12 documents found, page 1 of 2
Cu(In,Ga)Se$$_2$$-based solar cells for space applications: Proton irradiation ...
Candeias, Maria B.; Fernandes, Tiago V.; Falcão, Bruno P.; Cunha, António F.; Cunha, José M. V.; Barbosa, João; Teixeira, Jennifer P.In this work, we present an experimental study of a Cu(In,Ga)Se2 (CIGS)-based solar cell (SC), irradiated with protons of energy 80 and 180 keV and with fuences of 1012 , 1013 , and 1014 cm−2 , as well as a strategy to recover the induced damage. The possible modifcations of the structural, electrical, and optical properties, induced by the proton irradiation, were investigated. Although the irradiation did not...
Molybdenum oxide thin films grown on flexible ITO-coated PET substrates
Marciel, Alice; Graça, Manuel; Bastos, Alexandre; Pereira, Luiz; Suresh Kumar, Jakka; Borges, Joel; Vaz, F.; Peres, Marco; Magalhães, SergioMolybdenum oxide thin films were deposited on stiff and flexible substrates by reactive DC magnetron sputtering. Two sets of samples were prepared. The first with different O<sub>2</sub>/Ar flow rate ratios and the second, fixing the oxygen content, with different time of deposition. As the O<sub>2</sub>/Ar flow rate ratio varies from 0 up to 0.56, a threshold was found, ranging from crystalline to amorphous na...
Variações anatómicas dos seios perinasais
Boavida, Margarida; Peres, Marco; Gião, Marta; Adónis, Cristina; Freire, FilipeDevido à grande proximidade dos SPN com a órbita, SNC e outras estruturas, o cirurgião deve estar bem familiarizado com a anatomia nasossinusal. Foi efectuado um estudo retrospectivo de 150 TC-SPN realizadas no nosso centro, durante 2015. 75 exames preencheram os critérios de inclusão. Foi realizada análise de variáveis demográficas e anatómicas. A idade média foi 48 anos. Observámos agenésia do seio frontal em...
Rastreio Auditivo Neonatal em 17 732 Recém-Nascidos
Gabriel, Teresa; Martins, Elsa; Carvalho, Graciete; Fontes, Nuno; Ramos, Maria José; Peres, Marco; Moura, Ivo; Rêgo, João; Guimarães, AnaIntrodução: A surdez infantil representa uma das anomalias congénitas mais frequentes. Em Portugal, foi desenvolvido o Grupo de Rastreio e Intervenção na Surdez Infantil (GRISI), cujo principal objetivo é implementar um programa de rastreio nacional através da aplicação de técnicas e métodos definidos e semelhantes nos vários hospitais. Objetivos: Analizar a polupação de recém-nascidos rastreados num hospital ...
The Role of Edge Dislocations on the Red Luminescence of ZnO Films Deposited by...
Felix, Rocio; Peres, Marco; Magalhaes, Sergio; Correia, Maria Rosario; Lourenco, Armando; Monteiro, Teresa; Garcia, Rafael; Morales, Francisco M.The existence of extended defects (i.e., dislocations) in inorganic semiconductors, such as GaN or ZnO, responsible for broad emission peaks in photoluminescence analysis remains unresolved. The possible assignments of these luminescence bands are still matter of discussion. In this study, two different zinc oxide samples, grown under different oxygen partial pressures and substrate temperatures, are presented....
Red light from ZrO2:Eu3+ nanostructures
Soares, Maria Rosa; Nico, Cláudio.; Oliveira, D.; Peres, Marco; Rino, Luís; Fernandes, António; Monteiro, Teresa; Costa, FlorindaZirconia nanocrystals doped with europium ions were developed envisaging optical applications. The nanostructures were produced using zirconyl nitrate (ZrO(NO3)2·H2O) and europium nitrate (Eu(NO3)3·5H2O) as cation precursors, and urea (C2H5NO2) as the fuel, by the combustion synthesis process. The lanthanide-doped nanostructures were characterized by X-ray diffraction, transmission electron microscopy, Raman sp...
Effect of Eu-implantation and annealing on the GaN quantum dots excitonic recom...
Peres, Marco; Magalhães, Sérgio; Fellmann, Vincent; Daudin, Bruno; Neves, Armando José; Alves, Eduardo; Lorenz, Katharina; Monteiro, TeresaUndoped self-assembled GaN quantum dots (QD) stacked in superlattices (SL) with AlN spacer layers were submitted to thermal annealing treatments. Changes in the balance between the quantum confinement, strain state of the stacked heterostructures and quantum confined Stark effect lead to the observation of GaN QD excitonic recombination above and below the bulk GaN bandgap. In Eu-implanted SL structures, the Ga...
The role of the annealing temperature on the optical and structural properties ...
Peres, Marco; Magalhães, Sérgio; Rodrigues, Joana; Soares, Manuel; Fellmann, V.; Neves, Armando; Alves, E.; Daudin, B.; Lorenz, K.; Monteiro, TeresaSelf assembled molecular beam epitaxy grown GaN quantum dots stacked with AlN spacers were implanted with Eu ions. The as-implanted samples were further submitted to thermal annealing treatments in nitrogen, between 1000 °C and 1200 °C. Eu3+ luminescence was observed in all samples with the most intense emission assigned to the 5D0 → 7F2 transition in the red spectral region. The preferential excitation paths o...
Structural, optical and magnetic resonance properties of TiO2 fibres grown by l...
Rodrigues, Joana; Peres, Marco; Fernandes, António; Graça, Manuel; Sobolev, Nicolai; Costa, Florinda; Monteiro, TeresaTiO2 fibres grown by the laser floating zone technique show the rutile crystalline phase as identified by X-ray diffraction and Raman spectroscopy. Scanning electron microscopy evidences a uniform surface, free of inclusions and without low-angle grain boundaries and bubbles. At low temperatures, the fibres luminescence is dominated by a richly structured optical centre with two well-defined zero-phonon lines a...
High temperature annealing of Europium implanted AlN
Lorenz, K.; Magalhães, Sérgio; Alves, E.; Peres, Marco; Monteiro, Teresa; Neves, Armando; Boćkowski, M.AlN was implanted with 300 keV Eu ions within a wide fluence range from 4 × 1014 to 1.4 × 1017 at/cm2. The damage build-up was investigated by Rutherford Backscattering/Channelling. Sigmoidal shaped damage build-up curves indicate efficient dynamic annealing. A regime with low damage increase for fluences below 1015 at/cm 2 is followed by a strong increase for intermediate fluences. For the highest fluences the...