Fabrication of p-type porous GaN on silicon and epitaxial GaN

Abstract : Porous GaN layers are grown on silicon from gold or platinum catalyst seed layers, and self-catalyzed on epitaxial GaN films on sapphire. Using a Mg-based precursor, we demonstrate p-type doping of the porous GaN. Electrical measurements for p-type GaN on Si show Ohmic and Schottky behavior from gold and platinum seeded GaN, respectively. Ohmicity is attributed to the formation of a Ga2Au intermetallic. Porous p-type GaN was also achieved on epitaxial n-GaN on sapphire, and transport measurements confirm a p-n junction commensurate with a doping density of 1018 cm 3. Photoluminescence and cathodoluminescence confirm emission from Mg-acceptors in porous p-type GaN

Fully porous GaN p-n junction diodes fabricated by chemical vapor deposition

Producción CientíficaModern society is experiencing an ever-increasing demand for energy to power a vast array of electrical and mechanical devices. A significant amount of the energy consumed is used for lighting purposes. For instance, this demand is ~17% of the total energy consumed in the USA in 2011 [1]. Thus, any approach that can reduce energy consumption is important. In this context, the development of light emitting diodes (LEDs) incorporating at least one porous component, with improved light extraction efficiency, is being explored intensively [2]. However, up to now, only partially porous p-n junctions have been analyzed for this purpose.Junta de Castilla y León (programa de apoyo a proyectos de investigación – Ref. VA166A11-2 and VA293U1

Fully porous GaN p-n junctions fabricated by Chemical Vapor Deposition: a green technology towards more efficient LEDs

Producción CientíficaPorous GaN based LEDs produced by corrosion etching techniques demonstrated enhanced light extraction efficiency in the past. However, these fabrication techniques require further postgrown processing steps, which increase the price of the final system. In this paper, we review the process followed towards the fabrication of fully porous GaN p-n junctions directly during the growth step, using a sequential chemical vapor deposition (CVD) process to produce the different layers that form the p-n junction.Junta de Castilla y León (programa de apoyo a proyectos de investigación – Ref. VA302U13

Community Engagement with Inclusive Design: A Conceptualisation Framework

The Cambridge Workshop on Universal Access and Assistive Technology (CWUAAT) series has been running since 2002, hosting the multifaceted dialogue on design for inclusion. It involves a wide range of disciplines including design, computer science, engineering, architecture, ergonomics, policy and gerontology. CWUAAT has been running every 2 years since 2002, with a break during the COVID-19 pandemic. This report arises from the 12th CWUAAT workshop, held at St Catharine's College, Cam-bridge on 2-4 April 2025. It contains the papers selected by an international panel of currently active researchers for poster presentation at the conference. The conference theme was New Frontiers for Inclusion, including the possibilities and challenges for inclusive design offered by AI and other emerging technologies. The poster papers were divided into the following groups: Design approaches; Designing for an ageing population; Designing for particular needs; Interaction techniques and modalities; and AI and inclusive design. We would like to thank all the authors and researchers who have contributed to CWUAAT2025.As part of the EU-funded VOICE project, a conceptualisation framework is being developed to guide and support artist-led community engagement in tackling Sustainable Development Goals (SDGs) 11, 12, 13 and 17. Inclusive design plays an important role in developing the framework and associated resources. This paper summarises key artist-led initiatives in Europe, and identifies two unique features of the VOICE project in comparison to existing initiatives. Through engaging the project consortium partners, the authors illustrate an initial framework, and outline the plan for further, iterative development, aiming to make it useful for all potential users including the VOICE consortium, artists in communities, community organisations and local government, and the EU public.Funded by the European Union. This work has received funding from the UK research and Innovation under contract number 101135803

Synthesis of silicon–germanium axial nanowire heterostructures in a solvent vapor growth system using indium and tin catalysts

The Si–Ge–Si1−xGex nanowires (a,b) are grown directly on substrates placed in the vapour zone of a high boiling point solvent. DFSTEM image of In catalysed triple segmented Si–Ge–Si Ge nanowire is shown in (c) with arrow indicating the direction of the EDX line profile shown in (d).</p

Cholinergically mediated augmentation of cerebral perfusion in Alzheimer's disease and related cognitive disorders: the cholinergic-vascular hypothesis.

Contains fulltext : 50920.pdf (preprint version ) (Open Access)The treatment of Alzheimer's disease (AD) with cholinesterase inhibitors (ChEIs) is based on the cholinergic hypothesis. This hypothesis fails to account for the global nature of the clinical effects of ChEIs, for the replication of these effects in other dementias, and for the strong and unpredictable intraindividual variation in response to treatment. These findings may be better explained by the premise that ChEIs primarily act by augmenting cerebral perfusion: the cholinergic-vascular hypothesis. This article will review the evidence from preclinical and clinical investigations on the vascular role of the cholinergic neural system. The clinical relevance of this hypothesis is discussed with respect to its interactions with the vascular and amyloid hypotheses of AD. Implications for treatment are indicated. Finally, we propose that the role of the cholinergic system in neurovascular regulation and functional hyperemia elucidates how the cholinergic deficit in AD contributes to the clinical and pathological features of this disease