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).
Martins, R., Águas Silva Ferreira Cabrita Fortunato H. V. I. "
Nanostructured silicon films produced by PECVD."
Materials Research Society Symposium - Proceedings. Vol. 664. 2001. A961-A966.
AbstractThis paper presents the process conditions that lead to the production of nanostructured silicon films grown by plasma enhanced chemical vapour deposition close to the so-called gamma regime (powder formation), highly dense and with low density of bulk states. Thus, the powder management is one important issue to be addressed in this paper. As a general rule we observed that high quality films (low density of states and high μτ products) are obtained when films are grown under low ion bombardment at high hydrogen dilution and deposition pressure conditions, to allow the proper surface passivation and surface activation.
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.
c c Martins, N.a, Canhola Quintela Ferreira Raniero Fortunato Martins P. a M. b. "
Performances of an in-line PECVD system used to produce amorphous and nanocrystalline silicon solar cells."
Thin Solid Films. 511-512 (2006): 238-242.
AbstractThis paper presents the performances of an in-line plasma enhanced chemical vapor deposition system constituted by 5 chambers and one external unloaded chamber used in the simultaneous manufacturing of 4 large (30 cm × 40 cm) solar cells deposited on glass substrates. The system is fully automatically controlled by a Programmable Logic Controller using a specific developed software that allows devices mass production without losing the flexibility to perform process innovations according to the industrial requests, i.e. fast and secure changes and optimizations. Overall, the process shift is of about 15 min per each set of 4 solar cells. Without a buffer layer, solar cells with efficiencies of about 9% were produced by the proper tuning of the i-layer production conditions. © 2005 Elsevier B.V. All rights reserved.
Martins, R., Ferreira Fortunato I. E. "
Growth model of gas species produced by the hot-wire and hot-wire plasma-assisted techniques."
Key Engineering Materials. 230-232 (2002): 603-606.
AbstractThe model presented is based on the heat transfer and energy balance equations that rule the set of physical and chemical interactions that take place on the gas phase of a growth process, assuming that the deposition process occurs under laminar dynamic flow conditions (Knudsen number below 1). In these conditions, the chemistry and physics of the process involved in the growth mechanism of silicon thin films produced by the hot wire or the hot-wire plasma assisted technique can be proper derived by balance equations that supply information about how the plasma density, the gas dilution and the gas temperature influence the growth mechanism and the equilibrium of the concentration of species presented on the growth surface. The model developed establishes a relation between the abundance species formed and the parameters initiators of the process such as the filament temperature and the rf power density used.
b b b b b b b Martins, R.a b, Figueiredo Silva Águas Soares Marques Ferreira Fortunato J. a V. a. "
32 Linear array position sensitive detector based on NIP and hetero a-Si:H microdevices."
Journal of Non-Crystalline Solids. 299-302 (2002): 1283-1288.
AbstractIn this paper we present results concerning the performance exhibited by an integrated array of 32 one-dimensional amorphous silicon thin film position sensitive detectors based on nip and hetero amorphous silicon structures, with a total active area size below 1 cm2 linearity, its spatial resolution and response time, that make it one of the most interesting analog detector to be used in unmanned optical inspection control systems where a continuous detection process is required. This opens a wide range of applications for amorphous silicon devices in the area of image processing. © 2002 Elsevier Science B.V. All rights reserved.
Martins, R.a, Pereira Fortunato L. b E. c. "
Paper electronics: A challenge for the future."
Digest of Technical Papers - SID International Symposium. Vol. 44. 2013. 365-367.
AbstractIn this paper we report results concerning the use of paper as substrate and as an electronic component for the next generation of sustainable low cost electronic systems, where different examples of applications are given. © 2013 Society for Information Display.
i Martins, R.a, Águas Ferreira Fortunato Raniero Roca Cabarrocas H. a I. a. "
Composition, structure and optical characteristics of polymorphous silicon films deposited by PECVD at 27.12 MHz."
Materials Science Forum. 455-456 (2004): 100-103.
AbstractThis paper presents data concerning the composition structure and optical characteristics of polymorphous silicon films produced by plasma enhanced chemical vapour deposition at 27.12 MHz and determined respectively by infrared spectrometry, micro Raman, exodiffusion and spectroscopic ellipsometry measurements. When compared to the pm-Si:H films produced at 13.56 MHz, the films produced at 27.12 MHz present hydrogen contents in the range of 21 at%, the sharp peak ascribed to the exodifusion measurements is shifted towards high temperatures and the imaginary part of the dielectric function 〈ε2〉 is larger and shifted to high energies. Apart from that the peaks of the infrared spectra ascribed to the stretching modes shift towards high wave numbers and the half width of the micro Raman peaks shrinks, meaning that the films produced at 27.12 MHz are more compact and dense.
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.
AbstractThe 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.