5 research outputs found

    Activating the core economy by design

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    The traditional provision of public services needs to be transformed, and this transformation includes ceasing to consider users as passive recipients of services. Instead, the process of service development should be opened up to more participatory methods, whereby users and providers, working together, transform the way in which the welfare state is conceived and services designed and delivered. In achieving conditions of wellbeing, societies face very complex problems, particularly such groups as the elderly, who depend most heavily on the social care services. The paper describes the research developed, as part of the major project of MA Sustainable Design in Kingston University, London, whereby, through the core economy of all the human resources and social networks that support social life, new possibilities for services may emerge, capable of addressing the ageing and wellbeing agenda. The paper also reflects upon dialogic conversation, and social interaction, as the ideal means of engagement when working with social agendas

    (001)-Oriented Sr:HfO<sub>2</sub> Ferroelectric Films Deposited by a Flexible Chemical Solution Method

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    Remnant polarization values of ferroelectric HfO2-based films depend on proper control of the polar orthorhombic phase crystallization and the orientation of the polar domains. Most of the best quality films reported so far are (111)-oriented. While the largest polarization is expected in (001)-oriented films, with the polar axis out of the plane, such orientation is far less common. This paper demonstrates that highly (001)/(010)-oriented heterostructures of Sr:HfO2 on Pt(111)-buffered Si can be attained in layered films deposited by a recently reported chemical solution deposition route. The oriented films display the short c-axis out of plane, giving place to a longer a lattice in plane. By tailoring the duration of rapid thermal processing, such oriented films produce highly ferroelectric, leakage-free capacitors. After wake-up cycling, a remnant polarization of 17 μC/cm2, which is the highest reported for this dopant and technique, was achieved. Even though optimization is still needed to improve the electrical cyclability, our facile approach produces high-k, highly oriented Sr:HfO2 films, through chemical deposition and annealing, and shows that the crystal orientations and phase purity of HfO2-based films can be further optimized by cost-effective chemical methods.</p

    Low-toxicity chemical solution deposition of ferroelectric Ca:HfO2

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    So far, a few chemical solution routes for the fabrication of ferroelectric HfO2 films have been reported. Most of them employ precursors, solvents or additives that are considered difficult to handle, unstable, toxic, generally unfriendly with the environment and/or unsuitable for large scale industrial processes. In this work, we present a new effective chemical route for the preparation of ferroelectric doped-HfO2 films. The solution is prepared from simple, stable, and available precursors, handled in an open atmosphere and requires no restrictive processing conditions. We used 5 at% Ca as the dopant of HfO2 to induce a maximum remnant polarization of 9.3 and 11.1 μC cm−2 for 54 and 90 nm thick Ca:HfO2 films, respectively. The current-electric field loops show intense and distinctive ferroelectric switching peaks and the corresponding ferroelectric loops show excellent saturation, which speaks of good device quality with low leakage. Crystallization and the wake-up of ferroelectricity in Ca:HfO2 films were achieved by means of rapid thermal annealing at different temperatures and times in an Ar:O2 atmosphere. In comparison to thin films, thicker ones exhibited the highest remnant polarization at shorter annealing times, thus evidencing the need for precise control of thermal processing. The Ca:HfO2 films with a thickness of 50 nm displayed a good balance between leakage and retention, maintaining the ferroelectric response above 105 cycles at 1 kHz. The developed precursor solution is promising for its use in spray-coating and ink-jet printing techniques

    Low-toxicity Chemical Solution Deposition of Ferroelectric Ca:HfO2

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    So far, a few chemical solution routes for the fabrication of ferroelectric HfO2 films have been reported. Most of them employ precursors, solvents or additives that are considered difficult to handle, unstable, toxic, generally unfriendly with the environment and/or unsuitable for large scale industrial processes. In this work, we present a new effective chemical route for preparation of ferroelectric doped-HfO2 films. The solution is prepared from simple, stable, and available precursors, handled in an open atmosphere and requires no restrictive processing conditions. We used 5 at.% Ca as dopant of HfO2 to induce a maximum remnant polarization of 9.3 and 11.1 µC/cm2 for 54 and 90 nm thick Ca:HfO2 films, respectively. The current-electric field loops show intense and distinctive ferroelectric switching peaks and the corresponding ferroelectric loops show excellent saturation, which speaks of good device quality with low leakage. Crystallization and the wake-up of ferroelectricity in Ca:HfO2 films was attained by means of rapid thermal annealing at different temperatures and times in Ar:O2 atmosphere. In comparison to the thin films, thicker ones exhibited the highest remnant polarization at shorter annealing times, thus evidencing the need for precise control of thermal processing. The Ca:HfO2 films with thickness of 50 nm displayed a good balance between leakage and retention, maintaining the ferroelectric response above 105 cycles at 1 kHz. The developed precursor solution is promising for its use in spray-coating and ink-jet printing techniques
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