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This paper presents the role of the deposition pressure and the rf power density on the optimization of the electrical, optical and structural properties of large area (30×40 cm2) indium-tin oxide films produced by rf magnetron sputtering, with growth rates exceeding 30 nm/min. The films were produced at room temperature under reactive plasma, followed by a thermal annealing in air or formic gas. The best films' uniformity (≤±5%), compactness and surface smoothness (preferential growth orientation along (222)); and electro-optical properties (resistivity and mobility, respectively, of about 7×10-4 Ω cm and 19.6 cm2 V -1 s-1, with transmittance of about 92%) were achieved using a rf power density of 0.92 W cm-2 and a pressure of 8.5×10-2 Pa, followed by its annealing in air by about 2 h at 773 K. © 2005 Elsevier B.V. All rights reserved.

The aim of this paper is to present results concerning the role of the buffer layer on pin devices, deposited in a single chamber for plasma enhanced chemical vapor deposition, using high hydrogen dilution and pressures at 27.12 MHz. By doing so, we allow the incorporation of nanoparticles into the i-layer, during plasma process. The results show solar cells with 8.8% efficiency with a collection efficiency of 95% in the blue region of the spectra. Apart from that, the results from impedance spectroscopy, imaginary impedance vs. real impedance, show difference of a semicircle radius as function of sample temperatures, which could be explained by total device series resistance variation. © 2005 Elsevier B.V. All rights reserved.

This paper studies the dc and ac impedance behaviour of undoped ZnO thin films produced by spray pyrolysis and rf magnetron sputtering under UV light illumination, at room temperature, emphasising the role that the crystallite size, structure, surface morphology and the state of surface have on the electrical responsivities obtained. The results achieved show that the sputtered films with crystal sizes of about 4 nm exhibit dc electrical UV responsivities of 108. On the other hand, the spray pyrolysis films exhibit the lowest dc responsivities, due the high crystal sizes and state of surface contamination, to which very good capacitance responses were obtained, mainly due to the degree of porosity exhibit by these films when produced at low temperatures. Based on that, a two-phase electrical model is proposed to explain the set of behaviours observed. © 2005 Elsevier B.V. All rights reserved.

Energies of two-electron one-photon transitions from initial double K-hole states were computed using the Dirac–Fock model. The transition energies of competing processes, the Ka hypersatellites, were also computed. The results are compared with experiment and to other theoretical calculations.

In this working paper are present the main provisional results of the first round of a Delphi survey held in Portugal on the automotive sector. It was done under the WorTiS project, developed by IET – Research Centre on Enterprise and Work Innovation, and financed by the Portuguese Ministry of Science and Technology. The majority of experts consider to have an average of less knowledge in almost all the scenario topics presented. Nevertheless, we considered specially the topics where the experts considered themselves to have some knowledge. There were no “irrelevant” topics considered as such by the expert panel. There are also no topics that is not considered a need for co-operation (that happens in jus tone case). The lack of technological infra-structrures was not considered as an hindered factor for the accomplishement of any scenario. The experts panel considered no other international competence besides US, Japan or Germany in these topics. Although the members of the expert panel were not as many as needed, These situations will be taken into consideration for a second round of the Delphi survey

This paper deals with the role the substrate on the structure of undoped and n-doped polycrystalline silicon (poly-Si) films produced by Low Pressure Chemical Vapour Deposition (LPCVD). The structural and electrical properties of the films deposited on glass, glass covered with molybdenum (Mo), oxidised crystalline silicon and oxidised crystalline silicon covered with Mo were analysed using X-ray diffraction and Spectroscopic Ellipsometry, dark conductivity and Hall effect measurements. Undoped poly-Si films deposited over Mo present modifications in the crystalline structure relatively to those deposited on the other substrates. The presence of Mo changes the preferential growth orientation, enhancing the Si {111} grains orientation, leading to more compact films. The electrical measurements also confirm that the films grown on Mo substrates present better characteristics. Some differences are also observed during the initial growth stages when using glass or oxidised silicon. Very thin n-doped films present a less effective doping effect when deposited on oxidised silicon than the ones deposited on glass substrates.

In this work we present results of structural composition and morphological characteristics of polymorphous silicon (pm-Si:H) films deposited by PECVD at 13.56 and 27.12 MHz. In addition, the role of the excitation frequency on the growth rate will be also analyzed. The results show that by using the 27.12 MHz excitation frequency the hydrogen dilution in the plasma needed to produce pm-Si:H can be reduced by more than 50% as well as the rf power density, leading to an increase on the growth rate to values higher than 3 Å/s. Spectroscopic ellipsometry and Raman spectroscopy show that the 27.12 MHz pm-Si:H films are more ordered than the pm-Si:H films produced at 13.56 MHz, while the infrared spectroscopy show that the SiH2 concentration in the films is strongly reduced. AFM measurements reveal that the films produced at 27.12 MHz films are more structured, presenting also higher roughness. © 2004 Elsevier B.V. All rights reserved.