The aim of this work is to present an analytical model able to interpret the role of the thin collecting resistive layer on the static performances exhibited by 2D amorphous silicon hydrogenated pin thin film position sensitive detectors. In addition, experimental results concerning the device linearity and spatial resolution are presented and checked against the predicted values of the analytical model proposed.

Nanocrystalline p-doped silicon films were deposited at low substrate temperatures (around 200°C) in a hot wire reactor. In this paper we present the results on the role of the hydrogen dilution and filament temperature on the film's structure, composition, morphology and transport properties. The film's structure changes from honeycomb-like to a granular needle shape as the filament temperature changes from about 2000°C and hydrogen dilution 87%, to values above 2100°C and hydrogen dilution 90%, respectively. The nanocrystalline silicon-based films produced have optical gaps varying from 1.6 to 1.95 eV, with conductivities up to 0.2 S cm-1 and grain sizes (obtained by X-ray diffraction) in the range of 10-30 nm. © 1999 Elsevier Science B.V. All rights reserved.

The aim of this work is to present an analytical model which can to interpret the role of the collecting resistive layer on the static performances exhibited by 2D amorphous silicon hydrogenated p-i-n thin film position sensitive detectors. In addition, experimental results concerning the device linearity and spatial resolution are presented and checked against the predicted values of the analytical model proposed. © 1999 Elsevier Science S.A. All rights reserved.

We present theoretical results for the photoabsorption spectrum of an atom in parallel electric and magnetic fields, using the R-matrix method combined with quantum-defect theory. We introduce a radial basis set which is complete and orthonormal over a semi-infinite interval [r0,(infinity)), to allow calculations to be performed for high Rydberg states in nonhydrogenic atoms without encountering problems due to linear dependence of the basis set. The nonhydrogenic character of the spectra is analyzed for Li and Rb, and a comparison is made with previous high-precision experiments which shows that the theoretical results agree very well with experiment.

This paper is concerned with the modelling and simulation of amorphous and microcrystalline silicon optoelectronic devices. The physical model and its mathematical formulation are extensively described. Its numerical reduction is also discussed together with the presentation of a computer program dedicated to the simulation of the electrical behaviour of such devices. This computer program, called ASCA (Amorphous Silicon Solar Cells Analysis), is capable of simulating, on one- and two-dimensional domains, the internal electrical behaviour of multi-layer structures, homojunctions and heterojunctions under simple or complex spectra illumination and externally applied biases. The applications of the simulator presented in this work are the analysis of μc/a-Si:H p-i-n photovoltaic cell in thermal equilibrium and illuminated by monochromatic light and the AMI.5 solar spectrum, with and without polarisation. We also study the appearance within the device of lateral components of the electric field and current density vectors when the illumination is not uniform. © 1999 IMACS/Elsevier Science B.V. All rights reserved.

This is the second interim report of the research project "Information Society, Work and the Generation of New Forms of Social Exclusion" (SOWING). It is based on a firm survey conducted in the eight regions participating in the research project — Flanders (Belgium), Lazio (Italy), Niederösterreich (Austria), Portugal, the Republic of Ireland, the Stuttgart area (Germany), the Tampere region (Finland) and the West London area (U.K.). The aim of this report is to present a broad overview of the collected data. In general, only simple statistical methods have been applied. The report focuses on a regional comparison; however, the data have also been analysed by firm size, measured by quantity of staff, and industrial sector. It should be seen as a first step in the data analysis; it may also give some hints for a more strategic analysis of the survey data.

In previous papers the mean excess chemical potential, μ1(E), in ternary systems of the type I sulphate + II sulphate + H2O, at 25°C was determined. Results obtained for systems with CuSO4(I), and ZnSO4(I) respectively, pointed out an obvious disparity between their behaviours. They show the existence of some important association phenomena partially accounting for the substantial deviations from ideal behaviour. The ternary sulphate systems (CuSO4 + Me(I,II)SO4 + H2O; ZnSO4 + Me(I,II)SO4 + H2O) studied were characterized against the binaries of the same ionic strength, experimental data being obtained using both e.m.f. and spectrophotometric methods. Deviations from the ideal behaviour were discussed in terms of thermodynamic excess functions and association constants. A comparative study between the results obtained with the two above mentioned methods is presented. In previous papers the mean excess chemical potential, μ1 E, in ternary systems of the type I sulphate+II sulphate+H2O, at 25 °C was determined. Results obtained for systems with CuSO4(I), and ZnSO4(I) respectively, pointed out an obvious disparity between their behaviours. They show the existence of some important association phenomena partially accounting for the substantial deviations from ideal behaviour. The ternary sulphate systems (CuSO4+MeI, IISO4+H2O; ZnSO4+MeI, IISO4+H2O) studied were characterized against the binaries of the same ionic strength, experimental data being obtained using both e.m.f. and spectrophotometric methods. Deviations from the ideal behaviour were discussed in terms of thermodynamic excess functions and association constants. A comparative study between the results obtained with the two above mentioned methods is presented.

Microcrystalline silicon is a two-phase material. Its composition can be interpreted as a series of grains of crystalline silicon imbedded in an amorphous silicon tissue, with a high concentration of dangling bonds in the transition regions. In this paper, results for the transport properties of a μc-Si:H p-i-n junction obtained by means of two-dimensional numerical simulation are reported. The role played by the boundary regions between the crystalline grains and the amorphous matrix is taken into account and these regions are treated similar to a heterojunction interface. The device is analyzed under AM1.5 illumination and the paper outlines the influence of the local electric field at the grain boundary transition regions on the internal electric configuration of the device and on the transport mechanism within the μc-Si:H intrinsic layer.

Microcrystalline silicon is a two-phase material. Its composition can be interpreted as grains of crystalline silicon imbedded in an amorphous silicon tissue, with a high concentration of danglind bonds in the transition regions. In this paper, results obtained by means of numerical simulations about the transport properties of a μc-Si:H p-i-n junction are reported. The role played by the boundary regions between the crystalline grains and the amorphous matrix is taken in account, and these regions are treated similarly to a heterojunction interface. The influence of the local electric field at the grains boundary transition regions on the internal electric configuration of the device is outlined under illumination and applied external bias. © 1999 Elsevier Science S.A. All rights reserved.