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One Dimensional Metal Oxide Semiconductor Nanotransistors
Publication . Cortinhal, Mariana D.; Rovisco, Ana I.B.; Barquinha, Pedro M.C.; CENIMAT-i3N - Centro de Investigação de Materiais (Lab. Associado I3N); DCM - Departamento de Ciência dos Materiais; Faculdade de Ciências e Tecnologia (FCT); UNINOVA-Instituto de Desenvolvimento de Novas Tecnologias; Wiley
The goal of miniaturization in microelectronics catalyzes the evolution of field-effect transistors (FETs), transitioning from classical scaling approaches to innovative architectures like gate-all-around FETs. Among these advancements, nanowire field-effect transistors (NW-FETs) emerge as a promising solution to the limitations of traditional FET designs, offering improved electrostatic control, reduction of short-channel effects, and better overall device performance metrics. Metal oxide nanowires (NWs) provide high mobility, excellent optical transparency, mechanical flexibility, and compatibility with thin-film technology, making them ideal candidates to be the pillar of a new wave of transparent and flexible electronics with unprecedented integration levels. This review highlights the different configurations of NW-FETs, exploring their fabrication techniques and different advantages, as well as state-of-the-art progress in metal oxide NW-FETs, such as zinc oxide (ZnO), indium oxide (In2O3), tin oxide (SnO2), and multicomponent materials. To further improve NW-FET performance, recent developments in doping, surface passivation methods, and post-fabrication treatments are examined, as well as emerging fabrication methodologies. By addressing material limitations and integrating innovative design strategies, metal oxide NW-FETs are set to play a pivotal role in sustaining Moore's Law and shaping the future of nanoelectronics.
Alginate scaffolds functionalised with zinc oxide nanostructures for osteochondral tissue regeneration
Publication . Silva, Hugo Afonso Pereira; Rovisco , Ana; Almeida , Henrique
The regeneration of osteochondral tissue remains a major challenge in tissue engineering because of the limited regenerative capacity of articular cartilage and the high mechanical demands of subchondral bone. Tissue engineering strives to develop strategies for this regeneration, often using natural polymers such as alginate. Nevertheless, these materials rarely combine the necessary mechanical properties with the biocompatibility and stability required to mimic bone tissue.
A promising strategy to overcome these limitations is the incorporation of nanomaterials. Among them, zinc oxide (ZnO) stands out for its biocompatibility, chemical stability, and its piezoelectricity, a property capable of generating local electrical stimulation under mechanical load, partially mimicking electromechanical phenomena in bone tissue.
In this work, alginate scaffolds were functionalised with ZnO nanostructures in three morphologies: nanowires, nanoplates, and nanoflowers. The incorporation of ZnO did not prove to be a differentiating factor in porosity or average pore size, as all groups, including pure alginate scaffolds, presented conditions favourable to nutrient diffusion and cell adhesion. However, in liquid media, the functionalised scaffolds exhibited greater robustness and a more gradual and controlled swelling profile compared to pure alginate scaffolds. This greater absorption capacity was inversely related to mechanical strength: the nanoplates, which exhibited the greatest swelling, also had the lowest modulus. Nanoflowers showed the best compromise between absorption and mechanical resistance, presenting a Young’s modulus of 4.44 ± 1.19 kPa, standing out from the other morphologies. Nevertheless, these values remain below those desirable for bone tissue applications, highlighting the need for optimisation to reinforce the mechanical performance without compromising the excellent absorption capacity and stability observed.
These results, accompanied by the high cell viability observed across the tested groups, provide a basis for future studies addressing strategies to reinforce mechanical performance, as well as the investigation of piezoelectric stimulation in osteochondral tissue engineering.
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Entidade financiadora
Fundação para a Ciência e a Tecnologia
Programa de financiamento
Concurso de Projetos Exploratórios em Todos os Domínios Científicos 2023
Número da atribuição
2023.11887.PEX