Fantoni, Alessandro, Vieira Manuela Martins Rodrigo. "
Spatial microscopic/macroscopic control and modeling of the p.i.n devices stability."
Proceedings of SPIE - The International Society for Optical Engineering. Vol. 2397. 1995. 695-702.
AbstractThe introduction into a traditional p.i.n. structure of two defective buffer layers near the p/i and i/n interfaces can improve the device stability and efficiency through an enhancement of the electric field profile at the interfaces and a reduction of the available recombination bulk centers. The defectous layer (`i-layer'), grown at a higher power density, present a high density of the defects and acts as `gettering centers' able to tailor light induced defects under degradation conditions. If the i-layer density of states remains below 1016 eV-1 cm-3 and assuming a Gaussian distribution of defect states, the gettering center distribution will not affect significantly the carrier population but only its spatial distribution. We report here about a device numerical simulation that allows us to analyze the influence of the `i- layer' position, thickness and density of states on the a-Si:H solar cells performances. Results of some systematic simulation rom the ASCA program (Amorphous Solar Cell Analysis), and for different configurations will be presented.
Martins, R., Fortunato E. "
Static and dynamic resolution of 1D thin film position sensitive detector."
Journal of Non-Crystalline Solids. 198-200 (1996): 1202-1206.
AbstractThe aim of this work is to present a model to interpret the static and the dynamic detection and resolution limits of 1D thin film position sensitive detectors based on p-i-n a-Si:H devices. The model can determine the device characteristics that influence the spatial limits and the response time of the device.
Nunes, P., Braz Fernandes Silva Fortunato Martins F. M. R. J. "
Structural characterisation of zinc oxide thin films produced by spray pyrolysis."
Key Engineering Materials. 230-232 (2002): 599-602.
AbstractIn this work, we present a study of the effect of temperature, type and concentration of the dopant on the structural characteristics of ZnO thin films produced by spray pyrolysis; the crystallite size has been determined from profile peak shape analysis. These results are compared to the electrical characterisation performed on these materials. The effect of the dopant on the properties of ZnO thin films depends on its characteristics, mainly its ionic radius. Al, Ga and In have been studied as dopants, the best one being In, since it leads to the lowest resistivity.