Martins, R.a, Costa Águas Soares Marques Ferreira Borges Fortunato D. a H. a. "
Detection limits of a nip a-Si:H linear array position sensitive detector."
Materials Research Society Symposium Proceedings. Vol. 808. 2004. 507-512.
AbstractThis paper presents results of the spatial and frequency detection limits of an integrated array of 32 one-dimensional amorphous silicon thin film position sensitive detectors with a nip structure, under continuous and pulsed laser operation conditions. The data obtained show that 0.45×0.06 cm arrays, occupying a total active area of about 1 cm2 have a spatial resolution better than 10 μm (modulation transfer function of about 0.2), with a cut-off frequency of about 6.8 KHz. Besides that, under pulsed laser conditions the device non-linearity has its minimum (about 1.6%), for a frequency of about 200Hz. Up to the limits of the cut-off frequency, the device non-linearity increases to values above 4%.
Martins, R., Macarico Ferreira Fortunato A. I. E. "
Role of the gas flow parameters on the uniformity of films produced by PECVD technique."
Materials Research Society Symposium - Proceedings. Vol. 467. 1997. 609-614.
AbstractThe aim of this work is to present an analytical model able to interpret the experimental data of the dependence of film's uniformity on the discharge pressure, gas flow and temperature used during the production of thin films by the plasma enhancement chemical vapour deposition technique, under optimised electrode's geometry and electric field distribution. To do so, the gas flow is considered to be quasi-incompressible and inviscous leading to the establishment of the electro-fluid-mechanics equations able to interpret the film's uniformity over the substrate area, when the discharge process takes place in the low power regime.
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.
AbstractA 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).
b b b b b b b Martins, R.a b, Carvalho Fortunato Maçarico Santos Baia Viera Guimarães N. a E. a. "
Effects of U.V. light on the transport properties of a-Si : H films during their growth."
Journal of Non-Crystalline Solids. 97-98 (1987): 1399-1402.
AbstractThe influence of U.V. light on the transport properties of a-Si : H films during its growth in a r.f. double chamber system was investigated by conductivity, optical absorption, I.R. absorption, spectral photoconductivity and X-ray diffraction measurements. It was concluded that the presence of U.V. light during the deposition process controls the way how hydrogen is incorporated in the structure as well as the impurity atoms. The microcrystalline films investigated present sharp peaks in the I.R. spectra. Both boron and phosphorus doped films show conductivities higher than 10 S cm-1 and estimated crystalline sizes of the order of 80 Å. © 1987.
Mei, S.a, Yang Ferreira Martins J. a J. M. "
Aqueous tape casting of low-k cordierite substrate: The influence of glass content."
Materials Science Forum. 455-456 (2004): 168-171.
AbstractThick films of cordierite-based glass ceramics were prepared by aqueous tape casting from suspensions containing 80-wt% solids. The weight proportions of cordierite/glass ranged from 70/30 to 30/70 in order to investigate the effect of glass content on the rheological behaviour and on the microstructures and properties of the green tapes. Suspensions with 50 to 60-wt% glass content exhibited the lowest viscosity values among all the slurries investigated, while the green tape containing 30-wt% glass presented homogenous microstructures at both top and bottom surfaces, contrarily to the observations for the other compositions. The green densities increased with glass content. The sintered tapes (1150°C, 2h) containing 50 to 60-wt% glass exhibited the lowest values for the dielectric constant (∼5.2) and dielectric loss (∼0.002) at 1MHz.
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.
AbstractTin 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.
b d Morawiec, S.a b, Mendes Filonovich Mateus Mirabella Aguas Ferreira Simone Fortunato Martins Priolo Crupi M. J. a S. "
Photocurrent enhancement in thin a-Si:H solar cells via plasmonic light trapping."
Conference on Lasers and Electro-Optics Europe - Technical Digest. Vol. 2014-January. 2014.
AbstractPhotocurrent enhancement in thin a-Si:H solar cells due to the plasmonic light trapping is investigated, and correlated with the morphology and the optical properties of the selfassembled silver nanoparticles incorporated in the cells' back reflector. © 2014 Optical Society of America.