Er3+-doped glass-polymer composite thin films fabricated using combinatorial pulsed laser deposition

Siloxane Polymer exhibits low loss in the 800-1500 nm range which varies between 0.01 and 0.66 dB cm1. It is for such low loss the material is one of the most promising candidates in the application of engineering passive and active optical devices [1, 2]. However, current polymer fabrication techniques do not provide a methodology which allows high structurally solubility of Er3+ ions in siloxane matrix. To address this problem, Yang et al.[3] demonstrated a channel waveguide amplifier with Nd 3+-complex doped polymer, whilst Wong and co-workers[4] employed Yb3+ and Er3+ co-doped polymer hosts for increasing the gain. In some recent research we demonstrated pulsed laser deposition of Er-doped tellurite glass thin films on siloxane polymer coated silica substrates[5]. Here an alternative methodology for multilayer polymer-glass composite thin films using Er3+ - Yb3+ co-doped phosphate modified tellurite (PT) glass and siloxane polymer is proposed by adopting combinatorial pulsed laser deposition (PLD). © 2011 IEEE.

Gas-phase production of multifunctional composite nanoparticles by photoinduced chemical vapor deposition

As these results indicate, photo-CVD coating is a robust process that allows for the creation of core-shell nanoparticles. In the present work we demonstrated that photo-CVD can effectively coat Fe2O3 particles with silica for purposes of biological applications. TDMA results combined with TEM images indicate that all particles are effectively coated and that particle coating thicknesses can be tuned to desired thickness depending on the application. In addition, the ability to vary coating properties and to coat high concentrations of particles makes this technique of interest for industrial production where uniform properties are needed for large quantities of particles [2]. Copyright © 2010 by ASME.

Formation of composite organic thin film transistors with nanotubes and nanowires

Plastic electronics is a rapidly expanding topic, much of which has been focused on organic semiconductors. However, it is also of interest to find viable ways to integrate nanomaterials, such as silicon nanowires (SiNWs) and carbon nanotubes (CNTs), into this technology. Here, we present methods of fabrication of composite devices incorporating such nanostructured materials into an organic matrix. We investigate the formation of polymer/CNT composites, for which we use the semiconducting polymer poly(3,3‴-dialkyl-quaterthiophene) (PQT). We also report a method of fabricating polymer/SiNW TFTs, whereby sparse arrays of parallel oriented SiNWs are initially prepared on silicon dioxide substrates from forests of as-grown gold-catalysed SiNWs. Subsequent ink-jet printing of PQT on these arrays produces a polymer/SiNW composite film. We also present the electrical characterization of all composite devices. © 2007 Elsevier B.V. All rights reserved.

3D thermo-electro-mechanical simulations of gas sensors based on SOI membranes

3D thermo-electro-mechanical device simulations are presented of a novel fully CMOS-compatible MOSFET gas sensor operating in a SOI membrane. A comprehensive stress analysis of a Si-SiO2-based multilayer membrane has been performed to ensure a high degree of mechanical reliability at a high operating temperature (e.g. up to 400°C). Moreover, optimisation of the layout dimensions of the SOI membrane, in particular the aspect ratio between the membrane length and membrane thickness, has been carried out to find the best trade-off between minimal device power consumption and acceptable mechanical stress.

Design and coupled-effect simulations of CMOS micro gas-sensors built on SOI thin membranes

This paper describes coupled-effect simulations of smart micro gas-sensors based on standard BiCMOS technology. The smart sensor features very low power consumption, high sensitivity and potential low fabrication cost achieved through full CMOS integration. For the first time the micro heaters are made of active CMOS elements (i.e. MOSFET transistors) and embedded in a thin SOI membrane consisting of Si and SiO2 thin layers. Micro gas-sensors such as chemoresistive, microcalorimeteric and Pd/polymer gate FET sensors can be made using this technology. Full numerical analyses including 3D electro-thermo-mechanical simulations, in particular stress and deflection studies on the SOI membranes are presented. The transducer circuit design and the post-CMOS fabrication process, which includes single sided back-etching, are also reported.

Using internal fibre geometry to improve the performance of pin-loaded holes in composite materials

The anisotropic nature of fibre reinforced composites leads to large stress concentrations around pin-loaded holes through standard weave cloths. Proper understanding of how this anisotropic nature affects the load distribution around holes can be utilised to reduce these con-centrations if sufficient thought is given to the internal fibre geometry near to the hole. Such local reinforcements need not be highly complex and can be readily produced without excessive effort, producing significant improvements in performance. © 1996 Kluwer Academic Publishers.

Practical matching of principal stress field geometries in composite components

A simple composite design methodology has been developed from the basic principles of composite component failure. This design approach applies the principles of stress field matching to develop suitable reinforcement patterns around three-dimensional details such as lugs in mechanical components. The resulting patterns are essentially curvilinear orthogonal meshes, adjusted to meet the restrictions imposed by geometric restraints and the intended manufacturing process. Whilst the principles behind the design methodology can be applied to components produced by differing manufacturing processes, the results found from looking at simple generic example problems suggest a realistic and practical generic manufacturing approach. The underlying principles of the design methodology are described and simple analyses are used to help illustrate both the methodology and how such components behave. These analyses suggest it is possible to replace high-strength steel lugs with composite components whose strength-to-weight ratio is some 4-5 times better. © 1998 Elsevier Science Ltd. All rights reserved.