Encontrados 39 documentos, a visualizar página 1 de 4
Hidrocefalia — Experiência dos Serviços de Pediatria e Neurocirurgia do Hospita...
Gomes, L.; Borges, T.; Simões, D.; Ribeiro, I.; Guedes, M.; Monteiro, T.A história natural da Hidrocefalia é conhecida. Quando não tratada, está associada a taxas de mortalidade da ordem dos 80 a 90%, sendo também elevada a incidência de complicações. A introdução dos shunts no tratamento constituiu um avanço inegável, reduzindo a mortalidade de forma significativa (7,5 a 30%).O objectivo deste trabalho foi caracterizar uma amostra de crianças que foram submetidas a colocação de sh...
Optical properties of LFZ grown β-Ga2O3:Eu3+ fibres
Santos, N.F.; Rodrigues, J.; Fernandes, A.J.S.; Alves, L.C.; Alves, E.; Costa, F.M.; Monteiro, T.Due to their relevance for electronic and optoelectronic applications, transparent conductive oxides (TCO) have been extensively studied in the last decades. Among them, monoclinic β-Ga2O3 is well known by its large direct bandgap of ∼4.9 eV being considered a deep UV TCO suitable for operation in short wavelength optoelectronic devices. The wide bandgap of β-Ga2O3 is also appropriate for the incorporation of s...
ZnGa2O4:Mn2+ phosphors grown by Laser Floating Zone
Santos, N.F.; Rodrigues, J.; Nico, C.; Fernandes, A.J.S.; Costa, F.M.; Monteiro, T.Cubic zinc gallate (c-ZnGa2O4) has attracted the attention of the scientific community due to its potential phosphor applications, namely in field emission displays (FEDs) and other electroluminescent devices. Among other advantages, this oxide matrix shows superior thermal and chemical stability when compared to ZnS based phosphors. Most of the above mentioned works comprise nanostructures, thin films or press...
Laser assisted flow deposition: a new method to grow ZnO
Rodrigues, J.; Soares, M.R.N.; Fernandes, A.J.S.; Monteiro, T.; Costa, F.M.Zinc oxide (ZnO) has been one of the most studied materials in the last decades. Either as bulk material, epilayers or nanostructures, this direct wide band gap semiconductor is known to possess great potential for fundamental science and modern technology applications.
Exotic manganese dioxide structures in niobium oxides capacitors
Nico, C.; Soares, M. R. N.; Matos, M.; Monteiro, R.; Graça, M. P. F.; Monteiro, T.; Costa, F. M.; Valente, M. A.Resumo não disponível.
Structural and optical properties of europium doped zirconia single crystals fi...
Soares, M.R.N.; Nico, C.; Peres, M.; Ferreira, N.; Fernandes, A.J.S.; Monteiro, T.; Costa, F.M.Yttria stabilized zirconia single crystal fibers doped with europium ions were developed envisaging optical applications. The laser floating zone technique was used in order to grow millimetric high quality single crystal fibers. The as-grown fibers are completely transparent and inclusion free, exhibiting a cubic structure. Under ultraviolet (UV) excitation, a broad emission band appears at 551 nm. The europiu...
Functionalizing self-assembled GaN quantum dot superlattices by Eu-implantation
Magalhães, S.; Peres, M.; Fellmann, V.; Daudin, B.; Neves, A.J.; Alves, E.; Monteiro, T.; Lorenz, K.Self-assembled GaN quantum dots (QDs) stacked in superlattices (SL) with AlN spacer layers were implanted with Europium ions to fluences of 1013, 1014, and 1015 cm−2. The damage level introduced in the QDs by the implantation stays well below that of thick GaN epilayers. For the lowest fluence, the structural properties remain unchanged after implantation and annealing while for higher fluences the implantation...
Optical doping and damage formation in AIN by Eu implantation
Lorenz, K.; Alves, E.; Gloux, F.; Ruterana, P.; Peres, M.; Neves, A. J.; Monteiro, T.AlN films grown on sapphire were implanted with 300 keV Eu ions to fluences from 3×1014 to 1.4×1017 atoms/cm2 in two different geometries: “channeled” along the c-axis and “random” with a 10° angle between the ion beam and the surface normal. A detailed study of implantation damage accumulation is presented. Strong ion channeling effects are observed leading to significantly decreased damage levels for the chan...
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...
Structural and optical properties of Zn0.9 Mn0.1 O/ZnO core-shell nanowires des...
Kaydashev, V.E.; Kaidashev, E.M.; Peres, M.; Monteiro, T.; Correia, M.R.; Sobolev, N.A.; Alves, L.C.; Franco, N.; Alves, E.Core-shell ZnO/ZnMnO nanowires on a-Al2O3 and GaN (buffer layer)/Si (111) substrates were fabricated by pulsed laser deposition using a Au catalyst. Two ZnO targets with a Mn content of 10% were sintered at 1150 and 550 °C in order to achieve the domination in them of paramagnetic MnO2 and ferromagnetic Mn2O3 phases, respectively. Cluster mechanism of laser ablation as a source of possible incorporation of seco...
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