24 documents found, page 1 of 3
SiGe layer thickness effect on the structural and optical properties of well-or...
Vieira, E. M. F.; Toudert, J.; Rolo, Anabela G.; Parisini, A.; Leitão, J. P.; Correia, M. R.; Franco, N.; Alves, E.; Chahboun, Adil; Martín-Sánchez, J.In this work, we report on the production of regular (SiGe/SiO2)20 multilayer structures by conventional RF-magnetron sputtering, at 350 °C. Transmission electron microscopy, scanning transmission electron microscopy, raman spectroscopy, and x-ray reflectometry measurements revealed that annealing at a temperature of 1000 °C leads to the formation of SiGe nanocrystals between SiO2 thin layers with good multilay...
Argon assisted chemical vapor deposition of CrO2: An efficient process leading ...
Duarte, A. C.; Franco, N.; Viana, A. S.; Polushkin, N. I.; Silvestre, António Jorge; Conde, O.A comparative study of the structural, microstructural and magnetic properties of CrO2 thin films grown onto (110) and (100) TiO2 rutile single crystal substrates by chemical vapor deposition (CVD), using CrO3 as chromium precursor and either oxygen or argon as carrier gas is presented. Our results show that growth under argon carrier gas leads to high quality CrO2 epilayers with structural and magnetic propert...
Composition, structure and morphology of Al1-xInxN thin films grown on Al1-yGay...
Magalhaes, S.; Watson, I. M.; Pereira, S.; Franco, N.; Tan, L. T.; Martin, R. W.; O'Donnell, K. P.; Alves, E.; Araujo, J. P.; Monteiro, T.; Lorenz, K.Four nominally Al0.85In0.15N thin films with different strains were grown simultaneously on Al1-yGayN (y = 1, 0.93, 0.87 and 0.69) templates by metal organic chemical vapour deposition. The nominal InN content of similar to 15% was chosen to achieve close lattice matching of Al1-xInxN with the templates of intermediate GaN molar fractions, a small tensile strain for growth on GaN, and compressive strain for the...
CdTe nano-structures for photovoltaic devices
Corregidor, V.; Alves, L. C.; Franco, N.; Barreiros, M. Alexandra; Sochinskii, N. V.; Alves, E.CdTe nano-structures with diameter of ∼100 nm and variable length (200–600 nm) were fabricated on glass substrates covered with conductive buffer layers such as NiCr, ZAO (ZnO:Al2O3 + Ta2O5) or TiPd alloys. The fabrication process consisted of the starting vapour deposition of metal catalyst dropped layer followed by the isothermal catalyst-prompted vapour growth of CdTe nano-structured layer of controllable sh...
Formation of oriented nickel aggregates in rutile single crystals by Ni implant...
Cruz, M. M.; Silva, R. C. da; Pinto, J. V.; Borges, R. P.; Franco, N.; Casaca, A.; Alves, E.; Godinho, M.The magnetic and electrical properties of Ni implanted single crystalline TiO2 rutile were studied for nominal implanted fluences between 0.5 x 10(17) cm(-2) and 2.0 x 10(17) cm(-2) with 150 keV energy, corresponding to maximum atomic concentrations between 9 at% and 27 at% at 65 nm depth, in order to study the formation of metallic oriented aggregates. The results indicate that the as implanted crystals exhibi...
Effects of helium and deuterium irradiation on SPS sintered W–Ta composites at ...
Mateus, R.; Dias, Marta; Lopes, J.; Rocha, J.; Catarino, N.; Franco, N.; Livramento, Vanessa; Almeida Carvalho, Patricia; Correia, J.B.; Hanada, K.Energetic He+ and D+ ions were implanted into different W–Ta composites in order to investigate their stability under helium and deuterium irradiation. The results were compared with morphological and chemical modifications arising from exposure of pure W and Ta. Special attention was given to tantalum hydride (Ta2H)formation due to its implications for tritium inventory. Three W–Ta composites with 10 and 20 at...
CdTe nano-structures for photovoltaic devices
Corregidor, V.; Alves, L. C.; Franco, N.; Barreiros, M. Alexandra; Sochinskii, N. V.; Alves, E.CdTe nano-structures with diameter of ∼100 nm and variable length (200–600 nm) were fabricated on glass substrates covered with conductive buffer layers such as NiCr, ZAO (ZnO:Al2O3 + Ta2O5) or TiPd alloys. The fabrication process consisted of the starting vapour deposition of metal catalyst dropped layer followed by the isothermal catalyst-prompted vapour growth of CdTe nano-structured layer of controllable sh...
Synergistic helium and deuterium blistering in tungsten–tantalum composites
Dias, Marta; Mateus, R.; Catarino, N.; Franco, N.; Nunes, D.; Correia, J.B.; Carvalho, Patricia Almeida; Hanada, K.; Sârbu, C.; Alves, E.Tungsten–tantalum composites with 10 and 20 at.% Ta were prepared by ball milling W powder with Ta fibers and by consolidating the milled materials with spark plasma sintering. The composites were implanted at room temperature with He+ (30 keV with a fluence 5 1021 at/m2) and/or D+ (15 keV with a fluence 5 x 1021 at/m2) ion beams. The materials were studied by scanning and high-resolution transmission electron ...
Structural and optical studies of Au doped titanium oxide films
Alves, E.; Franco, N.; Barradas, N. P.; Nunes, B.; Lopes, J.; Cavaleiro, A.; Torrell, M.; Cunha, L.; Vaz, F.Proceedings of the 17th International Conference on Ion Beam Modification of Materials (IBMM 2010); Thin films of TiO2 were doped with Au by ion implantation and in situ during the deposition. The films were grown by reactive magnetron sputtering and deposited in silicon and glass substrates at a temperature around 150 °C. The undoped films were implanted with Au fluences in the range of 5 × 1015 Au/cm2–1 × 101...
Structural and optical studies of Au doped titanium oxide films
Alves, E.; Franco, N.; Barradas, N. P.; Nunes, B.; Lopes, J.; Cavaleiro, A.; Torrell, M.; Cunha, L.; Vaz, F.Thin films of TiO2 were doped with Au by ion implantation and in situ during the deposition. The films were grown by reactive magnetron sputtering and deposited in silicon and glass substrates at a temperature around 150 degrees C. The undoped films were implanted with Au fiuences in the range of 5 x 10(15) Au/cm(2)-1 x 10(17) Au/cm(2) with a energy of 150 keV. At a fluence of 5 x 10(16) Au/cm(2) the formation ...