interactions and for survey analysis. SIMS, XPS and AES are the main techniques used. Primary sources are an argon source for standard SIMS and a cesium source for negative and cathionized SIMS, a twin anode (Mg and Al) X-ray source for XPS, and a small spot electron gun for AES and low resolution electron microscopy. The mass spectrometer is a modified quadrupole based probe with an energy analyzer, Dynamic and static SIMS are possible as well as depth profiling. Photoelectrons and Auger electrons are analyzed by a true hemispherical energy analyzer that can also be used for ion spectroscopy. A secondary electron detector is also available. Exchanging the samples is possible through a fast entry air lock. In this small chamber a sputter gun is used to clean the sample. The sample under analysis is supported by a XYZ manipulator and can be temperature controlled in the range 130-850 K