Martins, R., Ferreira Cabrita Fortunato I. A. E. "
Improvement of a-Si:H device stability and performances by proper design of the interfaces."
Journal of Non-Crystalline Solids. 266-269 B (2000): 1094-1098.
AbstractThis paper deals with a new design method for the interfaces of a-Si:H pin solar cells that improves the stability and performances of devices deposited in a single batch chamber process. The method consists in removing a deposited sacrificial layer placed between the p/i and/or i/n interfaces by etching. This layer is an absorber of defects and impurities that are introduced in the interfaces, mainly from the chamber walls cross-contamination and the substrate surface. The results achieved increase the device fill factor and short circuit current density, respectively towards 75% and 16.3 mA cm-2, with a final efficiency of about 10%, before light soaking experiments. © 2000 Elsevier Science B.V. All rights reserved.
Malik, A.a, Sêco Fortunato Martins A. c E. b. "
Microcrystalline thin metal oxide films for optoelectronic applications."
Journal of Non-Crystalline Solids. 227-230 (1998): 1092-1095.
AbstractWe report the properties and optoelectronic applications of transparent and conductive indium and tin oxide films prepared by the spray pyrolysis method and doped with Sn or F, respectively. The film properties have been measured using X-ray diffraction, optical and electrical absorption. As examples of applications we produced a set of selective optical detectors for different spectral regions, covering the wavelength range from 0.25 to 1.1 μm, based on metal oxide-semiconductor heterostructures and using different substrates such as: GaP, GaSe, AlxGa1-xAs, GaAs and Si. The fabricated devices exhibit several features such as: production simplicity, high quantum efficiency, uniform sensitivity over the entire active area and a high response speed. Finally, we present a high quantum efficiency and solar blind monocrystalline zinc sulphide optical sensor fabricated by spray deposition as an alternative to the ultraviolet-enhanced SiC and GaN photodetectors and the performances of a solar cell. © 1998 Elsevier Science B.V. All rights reserved.
Maçarico, A.a, Vieira Fantoni Louro Sêco Martins Hollenstein M. a A. a. "
On the a-Si:H film growth: The role of the powder formation."
Journal of Non-Crystalline Solids. 198-200 (1996): 1207-1211.
AbstractResults are presented which are geared towards an understanding of the influence of powder formation during film growth. Plasma chemistry is correlated with the morphology, structure (inferred through infrared spectroscopy, scanning electron microscopy and X-ray diffraction) electro-optical and density of states of intrinsic films deposited under continuous and power modulated operation. Results show that for modulation frequencies where no powder formation occurs and low substrate temperatures T (150°C), silane decomposition gives rise to the growth of inhomogeneous films while in the high modulation frequency regime, at the same temperature, the anions and powder are trapped resulting in films with high deposition rates and low defect density.
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.