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Erbium-doped nanocrystalline silicon thin films produced by RF sputtering : ann...
Cerqueira, M. F.; Monteiro, T.; Soares, Manuel Jorge; Kozanecki, A.; Alpuim, P.; Alves, E.In order to improve the transparent contact layer in amorphous silicon solar cells fabricated on low-temperature plastic substrates, Al and Ga doped ZnO films were deposited at room temperature on plastic and glass and their optical, electronic and structural properties were correlated and optimized. Aiming to explore light trapping effects, plastic substrates were laser textured and their haze and total transm...
Photoluminescence of nc-Si:Er thin films obtained by physical and chemical vapo...
Cerqueira, M. F.; Losurdo, M.; Stepikhova, M.; Alpuim, P.; Andrês, G.; Kozanecki, A.; Soares, Manuel Jorge; Peres, M.Erbium doped nanocrystalline silicon (nc-Si:Er) thin films were produced by reactive magnetron rf sputtering and by Er ion implantation into chemical vapor deposited Si films. The structure and chemical composition of films obtained by the two approaches were studied by micro-Raman scattering, spectroscopic ellipsometry and Rutherford backscattering techniques. Variation of deposition parameters was used to dep...
Visible and infrared photoluminescence from erbium-doped silicon nanocrystals p...
Cerqueira, M. F.; Losurdo, M.; Monteiro, T.; Stepikhova, M.; Soares, Manuel Jorge; Peres, M.; Alpuim, P.Erbium-doped low-dimensional Si films with different microstructures were deposited by reactive magnetron sputtering on glass substrates by varying the hydrogen flow rate during deposition. Amorphous, micro- and nanocrystalline samples, consisting of Si nanocrystalls embedded in silicon-based matrices with different structures, were achieved with optical properties in the visible and IR depending on nanocrystal...
Effect of the matrix on the 1.5 microm photoluminescence of Er-doped silicon qu...
Cerqueira, M. F.; Stepikhova, M.; Losurdo, M.; Monteiro, T.; Soares, Manuel Jorge; Peres, M.; Neves, A.; Alves, E.Erbium doped nanocrystalline silicon thin films were produced by reactive magnetron r.f. sputtering. Their structural and chemical properties were studied by micro-Raman, spectroscopic ellipsometry and Rutherford backscattering spectroscopy. Films with different crystalline fraction and crystallite size were deposited by changing the deposition parameters. The impact of the composition and structure of Erbium i...
The role of microstructure in luminescent properties of Er-doped nanocrystallin...
Stepikhova, M.; Cerqueira, M. F.; Losurdo, M.; Giangregorio, M. M.; Alves, E.; Monteiro, T.; Soares, Manuel JorgeIn this contribution, we present a structural and photoluminescence (PL) analysis of Er-doped nanocrystalline silicon thin films produced by rf magnetron sputtering method. We show the strong influence of the presence of nanocrystalline fraction in films on their luminescence efficiency at 1.54 microm studied on a series of specially prepared samples with different crystallinity, i.e., percentage and sizes of S...
Estudo óptico de cristais e heterostruturas de CdTe
Soares, Manuel Jorge de Araújo PereiraNeste trabalho privilegiam-se as técnicas ópticas, nomeadamente a fotoluminescência a transmissão, a reflexão e a difusão de Raman na caracterização de defeitos e impurezas em cristais e heterostruturas de CdTe/GaAs. No primeiro capítulo efectua-se uma revisão sucinta das propriedades dos compostos II-VI e são colocados os problemas a investigar. O segundo capítulo é dedicado a alguns aspectos teóricos relevant...
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